Managing invasive species Juan Fernández Archipelago

Feasibility of managing invasive

species in the Juan Fernández

Archipelago, Chile

Feasibility of managing invasive species in the Juan Fernández Archipelago, Chile

Alan Saunders1, Al Glen

1, Karl Campbell

2, Rachel Atkinson

3, John Sawyer

3, Erin

Hagen2, Hernán Torres

4

1Landcare Research, 2Island Conservation, 3Private Consultant, 4Torres Associados Limitada

Prepared for:

The Corporación Nacional Forestal and The Municipalidad de Juan Fernández

Commissioned and Funded by:

Island Conservation

100 Shaffer Road LML, Santa Cruz CA 95060 USA

February 2011

1Landcare Research, Gerald Street, PO Box 40, Lincoln 7640, New Zealand, Ph +64 3 321 9999, Fax +64 3 321 9998, www.landcareresearch.co.nz

2Island Conservation, 100 Shaffer Rd LML, Santa Cruz CA 95060, USA

4Torres Associados Limitada, Fidel Oteiza 1941, Office 306, Providencia, Santiago, Chile.

http://www.landcareresearch.co.nz/

Reviewed by: Approved for release by:

John Parkes Phil Cowan Landcare Research

Andrea Byrom Science Team Leader Wildlife Ecology & Epidemiology

Landcare Research Contract Report: LC 0008

Disclaimer

This report has been prepared by Landcare Research for Island Conservation. If used by other parties, no warranty or representation is given as to its accuracy and no liability is accepted for loss or damage arising directly or indirectly from reliance on the information in it.

© Landcare Research New Zealand Ltd 2011

No part of this work covered by copyright may be reproduced or copied in any form or by any means (graphic, electronic, digital or mechanical, including photocopying, recording, taping, information retrieval systems, or otherwise), in whole or in part, without the written permission of Landcare Research or Island Conservation.

Landcare Research Page iii

Contents

Summary and Recommendations ............................................................................................. vii

1 Introduction ..................................................................................................................... 13

1.1 Objectives .......................................................................................................................... 13

1.2 Methods ............................................................................................................................ 14

2 Background ...................................................................................................................... 15

2.1 Biodiversity values of the Juan Fernández Archipelago .................................................... 15

2.2 Environmental degradation ............................................................................................... 16

2.3 Invasive species and their impacts .................................................................................... 18

3 Invasive species and conservation management to date ............................................... 19

3.1 The ‘Holland Project’ ......................................................................................................... 19

3.2 Other invasive species management activities ................................................................. 21

3.3 Other biodiversity conservation activities......................................................................... 22

4 The situation today .......................................................................................................... 25

5 Options for Invasive species management ..................................................................... 26

5.1 Biosecurity ......................................................................................................................... 27

5.2 Eradication ......................................................................................................................... 28

5.3 Sustained control ............................................................................................................... 29

5.4 Impact mitigation .............................................................................................................. 30

5.5 Do nothing ......................................................................................................................... 31

5.6 Social, institutional and financial dimensions ................................................................... 31

5.7 A multi-species focus ......................................................................................................... 32

6 A phased invasive species management program .......................................................... 33

7 Phase 1: Establish A Juan Fernández Biosecurity Program ............................................. 34

7.1 Border control ................................................................................................................... 34

Page iv Landcare Research

7.2 Eliminating incipient weeds............................................................................................... 37

7.3 Containment of valued but potentially invasive plants .................................................... 41

8 Phase 2: Building capacity through species-led and site-led management .................... 45

8.1 Site-led management ........................................................................................................ 46

8.2 Species-led management .................................................................................................. 57

9 Phase 3: Eradication and control ..................................................................................... 63

9.1 Eradicating invasive mammals .......................................................................................... 63

9.2 Managing cattle ................................................................................................................. 94

9.3 Managing other species .................................................................................................. 102

10 Multi-species eradications and anticipated costs ......................................................... 119

10.1 Rodents, feral cats and feral goats on Alejandro Selkirk Island ...................................... 119

10.2 Feral goats on Robinson Crusoe Island ........................................................................... 119

10.3 Rodents, rabbits and feral cats on Robinson Crusoe Island ............................................ 119

10.4 Experimental eradications: coatis, sparrows and pigeons .............................................. 119

10.5 Risks and their management ........................................................................................... 120

11 Restoration activites ...................................................................................................... 123

11.1 Santa Clara Island ............................................................................................................ 123

11.2 Robinson Crusoe Island ................................................................................................... 124

11.3 Alejandro Selkirk Island ................................................................................................... 126

12 Suggested timing of management activities ................................................................. 128

13 Acknowledgements ....................................................................................................... 131

14 References ..................................................................................................................... 132

Appendix 1: The feasibility study team and the peer-review process ................................... 141

Appendix 2: Itinerary .............................................................................................................. 143

Appendix 3: Possible outline of a Santa Clara Island Restoration Plan .................................. 146

Appendix 4: Weed species for eradication from Robinson Crusoe Island ............................. 148

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Appendix 5: Weed species for eradication from Alejandro Selkirk Island ............................. 151

Appendix 6: Weed species for containment on Robinson Crusoe Island ............................... 152

Appendix 7: Weed species for site-led control at high priority sites...................................... 153

Appendix 8: Glossary .............................................................................................................. 155

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Summary and Recommendations

Summary

A multi-disciplinary team investigated the feasibility of managing invasive species in

the Juan Fernández Archipelago. This study was commissioned and funded by Island

Conservation, and is intended to inform decisions by government agencies.

While important progress has been made, more effective management of invasive

plants and animals is urgently required in the archipelago if its biodiversity is to be

conserved and the status of the archipelago as an internationally important protected

natural area is to be maintained.

A comprehensive invasive species management program is needed that addresses the

key threats posed by invasive plants and animals so that ecological, social and

economic restoration goals may be achieved and sustained.

There are major risks related to the scope and scale of the program, a lack of precedents

and limited institutional capacity in Chile. However, we suggest that these risks are

manageable.

Based on assessments of risks and feasibility, we recommend a range of management

actions, including biosecurity, eradication and sustained control.

An 8-year invasive species management program involving the sequential initiation of

three phases is recommended: 1) Biosecurity; 2) Capacity building through

management of priority sites and species, as well as research targeting key information

gaps; and 3) Eradication and control. Monitoring of management effectivenesss and

ecological repsonses will be important throughout this program, and will allow adaptive

management to be applied.

Inadequate resources have been allocated to biodiversity conservation in the

archipelago. Significant additional commitments of resources will need to be made. Our

initial estimates suggest the 8-year program outlined here will cost US $15–20M. There

will also be on-going costs.

Provided a proactive approach is taken to sustainable financing there are prospects of

securing the support of international donors to augment resourcing by Chilean agencies.

Undertaking a comprehensive invasive species management program will take time.

We suggest five interim actions to be taken as soon as possible to prevent further

biodiversity loss and to provide a basis for subsequent management.

Because people live in the archipelago, their perspectives must be reflected in all

conservation management decisions. By including the local community as a

fundamental part of this process, the Juan Fernández Restoration Program could

become an international model for conservation on inhabited islands.


Page viii Landcare Research

Recommendations

Three sets of recommendations are listed below: the first involves initiating the sequential

phases of an invasive species management program, the second includes consultation and

planning activities, and the final set are recommended interim management actions that

should be taken as soon as possible. More specific recommendations are included in the

relevant sections.

1. The phased initiation of an invasive species management program

Addressing the impacts of invasive species will be critical if longer-term restoration goals are

to be achieved and sustained. A phased approach is recommended through which the capacity

to manage invasive species may be progressively developed and objectives achieved. The

three phases each involve on-going activities and will overlap to some extent.

Phase 1. Development and implementation of a Juan Fernández Biosecurity Program, with

supporting regulations, should be in place and consistently applied within two years (by

January 2013). Important progress has already been made by Servicio Agrícola y Ganadero

(SAG) in developing a biosecurity program, including voluntary compliance measures.

Biosecurity should include quarantine (between the archipelago and the mainland, and within

the archipelago), early detection and rapid elimination of incipient invaders, and the

containment of valued but potentially invasive plant species. A number of other activities

should also be undertaken during this first phase including planning for subsequent phases,

and some interim actions (see Recommendation 3 below).

Phase 2. Capacity building through management of priority sites and species. A 3-year

‘Capacity Building Phase’ should be initiated by January 2012 during which invasive species

will be intensively managed and ecological responses monitored. Management activities will

be either ‘site-led’ or ‘species-led’. Important outcomes from this phase will include a better

understanding of the impacts of particular invasive species, and of responses in populations

of native plants and animals following the removal of invasive species impacts. Effective

management techniques will also be developed, along with enhanced capacity within

agencies and the local community to undertake management programs. Increased awareness

and support among stakeholders for conservation activities will also be an important outcome

of this capacity building phase. Increasing support by donors can be anticipated during this

phase as project objectives are achieved, and capacity to undertake further projects is

developed.

Phase 3. Eradication and control. With effective biosecurity measures in place and capacity

developed to effectively undertake management tasks, this phase involves a series of

eradication operations and the initiation of control programs that will be sustained into the

long term. Eradication and control operations should have a multi-species focus and be

implemented with regard to the interrelationships between species. We have suggested that

most invasive mammals in the archipelago be eradicated. Some species – particularly wide-

spread invasive plants – cannot be eradicated with current technology and will require on-

going control. Control programs must be sustained indefinitely, which requires significant

investments – including for monitoring and adaptive management – and may entail major


Landcare Research Page ix

risks. Biological control may also be an important management tool in the archipelago, and

should be considered as an option for the worst weed and invertebrate pests. The eradication

and control phase should be initiated by January 2016, or once it has been determined that

these operations should proceed and capacity has been developed.

2. Consultation, planning and governance

People live in the Juan Fernández Archipelago. They will directly experience the costs and

benefits of invasive species management. Consulting and involving island residents and other

stakeholders will be important. Acknowledging their interests and concerns, obtaining and

maintaining their support, and facilitating their involvement in project activities will improve

the prospects of conservation outcomes being achieved and sustained. There are few

precedents anywhere for eradications on inhabited islands, and much has still to be learned

about how best to reflect the views of the community and other stakeholders in management

objectives. It was our perception that there is a high level of understanding of the threats

posed by invasive species management within the community, and potential support for their

management. Strong leadership and consistent institutional support are required.

Rigorous planning will also be important. The process of planning will require consultation

with key stakeholders and inputs from management agencies, donors and advisors. It will

also allow for necessary program management and support infrastructure and procedures to

be identified. We suggest the following key steps to allow for smooth running of the project:

a) Establish a Program Coordinating Committee. It is essential that a multi-faceted invasive

species management program such as that proposed here is effectively coordinated. A small

group of people representing key organisations (governmental and non-governmental), the

community, and groups with appropriate expertise will be required to oversee the program

from the outset. Important roles of this group would include providing leadership, promoting

the program for institutional support and funding, overseeing the preparation of strategic and

operational plans, coordinating and evaluating activities, and keeping participants and

stakeholders informed.

Responsibility1: CONAF and the Municipality

Timing: By 30 June 2011

b) Create an Environmental Planning position within the Municipality. The presence of an

Environmental Planner in the Municipality of Juan Fernández will be important if an invasive

species management program is initiated. In addition to ensuring that community views are

properly acknowledged, this person will also be responsible for coordinating planning and

reporting activities, preparing funding proposals, and undertaking other tasks set by the

Municipality, or suggested by the Program Coordinating Committee.

Responsibility: Municipality, with support from the Ministry for the Environment

Timing: By 30 September 2011

1 We have identified government agencies with appropriate mandates to oversee tasks. These may change, for

example subject to formation of new government departments.


Page x Landcare Research

c) Convene a workshop. A well-facilitated workshop involving key organisations, community

representatives and technical advisors will be valuable to identify agreed restoration goals,

and invasive species management actions to achieve them. Outcomes from this workshop

might include a set of goals for a restoration plan and invasive species operational plans.

Responsibility: CONAF and the Municipality

Timing: By 30 November 2011

d) Prepare project plans. Detailed project plans will be required for ‘Capacity Building’ and

subsequent operational phases. Project plans should set out objectives, tasks, timeframes,

responsibilities, costs, and performance measures for site-led and species-led projects

(including urgent interim actions recommended below). They should also cover research,

monitoring, trials, training, community outreach and other capacity building activities.

During Phase 2, detailed plans for eradication and control operations should also be prepared.

Responsibility: Participating management agencies, with inputs from technical specialists,

and overseen by the Program Coordinating Committee.

Timing: By 31 July 2012

3. Interim actions

Preparing plans, engaging agencies, stakeholders and others and gathering the necessary

resources will take some time. Five interim actions are identified below which we

recommend should be undertaken as soon as possible to prevent further avoidable biological

declines.

a) Identify and implement urgent recovery actions for the critically endangered Másafuera

rayadito and Juan Fernández firecrown, and threatened plants. A range of recovery actions

are urgently needed to prevent imminent extinctions. Small teams of people with knowledge

of these species and with experience in recovering threatened island birds should be

established as soon as possible to oversee the development and implementation of recovery

programs for these species.

Responsibility: SAG and CONAF, in association with selected researchers and species

recovery specialists.

Timing: Recovery Teams established by 30 June 2011

Recovery plans drafted by September 2011

Prioritised ‘on-the-ground’ actions initiated by November 2011

b) Initiate an interim biosecurity program that prevents new invasive species arriving in the

archipelago, or being transferred between islands. The recent initiative by SAG to establish

an interim voluntary Juan Fernández Biosecurity Program should continue to be supported,

including the refinement of protocols and training programs.

Responsibility: SAG

Timing: Voluntary scheme in place by 30 June 2011


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c) Eradicate incipient weeds from urban areas. Plants that are currently restricted within or

adjacent to the towns and which present significant environmental threats should be

eradicated as soon as possible. Removing plants from gardens and urban areas will require

strong community support and engagement. We suggest this is carried out in conjunction

with a Gardening with Natives program where invasives can be swapped for nursery-grown

native plants.

Responsibility: SAG and CONAF

Timing: Initiated by June 2011

d) Approve local legislation regarding domestic pets. A local ordinance is required that limits

the importation of pets that may become invasive species. Individuals of species targeted for

eradication currently kept as pets should be sterilised before eradication operations began.

This ordinance will complement biosecurity activities being executed by SAG.

Responsibility: Municipality

Timing: By 31 December 2011

e) Conduct aerial weed surveys. Low-level aerial surveys of Robinson Crusoe and Alejandro

Selkirk Islands using a helicopter and experienced crew should be undertaken as soon as

possible to allow for island-wide mapping of selected weeds, including Rubus ulmifolius,

Aristotelia chilensis and Ugni molinae. In addition to mapping weeds, threatened plants may

also be surveyed and mapped. Given the very steep terrain on both of these islands, aerial

surveys are likely to be the only effective means to undertake fine-scale, whole-island

surveys, and will be cheaper and safer than ground-based approaches.

Responsibility: CONAF in association with selected researchers and technical experts

Timing: By March 2012

Landcare Research Page 13

1 Introduction

The Juan Fernández Archipelago is an internationally important biodiversity2 hotspot and

protected natural area. Its status as a globally significant conservation site is under threat, due

mainly to the impacts of invasive species. Invasive plants and mammals are causing serious

ecological degradation including forest loss and fragmentation, soil disturbance and

accelerated erosion. Populations of native and endemic plants and animals have declined, in

some cases markedly, as a result of habitat loss, predation and competition.

In response to growing concerns about continuing biological declines in the archipelago,

CONAF, SAG and CONAMA, in association with Biodiversa, organised an international

workshop in November 2009 to discuss further actions. An important recommendation from

this workshop was that an independent and authoritative assessment should be urgently

undertaken of the feasibility of more effectively managing invasive species in the

archipelago.

In May 2010 Island Conservation contracted Landcare Research to lead a multi-disciplinary

team to assess the feasibility of managing invasive species in the archipelago. This feasibility

study report outlines the conclusions of team members following visits to the three islands

and discussions with local residents, agency representatives and others with knowledge of the

islands’ biota. It also includes recommendations which are intended to inform decisions by

the Corporación Nacional Forestal, the Municipalidad de Juan Fernández, and other agencies

with natural resource management responsibilities and interests in halting further biological

declines and restoring the biodiversity of the archipelago.

1.1 Objectives

The objectives of the feasibility study were to:

Comment on the justification for managing invasive plants and animals to conserve

biodiversity in the Juan Fernández Archipelago and review available information.

Discuss invasive species management in the context of wider/strategic goals for the

archipelago.

Review past invasive species management activities and their outcomes.

Identify potential invasive species management options and anticipated outcomes –

including recommendations from the November 2009 workshop, and assess their

relative merits.

Assess the achievability, risks and costs of suggested management activities – including

of eradication operations in relation to prerequisite criteria.

Undertake a weed risk assessment incorporating species biology, distribution and

behaviour, as well as predicted trends under different management regimes, and

recommend appropriate weed management approaches.

2 Words or phrases whose first mention appears in bold type are explained in the glossary (Appendix 8)


Page 14 Landcare Research

Identify information gaps that will need to be filled.

Suggest management objectives and activities and describe a sequence for their

implementation over a prescribed period.

Describe associated constraints and risks – and how these should be managed, as well

as anticipated costs.

Summarise capacity needs and suggest institutional capacity building activities.

List key conclusions.

Recommend necessary next steps and, where appropriate, suggest agency roles and

responsibilities.

1.2 Methods

Assessments of the feasibility of managing invasive species typically include evaluations of

particular management options with critical analyses of the risks, constraints and costs

associated with each. Feasibility studies are aimed at providing decision-makers with clear

choices on their options and the associated risks. These studies typically do not include

detailed analyses of the benefits of invasive species management. These are usually left to

proponent agencies, although feasibility study reports may summarise these benefits and

wider restoration or biodiversity goals. Similarly, feasibility studies may provide initial

estimates of costs of management options to inform decision-makers, but more precise cost

estimates are only possible once an option is chosen and operational plans developed.

This report was prepared by an international team of invasive species management specialists

supported by advisors with extensive local knowledge and expertise in conservation

management and research in Chile. The report was peer-reviewed by scientists and managers

with relevant expertise from Landcare Research and Island Conservation. Details of

feasibility study team members and reviewers are provided in Appendix 1. Briefing material

was circulated to team members prior to visiting Chile. The team visited the archipelago and

met with agency representatives and local residents during visits in May and December 2010

(Appendix 2: Itinerary).

The three main islands in the Juan Fernández Archipelago were visited: Robinson Crusoe and

Santa Clara Islands (May 2010) and Alejandro Selkirk Island (December 2010). Because of

its isolation and relative inaccessibility the Desventuradas Group was not included.

Information was gathered from a variety of sources including meetings and discussions,

literature reviews and observations made during our visits to the islands. We consulted local

community members, management authorities and interest groups. Meetings were held with

staff from the CONAF, SAG and the Municipality, as well as representatives of the

Cattlemen’s and Fishermen’s Associations. We also consulted as widely as possible with

individual community members. We sought people’s views on the environmental, economic

and social impacts of invasive species in the archipelago, as well as the implications they

expected in managing them.

We also reviewed and synthesised the literature on invasive species in the archipelago, their

impacts and past management. This included published studies and unpublished reports

provided by CONAF and SAG. Based on current international best practice we then



identified possible management approaches for invasive species in the archipelago, as well as

anticipated outcomes and associated risks, constraints and costs.

On returning to the mainland, meetings were held with senior administrators of regional and

national government agencies, and with researchers with expertise in the Juan Fernández

Archipelago.

It was decided that invasive plants (‘weeds’), as well as invasive animals, should be included

in this assessment. This will allow recommendations for their management to be considered

as part of the development of an integrated invasive species management program.

2 Background

2.1 Biodiversity values of the Juan Fernández Archipelago

The Juan Fernández Archipelago is of global biodiversity significance. The archipelago’s

isolation and topographic variation have led to high levels of species diversity and endemism.

Despite the small area of the islands, there are more than 200 species of native plants, over

60% of which are endemic (Arroyo 1999; Hobohm 2003). This includes several genera and

one entire family of plants that occur nowhere else in the world (Arroyo 1999). In addition,

six of the seven native land birds are single-island endemics (Hahn et al. 2005). Some of

these species, such as the Másafuera rayadito and Juan Fernández firecrown, are critically

endangered.

The entire archipelago, with the exception of the town of San Juan Bautista and the airport, is

included within a national park. The islands’ outstanding natural values have led to

international recognition of the Juan Fernández National Park, which has been declared a

UNESCO biosphere reserve, and is also being considered for World Heritage listing. The

Juan Fernández Archipelago is recognised as a biodiversity ‘hotspot’ of international

importance (Arroyo 1999). The islands have been recognised as an international biodiversity

conservation priority by several organisations including BirdLife International, Alliance for

Zero Extinction, WWF and the Durrell Wildlife Conservation Trust. However, the threats

posed to these unique natural values by invasive species have been recognised for some years

(Sanders et al. 1982; Bourne et al. 1992; Arroyo 1999; Hahn & Römer 2002).



Figure 1 The Juan Fernández Archipelago, situated between 670 and 850 km west of mainland Chile

consists of Robinson Crusoe Island (4 794 hectares), Santa Clara Island (221 hectares) and Alejandro Selkirk

Island (4 952 hectares).

2.2 Environmental degradation

Since people first discovered the Juan Fernández Islands the archipelago’s indigenous

ecosystems have undergone catastrophic changes. The impact of 400 years of human

influence has been recorded in historical documents, pollen records and through botanical

surveys (Johow 1896; Haberle 1997), all of which indicate dramatic environmental changes

over this period. These include a severe reduction in the extent of indigenous vegetation, and

increased abundance and diversity of introduced plants. This process of invasion and decline

leading to widespread degradation has been accelerated by negative feedback loops between

a range of factors. These include the exploitation of valued plant species (e.g. the now extinct

endemic sandalwood Santalum fernandezianum, and the endangered edible endemic palm

Juania australis), logging for construction of ships and houses, forest clearance for

agriculture (especially in the valleys near San Juan Bautista, Puerto Frances and Puerto

Ingles) and frequent large-scale fires left to burn over extended periods on both islands

(particularly during the years of Spanish occupation). Fungal diseases, the introduction of

plants for food, wood, medicine and ornaments that have since become invasive, over-

grazing and seed predation by introduced mammals, as well as harsh winds and seasonal

droughts have also been important (Johow 1896; Wester 1991; Greimler et al. 2002). As a

result large areas of Robinson Crusoe Island are completely denuded of vegetation. Steeper

slopes are suffering severe erosion (Figures 2 and 3), Alejandro Selkirk Island also has little

forest cover left on its lower slopes, but due to a combination of factors including a different

geological history and the suite of invasive species present, these areas are covered in

grassland, and bare soil and rock is less common.



Native forest

cover

Fragmented forest

cover

Forest without

regeneration

Bare

hillsides

Fires and clearance

Herbivory, seed predation & competition with

weeds

Soil erosion , run-off and sedimentation

Figure 2 A schematic representation of the forest degradation process.

Figure 3 Denuded and eroded hillsides, Robinson Crusoe Island.

Today, the Juan Fernández Archipelago faces a biodiversity conservation crisis. More than

half of its native plant species are extinct, critically endangered or endangered. Half of the

endemic bird species are critically endangered or vulnerable (Hagen 2010). Native forests are

fragmented and a lack of regeneration and recruitment means that remaining patches will



likely disappear in coming decades. Extensive areas are denuded and suffering from

advanced erosion. Over the last 80 years one third of the remaining forest cover has been lost

and 50% more could disappear in the next 80 years if no action is taken (Dirnböck et al.

2003). The overall result is an island ecosystem in a state of collapse. Without urgent

intervention there will be further extinctions, not just of species, but of entire ecological

communities.

2.3 Invasive species and their impacts

While some agents responsible for the environmental degradation (e.g. fire and land clearing)

are no longer present on the islands, the impacts of invasive species continue. Weeds are

displacing native plants and altering entire communities. Invasive rodents and coatis are

impeding forest regeneration through their consumption of fruit, seeds and seedlings. Rodents

are also likely to be significant predators of native birds (adults, nestlings and eggs) and large

invertebrates. Goats, rabbits and cattle disperse seeds of introduced species, consume native

plants and cause severe erosion and sediment runoff over extensive areas. Feral and

domestic cats, as well as coatis, prey upon critically endangered native birds. As a result of

these and other impacts, the archipelago has been listed by the IUCN as one of the world’s

most threatened protected natural areas (Allen 1985). The impacts of invasive species are

discussed in greater detail in later sections.

Figure 4 Burnt and over-grazed lower slopes, Alejandro Selkirk Island.

The archipelago’s invasive species problems are recognised locally, nationally and

internationally (CONAF 2009). The sentiment expressed to us by the Mayor of the

Municipality was that the time has come for action rather than words. Some progress has



been made in managing invasive species in the Juan Fernández Archipelago. Further actions

are urgently required, however, to address these threats, to halt further ecological declines,

and to create opportunities for restoration.

3 Invasive species and conservation management to date

A number of management activities have been undertaken to address the impacts of invasive

species in the archipelago. Other projects are currently under way. In briefly summarising

these activities we comment on achievements and the lessons learned that may inform future

decisions and guide further action.

3.1 The ‘Holland Project’

Many of the previous invasive species management activities in the Juan Fernández

Archipelago were related to a collaborative program, Conservación, Restauración y

Desarrollo del Archipiélago Juan Fernández (Conservation, Restoration and Development of

the Juan Fernández Archipelago), which ran from 1997 to 2003 (Muñoz Pedreros et al.

2003). This project, jointly funded by the Chilean and Dutch Governments, is locally referred

to as the ‘Holland Project’. It consisted of 12 separate programs focusing on social, economic

and environmental objectives. Programs focused on invasive species included protection of

native forest, integrated control of weeds, and control of rabbits and goats.

3.1.1 Protection of native forest on Robinson Crusoe Island

This program aimed to reduce the impact of domestic animals on native forest by erecting 10

km of fencing to exclude livestock (mainly cattle) from three areas, representing 40% of the

forest in the national park. Trials were also established to enhance the retention of leaf litter

and promote germination of new seedlings. While the impact of domestic animals was

reduced, seed germination and forest regeneration was suppressed by rodents (Zunino & van

Bodegom 2000). This demonstrates that the various species of invasive mammals present

must be managed together. Treatment of species in isolation is unlikely to promote ecosystem

recovery. For example, excluding cattle without controlling rodents and other herbivores (or

vice versa) may have little benefit for native vegetation recovery. We observed that few, if

any, fenced areas are excluding cattle today. This illustrates the risks in relying on fences to

exclude ungulates, especially on steep terrain like that in many parts of Robinson Crusoe and

Alejandro Selkirk Islands. In our experience, building and maintaining fences in these areas

to effectively and consistently exclude cattle would be extremely difficult.

3.1.2 Control of weeds on Robinson Crusoe and Alejandro Selkirk Islands

This program aimed to develop optimal control methods for weeds. It focused on three

species: blackberry and poppies, which were both widespread on the islands, and retamilla or

Montpellier broom, which was still limited almost entirely to San Juan Bautista. The main

foci of these weed invasions in San Juan Bautista were controlled using herbicide, as were the

eight main foci of blackberry on Alejandro Selkirk Island. Control work was also undertaken

on lantana and Solanum marginatum, both with very limited distributions. This program



resulted in an immediate reduction in all targeted species, but lacked the resources to control

the re-growth and new infestations that appeared, and thus failed in the longer term (Zunino

& van Bodegom 2000). All these weeds are still present in the control sites. There was also

some indication that poppies may actually be useful in the short term as they help prevent soil

erosion. Building on this experience weed management in the Juan Fernández Archipelago

will require appropriate and achievable objectives, adequate commitments of time and

resources, and a systematic approach to on-going control. These are fundamental

requirements of weed management anywhere and represent existing ‘best practice’ for weed

control.

3.1.3 Management of rabbits on Robinson Crusoe and Santa Clara Islands

Rabbit populations on Robinson Crusoe and Santa Clara Islands were targeted by intensive

hunting using snares and firearms between 1998 and 2003 in order to control their numbers

(Saiz & Ojeda 2002). On Santa Clara this was augmented in 2003 with burrow fumigation

using phosphine gas and poisoning using anticoagulant baits (Ojeda et al. 2003). Eradication

was achieved on Santa Clara in 2003 (Ojeda et al. 2003; CONAF 2005). However, the

program had little impact on the rabbit population on the much larger Robinson Crusoe Island

(Saiz & Ojeda 2002). In our view these results demonstrate that eradicating rabbits requires

an integrated, multi-tactical approach. Shooting and trapping, alone, were not sufficient to

achieve eradication. However, when these methods were followed up with additional

measures, successful eradication was achieved on Santa Clara.

3.1.4 Control of goats on Alejandro Selkirk Island

Goats were hunted on Alejandro Selkirk Island between 1999 and 2003 with the aim of

limiting the population to 500 animals. This level of reduction was judged sufficient to allow

for regeneration of native vegetation. However, it was estimated that more than 800 goats

remained on the island at the cessation of the project (González et al. 2003). It is likely goat

populations will have recovered since the cessation of hunting, largely negating any benefits

from the operation. We suggest this illustrates the importance of either complete eradication,

or ecologically based sustained control objectives and appropriate performance measures that

are able to be objectively monitored, and involving effective control measures which may be

sustained indefinitely.

3.1.5 Other outcomes of the Holland Project

The Holland Project included a literature review and compilation of an extensive

bibliography which lists 1205 publications relevant to pest management generally, or to the

Juan Fernández Archipelago specifically (Muñoz Pedreros et al. 2003). There is enormous

value in having access to a comprehensive bibliography such as this if consideration is to be

given to initiating a new management program. Recommendations from the Holland Project

included the establishment of biosecurity measures and a campaign to raise awareness of the

importance of preventing further arrivals of exotic species (Muñoz Pedreros et al. 2003).



3.2 Other invasive species management activities

In addition to the activities undertaken as part of the Holland Project, a number of other

efforts have been made to manage invasive species in the archipelago (Hagen 2010). Goats

were thought to have been eradicated from Santa Clara Island in 1997 (CONAF 2009; Hagen

2010), although one remaining animal was found and removed in 2001 (H. González, pers.

comm.). Santa Clara is now reported as being free of all invasive mammals (Hagen 2010).

Feral cats have been hunted opportunistically within the national park at least since 1998,

although numbers killed annually are low (R. Schiller, pers. comm.). A program of

sterilisation and registration of pet cats, as well as voluntary euthanasia of unwanted animals,

has been in place in San Juan Bautista since 2005. The program has achieved a high level of

compliance with 90–95% of all cats having been sterilised by early 2010. However, some

owners do not wish to have their cats sterilised, and there are no restrictions to prevent

additional cats being brought to the island (Hagen 2010). Feral dogs and pigs have reportedly

been removed from Robinson Crusoe Island by CONAF (Bourne et al. 1992; Hahn & Römer

2002). Sheep were removed from all three islands in the 1980s (Hahn & Römer 2002). A

small population of house sparrows were eradicated from Alejandro Selkirk Island by 1994

using opportunistic shooting of birds in town (Hahn et al. 2009; H. González, pers. comm.)

We were unable to find any reports of conservation outcomes from these activities.

Efforts have been taken to control invasive rodents in San Juan Bautista using anticoagulant

baits. Baits were provided initially through the Holland Project, and subsequently by a

community committee focused on conservation and responsible pet ownership (Hagen 2010).

It is not clear what effect these efforts are having on rodent numbers, or on their impacts in

the town, although we understand some residents are keen to retain cats as a control method

as long as rodents are present.

As part of the rabbit control program under the Holland Project, bounties were paid for coati

tails (Hagen 2010). It is not clear what effect this had on coati numbers. Currently, less than

20 coatis are killed each year (R. Schiller, pers. comm.).

Some weed control activities are also on-going. Following the completion of the Holland

Project, the Unión de Ornitólogos de Chile (AvesChile) and the Juan Fernández Islands

Conservancy (JFIC) began weed control in 2003 at the Plazoleta el Yunque, working with

community members. About 2.5 hectares of maqui and blackberry have been cleared each

year for 6 years, allowing regeneration of native forest (Hagen & Hodum 2008). This area

continues to be maintained and additional areas important to endemic bird breeding are also

now being addressed. As a result of this weeding program rapid regeneration of indigenous

plants has been reported, especially Gunnera peltata. Some invasive plants remain at this site

including Myosotis sylvatica (water forget-me-not) Hydrangea macrophylla and Vinca major

(periwinkle), but the overall trajectory of the regeneration is towards an indigenous-

dominated plant community.

Since 2007, CONAF have carried out an annual program on Alejandro Selkirk Island aimed

at controlling Rubus ulmifolius and Aristotelia chilensis. One staff member is based on

Alejandro Selkirk from September to May and is responsible for checking the small patches

of these weeds that are found over an area of about 30 hectares. All sites are recorded using

GPS. This work uses the herbicide Garlon4® (active ingredient Picloram) (CONAF

unpublished data). However, this work has been interrupted since the tsunami in 2010. There

is a small amount of weed control being undertaken in the best quality forest on Robinson



Crusoe Island for Rubus ulmifolius, Aristotelia chilensis and Ugni molinae. Staff currently

conduct day trips to undertake weed control work. This means a considerable amount of the

working day is spent travelling to sites, rather than carrying out weed control.

Active surveillance of introduced plant species has been carried out over the past 30 years by

visiting botanists such as Philippe Danton (11 years) and Tod Stuessy (30 years). This has

resulted in the availability of detailed checklists of native and exotic plants that occur on the

islands (Danton et al. 2006), as well as detailed vegetation maps (Greimler et al. 2002). This

work is now being supplemented by SAG with records being collected of new exotic species

planted in the town, and new naturalisations and their distributions. SAG is now developing a

list of species that should be eliminated from the town because of the risk they pose to the

national park. This list has been developed by Hernán González (SAG) in collaboration with

Philippe Danton and has been most recently updated by contributions from the weed risk

assessment conducted within this feasibility study.

The Municipality employs a team (Areas Verdes) that manage open spaces within San Juan

Bautista. This team uses a mixture of native species from the CONAF nursery in San Juan

Bautista and exotic species imported from mainland Chile. There is currently no plan or

established process to influence which species are used for these plantings and the potential

remains for further incipient invasives to be planted.

Control of invasive insects has also been undertaken by SAG. Biological control has been

successfully used to suppress an outbreak of cottony cushion scale (Hagen 2010). Poison

baits were deployed in an unsuccessful attempt to control European wasps.

3.3 Other biodiversity conservation activities

3.3.1 Site and habitat restoration

Ecological restoration work in the archipelago has been limited although some significant

work has been undertaken to restore vegetation communities and eroded sites. Again the

Holland Project provided an impetus for some of these initiatives. As part of the Holland

Project work was undertaken to restore several sites following weed control. In addition, four

hectares of Cupressus species were planted as a source of wood for the town. Propagation

methods for 22 indigenous plant species were developed in conjunction with the botanic

gardens in Viña del Mar (Cuevas & Figueroa 2007). A restoration planting program with a

very low density of planting (fewer than 150 individuals over an area of several hectares) was

undertaken at Puerto Frances. This included planting of eroded slopes and the construction of

soil traps and dykes. Species used included Blechnum cycadifolia, Haloragis massatrierrana,

Dendroseris litoralis, Dendroseris pruinata and Lophosoria quadripinnata. In some cases

exotic plants were used as part of erosion control programs. This included species such as

Acaena argentea. At Puerto Vaqueria, the Holland Project undertook a seed rain project that

showed rodents were seriously impeding regeneration.

Aside from the Holland project, planting has also been undertaken as part of recovery work

for several threatened species including Chenopodium sanctae-clarae which has been planted

on Santa Clara Island, and in San Juan Bautista. At Plazoleta el Yunque, in a project

undertaken in conjunction with Universidad Mayor, CONAF and Oikonos, a 5 × 5 metre trial

restoration planting area was established. A suite of species including Dendroseris



marginata, Sophora fernandeziana, Coprosma pyrifolia and Rhaphthamnus venustus was

planted at several sites using plants grown from seed from the same areas. CONAF have

continued to experiment with planting trees in light gaps in the indigenous forest remnant

above Puerto Frances. These plantings include Rhaphithamnus venustus and Myrceugenia

fernandeziana.

Dr Cecilia Smith from the University Austral is leading a research program to identify best

techniques and to determine the costs of restoring degraded areas. The portfolio of projects

currently being carried out includes:

Evaluating invasion dynamics of Aristotelia chilensis and Rubus ulmifolius in forest

clearings

Determining changes in distribution of R. ulmifolius, A. chilensis and U. molinae from

satellite imagery between 1983, 2003 and 2010

Determining priority sites for restoration on Robinson Crusoe Island

Determining the genetic variability of austral thrushes on Robinson Crusoe Island and

on the continent

Measuring the effect of austral thrushes on seed dispersal and germination of native and

introduced plant species

Developing control methods for austral thrushes

Determining the role of ferns and Gunnera in native forest succession, and the potential

of these species in controlling invasives

Carrying out a social study to determine community opinions of conservation activities

in the National Park, with particular reference to invasive species eradications

In vitro cultivation of four species of critically endangered plant

Carrying out an economic analysis of different weed control methods to determine the

most efficient methods.

3.3.2 Threatened species recovery

In addition to restoring vegetation communities and eroded sites there has also been a focus

on recovering threatened plants and animals in the archipelago.

Plants

Several threatened endemic plants are being intensively managed as part of a planned

program (Plan de Conservación Especies Endemicas 2010 CONAF). Each park guard has

been assigned responsibility for several of the archipelago´s rarest species. Activities include

in situ monitoring and ex situ propagation. Some notable successes have been reported,

including the propagation of the Selkirk endemic Dendroseris gigantea. Several individuals

of this species have been returned to the wild, while others have been planted in private

gardens. However, problems with this program include the difficulty in accessing remaining

individuals (many are on steep cliffs or mountain tops, and are more than a day´s walk from

the town); a lack of knowledge of the entire distribution of each species; difficulties with seed

collection and germination; the lack of a restoration plan; concerns about insect and fungal



pests on seedlings (limiting growth and also movement of introduced pests with outplanting

activities), and; limitations on the size and number of plants grown at CONAF greenhouses.

In order to help in this work, CONAF is establishing an ex situ living collection of threatened

plants in San Juan Bautista. This collection will help park guards understand more about

species requirements, growth rate and phenology and thus help identify appropriate timing

for field interventions.

Animals

Másafuera rayadito

The Másafuera rayadito is an insectivorous songbird endemic to Alejandro Selkirk Island and

regarded by Hahn et al. (2010) as Chile’s most endangered bird. Given that the population

may have declined to as few as 140 birds (Hahn et al. 2004; 2005), it is considered critically

endangered, although a more recent survey suggested a conservative estimate of 500 birds

(Tomasevic et al. 2010). A series of studies have investigated the abundance, distribution,

diet and nesting behaviour of the species, as well as possible threats to its survival (Hahn &

Römer 1996; 2002; Hahn et al. 2004; 2005; 2009; 2010). This very small population is

threatened by predation from feral cats and rodents, as well as habitat fragmentation and

degradation due to grazing and trampling by feral goats and subsequent conversion to

invasive plant cover (Hahn et al. 2004; 2009). Other possible threats include predation by

Másafuera hawks and competition with another native insectivorous bird, the Másafuera

cinclodes (Hahn et al. 2010).

Limited conservation actions have been undertaken for the rayadito. Habitat restoration

efforts aimed at reducing the impact of feral goats were carried out by the Chilean

government between 1997 and 2003 (BirdLife International 2011). Additional efforts to

protect native vegetation and habitat are on-going seasonally as funding allows (CONAF,

JFIC, pers. comm.). These actions have been directed to address the primary threats to the

rayadito population, however a comprehensive conservation plan is needed to guide rigorous

and continuous conservation actions as well as community education campaigns (P. Hodum,

pers. comm.).

Juan Fernández firecrown

The Juan Fernández firecrown is a critically endangered hummingbird endemic to Robinson

Crusoe Island. Hahn et al. (2005) estimated that 1100 firecrowns remain on the island. A

number of studies have investigated the biology of the species and threats to its survival

(Colwell 1989; Bourne et al. 1992; Roy et al. 1999; Hagen & Hodum 2008; Hagen 2009;

Hahn et al. 2009). These threats include predation by cats (Hahn & Römer 2002; Hahn et al.

2009), rodents (Roy et al. 1999) and coatis (Colwell 1989; Bourne et al. 1992), as well as

habitat degradation (Roy et al. 1999), including destruction of food plants by rabbits (Colwell

1989).

Some conservation actions have been undertaken for the endemic firecrown. Habitat

restoration efforts aimed at protecting native vegetation and controlling invasive plants was

carried out by the Chilean government between 1997 and 2003, and similar efforts focused

on important nesting habitat have been carried out by AvesChile and JFIC since 2004. A

community committee motivated largely by the need to protect the critically endangered



firecrown has worked to reduce the number of cats in San Juan Bautista since 2006. A

national conservation plan was created by CONAF in 2005; however, a review and update of

this plan is needed to guide future conservation actions.

Pink-footed shearwater

A number of conservation actions have been undertaken for the recovery of pink-footed

shearwaters, including research on their breeding population size, breeding biology and

behaviour and foraging ecology (Hodum & Wainstein 2002). Research has also investigated

competition and predation by introduced mammals. Evidence suggests that rabbits compete

with shearwaters for burrows, while cats, coatis and rodents prey on nesting birds or their

eggs (Hodum & Wainstein 2002).

A shearwater reserve is being established on Labrador Ridge, within the town limits of San

Juan Bautista, in order to protect a breeding colony that has declined due to residential

development. Efforts to conserve shearwaters have had a strong emphasis on engaging and

informing the community. Educational materials have been produced, and students and

interested members of the public have been invited to view shearwaters in their burrows with

an infra-red camera probe (Hodum & Wainstein 2002).

4 The situation today

These past and on-going management activities have led to a number of important outcomes.

Perhaps most notable, Santa Clara Island is now free of invasive mammals and some

regeneration of native vegetation is beginning to occur (Figure 5). Community awareness of

invasive species has also been raised, with many people being aware of current problems, and

supportive of further action. However, although the Holland Project made creditable efforts

to reduce the impacts of invasive species and to restore ecosystems, it included little

monitoring of outcomes to allow us to assess its merits. Invasive species management should

include the declaration of anticipated outcomes as part of project design, and the inclusion of

monitoring so that progress may be evaluated in relation to management objectives and

performance indicators.

Current conservation activities are limited by a lack of institutional resourcing. Although we

met motivated and highly capable CONAF and SAG staff in the archipelago, they do not

have the resources to undertake effective invasive species management activities. Within the

constraints of the current annual budget, CONAF staff undertake a range of activities

including limited weed control, threatened endemic plant management, nursery production,

track maintenance and, with external collaborators, conservation measures for endangered

endemic birds. SAG also monitors new introductions to the islands. Two extra SAG staff

members have recently been appointed to assist with biosecurity work. These government

agencies have been supported by JFIC and AvesChile for nearly a decade. Despite these

significant contributions the resources available are inadequate to reverse current trends.



Figure 5 Native plants such as Dendroseris litoralis are beginning to regenerate on Santa Clara Island since

the eradication of invasive mammals.

The archipelago is home to several hundred people who will have interests in any

management activities proposed, and a stake in anticipated outcomes. In recognising the

importance of social dimensions to conservation it is essential that local residents participate

actively in planning and implementation of conservation activities. In addition to ensuring

that community needs and perspectives are properly reflected, resident participation in

conservation activities will ensure that the community is regularly consulted and kept well

informed, and benefits from conservation activities. Residents will be an important

component of the Program Coordinating Committee outlined in the beginning of this

document. We were impressed by the level of understanding of environmental issues

expressed by local residents we met during our visit, and by their support for more effective

management to address invasive species threats and to restore the natural character of the

archipelago.

5 Options for Invasive species management

There is a spectrum of interlinked management options which may be applied to address

invasive species impacts:

Biosecurity

Eradication



Sustained control

Impact mitigation and ex situ endangered species conservation

Do nothing

The most appropriate invasive species management strategy will depend on the species being

managed, its impact, and technical, social, political and economic factors associated with its

management. Each option is outlined in more detail below. However, species do not exist in

isolation but are part of an interlinked community, and the management of one species will

have an effect on others. It is thus important to consider interactions between species in order

to determine an effective management strategy. We consider the need for an integrated

approach in more detail at the end of this section.

5.1 Biosecurity

By far the best way to minimise the impacts of invasive species is to prevent them from

arriving and becoming established. Islands present unique opportunities for preventing

invasions (‘biosecurity’) in that they are isolated from other landmasses and invasion

pathways for many species are relatively easy to identify. The costs involved in biosecurity

are often much lower than the costs of invasive species impacts, or the costs of managing

them after they have become established.

Being around 700 km from the Chilean mainland, and with no neighbouring islands, the Juan

Fernández Archipelago is well suited to biosecurity measures. There would be little sense in

undertaking eradication and/or sustained control projects in the archipelago, as proposed in

this report, if inadequate biosecurity measures allowed undesirable species to re-invade and

perhaps re-establish. In addition to helping exclude invasive plants and animals, biosecurity

may also be effective in preventing the spread of human, plant and animal diseases.

Biosecurity measures have previously been recommended as an essential management tool

for the Juan Fernández Archipelago (Cuevas & van Leersum 2001; Danton et al. 2006), and

are identified as a priority in the national park management plan (CONAF 2009). Residents

have also recognised that the importation of materials is a high-risk activity. The European

wasp, which was first detected in the archipelago in 2001, is believed to have arrived with

cargo from the Chilean mainland (Hagen 2010). Under a voluntary scheme between SAG and

the Fishermans Association, boats are sprayed for insects and material is checked before

travelling from Robinson Crusoe to Alejandro Selkirk Island (R. Contreras Schiller, pers.

comm.), indicating a local understanding of biosecurity threats, and support for biosecurity

measures within the archipelago.

While Chile has a well-developed biosecurity system to prevent threats to agriculture, both

between regions and at international borders, there is currently no legal basis for intercepting

species that constitute a risk to biodiversity. We suggest it would be appropriate for SAG to

extend its biosecurity activities to include biodiversity protection, perhaps using the

development and refinement of a Juan Fernández Biosecurity Program as a model and a

capacity building exercise. SAG has a presence on the islands and has recently employed two

extra staff members. They currently inspect and make an inventory of materials being bought

to Robinson Crusoe Island. SAG is also investigating how to develop the necessary

legislation and regulations to underpin a biosecurity program here. In the meantime it is



leading the development of a voluntary system, including the preparation of a list of ‘high-

risk’ species, as well as signed voluntary declarations to allow for the checking of equipment,

baggage and products being transported to the archipelago.

Surveillance and Contingency are also essential parts of biosecurity to identify and eliminate

incipient species that have the potential to cause impacts before they become established. The

towns on both islands have several plant species that are known to be highly invasive in other

parts of the world, and there is an urgent need recognised by SAG to remove all individuals

of these species.

A biosecurity program for the archipelago will require significant institutional commitment to

development of legislation, the identification of invasion pathways, and detailed risk

analyses. It will also require community support and acceptance of obstructions and

impediments associated with quarantine and border control measures. Island residents and

other stakeholders will need detailed information about proposed biosecurity measures so that

they can consider the implications and suggest any alternative approaches. While support has

been expressed by island residents for voluntary biosecurity measures, their on-going support

cannot be presumed. Appropriate mechanisms should be in place to ensure community and

stakeholder inputs to a Juan Fernández Biosecurity Program are appropriately incorporated

into its design, implementation and refinement.

5.2 Eradication

Eradication is defined as ‘The complete and permanent removal of all wild populations from

a defined area by a time-limited campaign’ (Bomford & O'Brien 1995). Where it is

achievable, eradication is often preferable to on-going control because it offers indefinite

freedom from all impacts of the pest in question, and from the on-going costs of its

management. Eradication is most feasible when directed at removing new incursions

involving small, localised populations, or when it is undertaken at isolated sites, particularly

islands. The recently tabulated Global Islands Invasive Vertebrate Eradication Database

documents 949 eradication attempts world-wide of more than 30 vertebrate species (Keitt et

al. 2010) (http://db.islandconservation.org/). Although early eradications generally involved

single species on small islands, advances in recent decades have seen more complex suites of

invasive species removed from increasingly large areas (Innes & Saunders 2011). However,

eradication is not always achievable, especially for plant and invertebrate species, and the

costs of failure can be high (Parkes & Panetta 2009). Eradication should not be attempted

unless the following criteria for feasibility (adapted from Bomford and O’Brien (1995);

Cromarty et al. (2002); and Parkes and Panetta (2009)) can be satisfied:

Every individual of the targeted pest must be put at risk by the techniques used

Mortality must exceed recruitment at all population densities

Re-invasion risks must be near zero

Techniques used must be acceptable to key stakeholders

Financial and institutional support must be declared from the outset

The benefits of eradication outweigh the risks and costs

http://db.islandconservation.org/



These criteria reflect the importance of social, institutional and economic dimensions, in

addition to biological and logistical ones. Evaluations in this report of the feasibility of

eradicating various invasive species from the Juan Fernández Archipelago are based on these

criteria and on our knowledge of successful and unsuccessful eradication campaigns

elsewhere.

Two general approaches to eradication may be taken: ‘single-hit’ or progressive operations.

Single-hit eradications are typified by the aerial distribution of toxic baits to eradicate

(usually) rodents from islands. They are short, intensive operations, ranging from less than a

day for a helicopter to cover a small island (e.g. Merton et al. 2002) to weeks or perhaps

months for larger islands (greater than 10 000 hectares) in polar regions where weather

conditions frequently prevent flying (e.g. McClelland 2002). Meticulous planning of all

components of the operation is required at the outset because there is little opportunity to

change things mid-operation. The implications of overlooking important elements can mean

failure to achieve eradication (Cromarty et al. 2002), or unexpected and unwanted outcomes

such as unacceptable impacts on non-target species (e.g. Courchamp et al. 2003; Bergstrom et

al. 2009). In the case of single-hit eradications, there is usually no option to salvage a failure

other than to wait and try again.

Progressive eradication operations involve repeated or on-going removal, often using several

techniques simultaneously, or sequentially, over periods of weeks, months, or even years (e.g.

Phillips et al. 2005). In progressive operations, methods may be adapted and refined as the

project proceeds and new experience and information is gained. Adaptive management is a

key component of plans for progressive eradication operations. Monitoring in relation to

performance targets is important to ensure progress towards the eradication goal. In

progressive eradications (e.g. Parkes et al. 2010) the key is knowing when to stop and declare

the operation successful. Several recent successful eradication campaigns have measured

these ‘stop rules’ by estimating the probability that eradication has been achieved, given that

the target species can no longer be detected (e.g. Ramsey et al. 2009; 2011).

Both single-hit and progressive eradications will have to be employed in the Juan Fernández

Archipelago. Confidence is growing internationally in the ability to eradicate invasive species

and apply biosecurity measures so that important outcomes may be achieved and sustained.

These international developments in eradication techniques underpin many of the

recommendations in this report.

5.3 Sustained control

Controlling invasive species is the next preferred option when eradication is not appropriate

or feasible. Control objectives involve keeping the density of the targeted species at or below

a defined level and/or reducing its distribution (e.g. containment within fenced areas).

Sustained control can result in desired outcomes being achieved, but requires an on-going

commitment of resources and labour. Sustained control programs may be justified where

limited impacts on resources are acceptable, where the species has a social value, or as a

temporary measure until more effective techniques are available or eradication becomes

feasible. In addition to on-going costs and impacts, effective control programs require a good

understanding of the relationship between pest numbers and their impacts to inform decisions

about control targets. This information is often only available as the outcomes of the control

are monitored and the actions adapted.



While sustained control is seldom the preferred management option for invasive mammals on

islands from which they could potentially be eradicated, social reasons may dictate that

control, rather than eradication, is preferred. This is so for cattle on Robinson Crusoe Island,

where cattle are not regarded as an invasive species and a high value is placed by the

community on retaining some on the island. It is also the case for the introduced timber trees

(Pinus radiata, P. pinaster and Eucalyptus globulus) planted in exotic woodland around San

Juan Bautista. Additionally, several Acacia and Eucalyptus species provide a food source for

the critically endangered firecrown.

Sustained control may be the only current realistic management option for some invasive

plants. Due to their biology, eradication is seldom a realistic objective for invasive plants or

invertebrates except where new incursions are involved and the infested site is no more than a

few hectares in size (Rejmánek & Pitcairn 2002). Research into the ecology of the targeted

species and field trials to determine results from different control techniques and regimes

may be required before a project is initiated. Once weeds are widespread often the only

practical and sustainable method of control is biological control. Biocontrol programs can be

expensive to put in place, but this is typically a ‘one-off’ cost whereas other forms of control

may require expenditure in perpetuity. Biocontrol should therefore be considered for all

widespread invasive plant species for which eradication or containment is not feasible.

Biological control agents exist or are being developed for many of the weed species present

in the Juan Fernández Archipelago (L. Hayes, pers. comm.). Use of these agents should be

considered after risk analysis to non-target, native species has been undertaken.

The sustained control of invasive plants as part of the management of identified sites (‘site

management’) will be important, along with impact mitigation measures for other weeds also

present. Intensive sustained weed control and impact mitigation activities should be focused

on sites of high biological importance where effective weed management is expected to lead

to important conservation outcomes. Impact mitigation, including the removal of individual

native plants for propagation and establishment (perhaps) elsewhere may be the only realistic

conservation option for some threatened native plants.

Because they require an on-going commitment of effort and resources, sustained control

projects also require careful planning to identify risks and constraints, as well as anticipated

outcomes. On-going monitoring will also be required to ensure progress is being made, and

that wider ecological responses are acceptable.

5.4 Impact mitigation

The ultimate aim of managing invasive species is to minimise the damage they cause. Where

biosecurity, eradication or sustained control is not achievable, an alternative approach is to

focus directly on mitigating their impacts. Impact mitigation may involve protecting

individuals of a vulnerable native species. Trapping around nest sites of endangered birds, for

example, can be effective in reducing predation and enhancing their productivity. Capturing

endangered animals and translocating them to pest-free islands has been used to avert

extinctions in New Zealand, and elsewhere. Other examples of impact mitigation include the

use of deterrents to discourage animals from congregating or feeding in areas where they

cause undesirable impacts, habitat modification to provide refuge for vulnerable native

species, or earthworks to reduce erosion caused by ungulates.



Mitigation measures are often not as effective or sustainable as longer term management

strategies, but they can be valuable as short-term measures until alternative, more sustainable

strategies and techniques are available. Impact mitigation measures may be used in

conjunction with threatened species management. For example, ex situ captive breeding has

been employed as an ‘insurance strategy’. In some cases captive breeding may be the only

impact mitigation option remaining.

Some attempts at mitigating the impacts of erosion caused by ungulate browsing and

trampling were made as part of the Holland Project. Wooden retaining structures were built

on slopes to stabilise the soil. Mitigation measures to prevent goat browsing have also been

implemented to protect new plantings of critically threatened plant species by CONAF.

Measures may be needed to protect native birds from cats, rats and coatis at breeding sites, at

least until these invasive species have been eradicated.

5.5 Do nothing

In many cases there are no management programs in place to reduce or mitigate invasive

species impacts. This may be due to:

Invasive species impacts are not recognised and their management is not a priority

There is no agency with the appropriate mandate to undertake management

Tools and techniques are unavailable, or there are few precedents

There is a lack of capacity in management agencies

Funds and resources are unavailable

Stakeholder concerns have been expressed about techniques or anticipated outcomes

Where introduced species are known or suspected to have negative impacts on a high-value

site like the Juan Fernández, ‘doing nothing’ is rarely appropriate.

5.6 Social, institutional and financial dimensions

Conservation is essentially a social activity. Trading off ecological benefits against social and

economic costs can be difficult. This may be particularly so on inhabited islands where

people have strong ties with their natural environment. It will be important that the interests

and concerns of island residents are appropriately acknowledged and that conservation

decisions reflect the costs and constraints of management, as well as the benefits that

stakeholders can anticipate. It will be critical that stakeholder groups such as residents, cattle

owners, fishermen and other local groups, as well as government and donor agencies, are able

to contribute to the design of a Juan Fernández invasive species management program from

the outset. Because each organisation will have different interests and capacities, effective

communication, an agreement to cooperate to achieve declared goals and a clear

understanding of agency roles will be essential.

Because the archipelago is an internationally recognised biodiversity hotspot and a biosphere

reserve, further international support can be expected for initiatives to mitigate threats to its

natural values. However, potential supporters and donors will require leadership from within



Chile and a clear demonstration of political and institutional commitment to the success of

the program, and to sustaining outcomes from managing invasive species. From our

discussions with senior agency staff it was our impression that there is every prospect

institutional leadership and support will be forthcoming for an integrated invasive species

management program involving cooperative inputs from within and beyond Chile. Following

declaration of their support for a Juan Fernández invasive species management program we

suggest relevant agencies enter into dialogue with a range of international funding institutions

to determine their interests in becoming involved.

5.7 A multi-species focus

Management of invasive species in the past has often focused on individual species, such as

ship rats, feral goats or blackberry. However, there is increasing recognition that when

species are managed in isolation, unexpected and undesired effects may result. For example,

other species may be ‘released’ from predation or competition, potentially leading to more

severe problems (e.g. Courchamp et al. 2003; Glen & Dickman 2005; Caut et al. 2007). The

eradication of feral goats from Alejandro Selkirk Island, for example, could exacerbate weed

problems there since goats are known to eat invasive as well as native plants. Weed control

will need to be undertaken in anticipation of this response. Similarly, the eradication of feral

cats could lead to higher numbers of rodents following their release from cat predation,

unless rodents were also targeted. This concept is illustrated using a food web in Figure 6.

Each species (or group of species) in this food web is linked to multiple others, so that

changes in any part of the system can have flow-on effects for other species. For example, a

single-species operation to remove cats may lead to increased numbers of rabbits and rodents.

In turn, this may have detrimental impacts on native vegetation or birds. Invasive species

management projects should be designed which take into account known interactions

between species, and anticipated responses. An adaptive management approach should be

applied as part of any progressive eradication operation so that management activities may be

adjusted as new information about these interactions becomes available.

Figure 6 A simplified food web involving selected native and invasive species in the Juan Fernández

Archipelago. Arrows indicate that one species (or group of species) feeds on or provides a source of food for the

other. Changes to the system can flow from the top down (e.g. removal of cats leading to reduced predation on

native birds) or from the bottom up (e.g. removal of rodents and rabbits leading to reduced availability of prey

for cats).

Cats

Rabbits Rodents Native birds

Native plants Weeds Invertebrate

s



A multi-species approach may also lead to important efficiencies. Feral cat populations have

been significantly reduced in eradication operations elsewhere as a result of toxic baits being

spread for rodents. Although cats will not eat the baits directly, they may succumb to the

toxin after eating rodents which have consumed baits. This ‘secondary poisoning effect’ can

lead to a substantial knock-down of feral cat populations, and on one occasion has even led to

a feral cat population being eradicated as part of a rat eradication operation on Tuhua/Mayor

Island, New Zealand (C. R. Veitch, pers. obs. in Nogales et al. 2004). Secondary poisoning to

achieve an initial knock-down of feral cats was an option considered in a number of rodent

eradications (e.g. Parkes 2009). We suggest that the potential to achieve initial knock-downs

of cats as part of a rodent eradication on Alejandro Selkirk Island, and rabbits and cats as part

of a rodent eradication on Robinson Crusoe Island, will lead to important reductions in risks

and costs in eradicating rabbits and feral cats (See Sections 9.1.2-9.1.4).

6 A phased invasive species management program

Effectively managing the impacts of invasive species in the Juan Fernández Archipelago will

require a complex, long-term and expensive program. Technical solutions to some of the

invasive species issues facing the archipelago are well known and have international

precedents. For other issues it will be the first time that management has been carried out, and

thus a firm research base will be required in order to ensure efficient and effective

management. The program also represents the first time that management of such a broad

range of invasive species will be carried out on an inhabited island. It is also the first time

that Chilean government agencies will undertake such a project. For these reasons we

recommend a carefully planned and executed three-phased invasive species management

program, initially spanning eight years (Table 1). Actions should increase in pace and scale as

knowledge and capacity is developed. A number of urgent interim actions should be

undertaken before the full invasive species management program is initiated.

Phase 1. Development and implementation of a Juan Fernández Biosecurity Program, with

supporting regulations, should be in place and consistently applied within 2 years (by January

2013). Important progress has already been made by SAG in developing a biosecurity

program. This includes quarantine between the archipelago and the mainland, and within the

archipelago, early detection and elimination of key weed species found at present only in the

inhabited areas, and containment of valued invasive species to defined areas.

Phase 2. Building capacity through management of priority sites and species is a three-year

phase that should focus on 1) increasing understanding and enhancing the effectiveness of

management approaches and techniques through the active management of invasive species

at priority sites; 2) developing effective management techniques for key invasive species

(including the development of biological control), and; 3) implementation of species recovery

plans for the most critically endangered species of plants and animals. Important outcomes

from this phase will include a better understanding of the impacts of particular invasive

species, and ecological responses to their removal. Other outcomes may include rapid

recovery of endangered species, development of effective management techniques, enhanced

capacity to undertake management programs, and increased awareness and support for

conservation activities.

Phase 3. Eradication and Control is the operational phase, following the establishment of a

consistently effective biosecurity program and the development of appropriate capacity



within relevant agencies to undertake management projects with reasonable prospects of

success. Eradication and control projects should be initiated by January 2016, or once it has

been determined that these operations should proceed.

Eradication involves the removal of every individual of a targeted population within a

prescribed timeframe (Bomford & O'Brien 1995). Funding for eradications is essentially

‘one-off’, although on-going surveillance and biosecurity measures will be required.

Eradications entail major risks but there are well established criteria which must be satisfied

for an eradication to be successful (Bomford & O'Brien 1995; Parkes & Panetta 2009). We

have suggested that it is feasible and appropriate that most invasive mammals in the

archipelago be eradicated.

Control involves the reduction of a targeted population to a prescribed density, or its

limitation to defined areas, or both. Because control programs must be sustained they involve

significant long-term investments and may entail major risks. We suggest sustained control is

the most appropriate objective for many weed species. Biological control is also an important

management tool, and should be considered as an option for the worst weed and invertebrate

species.

Table 1 Proposed timeline for the three invasive species management phases and subsequent restoration

2011 2012 2013 2014 2015 2016 2017 2018 Continue indefinitely

Biosecurity

Capacity building

Eradication & control

Restoration

7 Phase 1: Establish A Juan Fernández Biosecurity Program

An effective Juan Fernández Biosecurity Program will be essential if further incursions are to

be avoided and conservation outcomes sustained. This program should be in place within two

years and before any management action begins. We have identified three key components to

this phase:

1) Development and implementation of a border control system with supporting legislation

2) Eliminating incipient weeds

3) Containment of valued but potentially invasive plants

7.1 Border control

The importance of border control to protect the biodiversity of the archipelago is recognised

by SAG. Significant progress has been made, with the support of island residents, in

establishing voluntary biosecurity measures. The legal basis and resources to enforce

biosecurity measures, however, are lacking (H. González, pers. comm.). A number of



additional measures are recommended here in order to establish an effective biosecurity

program.

7.1.1 Biosecurity systems

Chile has in place effective biosecurity systems for agricultural protection. However, little

priority has been given to date to developing biosecurity measures aimed at biodiversity

protection. Biosecurity protocols to protect the biodiversity of the Juan Fernández

Archipelago will be required for all goods leaving mainland Chile, for its arrival in San Juan

Bautista, and for movement between islands within the archipelago. A Juan Fernández

Biosecurity Program could be based on current agricultural procedures, and on biodiversity

protection systems used in countries with islands elsewhere (e.g. Ecuador/Galápagos).

7.1.2 Legislation

A clear legal framework to underpin biosecurity measures to protect the archipelago’s

biodiversity will be essential. This may include schedules of permitted and prohibited

species, locations for pre- and post-border checks (at ports and airports), a penalty system

(e.g. fines for infringements) and identified responsibilities for implementation and

enforcement (e.g. SAG staff). Chile already has comprehensive national biosecurity

legislation. In addition, some internal regional borders are already controlled to protect

against agricultural pests (e.g. legislation to prevent movement of potato nematodes to the

south of Chile, movement of pets to and from Easter Island). While there are various options

for a biosecurity system to protect the Juan Fernández Archipelago, we suggest the most

effective solution would be to create new legislation covering all aspects of biosecurity in the

archipelago. We acknowledge this could take time to develop. The development and

implementation by SAG of a voluntary system is a commendable interim measure and an

important and urgent first step. In our view it will be essential that priority is given to the

development of legislation to underpin a Juan Fernández Biosecurity Program. SAG’s current

statutory responsibilities are limited to weeds, pets and agricultural pests. However, we

understand an ordinance from the Municipality of Juan Fernández and a memorandum of

understanding with CONAF could empower SAG to carry out a more comprehensive

biosecurity program even before new legislation is in place.

7.1.3 Quarantine

The prohibition of potentially invasive species introductions is critical to the protection and

restoration of the Juan Fernández Archipelago’s biodiversity (Dirnböck et al. 2003). This

means blocking invasion pathways of further species with the potential to invade and

establish. Materials arrive from the Chilean mainland by sea (from Valparaiso) and by air

(from Santiago). Commercial fishing, tourism and private yachts arrive from other countries

and mainland ports. All such pathways must be evaluated as biosecurity risks and appropriate

measures put in place to minimise new incursions. Although some plants may be introduced

accidentally, the greatest risk is likely to be posed by deliberate introductions (e.g.

ornamental plants).

Ideally, biosecurity measures would include inspection of goods before they leave the

mainland and again on their arrival in the Juan Fernández Archipelago. However, if this is



not practicable, resources for inspection and quarantine should be allocated based on an

analysis of the risks and most likely pathways of invasion. We suggest a conservative

approach in which a list is prepared of permitted species. The importation of all other species

should be prohibited.

Biosecurity within the archipelago is also needed, which will require preventing or restricting

transfer of species between islands. This will also be essential for the movement of native

plants or other material for conservation purposes between the islands. We suggest below

some legislative and technical measures to resolve this problem.

7.1.4 Surveillance and contingency actions

Surveillance and contingency actions are also essential parts of a biosecurity program in

order to identify and eliminate incipient species that have the potential to cause impacts,

before they become established. Priorities for surveillance and contingency actions should be

guided by risk analyses. With a supportive local community, there is a potential for local

people to assist in surveillance by reporting new arrivals.

Table 2 discusses the feasibility of implementing biosecurity measures. Given the history of

successful biosecurity programs in Chile, we believe it to be an entirely feasible program.

Table 2 Feasibility of enforcing biosecurity measures in the Juan Fernández Archipelago.

Type of risk Situation Problems Solution

Technical Chile already has effective national and regional biosecurity legislation and systems for agriculture

Current legislation does not allow for biodiversity protection and new legislation will take time

Develop new legislation, but in the meantime adopt interim measures adding to current law to cover some of the basic issues

Social The population understands the need for biosecurity

Community members may be limited in what they can import to the island

Develop a clear process and a comprehensive education and awareness program

Institutional SAG has experience in running quarantine controls

SAG legislation does not cover biodiversity protection, and SAG does not have the authority to carry out intra-archipelago control as the whole area is national park

One agency needs to take responsibility for the entire biosecurity program for the archipelago. Given the experience of SAG in biosecurity, it could expand its remit to include both biodiversity protection and inter-island control within the national park

Economic The archipelago already has 2 full-time SAG representatives and biosecurity operating costs are much less than control or eradication of future problems

Initial set up of systems and education will require resources

Allocate sufficient resources to allow for biosecurity system to be implemented



7.1.5 Specific recommendations

We recommend the urgent creation of legislation to support biosecurity in the archipelago,

including a list of species permitted for importation. Interim voluntary measures should be

maintained, with community support, until the legislation can be prepared.

One agency should take responsibility for the entire biosecurity program for the archipelago.

Given the experience of SAG in agricultural biosecurity, its remit could be expanded to

include both biodiversity protection and inter-island quarantine within the national park. If

SAG were to take responsibility for this program, an ordinance from the Municipality of Juan

Fernández and a memorandum of understanding with CONAF should be completed to

empower SAG to carry out a comprehensive biosecurity program.

Ideally, cargo should be inspected before leaving the mainland, and again on arrival in the

archipelago.

Time-frame

As soon as possible.

Resources

Capital

Building of biosecurity facilities at the port in Valparaiso, as well as in San Juan

Bautista, the airport, Alejandro Selkirk and Santa Clara Islands (e.g. secure unpacking

rooms). Includes signage and educational materials (e.g. leaflets, radio broadcasts,

airport signage and in-flight documents).

Staff

Biosecurity staff will be required in the archipelago as a priority, and preferably also at

mainland ports.

Cost estimate for biosecurity

Start-up: US $300 000

Annual running costs: US $75 000

Responsibilities

SAG

7.2 Eliminating incipient weeds

The most cost-effective and efficient way to manage potentially invasive plants that have

already arrived in the archipelago is through an early detection and removal system. The aim



of this is to remove all individuals of these species before they become established

(naturalised). These species represent a subset of those introduced onto the archipelago. They

are known to be problematic due to their behaviour in other areas of the world with similar

environmental conditions, but at present are only recorded in restricted areas of the

archipelago, making it potentially feasible to remove all individuals (i.e. eradicate them).

Among the 568 introduced plant species known on the islands, 368 (65%) have only been

recorded from the inhabited areas. A risk assessment based on data from previous researchers

(Danton et al. 2006) and collected during this study has identified 43 plant species on

Robinson Crusoe Island (listed in Appendix 4) and ten species on Alejandro Selkirk Island

(listed in Appendix 5) that should be eradicated as soon as possible. They occur mostly in

private gardens in San Juan Bautista (including the track and former house sites at Plazoleta

el Yunque) and Rada la Colonia (the settlement on Alejandro Selkirk Island), and many

have been planted for a reason (e.g. as an ornamental plant, for food, or for medicinal

purposes). These species pose an extreme risk to the biodiversity of the Juan Fernández

Archipelago should they naturalise and spread beyond their current distribution and it is

critical – and we believe feasible – that all populations of each of these species are eradicated

immediately using current best practice techniques. Regular surveillance must be carried out

for new incursions and to determine the effectiveness of the eradication work.

Although control work is technically easy and inexpensive for small populations of plants,

successful eradication will require the cooperation of local gardeners. This may be hard to

achieve, especially for those species with cultural or medicinal values. In some cases

eradication may have a higher chance of success if undertaken in conjunction with a

replacement planting program using native species or low-risk exotics. Support from the

Municipality is imperative to the success of early weed detection and eradication. There is

also a need for public education about the potential risks if these species are not prevented

from becoming established.

Figure 7 Prickly pear (Opuntia ficus-indica, left) and lantana (Lantana camara, right): two of the weed

species recommended for eradication.

There are other weed species that occur in the archipelago that are highly invasive but their

distribution and biology are such that eradication is impossible. These species have been

included in the Containment and Site-led control group below.



7.2.1 Feasibility of eradicating selective invasive plants

This program will only be feasible with the support of the entire community, and it is very

important that this is gained. More details are discussed in Table 3.

Table 3 Feasibility of eradicating selected invasive plants from the Juan Fernández Archipelago

Type of risk Situation Problems Solution

Technical Settlements are small and many of the species present have not yet become established

Requires good plant identification skills and regular monitoring

Requires effective control methods

Annual survey by trained botanist

Develop and adapt suitable methods

Social General awareness of the threats posed by invasive species has been created by the Holland Project and by SAG

Access to all properties will be required

The entire community must support this program

Clear education campaign and materials

Exchange program of native or safe exotics for the removal of potentially invasive species

Institutional Municipality already has a gardening group

Groups have little knowledge of future weed risks through their planting program

Involve the gardening group in this early detection program

Economic Low cost, reducing with number of years the program runs and with the establishment of a biosecurity program

Continuous cost for the first 5 years at least

Allocate resources for immediate eradication work

7.2.2 Specific Recommendations

The High Risk plant species listed in Appendices 5 and 6 should be eradicated from the

Eradication Zone on Robinson Crusoe Island (see Figure 8) and from Rada la Colonia

on Alejandro Selkirk Island.

An annual survey of the town and environs (see Figure 8) should be undertaken by a

trained botanist to ensure successful eradication and to detect new species incursions.

This will be necessary even following the establishment of an island biosecurity

system.

The Municipality should use exotic species in its gardening program only if the species

have been identified as low-risk.

A list should be developed of low-risk exotic species that could be planted or

introduced by residents to the archipelago without risk of naturalisation. Guidelines

for permitted substrate will also need to be developed in order to prevent the

introduction of soil-borne organisms or diseases.



A Gardening with Natives program should be developed that includes regular supply of

a wide range of native species and the construction of demonstration native gardens

(e.g. at the Municipal buildings).

Capacity building within the Areas Verdes team should be undertaken to increase their

skills in landscape gardening using native species.

Propagation of a wide range of native species and low-risk exotic plants should be

increased (perhaps 3000 plants per year).

A plan should be prepared for amenity areas within the town to designate areas where

each native or low-risk exotic plant species could be used.

Illustrated educational materials should be developed for the town and school including

information about exotic species and the threats they pose, as well as environmentally

friendly alternatives.

Time-frame

It is important that this work begins immediately. The reconstruction of the town following

the tsunami provides an ideal opportunity to initiate and implement an on-going eradication

and replacement program.

Resources

Capital

Expansion and redevelopment of the plant nursery

Purchase of gardening equipment

Publication of education materials

Incinerator and weed disposal system

Operating

Chemicals

Nursery annual plant production

Transport for botanist for weed surveillance

Staff

Training in weed identification and control, nursery management and landscape design

Weed control work

Nursery management

Writing of education materials

Exchanges to mainland or other places where eradication programs are under way and

conservation nurseries are being managed



Cost estimate for weed eradications



Responsibilities

Ideally, these activities should be undertaken by agencies involved in protected natural area

management, as managing threats in buffer zones adjacent to the national park should be a

component of best-practice park management. Currently, CONAF staff do not see this as a

priority. We recommend SAG assume responsibility for implementing this program, in

conjunction with Areas Verdes, the community and outside experts.

There are other weed species that occur in the archipelago that are highly invasive but their

distribution and biology are such that eradication is impossible. These species have been

included in the Containment and Site-led control group below.

7.3 Containment of valued but potentially invasive plants

There is a group of potentially invasive plant species in the archipelago which are not yet

widespread but for which eradication is no longer an option. This is due either to difficulties

in detecting every individual, the presence of long-lived seed banks in the soil, or because the

species has a social value. Despite this, they pose a severe threat to remaining intact

indigenous plant communities and the most feasible management tool available is

containment within particular areas.

The town of San Juan Bautista on Robinson Crusoe Island is encircled by exotic forest

plantations composed of species that are actively used by the community for various purposes

(Map 2). They also provide an important food resource for the endangered endemic

hummingbird. While these plantations act as a buffer between the town and the national park,

many of the plantation species are highly invasive and are rapidly colonising the surrounding

hillsides. There are also some invasive species that are now too well established in the town

to be eradicated, but which must be contained within this area to prevent further impacts on

indigenous ecosystems. We have identified 12 species in this category on Robinson Crusoe

Island (Appendix 6). Management will require creation of a containment zone around the

town, and removal of every individual of these species found outside the containment zone.

On Alejandro Selkirk Island we believe it is feasible (and hopefully socially acceptable) to

remove all the introduced and potentially invasive species from the town and surrounding

small plantation. However, if the community is not willing to allow eradication of Eucalyptus

globulus because of its use as firewood for barbeques and for mending lobster traps, this

species may have to be contained to a defined area around the village of Rada la Colonia.



Figure 8 The eradication zone from which potentially invasive plant species should be removed is indicated

by the grey area around San Juan Bautista. The containment zone, beyond which designated species should not

be allowed to spread, is indicated by the red line.

Figure 9 Periwinkle (Vinca major, left) and German ivy (Delairea odorata, right); two of the species

recommended for containment.



7.3.1 Feasibility of containment of selected invasive plants

Table 4 outlines the feasibility of containing selected invasive plants within restricted areas.

We believe this is a highly practical project, the major difficultly being the need to remove

some species from steep cliffs above the two inhabited areas.

Table 4 Feasibility of containment of selected invasive plants

Type of risk Positives Problems Solution

Technical Relatively easy detection due to the restricted area of the containment zone

Difficult sites for management work

Control methods need to be optimal

Expert trained weed control staff will be required to undertake work in difficult locations

Social No conflict as species will still be available in the containment zone

Requires working in very difficult sites

Good training and equipment supplied

Institutional SAG has capacity to review biosecurity priorities regularly

Requires understanding that containment is a necessity

CONAF have not included containment as part of their work program

Education of staff involved in weed management as to the importance of containment

Economic Low cost for achieving major weed control benefits

Work and therefore costs will be on-going

Could be part of other programs

After a period of intensive work the program will reduce to a smaller scale surveillance and control operation


We recommend the establishment of containment zones (see Figure 8) for all species listed in

Appendix 6.

All individuals of those species found outside the containment zones should be removed. This

will require annual surveillance of the areas surrounding the containment zones to prevent

their spread.

Time-frame

This program will be on-going and will require vigilance over a wide area surrounding San

Juan Bautista.



Resources

Capital

Equipment for weed control

Operating

Herbicide

Staff

Weed control work

Cost estimate for weed containment



Responsibilities

CONAF



8 Phase 2: Building capacity through species-led and site-led management

For the purposes of this study capacity may be defined as the ability of management agencies

and stakeholders to achieve invasive species management objectives and to sustain

conservation outcomes. Invasive species management capacity includes:

Knowledge – through scientifically robust investigation and monitoring, to improve

understanding and the ability to predict outcomes.

Tools – approaches, techniques and technology to effectively and consistently

undertake management.

Skills – training and support programs to empower people to consistently apply best

practice management procedures.

Commitment – declarations of consistent and appropriate support for invasive species

management objectives by management agencies with relevant mandates and missions.

Support – commitments by management agencies, donors and stakeholders to ensure

management activities are adequately funded and resourced.

A focus on building capacity in the Juan Fernández Archipelago will be essential if the range

of invasive species management objectives recommended here are to be achieved, and

restoration outcomes sustained. In recognising the scale and rate of biological declines in the

archipelago it will be important that capacity building is closely linked to invasive species

management activities and monitoring. We suggest that both species- and site-led

management projects should be used to develop capacity, as well as to achieve ecological

(species or site) objectives. In effect this will involve pursuing research, training, community

engagement and other objectives aimed at addressing identified capacity needs, together with

species and site-focused ones.

Intensive invasive species management may present opportunities to study the effectiveness

of control methods (using reliable techniques such as the Digital Sampling Method

(Gillingham et al. 2010; Landcare Research 2010), and the effects of management on other

species. As part of the design of the invasive species management program overall it would

be useful to identify strategic research themes that might be addressed, creating opportunities

to improve management as it proceeds. Examples of research themes might include:

Elaborating the life histories of the worst weeds

Determining suitable species for restoration planting following weed control

Developing biological control agents for Rubus ulmifolius, Aristotelia chilensis and

Ugni molinae

Improving control methods for key weed species

Determining the effectiveness of aerial seeding on open areas free of herbivores

Determining the part the austral thrush plays in the dispersal of native and introduced

plants

Determining effectiveness of pest control on conservation targets (plants and animals)

at priority sites



The preparation of an invasive species research strategy might also provide important

opportunities for universities and other research institutions to engage and participate. Some

important progress has already been made in addressing important research themes (C. Smith,

pers. comm.).

8.1 Site-led management

Vegetation communities on the archipelago comprise upper montane and lower montane

forests, fern assemblages and native grassland. However, centuries of habitat destruction

caused by humans and fire, as well as invasive herbivores and seed predators, have

significantly reduced intact indigenous forest cover throughout the archipelago. Remaining

indigenous vegetation occurs in fragments, mainly at high altitudes but these fragments are

critically important for endemic species. On Robinson Crusoe Island montane forest supports

124 endemic plant species, more than 30 of which have fewer than 25 individuals remaining.

These fragments are in varying degrees of degradation and it has been estimated that without

management 50% of the remaining native montane forest will be invaded by exotic weeds

within 80 years (Dirnböck et al. 2003).

Preventing further degradation of the remaining plant communities and associated fauna is

one of the highest conservation management priorities for the archipelago. Without protection

of these remnants, future restoration options will be foreclosed and regeneration of degraded

areas will be impossible. Many of these high priority biodiversity conservation sites have

already been identified by Greimler et al. (2002) and by CONAF (2009) (See Map 3) and are

in desperate need of management. In addition to these remnants, there are other sites of high

biological importance within the archipelago including sea bird nesting sites and habitats for

threatened bird species.

The existing threats to these high priority conservation sites are:

Seed predation: Rats are important seed predators on the islands and reduce the number

of intact seeds reaching the forest floor. For example, more than 60% of seeds of

Coprosma pyrifolia were found to be destroyed by rats (Cuevas 2002). Seed predators

will also be affecting the seeds of introduced species. We do not know, however, if

seed predation is the limiting factor for plant recruitment.

Herbivory: Evidence of damage to seedlings and understorey plants by rabbits, goats

and cattle is clear, leading to forests where only the canopy remains. Herbivores will

also be impacting on the introduced plants in the same way, although these species are

often better adapted to herbivory and seed dispersal by mammals.

Weed competition: Invasive plant species enter light gaps in the forest and out-compete

natives for space and nutrients. The worst weeds in forest fragments are Aristotelia

chilensis, Ugni molinae and Rubus ulmifolius. We regard the former as a transformer

weed which is especially problematic as its large size and growth form rapidly

dominate forest gaps.

Priority site management will involve intensive weed and animal control. There are 16 weeds

on Robinson Crusoe Island and at least one (Aristotelia chilensis) on Alejandro Selkirk Island

that cause severe ecological impacts but are so widespread across the islands that we consider

they are impossible to eradicate (Listed in Appendix 7). We recommend management actions



focus on controlling these species in the best remaining fragments of each type of indigenous

plant community.

Protection of these priority conservation sites will also need to involve the management of

invasive animals including rats, rabbits and feral goats (Section 9). This work will have

immediate and positive impacts for biodiversity conservation and is critical to prevent the

imminent extinction of a number of threatened species and species assemblages.

The threats described above are linked as parts of an ecological system, and a successful site-

led program must address them all in order to avoid further problems. For example, removing

herbivores and seed predators from a forest fragment may increase the speed of weed

invasion. Weed management must therefore be undertaken in parallel with management of

herbivores and seed predators. The importance of capacity building components to such

projects is clear. With detailed monitoring of ecological changes, and research aimed at better

understanding the nature of these responses, important refinements to management

approaches can be anticipated as management proceeds. Wherever possible, an adaptive

management approach (‘learning-by-doing’) should be adopted in which management

activities are used as experiments to improve knowledge and ability to manage.

Effective control (containment and restricting densities) is technically achievable for all

weeds in the archipelago. Almost inevitably this will require intensive management regimes

being maintained – with associated needs for long-term institutional support and committed,

motivated and skilled teams of control staff. A focus on capacity building as part of weed

control at selected sites is likely to promote research into more effective and sustainable

regimes and control techniques, training programs to ensure field staff remain motivated and

have the necessary skills and knowledge, and performance measures (e.g. photo points)

where stakeholders and others can see the progress being made. Because of the risks and

costs associated with maintaining effective weed control programs we suggest priority

management sites should be carefully selected, meticulously planned, rigorously

implemented and properly monitored.

Focusing on a site-led approach does not imply that managing invasive species elsewhere is

not important. Focusing on important selected sites, however, improves the chances of

making the greatest biodiversity conservation benefits, as well as building capacity to

effectively restore larger areas in the future. We do not suggest that projects to control large

expanses of weeds, such as that pictured in Figure 10, are initiated until capacity has been

developed to achieve control, and to restore these sites.

There is a large group of weeds present on the archipelago that we are not considering for

management. This is because, based on a weed risk assessment, they appear to pose no threat

to the islands’ indigenous plant communities. There are 486 species in this group (86% of the

island’s exotic flora). While they pose no immediate risk and thus do not generally require

management, localised control may be necessary in some situations. For example, spot

spraying of some species may be needed when undertaking restoration planting to reduce

potential competition. This will be the case should restoration planting be undertaken on

Santa Clara Island.



Figure 10 A ridge above San Juan Bautista invaded by Chilean guava (Ugni molinae), one of the species

recommended for site-led control.



Figure 11 An evaluation of the state of natural vegetation communities on Robinson Crusoe and Santa Clara

Islands (figure from CONAF (2009)).

8.1.1 Feasibility of site-led control of selected weeds

Although the management of selected sites is technically feasible it will be expensive, and

will require active, long-term management. If biological declines are to be halted, however,



commitments to managing an increasing number of sites, with associated costs and risks,

must be made (See Table 5).

Table 5 Feasibility of site-led control for selected weeds


Technical The general control methods are well known

Large scale program

Requires a systematic approach of monitoring and adaptive management

Social Community is behind active management

Requires working in difficult sites, and spending days or weeks away from the town

Work will be carried out in areas little visited by the public

Development of good infrastructure including transport, tracks and lodges for overnight stays

Institutional Priority site management has already been incorporated into the management plan

Requires investment in a dedicated team

High return for little investment and increased protection of remaining biodiversity fragments.

Economic Initial high set- up costs but then reducing to an on-going low cost operation

On-going program needed indefinitely to protect high value sites

Cost will decrease as key herbivore and seed predators and seed dispersers are eliminated or excluded from the system



Figure 12 Herbivory by invasive mammals has left areas of forest with no understorey.


Sites of high biological importance in the archipelago should be identified (including

examples of all remaining native vegetation types, populations of all threatened plant species

etc.).

All site-led control activities (see Appendix 7) should be managed as part of a single,

coordinated program. Site-specific management plans and work schedules should be

developed for each area; these may include the application of mechanical and chemical

control methods, and perhaps replanting.

Monitoring programs should be developed and maintained to determine the effectiveness of

this work and to allow for adaptive management.

Capacity building objectives to address identified needs (e.g. improved prediction,

development of a pool of experienced weed and pest animal controllers) should be

incorporated into the design of site management projects.

Time-frame

This work will be on-going but should begin as soon as possible. All prioritised sites should

be managed on a prescribed rotational basis.



Resources

Capital

Infrastructure (e.g. field huts and track network) to allow management teams to have

easy access to the sites and to allow for overnight stays near them

Purchase of GPS units, cameras, computers

Purchase of traps and non-brodifacoum toxicants

Field equipment for staff (machetes, raincoats, etc.)

Fence construction

Nursery equipment

Operating

Chemicals

Fence maintenance

Plant production

Staff

A dedicated threat management/weed team (a minimum of 5 staff)

A dedicated full time project coordinator

Training of field team (species ID)

Cost estimate for site-led control



Responsibilities

CONAF

8.1.3 Anticipated outcomes

Table 6 Anticipated outcomes with and without recommended weed management actions (RC = Robinson Crusoe; AS = Alejandro Selkirk).

Management type Number of species

Anticipated outcome with specified management Anticipated outcome with no management

Biosecurity (prevention of new incursions)

Not applicable Pros

Prevention of new disease and pest introductions to the islands

Reduced cost of future conservation management in the park

Cons

Reduced personal freedom / choice for residents (food, pets, ornamental plants)

Increased cost of imported produce from certified, non diseased sources

Cons

Continual ‘fire-fighting’ management approach to conservation

Increased number of invasive species leading to an increasingly complex degradation process

Increased management costs elsewhere

Increased risk of species extinction and loss of indigenous communities

Pros

Personal freedom

Community has no restriction on imports

Eradication (for potential problem species yet to become established)

RC: 43

AS: 10

Pros

Reduced expenditure on weed management in the park

Eliminates new threats to the indigenous ecosystems and species

Opportunity for indigenous gardening projects that increase islanders knowledge of their flora

Cons

Reduced choice of plants for gardeners

Cons

Increased complexity of invasive species degradation process

Increased management costs

Increased risk of species extinction and loss of indigenous communities

Pros

Freedom for gardeners to grow whatever they like

Containment and site-led control (plants)

RC: 16

AS: 1-3

Pros

Increased ecosystem health, structure and function (reducing competition)

Cons

Loss of indigenous communities (see Greimler et al. 2002)

Increased rate of loss of threatened plant and bird species

Reduced likelihood of threatened plant extinction

Streamlined goal-orientated weeding program to focus on priority high conservation value sites

Increased effectiveness of ecosystem service delivery from complex and healthy ecosystems

Increased opportunities for in situ threatened species recovery

Job creation for local community

populations

Site -led control (herbivores and seed predators)

RC: 8

AS: 4

Pros

Increased natural forest regeneration and seed germination

Improved recovery of threatened species reducing the need for intensive in situ and ex situ management

Reduced erosion

Cons

Increased invasion potential for weeds causing increased competition and impacting on indigenous forest regeneration and species recovery

Cons

Continued dispersal of weeds by herbivores

Continued seed predation, direct herbivory of seedlings and plants reducing natural forest regeneration

Rapid erosion process

Continued decline of threatened species

Pros

Some weeds may be held in check by herbivory



8.1.4 Risks associated with the main weed management techniques

Biological control

The risks associated with biological control are listed in Table 7, along with strategies to

manage these risks.

Table 7 Management of risks associated with biological control.

Type of risk Problem Solution

Institutional Long development phase before implementation (<10 years), which can lead to project abandonment due to lack of interest or funding

Ensure total funding, and agreement for long-term support before beginning, including institutional leadership

Technical Risk of non-target impacts

Risk of suboptimal effectiveness

May not eradicate the target invasive

Ensure careful testing of non-target species using best-practice methods to ensure specificity of agent outside country for release

Assess suitability of proposed control agent using established frameworks (e.g. Paynter et al. 2009)

Use in conjunction with other techniques

Social Concern over non-target effects

Expectation that the agent will be highly effective

Careful consultation throughout the development and release phase

Economic Cost can be very high, leading project to be abandoned due to lack of funding

Ensure total funding available before development begins

Chemical control

The risks associated with chemical control (use of herbicides) are listed in Table 8, along

with strategies to manage these risks.



Table 8 Managing risks associated with chemical control of weeds.


Institutional May cause pollution of water sources

Exposure of staff to toxins

Ensure thorough understanding of costs and benefits, as well as definition of areas where herbicide use is not permitted

Ensure all necessary safety measures, procedures and equipment available and in use

Technical Not totally effective (leading to reshooting, not 100% death)

Can cause non-target damage to other plants (including endemic / endangered species)

Carry out regular trials to ensure optimal concentrations, application methods and type of chemicals, and minimize non-target effects, paying particular attention to endangered species

Social Can cause pollution of water sources

Ensure thorough understanding of costs and benefits, as well as definition of areas where herbicide use is not permitted

Economic Can be expensive Ensure optimal use of chemicals

Mechanical control

Table 9 details risks associated with mechanical control (the use of physical removal methods

to kill individual plants, or seed banks), and methods to manage these risks.

Table 9 Managing risks associated with mechanical control of weeds.


Institutional Exposure of staff to potentially dangerous procedures

Ensure proper safety equipment and training

Technical Can lead to damage to surrounding vegetation or erosion

Use on sites that are less susceptible to these problems, over small areas, for seedlings or young plants, or carrying out in conjunction with replanting

Social Can cause large-scale short-term impacts on landscape

Carry out awareness raising to ensure understanding of the impact of this type of control

Undertake replanting in key areas if appropriate

Economic May require more labour (compared to other techniques)

Use only in certain areas or for certain species



8.2 Species-led management

In some cases it is appropriate to focus on particular species, rather than on sites. Populations

of some threatened species may be at such low levels that a focus on individuals is

appropriate. In other cases a focus on a particular weed species may lead to wider community

benefits.

8.2.1 Managing invasive species to conserve threatened species

Másafuera rayadito

The Másafuera rayadito is a critically endangered songbird endemic to Alejandro Selkirk

Island. Urgent action is required to prevent its impending extinction. Further research is

needed to clarify the impacts of invasive species and to guide management of the species’

recovery. We suggest, however, that there is sufficient information about the nature of the

threats posed by invasive species and habitat loss to endemic island birds globally to justify

urgent recovery actions. We also suggest there is enough experience in successfully

addressing these threats and recovering endemic island birds to justify a more proactive

adaptive management approach being adopted here to recover the rayadito. A small team of

recovery specialists should be established as soon as possible to coordinate activities. We

expect this team will quickly identify a number of priority actions including predator and goat

control and nest protection. We suggest a recovery plan should be drafted and identified

priority recovery actions initiated by the 2011/12 rayadito breeding season (November 2011).

Juan Fernández firecrown

The Juan Fernández firecrown is also a critically endangered species, endemic to Robinson

Crusoe Island. We suggest that further recovery actions are urgently required for this species.

As suggested for the rayadito we believe there are people with sufficient knowledge of the

firecrown and others with experience in successfully managing threats to critically

endangered island birds to justify a more proactive adaptive management approach being

adopted here to recover the firecrown. A small team of recovery specialists should coordinate

the preparation of an up-dated recovery plan and oversee its implementation as soon as

possible.

Threatened plants

The flora of the Juan Fernández Archipelago is severely threatened, with more than half its

native plant species being extinct, critically endangered or endangered. The impacts of

invasive species, including browsing by goats and seed predation by rats, are major threats

for many of these species. CONAF has a program to prevent further extinctions. Due to the

steep terrain, access to threatened plants and key sites on Robinson Crusoe and Alejandro

Selkirk Islands is extremely difficult. Furthermore, the steep topography has prevented

detailed distribution maps being prepared and updated for some of these plants. As a

consequence of limited access to key sites, and incomplete knowledge of the distribution of

some plants, setting priorities and undertaking effective recovery actions is severely impeded.

Most plant recovery activities are currently restricted to ex situ activities in San Juan Bautista



nursery and its environs, or involve the management of a few accessible individual threatened

plants.

Figure 13 The Másafuera rayadito (left) and Juan Fernández Firecrown (right).

Consideration should be given to which threatened species (plants and animals) require

recovery plans to be written, or up-dated to guide urgent recovery actions. Recovery teams

should then be established to prepare these plans, and to promote and oversee their

implementation.

Aerial weed surveys

We suggest the use of a helicopter with an experienced crew to carry out low-level aerial

surveys will be an important ‘new’ tool in the archipelago. This will allow for detailed and

complete distribution maps of selected weeds to be prepared as a basis for planning and

prioritising management actions. Helicopters will also be a key tool for locating and mapping

threatened plants. Helicopters will also allow field staff to be transported quickly and safely

to key sites for a range of other tasks. Because we understand helicopters have not been used

for these purposes in Chile before we recommend weed and threatened plant surveys are

undertaken initially as a trial, with costs, risks and benefits being evaluated and compared

with any alternative approach.

Figure 14 Helicopter being used in weed eradication operation, Santa Cruz Island, California.



Table 10 Feasibility of helicopter-based surveys and management.


Technical

Operational

Surveying of this type has been carried out successfully elsewhere

Rapid and comprehensive coverage of the archipelago

Efficient and safe means of accessing steep or remote locations – in effect, the only way to access many sites

Expertise or experience in this kind of work may not exist in Chile

Inability to identify plants from the air

shortage of experienced operators could be initial impediment

Use international crews (pilots, surveyors) to undertake trial and to train local operators

Ensure team is highly trained in species ID

Contract international crew with relevant experience and appropriate equipment for initial trial

Social Highly visual activity allowing for increased awareness of conservation activities, and of potential achievability of objectives previously seen as ‘impossible’

Temporary disturbance (people, cattle, horses)

Inform community of flying schedule and proposed tasks

Institutional Allow for streamlining of priorities for conservation and management action

Requires acceptance that survey results may lead to new priorities and different approaches

Involve management agencies and key stakeholders in planning and undertaking aerial surveys

Economic More cost efficient than carrying out land-based surveys (where these are feasible)

High helicopter placement and operating costs

Critically evaluate costs, risks and benefits. Investigate opportunities to mainstream aerial surveys (e.g. local operators)

Specific Recommendations

Consideration should be given by SAG to which threatened species (plants and

animals) require recovery plans to be written or up-dated to guide urgent recovery

actions. Recovery teams should then be established to prepare these plans, and to

promote and oversee their implementation.

A helicopter and experienced pilot and survey crew should be engaged to undertake

weed and threatened plant surveys in the archipelago to provide comprehensive maps

and information upon which detailed plans may be based. This work may be



undertaken as a trial, with costs and benefits of this approach being compared with

alternative measures.

Time-frame

By March 2012

Resources

Capital

None

Operating

Helicopter operational costs

Binoculars

Staff

Pilot and technicians

Observers/surveyors

CONAF staff

Scientist to interpret spatial data

Cost estimate

US $140 000

Responsibilities

CONAF in association with selected researchers and technical experts

8.2.2 Widespread weeds

Developing a strategy for biological control

The three worst weeds on the archipelago (Aristotelia chilensis, Ugni molinae and Rubus

ulmifolius) are widespread on Robinson Crusoe Island. They each have significant ecological

impacts and their control is complicated by their life histories. Island-wide control of these

three species, while seemingly desirable, is not a viable option at the moment with the tools

available. It would also lead to increased erosion as restoration on such a large scale would

not be possible before the weeds reinvade, and may cause conflict with the community as

some of these species are harvested. However, an island-wide program against Rubus



ulmifolius may be possible through the development of a biological control agent for this

species and is worthy of further research to assess its feasibility. The fungus Phragmidium

violaceum is being used successfully to control Rubus constrictus in mainland Chile, but has

been ineffective against R. ulmifolius (Ellison & Barreto 2004; Barreto 2009). Further

research aimed at the development of a specific biological control agent is urgently needed

for this, and for the other two species. It may also be appropriate to consider biological

control for A. chilensis and U. molinae. Typically, a biological control agent is a pest or

disease that is found in the native range of the target invasive species. It only affects the

target species, weakening it so that it becomes less competitive, and maintains the targeted

pest at a level that does not cause unacceptable impacts. Biological control does not usually

lead to eradication of the target species.

Typically, a biological control project consists of six steps and might take up to ten years to

meet its objectives. The six stages are:

Define the goal for the biological control project

Study the target weed in its introduced range to understand its impact, its natural history

and to determine if there are any enemies already present

Explore potential biological control agents in the native range that attack the same

genotype of the target invasive

Carry out a risk assessment of the selected agent to ensure that it will not affect any

native, endemic or agricultural species in the archipelago. Because of the specificity of

biological control agents, the species most at risk will be those within the same Genus

or Family. For example, Rubus geoides, Ugni selkirkii could be appropriate analogues

for trials with the proposed agent to determine impact.

Carry out importation and quarantine assessments prior to approving clearance for the

agent

Carry out release and evaluate its effectiveness in the field

Because there are substantial risks involved in the release of new organisms – especially into

the archipelago (See Table 7) – risk assessments and evaluations must be carried out

rigorously using current best practice, and must involve national and international experts. In

addition, the community must be involved, especially for those invasive species that have

social values.

We have recommended that a biological control strategy document be produced to inform

and underpin any decisions and actions to undertake biological control in the archipelago. We

have not carried out a detailed feasibility analysis here.

Specific Recommendations

Assess the feasibility of using biological control agents for Aristotelia chilensis, Ugni

molinae and Rubus ulmifolius



Time-frame

Within 18 months

Resources

Capital

None

Operating

Meeting costs with community and government

Site meeting for national and international experts in biological control

Staff

Scientist to compile information and produce report

Student to carry out basic life history work

Cost estimate

US $100 000

Responsibilities

SAG

8.2.3 Aerial surveys to map the location and distribution of the 3 most pervasive weeds on Alejandro Selkirk Island

Rubus ulmifolius is just beginning to invade Alejandro Selkirk Island and there is great

concern that this pervasive weed should not become widely established. Resources have been

allocated to control known infestations. Due to the difficult terrain, however, there are many

areas that are not accessible on foot, and surveying from ropes is slow and dangerous. It is

recommended that detailed and systematic surveys to establish the distribution of Rubus

ulmifolius, and of Ugni molinae and Aristotelia chilensis, are carried out urgently across

Alejandro Selkirk Island to ensure that the most effective and efficient approaches are applied

to achieve management objectives. The most likely objectives for each of these species would

involve their containment to known areas, with regular island-wide surveys to detect any new

plants that may have emerged from seed banks. With a systematic surveillance and

monitoring strategy, coupled with active removal, it may be possible to reduce their ranges

and, possibly, even eradicate one or more of them. However, until a comprehensive survey is

carried out, site-led control may be the most cost-effective management option. This work

should be carried out in conjunction with the aerial surveys recommended for threatened

plants.



9 Phase 3: Eradication and control

Phase three is the most ambitious phase, drawing on techniques and information from the

previous phase and expanding the scale of projects to that of the whole archipelago. This

phase will require significant funding, and external technical expertise. We have divided the

phase into three components:

1) Eradicating invasive mammals

2) Managing cattle

3) Managing other species

9.1 Eradicating invasive mammals

Invasive mammals in the Juan Fernández Archipelago will require a range of different

management activities. The rationale for our suggested actions is outlined in the following

sections. Operations targeting particular species will need to be carried out as part of a

coordinated and integrated multi-species program for greatest efficiency and effectiveness.

We recommend that the eradication of targeted mammals be carried out in a carefully

planned and monitored sequence. This should be designed in such a way as to maximise

efficiency and to ensure that eradication of one species does not make subsequent eradication

of another species more difficult. While the detailed scheduling of eradications is a matter for

operational planning, a suggested time frame is provided in Section 12.

9.1.1 Feral goat

Ecology and impacts

Goats were introduced to all three islands of the Juan Fernández Archipelago in 1574 to

provide food for future sailing expeditions (Muñoz Pedreros et al. 2003). They were

distributed throughout the archipelago but are now absent from Santa Clara Island. Feral

goats have a localised distribution and occur in relatively low numbers on Robinson Crusoe

Island, where they are hunted by residents (Sanders et al. 1982; CONAF 2009). However,

they remain abundant and widespread on Alejandro Selkirk Island (González et al. 2003)

despite hunting by fishermen who are present on the island for eight months each year

(Hagen 2010).

Feral goats are listed among the world’s worst invasive species (Lowe et al. 2000).

Historically, they have had significant impacts throughout the archipelago through

overgrazing and trampling, leading to loss of vegetation, soil compaction and erosion

(Sanders et al. 1982). They have contributed to substantial declines in the abundance and

distribution of native plants throughout the archipelago, including the total loss of native

vegetation on Santa Clara Island (Sanders et al. 1982). In many places these impacts have

occurred in combination with those of other mammal herbivores (rabbits, cattle, horses).



Feral goats are currently causing the most severe impacts on Alejandro Selkirk Island, where

they are most abundant (Sanders et al. 1982; González et al. 2003). In addition to the loss of

plant biodiversity, their destruction of vegetation and soil is considered a threat to native

animals, including the endangered Másafuera rayadito (Hahn & Römer 1996; Hagen 2010).

Previous management

Feral goats have been eradicated from Santa Clara Island, with the last remaining individual

having been removed in 2001. This, along with the subsequent eradication of rabbits, has

resulted in some regeneration of native shrubs (B. López, pers. comm.). On Alejandro Selkirk

Island feral goats were controlled by hunting between 1999 and 2003 as part of the Holland

Project. This led to some regeneration of native plants, as well as some weeds (González et

al. 2003). Since 2003 there has been no formal management of feral goats on Alejandro

Selkirk Island, although they are subject to occasional recreational hunting (Hagen 2010).

Feral goats on Robinson Crusoe Island are also subjected to some recreational hunting

(CONAF 2009).

Management options

As described in Section 5, there is a spectrum of management options available for feral

goats. These options, and their likely outcomes, are discussed below.

Do nothing: Feral goats will increase in numbers and become widespread in remaining

vegetated areas. Vegetation loss and accelerated erosion will continue. Weeds may be

locally suppressed.

Sustained control: If current techniques (local hunters with firearms) are employed the

number and distribution of feral goats may be reduced in localised areas for short

periods. Vegetation loss and accelerated erosion will continue, especially in steeper

areas. Refined ground hunting operations involving experienced hunters with trained

dogs could lead to effective control, with reduced vegetation loss and erosion in more

accessible areas. In areas where some goats remain, weeds may be locally suppressed.

This approach would require a significant increase in resourcing. Occasional aerial

shooting to achieve control objectives would be too expensive and inefficient to be

considered a realistic management option in perpetuity.

Eradication: There are a number of examples of successful feral goat eradications on

similar islands in this region which may be used as models (Campbell & Donlan 2005).

People with the necessary skills and experience to assist in goat eradication are

potentially available (Galápagos, Mexico, New Zealand, USA). As a result of these

successes, the outcomes reported and potentially available expertise, we suggest

eradication is a realistic option in the archipelago. We understand feral goats are

regularly hunted on Alejandro Selkirk Island for meat. Concerns were expressed to us

that removing the goats might lead to weeds proliferating. It will be important that these

concerns are properly addressed. We suggest that retaining feral goats for meat presents

unacceptable risks (of their re-establishing a population) on both islands, especially as

alternatives to goat meat are available for human consumption. Intensive control of

weeds favoured by feral goats will be required before and following goat eradication.

Apart from these concerns we sensed there might be a large measure of community



support for the eradication of feral goats, especially if local people were employed in

the eradication operation. Successful goat eradication projects in the Galápagos provide

an indication of the potential to employ local people in eradication work. About 50

local people were employed during these projects; some have gone on to permanent

jobs in the National Park Service.

Biosecurity: There is unlikely to be strong community interest in importing goats from

elsewhere for food, or as pets. Before any invasive mammal management programs are

in place, regulations should be enforced which preclude the importation of goats to the

archipelago. If Robinson Crusoe and Alejandro Selkirk Islands are treated sequentially,

community outreach and education programs will be required to ensure local residents

are aware of the need for biosecurity measures. Regulations will also be required to

prohibit the transfer of goats from one island to the other.

Recommended management objective

Eradication of feral goats from both Robinson Crusoe and Alejandro Selkirk Islands. This

should be carried out by a team including eradication specialists and local hunters, in

collaboration with CONAF.

Anticipated outcomes

Defoliation of native trees will be reduced and seedling survival enhanced. Increased

vegetation ground-cover and improved seedling survival of woody plants in areas where

goats, as well as rabbits and cattle, are absent.

Survival of rare and threatened plants will be improved, leading to population increases and,

eventually, down-grading and perhaps de-listing of species with IUCN threat categories.

Soil compaction and erosion will be reduced, especially on steeper slopes, possibly leading to

reduced impacts on the lobster fishery as sediment deposition may affect in-shore lobster

larvae settlement. While feral goats are an important contributor to this degradation, cattle

and rabbits will also need to be managed if protecting and restoring native vegetation and

conserving soils are declared objectives. Horses will also need to be excluded from sensitive

sites. Goats are able to feed on steeper slopes than cattle and horses and, along with rabbits,

are probably the major contributor to vegetation loss and accelerated erosion on upper slopes

and cliffs.

The removal of feral goats can be expected to lead to increased growth and expansion of

some weeds (e.g. blackberry). Weed control will be required in association with any goat

eradication. The weed management practices recommended in Section 8 should be in place

before goats are eradicated.

Removal of goats may reduce the availability of carrion for the endemic Másafuera hawk

(Hagen 2010).

The involvement of local hunters in goat eradication activities can be expected to encourage

communication between the community and eradication personnel, and ensure any

misunderstandings are effectively addressed.



Eradication techniques

It is anticipated that feral goat eradication in the archipelago will involve separate, but linked,

operations on Robinson Crusoe and Alejandro Selkirk Islands. A phased approach involving

an ‘Initial knock-down’ of most of the goats, followed by ‘Mop-up’ and ‘Confirmation’

phases should be applied. Once eradication is confirmed, on-going surveillance should be

undertaken as part of a comprehensive Juan Fernández Archipelago Biosecurity Program

(Section 7). Most goat eradications have involved the application of more than one technique.

Table 11 Possible techniques for eradicating feral goats.

TECHNIQUE EXPLANATION

Hunting with firearms Motivated and experienced hunters using firearms have been a key tool in many goat eradication projects

Some local residents are already experienced in shooting goats on Robinson Crusoe and Alejandro Selkirk Islands

There is potential to train and support local hunters to participate in the goat eradication project

Snares and traps Can be effective as a complement to other tools, and in remote/inaccessible areas

Potentially useful tools in ‘Mop-up’ and ‘Confirmation’ phases of an eradication

Hunting with firearms and trained dogs

Trained dogs used by experienced hunters, with firearms can significantly improve hunting effectiveness at low goat densities

Dogs are used for rodent and feral cat detection and for hunting goats in New Zealand. They are also used in the USA for hunting rabbits, cats and raccoons. Experienced dogs can be sourced for these species or similar species being targeted. Dogs are also used extensively in Chile and New Zealand for biosecurity checks at airports and ports. It is recommended that experienced dogs are used for each species or suite of species being targeted. Local dog handlers can be trained by experienced specialists

Judas goats The release of sterilised goats fitted with radio telemetry collars has emerged as a key tool in feral goat eradication projects. The radio-collared animals join groups of unmarked goats that may subsequently be located and removed (e.g. Proyecto Isabela, Galápagos)

Aerial hunting Recognising the steep terrain and difficulty of accessing many parts of Robinson Crusoe and Alejandro Selkirk Islands, a helicopter with an experienced pilot and crew is the only practicable way that feral goats can be eradicated here

In addition to providing an excellent aerial shooting platform, helicopters have proved indispensable in transporting hunters, dogs, Judas goats and equipment quickly and efficiently to virtually any location – especially in steep terrain



Risks and risk management

Removal of feral goats may release some invasive weeds from the impacts of herbivory. This

risk should be minimised by ensuring that control programs are in place for any weeds

expected to respond to the removal of feral goats are in place before goats are eradicated.

Removal of feral goats will lead to major recovery of vegetation, particularly on Alejandro

Selkirk Island, where goats are the dominant herbivore in the absence of rabbits. This

vegetation recovery will make eradication of feral cats more difficult. It is therefore

suggested that feral cat eradication is conducted more or less at the same time as the goat

eradication on Alejandro Selkirk Island. On Robinson Crusoe Island goats are more restricted

in numbers and distribution so that their removal would not be expected to cause such a

marked recovery in vegetation that it would increase the difficulty of removing cats or other

species.

Table 12 Satisfying the requirements to eradicate feral goats from Robinson Crusoe and Alejandro Selkirk

Islands.

REQUIREMENTS POTENTIAL TO SATISFY REQUIREMENTS

All individuals of targeted feral goat population are put at risk by the techniques employed

Relatively good understanding of goat ecology and behaviour exists

A range of proven techniques are potentially available to locate and destroy feral goats, as well as experienced people to advise and assist

The use of a helicopter to locate and destroy goats in remote or inaccessible areas, in combination with Judas goats and ground-based techniques, is the only way all individuals can be put at risk

Feral goats are removed faster than they can breed, at all densities

Experience has shown that a phased approach (Initial knock-down/Mop-up/Confirmation) using a mix of ground-based and aerial techniques will allow all feral goats to be quickly removed, even at low densities

The risks of feral goats re-invading are near-zero

Inadvertent re-introductions are unlikely

Outreach and education programs focused on the benefits of having no goats, coupled with appropriate regulations to prohibit deliberate re-introductions will be required

Stakeholders are generally supportive of the techniques employed

There is some scepticism of the efficacy of using helicopters for this purpose in the archipelago. DVDs of helicopters being used to eradicate feral goats (and rodents and feral cats) elsewhere could be shown, and arrangements made for local people to talk to practitioners about their experiences with helicopter-based operations on other islands

The consistent application of appropriate standards of humaneness and animal welfare should ensure any concerns about these issues are addressed

The involvement (and employment) of local people in the goat eradication operations on Robinson Crusoe and Alejandro Selkirk Islands should encourage community support

Concerns about a proposal to eradicate feral goats may be expressed by local people who hunt goats for meat. These concerns should be acknowledged. In our view, the benefits of retaining goats would be outweighed by the benefits which can be predicted following their eradication

There are few examples world-wide of eradications being successfully undertaken on inhabited islands. This is due, in part, to the fact that most eradications to date have been on uninhabited islands and few attempts have been made, so far, on inhabited islands. While there may be opportunities associated with biosecurity on inhabited islands, addressing



different views and requirements expressed by community members may present challenges. It will be important that authoritative information is readily available to inform discussions, and processes are in place through which decisions may be made.

Institutional support for the eradication and its outcomes is declared and maintained

It is hoped this feasibility study report will be useful in informing institutional decision makers as they consider whether they will declare their support for the restoration program overall, and for the feral goat eradication in particular

A Juan Fernández Restoration Plan and associated Integrated Invasive Species Management Plans should provide a useful basis for longer-term institutional commitments to be determined

Benefits outweigh costs Important ecological benefits can be anticipated from the eradication of invasive mammals. In addition to species recovery and community restoration, feral goat eradications are expected to create important opportunities for wider ecological restoration

Social benefits from this or any other eradications may include community pride in achieving multi-species eradications, and in recovering and restoring the natural environment

Economic benefits may include 1) employment of local people as part of eradication and on-going biosecurity measures; 2) development of eco-tourism; 3) improvements to ecosystem services, possibly including the lobster fishery. These benefits may also apply to other eradications

Potential institutional and donor support

It is clear that feral goats are recognised as an important pest in the Juan Fernández

Archipelago (CONAF 2009), and that their eradication should be a priority. Previous

successes such as their eradication from Santa Clara Island make it likely that international

funding institutions will be interested in supporting further feral goat eradication here as part

of an integrated restoration program.

Feasibility of eradication

Feasibility: HIGH (Robinson Crusoe). HIGH (Alejandro Selkirk)

All criteria for successful feral goat eradication can be met using existing approaches and

techniques provided appropriate community, institutional and funding support is secured.

9.1.2 Rabbits

Ecology and impacts

Rabbits have been introduced to many parts of the globe and are considered one of the

world’s worst invasive species (Lowe et al. 2000). They were introduced to Robinson Crusoe

and Santa Clara Islands in the 1930s, but not to Alejandro Selkirk Island (Hahn & Römer

2002; Hagen 2010). They were eradicated from Santa Clara in 2003 (CONAF 2005), but

remain abundant on Robinson Crusoe Island (Section 3.1). In combination with other

herbivores, rabbits are contributing significantly to ecological degradation in the archipelago



through overgrazing, leading to loss of native vegetation and widespread erosion of hillsides

(Sanders et al. 1982).

Herbivory by rabbits prevents regeneration of native vegetation and facilitates the spread of

invasive plants on Robinson Crusoe Island (Nelis 2008). In addition their destruction of food

plants used by the Juan Fernández firecrown presents a threat to this critically endangered

endemic bird (Colwell 1989). Prior to their eradication from Santa Clara Island rabbits

suppressed regeneration of native plants, which have now begun to reappear in the absence of

invasive herbivores (CONAF 2005). They also apparently competed for burrows with

threatened pink-footed shearwaters. Burrow occupancy of shearwaters on Santa Clara Island

increased by 10–20% after rabbits were removed (Hodum 2007).

Rabbits may also form an important part of the diet of native short-eared owls (Saiz 1982).

The population of owls on Santa Clara Island fell from eight breeding pairs to two after

rabbits were eradicated. The owls now feed primarily on storm petrels and spiders (Hodum

2007). Artificially elevated population densities of short-eared owls due to the presence of

rabbits may impact on populations of small seabirds like storm petrels, which could be

frequently found in owl pellets on Santa Clara before rabbit eradication.

Previous management

During the Holland Project, rabbits were subjected to a program of shooting and trapping

with the aim of eradicating them from Santa Clara Island and reducing their density on

Robinson Crusoe Island (Muñoz Pedreros et al. 2003). On Santa Clara these measures were

followed by burrow fumigation and poison baiting, which resulted in their successful

eradication (Section 3.1). However, the control measures on Robinson Crusoe Island had

little impact on rabbit numbers. This was probably because shooting and trapping alone are

unlikely to remove rabbits faster than they can reproduce on an island of this size. However,

when combined with techniques such as baiting and burrow fumigation, these techniques can

lead to successful eradication, as occurred on Santa Clara. The spreading of baits by

helicopter will overcome difficulties associated with the larger size and steeper terrain of

Robinson Crusoe Island relative to Santa Clara. There is currently no formal management of

rabbit populations on Robinson Crusoe, although they are occasionally hunted by local

people (CONAF 2009).



Management options

Do nothing: Rabbits will remain widespread in areas of suitable habitat, typically in

high, fluctuating numbers. Vegetation loss and associated erosion will continue.

Rabbits will continue to compete with cattle for food. Some rabbits will be shot by

local hunters to augment food supply.

Sustained control: Coordinated and sustained ground operations involving toxic baits

and experienced hunters, perhaps using trained dogs, could lead to control being

achieved in localised areas of high conservation priority. A sustained rabbit control

program based on ground-hunting and baiting would require specific, on-going

resourcing. Vegetation loss and accelerated erosion will continue in areas where rabbits

are not controlled, especially where other browsers and grazers are also present.

Biological control agents, particularly Myxoma virus or Rabbit Haemorrhagic Disease

(RHD) have been used as an effective control tool elsewhere (e.g. Cooke 1999), and are

particularly effective in conjunction with follow-up techniques such as destruction of

rabbit warrens (McPhee & Butler 2010). Any investigation of biological control would

require detailed consideration of legal requirements, potential non-target impacts on

native lagomorphs and social acceptability, as well as of their potential efficacy.

Myxoma virus was introduced in 1953 in southern Chile and is believed still active

there, but has not been released in the Juan Fernández Archipelago (Camus et al. 2008).

RHD is unlikely to be permissible in the Americas because of possible risk to native

lagomorphs.

Eradication: Rabbits have been successfully eradicated from a number of islands in this

region, as well as elsewhere. Most rabbit eradications have involved the application of

more than one technique. Robinson Crusoe Island is larger than most other islands from

which rabbits have been eradicated to date, although rabbits, along with rats and mice,

are the target of a planned Australian eradication operation on the much larger

Macquarie Island (12 400 ha). The relatively large size of Robinson Crusoe Island,

coupled with the fact that it is inhabited, presents risks that will need to be effectively

managed. We do not see any reason why the size of Robinson Crusoe Island should

prevent eradication being achieved, however, provided aerial baiting is used, followed

by ground hunting by experienced people using trained dogs, or other localised control

methods. Nor do we see the fact that the island is inhabited as a reason not to proceed

with rabbit eradication, provided local people are supportive of the eradication and

accept the techniques to be employed. Residents of San Juan Bautista will require

assurance that aerial baiting will not occur in the town or its environs. Some residents

may have concerns about the removal of rabbits as a source of food, or as a recreational

hunting resource. There is potential for local people to be employed as part of a rabbit

eradication operation. With appropriate training they could contribute to the ground-

hunting operation (‘Mop-up’ and ‘Confirmation’ phases), as well as on-going

surveillance. Based on concerns expressed to us about the impacts of rabbits, in

particular their competition with cattle for food, we would expect there to be strong

community support for rabbit eradication on Robinson Crusoe Island.

Biosecurity: There is unlikely to be strong community interest in importing rabbits

from elsewhere for food, or as pets. Regulations should be enforced which preclude the

importation of rabbits before any management of invasive mammals commences.

Community outreach and education programs will be required to ensure local residents

understand the need for biosecurity measures.



Recommended management objectives

Eradicate rabbits from Robinson Crusoe Island and put in place biosecurity measures to

ensure they are not re-introduced to the archipelago. Eradication should be carried out by a

team of specialists and trained local hunters, in collaboration with CONAF and the

Municipality. Biosecurity measures should be developed and enforced by Chilean

government agencies (e.g. CONAF, SAG) and the Municipality.


Increased vegetation ground-cover and improved seedling survival of woody plants in

areas where rabbits, as well as goats and cattle, are absent.

Reduced erosion and sediment runoff, possibly leading to increased productivity of the

lobster fishery.

Improved survival of rare and threatened plants, leading to population increases and,

eventually, down-grading and perhaps de-listing of species with IUCN threat

categories.

Opportunities for ecological restoration created where browsing and grazing mammals,

including rabbits, are removed.

Improved pasture growth and quality to sustain cattle and horses in areas designated for

this purpose.

Further experience and understanding of the implications of combined rabbit, rodent

and feral cat eradications.

Reduced availability of food for feral cats, making them more vulnerable to eradication

techniques.

Reduced competition for seabird burrows, including those of the threatened pink-footed

shearwater.


It is recommended that the eradication of rabbits from Robinson Crusoe Island should

proceed in conjunction with the eradication of rodents (see Section 9.1.3) and feral cats

(Section 9.1.4). The campaign should involve the aerial application of toxic baits from a

helicopter with an under-slung bait bucket (Figure 15). Planning for such an operation will

require the involvement of all land managers on the islands, including CONAF (the park) and

the Municipality (town, airport and surrounds). Provided sufficient quantities of an

appropriate bait and toxin are applied, it can be anticipated that rodents will be eradicated and

initial knock-downs of rabbits (~80–95%) and feral cats (~20–40%) will be achieved as part

of the one operation. Combining aerial baiting operations in this way presents opportunities

for increased efficiencies and reduced bait and helicopter costs. Associated increases in

complexity, however, may also present additional risks that would need to be managed.

While we see no particular reason at this stage why rabbits, rodents and feral cats should not

be simultaneously targeted, it should be noted that this would be only the second time all of

these species have been targeted together. On Motutapu Island, New Zealand, a similar suite

of invasive mammals (mice, rats, cats, rabbits, stoats, hedgehogs) were targeted in 2009 in a

single operation with three bait applications. The results of this operation have yet to be



confirmed. In the case of a rabbit eradication operation on Robinson Crusoe Island, aerial

baiting and possibly the use of disease should be followed by ‘Mop-up’ and ‘Confirmation’

phases using aerial hunting, ground hunters with trained dogs, fumigants and possibly other

methods. Once eradication is confirmed, on-going surveillance should be undertaken as part

of a comprehensive Juan Fernández Archipelago Biosecurity Program.

Figure 15 A helicopter distributing baits from an under-slung bucket.

Table 13 Possible techniques for eradicating rabbits.


Aerial baiting Aerial bait spreading using a helicopter and under-slung bucket is the only way that toxic baits may be distributed quickly and reliably to every rabbit on Robinson Crusoe Island

Aerial baiting has been successfully used in a number of rabbit eradications around the world as the initial knock-down tool. Most individual rabbits can be expected to be destroyed using this technique (Torr 2002; Parkes & Nugent 2010). Best-practice procedures have been established and experienced helicopter operators are available to ensure bait distribution performance measures are met

Hunting with firearms Motivated and experienced hunters using firearms and trained dogs have been a key



and trained dogs

tool in many rabbit eradication projects. Following aerial baiting, hunters and dogs have been the primary tool in ‘Mop-up’ and ‘Confirmation’ phases in rabbit eradication operations

There is potential to involve trained local hunters in ‘Mop-up’ and ‘Confirmation’ phases of a rabbit eradication project on Robinson Crusoe Island

Aerial hunting Hunting from helicopters is used cost-effectively on steep hillsides in southern New Zealand. It allows for large areas to be covered many times, quickly and safely. Based on the topography of Robinson Crusoe this is expected to be a useful method there

Snares and traps Snares and traps have been used as a complement to hunting operations in some rabbit eradications. They may be particularly useful in relatively inaccessible areas where rabbits persist

Snares and traps can also be useful tools in on-going surveillance programs

Burrow fumigation Fumigation of rabbit burrows with toxins such as phosphine or carbon monoxide can be effective in combination with other measures (Williams et al. 1995). For example, fumigation using phosphine was instrumental in the successful eradication of rabbits from Santa Clara Island (Section 3.1)

Disease Could provide an effective population knock-down tool, reducing the amount of toxic bait required

Myxoma virus is already present in Chile, however it is unknown if the vector, rabbit fleas, are present on Robinson Crusoe

Rabbit Haemorrhagic Disease (RHD) may have risks for native lagomorphs

The most appropriate timing for release of the disease would need to be determined by rabbit disease experts and eradication planners. The population would ideally be dramatically reduced by disease and resistant animals would not have initiated breeding

Predators Cats are effective predators of rabbits. By conducting cat eradication after rabbit eradication, predation can be used as a method that may facilitate the removal of rabbits surviving aerial baiting. Cats that are specialising on rabbits may survive secondary poisoning as they consume rabbit muscle which holds low amounts of brodifacoum, compared with rodents that are consumed whole (brodifacoum is concentrated in the liver and other internal organs)


The recommended approach of targeting five species (ship rats, Norway rats, mice, rabbits

and cats) with a single toxic baiting operation is likely to increase efficiency, as well as

reduce the risk of undesirable flow-on effects that can occur when individual species are

treated in isolation. As with any innovative approach, however, this carries some risks

associated with complexity and few precedents. These risks will need to be identified as part

of operational planning and appropriately managed.

Brodifacoum is non-water soluble. However, in recognition of perceived risks to water

supply following the aerial baiting operation, an alternative water supply should be provided

to residents for drinking until testing confirms the town water supply is free of any residue.

The presence of cattle and horses may also present some risks. Cattle and horses could

consume large numbers of baits, thus reducing their availability to the target animals. Human

consumption of meat from animals that have been exposed to toxic baits should be avoided,

and may not be permitted under health regulations. For these reasons cattle and horses would



either need to be temporarily removed from the island during the baiting operation, or be

confined to areas that are excluded from aerial baiting. These areas would need to be treated

using bait stations and/or traps to ensure they do not jeopardise the eradication attempt by

allowing some rodents to survive. Cattle and horses would need food and water supplied

during the holding period. Measures would also be required to ensure that domestic pets such

as dogs and cats are not exposed to the toxin.

Table 14 Satisfying the requirements to eradicate rabbits from Robinson Crusoe Island.


All individuals of the targeted rabbit population are put at risk by the techniques employed

Aerial baiting, combined with follow-up ground-hunting using firearms and trained dogs, aerial hunting, fumigation and perhaps additional techniques, as has been effective in achieving rabbit eradications elsewhere

A growing number of successful rabbit eradications internationally have led to the development of best-practice procedures and an increasing pool of people with the experience, skills and confidence to advise in the planning and implementation of rabbit eradications

San Juan Bautista and its environs, and possibly other areas where livestock are confined, should be excluded from the aerial baiting area. There is a risk that any wild rabbits living in these exclusion zones will not be put at risk by the techniques employed unless special care is taken to ensure all wild rabbits in these zones are removed

Rabbits are removed faster than they can breed, at all densities

Experience has shown that the application of a combination of established aerial baiting and subsequent ground-based hunting techniques will result in all rabbits being quickly removed from Robinson Crusoe Island

The risks of rabbits re-invading are near-zero

We are aware of pet rabbits being kept on Robinson Crusoe Island. Any pet rabbits in San Juan Bautista would not be part of the targeted rabbit population. Measures will need to be put in place before the eradication operation to ensure any pet rabbits were properly caged

A Juan Fernández Biosecurity Program should provide for either the prohibition of pet rabbits entirely, or measures through which all pet rabbits are de-sexed and properly caged. There are real risks that holding pet rabbits in captivity will eventually lead to escapees establishing wild populations.

Accidental introductions of rabbits to the archipelago are unlikely. Outreach and education programs focused on the benefits of having no rabbits in the archipelago, coupled with appropriate regulations to prohibit deliberate re-introductions will be required

Rabbits are relatively conspicuous (e.g. diggings, pellets). On-going surveillance should focus on areas of suitable habitat near likely re-introduction points


There is some scepticism among local residents and others with whom we met about the efficacy of using helicopters as part of eradications in the Juan Fernández Islands. This scepticism is understandable. Experience elsewhere has shown, however, that helicopters were a critical element in the success of many projects, especially on large and/or steep islands where access by other means is slow, difficult or dangerous. We suggest using helicopters is the only way prerequisites for success in most of the invasive vertebrate eradications recommended in this document can be satisfied. Information about eradications where helicopters have been used should be distributed amongst stakeholders, as well as DVDs showing their use could be shown. Arrangements could be made for local people to hear about the experiences of communities from other islands where helicopters have been used in eradication operations

Concerns about the use of toxins may be expressed. It will be important that legal



requirements, including for any assessment of anticipated environmental effects, are rigorously applied. Directions for use of any registered toxin are prescribed on product labels. Compliance with these directions should be stringently enforced

Specific concerns may also be expressed about the aerial distribution of baits and perceived risks associated with them falling in areas where they are not intended. It will be important that only helicopter operators with appropriate experience in eradication operations are involved, and that best-practice procedures for aerial bait application are rigorously applied. Experience suggests aerial baiting can be undertaken, which leads not only to successful eradication, but also meets environmental protection standards

As is the case with all vertebrate pest management activities, the consistent application of appropriate standards of humaneness and animal welfare will be important

We are not aware of any concerns within the local community about the eradication of rabbits from Robinson Crusoe Island. We would expect the prospect of involvement and employment of local people in the rabbit eradication operation to be favourably received in the San Juan Bautista community

Institutional support is declared and maintained for the eradication, and its outcomes

See Table 12

Benefits outweigh costs See Table 12


It seems there is general recognition in the local community that rabbits are a major pest on

Robinson Crusoe Island. Several people expressed their concerns that rabbits were competing

with cattle for food. It was suggested to us that removing the rabbits would allow more cattle

to be grazed. Previous successes make it likely that international funding institutions may be

interested in supporting rabbit eradication here as part of an integrated restoration program

where important ecological outcomes are anticipated.


HIGH

Explanation: All criteria for successful rabbit eradication can potentially be met using

existing approaches and techniques. Potential risks associated with Robinson Crusoe Island

being inhabited and the recommended aerial baiting operation (we understand for the first

time for conservation purposes in Chile) will need to be addressed.

9.1.3 Rodents

Ecology and impacts

Rodents have major impacts on island biodiversity (Moller 1983; Towns et al. 2006; Howald

et al. 2007). Where studies have been undertaken it is clear this is also the case in the Juan



Fernández Archipelago. For example, rodents are thought to suppress native plant

regeneration through seed predation (Muñoz Pedreros et al. 2003), and to facilitate the spread

of invasive plants by dispersing their seeds (CONAF/JFIC unpublished data). Rodents also

prey upon endemic birds including the critically endangered Juan Fernández firecrown

(Mann 1975; G. Araya/CONAF unpublished data), pink-footed shearwaters (Hahn & Römer

2002), and Juan Fernández and Stejneger’s petrels (P. Hodum unpublished data). In a study

using artificial eggs Tomasevic et al. (2007) found that rodents are also likely to prey on eggs

of the critically endangered Másafuera rayadito. Rodents probably also support populations

of feral cats by providing a source of prey for them (e.g. Courchamp et al. 1999a). Rodents

also have important social and economic impacts such as food spoilage (Hahn & Römer

2002), damage to crops, gardens and infrastructure, and disease transmission (Singleton et al.

1999). Three species of rodents occur in the archipelago: Norway rats (Rattus norvegicus),

ship rats (Rattus rattus) and house mice (Mus musculus). The latter two are listed among the

world’s worst invasive species (Lowe et al. 2000).

Management options

Do nothing: Measures to control rodents have been in place for many years in the

archipelago. Rodenticides, including the second-generation anticoagulant brodifacoum,

continue to be used around and inside buildings on both Robinson Crusoe and

Alejandro Selkirk Islands. It is possible other toxins are also used. Rat traps have also

been used. Based on this history of rodent control, doing nothing is unlikely to be an

acceptable option to local residents.

Sustained control: Achieving and sustaining rodent control presents major challenges.

Rodents are present virtually anywhere occupied by people. They are able to adapt

quickly to new environments and exploit available food resources. They are also

prolific breeders. In most cases toxic baits are regularly laid to minimise rodent impacts

around key resources such as food and dining areas. While on-going baiting programs

can be effective, there are risks of rodents becoming bait-shy or even toxin-resistant as

a result of prolonged, repetitive baiting. It was beyond the scope of this study to assess

the effectiveness of current rodent control on Robinson Crusoe or Alejandro Selkirk

Islands. Several people commented to us that rodents were a problem around San Juan

Bautista and Rada la Colonia, and we saw evidence of rodents in a number of places

during our visit. Improvements to current baiting strategies, perhaps including

coordinated and diversified baiting and trapping operations, coupled with refinements

to food protection and waste management practices could lead to significant

improvements.

Eradication: As pointed out in Section 5, where eradication is feasible it is almost

invariably the preferred management option, especially on islands where biosecurity

measures are generally more practicable. While further refinements are needed to

improve confidence in our ability to eradicate mice, rats and mice have been

successfully eradicated from a growing number of islands world-wide (Howald et al.

2007).

Biosecurity: Because of the wide range of invasion pathways rodents can use,

establishing and maintaining effective biosecurity measures to prevent their

establishment (or re-establishment) is challenging. Increasingly sophisticated rodent

biosecurity programs continue to emerge. Pre-requisites for successful rodent measures

on inhabited islands, such as Robinson Crusoe and Alejandro Selkirk, include high



levels of community awareness and support. The isolation of the Juan Fernández

Archipelago from the Chilean mainland, and the separation between Robinson Crusoe

and Alejandro Selkirk Islands constitute important attributes. The small number of

rodent eradications undertaken on inhabited islands to date means there are few

precedents upon which community education and involvement activities may be based.


Eradicate rats and mice from Robinson Crusoe and Alejandro Selkirk Islands and maintain

biosecurity measures to minimise the risks of their re-establishing in the archipelago.

Eradication should be carried out by a team of specialists, in collaboration with CONAF and

the Municipality. Biosecurity measures should be developed and enforced by Chilean

government agencies (e.g. CONAF, SAG) and the Municipality.


Increased survival and recruitment of native plants, large invertebrates and birds,

leading to population increases and, eventually, down-grading and perhaps de-listing of

species with IUCN threat categories.

Following the removal of other key invasive species (e.g. feral cats, rabbits and feral

goats) in addition to rodents, opportunities created to recover threatened species and

habitats, and to restore biological communities in the archipelago.

Improved food security, increased garden production, and less general inconvenience

around residential areas as a result of rodents being removed. Cost savings from

removal of rodent impacts and from stopping on-going control regimes.

Better understanding of rodent interactions and impacts, and improved capacity to

eradicate rodents along with rabbits and feral cats, as part of a single program (See

Section 9.1.2).

Reduced egg and chick predation, leading to increased survival of threatened birds.

Reduced human health risk.

Some costs and inconvenience will be incurred by local residents in maintaining

biosecurity measures for rodents and other invasive species.


It is recommended that the eradication of rodents (ship rats, Norway rats and house mice)

from both Robinson Crusoe and Alejandro Selkirk Islands should proceed in conjunction

with the eradication of rabbits and feral cats. All three operations would involve the aerial

application of toxic baits from a helicopter with an under-slung bait bucket. Provided

sufficient quantities of an appropriate bait and toxin are applied, it can be anticipated that all

the rodents will be eradicated following up to three applications of bait across both islands.

Initial knock-downs of rabbits and feral cats can be expected as a result of an aerial baiting

operation initially focused on eradicating the rodents (Section 9.1.2).

Detailed planning to eradicate the rodents from Robinson Crusoe and Alejandro Selkirk

Islands could be based on operational plans developed for similar operations undertaken



successfully elsewhere. Existing best-practice procedures for aerial baiting should also be

adapted as necessary and applied. Four important features will need to be considered in

relation to spreading baits for rodents. First, there are steep, eroded cliffs – especially around

the coasts – as well as a few offshore islets and rock stacks at both islands. Rodents are likely

to inhabit cliff areas and rock stacks, meaning that baits will need to be applied at these sites.

Aerial baiting techniques successfully developed on other islands with cliffs and stacks

should be employed here. Second, there is a permanent town (San Juan Bautista) on

Robinson Crusoe Island, and the seasonally inhabited settlement of Rada la Colonia on

Alejandro Selkirk Island. Residential areas on both islands should be excluded from aerial

baiting operations. Instead, best practice involves ground-based baiting and trapping in and

around habitations before and during the aerial baiting operation to ensure all rodents are

exposed to either baits or traps. Third, other species are being targeted simultaneously and

may consume significant amounts of bait that may cause gaps in coverage. To be able to

target all species effectively, bait uptake trials will be required to determine required baiting

rates. Fourth, domestic stock (cattle, horses, chickens) will need to be confined or temporarily

removed from the island. They may act as major bait consumers as baiting is likely to occur

at a time of little available food. This could potentially pose both an operational risk and a

risk to those consuming animal products (especially liver, other internal organs and perhaps

milk or chicken eggs).

Flight lines

Figure 16 Map of Isla San Pedro Martir showing helicopter flight lines to eradicate ship rats (Grupo

Ecología y Conservación de Islas, A.C.).



While detailed investigations should be undertaken into the availability and suitability of

different toxins, we suggest consideration should be given to using the second generation

anticoagulant brodifacoum as the preferred toxin to achieve rodent eradication in the

archipelago. Although first generation toxins such as diphacinone may also be effective, and

present lower risk to non-target species. However, the requirement for rodents to eat multiple

doses of baits constitutes a significant operational risk (Parkes & Fisher 2011). Detailed

consideration will need to be given to the toxin or toxins to be used. A cereal-based bait is

recommended that does not contain bitrex, a bittering agent used to stop children ingesting

baits. Bitrex in baits is responsible for several rodent eradication failures in New Zealand. As

there are currently no baits in Chile that are registered with these properties, bait registration

will be required before these projects can occur. The current use of brodifacoum for rodent

control in San Juan Bautista, Rada la Colonia and within the national park should stop as

soon as possible and be replaced by alternative toxins and/or trapping. This will reduce the

risk of rodents developing tolerance or bait shyness towards brodifacoum, which could

jeopardise the eradication effort.

Once rodent eradication is confirmed, on-going surveillance and biosecurity measures should

be undertaken as part of a comprehensive Juan Fernández Archipelago Biosecurity Program.

Table 15 Possible techniques for eradicating rodents.


Aerial baiting Aerial bait spreading using a helicopter and under-slung bucket is the only way that toxic baits may be distributed quickly and reliably to every potential rat and mouse home range on Robinson Crusoe and Alejandro Selkirk Islands

Aerial baiting has been successfully used as the sole tool in a growing number of rodent eradications around the world (45 eradications on 33 islands to date; Island Conservation 2010). Provided best-practice procedures are rigorously applied the eradication of all rats from both islands can be anticipated. The eradication of mice is more problematic. Before 2007, 19% of mouse eradications failed, possibly due to inadequate density of bait distribution (Howald et al. 2007) and/or behavioural differences in foraging between rats and mice (Macdonald & Fenn 1994). The implications of rats being eradicated, but not mice, will need to be considered as part of the risk assessment process

Helicopter operators experienced in aerial rodent eradication operations are available to ensure bait distribution performance measures are met

Timing of an aerial baiting operation should ideally coincide with periods of low food availability for rodents and rabbits, and the non-breeding season for seabirds. It was suggested to us that any aerial operation involving low-flying helicopters should also avoid hummingbird nesting habitats during their breeding season, due to disturbance risks. Further investigations may be required to determine optimal timing for an aerial baiting operation when the prospects of bait-take by target species are highest, and risks to non-target species are lowest. Timing should also coincide with suitable weather conditions

We suggest brodifacoum is the toxin of choice for this operation. Not only has it been used many times to successfully eradicate rodents from islands, its use here could also be expected to lead to initial knock-downs of rabbits (80–95%) and feral cats (20–40% if rabbits present, 80–90% if just rodents) through direct bait-take by rabbits, and through secondary poisoning of feral cats that eat poisoned rodents or rabbits. The environmental effects of using this second-generation anticoagulant, including any risks to humans and non-target species, should be carefully evaluated. We note that brodifacoum, along with other toxins, has been used extensively in San Juan Bautista



and, we understand, on Alejandro Selkirk Island

Non-target risk assessments and possibly trials will be needed to quantify risks to potential non-target species (particularly land-birds) and direct mitigation measures

Ground-based baiting and trapping

Rodents have been eradicated from relatively few inhabited islands to date. Best-practice procedures are still evolving for treating residential areas and other places where people, pets and domestic livestock are present. In principle, these areas should be excluded from aerial baiting zones in order to avoid a range of associated risks and costs. Instead, they are treated using ground-based techniques (e.g. presenting baits in bait stations, hand-laying baits, or using traps)

A ground-based program of baiting and trapping should be initiated in areas set aside from aerial baiting prior to, and during the aerial baiting operation. Many residents of San Juan Bautista appear comfortable with toxins, including brodifacoum, being used around their homes. We expect there would be strong support for ground-based baiting and trapping as part of a rodent eradication operation, especially if successful eradication meant they would not have to continue with rodent control measures into the future


Previous eradication attempts for mice have been less successful than those for rats.

Operational planning should include measures to increase the likelihood that all mice will be

removed, but should also consider the potential implications should mice remain after rats

have been eradicated. For example, it is possible that mice could increase in abundance in the

absence of competition from rats (e.g. Ruscoe et al. 2008).

It has been suggested that the presence of ship rats may alter the behaviour of mice, possibly

making their eradication more difficult. The size and palatability of baits may also influence

their consumption by mice (Parkes 2008). Factors such as this will need to be considered in

planning for the simultaneous eradication of mice and rats.

Másafuera hawks are known to eat rodents and carrion (Hagen 2010), and will be at high risk

of poisoning during bait applications for rodent eradication using brodifacoum. Other native

species such as short-eared owls and American kestrels will also be at risk. Mitigation actions

will be required to safeguard populations of these species. On other projects hawks have been

captured and held temporarily in captivity until rodent carcasses have degraded. Risks to

insectivorous birds are related to the insects that feed on bait and the feeding ecology of the

birds. Risks for insectivores vary. As small populations of island-endemic and archipelago-

endemic insectivorous birds are present, multiple mitigation strategies may be required to

safeguard populations. Risk assessments will be needed for each island and should be

completed prior to operational planning for rodent eradication. If required, mitigation plans

should be prepared for each species.

Other risks associated with a toxic baiting program targeting rabbits, rodents and cats are

discussed in Section 9.1.2.



Table 16 Satisfying the requirements to eradicate rodents from Robinson Crusoe and Alejandro Selkirk

Islands.


All individuals of the targeted rodent populations are put at risk by the techniques employed

Aerial baiting using established procedures is expected to remove all rodents, except in San Juan Bautista and its environs

A growing number of successful rodent eradications involving aerial baiting have led to increasing confidence in this approach, provided best-practice procedures are rigorously applied

Residential areas and their environs, and possibly other areas where livestock are confined should be excluded from aerial baiting zones. There is a possibility rodents living in these exclusion zones will not be put at risk by the techniques employed unless special care is taken in designing and applying ground-based regimes in these areas. Baiting and trapping in and around private residences may be problematic. Any exclusions could potentially jeopardise the entire eradication

We understand major changes are planned to improve waste management procedures, including the way the refuse tip is managed. These changes will be important if rodents are to be eradicated. It would be difficult to eradicate rodents from the current tip

Successful eradication from residential areas will require a high level of community support and compliance. There are few precedents of rodent eradications from inhabited islands. Risks associated with addressing any community concerns will need to be carefully considered.

Previous eradication attempts for mice have had a lower success rate than those for rats. Application of a higher density of baits (and perhaps additional bait applications) may be required to ensure all mice are put at risk

Rodents are removed faster than they can breed, at all densities

Aerial baiting involving up to three applications of bait approximately 10 days apart using established best practice, undertaken at a time of year when rodents are most likely to consume baits can be expected to kill all rodents, including any young

The risks of rodents re-invading are near-zero

Rodents are excellent dispersers capable of using a wide range of invasion pathways. Best practices in rodent biosecurity are still evolving, and there are risks that rodents may reach one more islands in the archipelago following eradication. In addition to quarantine procedures to minimise the risks of rodents reaching the islands, surveillance measures will need to be rigorously maintained to ensure any rodents which do arrive are quickly detected and removed before a new population is established. Consistent commitment to maintaining biosecurity programs, and community support for quarantine measures will be required if risks of rodents re-invading are to be kept to acceptable levels. Outreach and education programs focused on the benefits of having no rodents in the archipelago will be needed to reinforce community support

A Juan Fernández Biosecurity Program should include detailed quarantine measures, as well as surveillance and ‘rapid response’ provisions in the event that new incursions are detected

Advances continue to be made in understanding how rodents behave on arriving at a new island. Detection devices and tools to remove new arrivals are being developed


Possible scepticism about the use of helicopters in the eradication operation – See Table 12

Concerns about the use of toxins – See Table 12

Possible concerns about the aerial distribution of toxic baits – See Table 12



We expect there to be strong community support for the eradication of rodents, given the range of impacts they have and the costs and inconvenience of on-going control activities. We would expect the prospect of involvement and employment of local people in ground-baiting operations would be favourably received in the community


See Table 12



Rodents are recognised as an important pest in the Juan Fernández Archipelago. In addition

to their impacts on biodiversity, they are also a threat to human health. It is hoped that

support will be forthcoming from management agencies and donor organisations for their

eradication.


MODERATE–HIGH (rats); MODERATE (mice)

Explanation: All requirements to successfully eradicate rats can potentially be met using

existing approaches and tools. Special attention will need to be paid, however, to ensuring

appropriate bait coverage on cliffs and offshore islets and rock stacks. Risks associated with

applying ground-based methods within aerial baiting exclusion zones so that all rats and mice

are eradicated will also need to be carefully managed. Further investigations may be required

to evaluate the risks that mice will not be eradicated, and to consider any new approaches or

techniques which might be used to reduce these risks. This might include consideration of the

prospect and implications of mice remaining on one or both islands, in the absence of rats.

There are also risks that rodent biosecurity measures may not be effective and rodents may

re-establish on one or more islands in the archipelago. While the risks of re-invasion will

never be zero, new techniques are emerging and confidence in the consistent application of

appropriate measures is growing.

9.1.4 Feral cat

Ecology and impacts

Depending on their degree of association with humans, cats can be classified as domestic,

stray or feral (Moodie 1995). Although all three categories belong to the same species (Felis

catus), there are important differences in their behaviour and ecology. Domestic cats live in

close association with humans, who provide all their needs for survival. These cats often hunt

live prey, but do not need to do so to survive. Stray cats generally live around human

settlements where they obtain some resources such as food or shelter, but are not owned by

humans. Feral cats live in the wild, forming breeding populations that are not dependant on

humans (Moodie 1995). Both feral and domestic cats are present in the Juan Fernández



Archipelago, and different management objectives will be required for each. Stray cats may

also be present in San Juan Bautista (Robinson Crusoe) and Rada la Colonia (Alejandro

Selkirk). Domestic and stray cats are already being managed as part of an on-going project

(see below).

Feral cats are listed as one of the world’s worst invasive species (Lowe et al. 2000), and have

had catastrophic impacts on island faunas around the world (e.g. Courchamp et al. 1999b;

Burbidge & Manly 2002; Nogales et al. 2004; Hansen et al. 2007). In the Juan Fernández

Archipelago, they are known to prey on native birds, including pink-footed shearwaters, Juan

Fernández and Stejneger’s petrels and the critically endangered Juan Fernández firecrown

(Mann 1975; Colwell 1989; Hahn & Römer 2002; CONAF and E. Hagen unpublished data).

They are also considered a threat to the critically endangered Másafuera rayadito (Hahn &

Römer 2002).

When available, petrels are probably the main prey of cats in the Juan Fernández, but these

birds are absent during winter. During this time cats are often seen searching for carrion on

the shores (Hahn & Römer 2002). Although feral cats are usually considered to be generalist

predators, some individual cats develop specialised hunting behaviours, targeting specific

prey (e.g. Dickman 2008). In this way a small number of cats can have disproportionate

impacts on particular species. We are not aware of any population studies of cats in the Juan

Fernández Archipelago, but they are reported to be numerous (e.g. Mann 1975). This is

consistent with our observations of cat scats in a number of places on Robinson Crusoe

Island.

Figure 17 A pink-footed shearwater killed by a feral cat on Robinson Crusoe Island.



Previous management

Feral cats are subject to opportunistic hunting within the national park, with an average of

around five animals killed each year. This has occurred at least since the start of the Holland

Project in 1998 (R. Schiller, pers. comm.). In addition, there are a number of on-going

measures to reduce the population of domestic and stray cats in San Juan Bautista. Since

2005 AvesChile, the Corporación Cultural de Juan Fernández and the Municipality have

coordinated a program of sterilisation for pet cats. This has resulted in a high percentage of

pet cats being de-sexed, although a small number of residents have not been willing to have

their cats sterilised (JFIC unpublished data). Since 2008 a community working group, in

collaboration with the Juan Fernández Islands Conservancy (JFIC), AvesChile, CONAF and

the local health clinic has established a registry of pet cats in San Juan Bautista and provided

collars to identify the cats that have owners. In addition, an average of 30 cats per year have

been voluntarily submitted for euthanasia, bringing about a substantial reduction in the

number of registered cats (Hagen & Hodum 2008; Hagen 2009). Promoting the registration

and responsible ownership of pets is identified as a priority in the management plan for the

national park (CONAF 2009). However, there are no restrictions on bringing new cats to the

island and some residents continue to do so (JFIC unpublished data).

Management options

Do nothing: If cats are not managed they will continue to prey on native fauna

including nesting seabirds and forest birds on Robinson Crusoe and Alejandro Selkirk

Islands. Experience elsewhere suggests their impacts will lead to further declines and

perhaps extinctions of species such as the Juan Fernández firecrown and the Másafuera

rayadito.

Sustained control: Achieving and sustaining control to minimise cat impacts presents

major challenges. Feral cats are typically solitary, nocturnal hunters. Experience has

shown that individual cats can be trap-shy and extremely difficult to catch. While

sustained cat control programs at defined sites such as seabird breeding colonies can be

effective, the attributes of cats outlined above, and challenges in sustaining control

programs in the long term, mean that sustained control is generally not the preferred

management option when eradication is feasible.

Eradication: As pointed out in Section 5, where eradication is feasible it is almost

invariably the preferred management option, especially on islands where biosecurity

measures are generally more practicable. Feral cats have been successfully eradicated

from over 100 islands world-wide (Island Conservation 2010) (see also Nogales et al.

2004; Campbell et al. 2011). A range of possible eradication objectives might include:

The eradication of all cats from the archipelago. This would involve the removal

of all stray and feral cats from Robinson Crusoe and Alejandro Selkirk Islands,

and a gradual phasing out of pet cats in San Juan Bautista through a policy of

de-sexing pet cats, not replacing them as they die naturally and prohibiting

importation of cats into the archipelago (recommended objective).

Eradication of stray and feral cats from Alejandro Selkirk and Robinson Crusoe

Islands, while allowing de-sexed pet cats to be kept by San Juan Bautista

residents. Cats could be imported only if de-sexed.



Eradication of all cats from Alejandro Selkirk Island and sustained control at

key sites (e.g. seabird breeding colonies) on Robinson Crusoe Island.

Biosecurity: Cats are typically introduced to new islands deliberately rather than

inadvertently. Provided there was community support for cat-free islands, biosecurity

measures should not be difficult to apply. In addition to education and outreach

programs that would focus on the benefits of being cat-free, regulations will be required

to control or prohibit the introduction of additional cats.


Eradication of stray and feral cats from Robinson Crusoe and Alejandro Selkirk Islands, only

after all pet cats in San Juan Bautista have been sterilised and implanted with a microchip for

identification. Ideally, pet cats should not be replaced when they die naturally, so that the

archipelago will eventually become cat-free. Regulations to prohibit importation of cats (and

enforcement of those regulations) will be required. If this is not acceptable to the community,

then any newly imported cats must be sterilised. Otherwise the eradication of feral cats

should not be attempted as the presence of un-sterilised pet cats would present an

unacceptable risk of re-establishment of a feral population. Eradication should be carried out

by a team of specialists, in collaboration with CONAF and the Municipality. The

Municipality should take a lead role in fostering community support and implementing

measures dealing with domestic cats.


Increased survival and recruitment of native birds, as well as large invertebrates,


bird species with IUCN threat categories.

Following the removal of other key invasive species in addition to feral cats (e.g.

rodents, rabbits and goats), opportunities will be created to recover threatened species

(including the Juan Fernández firecrown and pink-footed shearwater) and habitats, and

to restore biological communities in the archipelago.

Following the eradication of rodents and feral cats, we would expect local residents to

notice increases in bird numbers within a short time.

Opportunities can be anticipated to expand eco-tourism in the archipelago following the

removal of key predators and competitors, perhaps focusing on island endemics such as

the firecrown.

Opportunities may be created for recolonisation by extirpated species, e.g. seabirds

restricted to offshore stacks.

Reduced risk of human diseases such as cat-scratch fever, which occurs commonly in

San Juan Bautista.


A range of techniques have been developed and effectively applied as part of feral cat

eradication operations around the world (Island Conservation 2010; Campbell et al. 2011).



These include the distribution of toxic baits, trapping, hunting with trained dogs, fumigation

and shooting. We recommend feral cats should be eradicated from both Robinson Crusoe and

Alejandro Selkirk Islands as part of a sequence of synergistic operations targeting rabbits and

rodents, as well as cats. These campaigns are likely to involve the aerial application of toxic

baits from a helicopter (Section 9.1.2). Experience from other eradication operations suggests

a large proportion of the feral cat population may die after eating rodents (80–95%) or rabbits

(20–40%) that have consumed baits (e.g. Alterio 1996; Norbury & McGlinchy 1996; Gillies

2001). Initial knock-down of feral cats through this secondary poisoning effect, coupled with

a reduction in their food supply following the removal of rabbits and rodents, would present

an opportunity to eradicate the feral cats. Follow-up measures to complete the cat eradication

may involve the aerial application of baits containing newly-developed formulations of the

toxin PAPP (para-aminopropiophenone) as well as trapping, hunting with trained dogs and

shooting. On Robinson Crusoe Island a smaller knock-down effect on feral cats (20–40%) is

anticipated due to the presence of rabbits. When cats consume rabbits they eat only muscle

and therefore are exposed to less toxicant. When just rodents are present (e.g. Alejandro

Selkirk Island) larger knock-downs (80–95%) can be expected as cats consume rodents

whole, including the viscera, which is where brodifacoum is typically concentrated. On

Robinson Crusoe Island, after rodent eradication, surviving cats can be expected to target the

remaining rabbits (and any seabirds present). Timing of an application of cat baits and any

trapping or follow-up efforts would ideally take this into account. Baiting would need to

occur before seabirds return to nest, to mitigate any potential impacts on them by hungry cats.

The use of toxic baits would require registration with SAG as there are currently no feral cat

baits or toxicants registered for use in Chile.

Once eradication of the feral cats from Robinson Crusoe and Alejandro Selkirk Islands has

been confirmed, on-going surveillance and biosecurity measures should be undertaken as part

of a comprehensive Juan Fernández Archipelago Biosecurity Program.

Table 17 Possible techniques for eradicating feral cats.


Aerial and ground baiting

The aerial distribution of baits (Section 9.1.2) can be expected to achieve an initial knock-down of feral cats through secondary poisoning (i.e. feral cats eating rodents and rabbits which have consumed rodenticide)

There may potential to use a newly-developed toxin (PAPP), either as the initial knock-down tool, or as a follow-up technique following aerial application of a rodenticide. However, the toxin will first need to be registered for use. Field trials on Robinson Crusoe and Alejandro Selkirk Islands will be needed to assess non-target risks, confirm bait-take by feral cats, and the efficacy of the toxin in this environment

Cat baits can be laid either by helicopter for covering large and/or inaccessible areas quickly, or from the ground for smaller areas and spot baiting specific areas

Trapping

Trapping has been used as the primary tool in most feral cat eradication and sustained control operations (Island Conservation 2010). Various traps have been used successfully and humanely, and a pool of experienced cat trappers is available to provide advice and support to any feral cat eradication operations in the archipelago if required

Use of helicopters for moving trappers is likely to be more cost-effective than a ground-based program in the terrain to be covered, especially when combined with other work



Protocols and procedures will be needed to ensure any trapping (or hunting – see below) in the vicinity of San Juan Bautista does not lead to any pet cats being inadvertently destroyed. The use of cage traps in and near town, in combination with electronic marking of pet cats, should ensure this risk is appropriately managed

Hunting using trained dogs

The use of trained dogs to indicate the presence of feral cats has emerged as a key tool. A small team of trained dogs operated by experienced handlers can constitute a major improvement to trapping and hunting regimes

Dogs can be particularly valuable in ‘Mop-up’ and ‘Confirmation’ phases of cat eradication projects where very few cats may persist.

Shooting Shooting by experienced operators can also be an important tool in cat eradication projects

Electronic devices such as image intensifiers and remote infra-red camera traps, as well as new lures are becoming available and improving our ability to detect any remaining cats

Fumigant Cats are highly sensitive to phosphine gas, and the use of fumigants is useful for cats that have been tracked to dens or seek refuge there from hunters


The fact that Robinson Crusoe Island is inhabited and that some residents have pet cats are

important aspects that will need to be taken into account if feral cat eradication is to be

contemplated. As companion animals, cats have a special relationship with people. Some

people feel very strongly about cats, whether domestic or feral, and will object to any

proposal to destroy them. Other people separate pets from feral cats, and are more pragmatic

about managing feral populations. The views of residents of San Juan Bautista will need to be

sought before any detailed planning to eradicate feral cats from the archipelago. Management

options, including total cat eradication from the archipelago, eventual eradication following a

phase-out period for pet cats, or eradication from Alejandro Selkirk Island and sustained

control on Robinson Crusoe Island, will need to be discussed within the community, as will

details and implications of the various techniques that are available. It will be important that

any concerns are openly discussed and agreement reached on how any issues arising from the

community may be addressed.

Provided pre-requisites for success are satisfied and best practice procedures are applied, we

suggest feral cat eradication could be initiated with some confidence of success. However,

two key risks will need to be managed. The first involves the added complexity in

undertaking a multi-species operation (i.e. focused on eradicating rodents and rabbits, as well

as feral cats). The second relates to the continued presence of domestic (pet) cats, and

perhaps some stray cats, in San Juan Bautista. The presence of any domestic or stray cats

with the ability to breed on Robinson Crusoe Island represents an unacceptably high risk of

re-invasion. Cat eradication should not be attempted if pets are capable of reproducing or if

the importation of cats has not been restricted at least to de-sexed cats. Community

agreement to measures to manage this re-invasion risk, and linking the de-sexing program in

San Juan Bautista with the wider feral cat eradication program, will clearly be important.



Table 18 Satisfying the requirements to eradicate feral cats from Robinson Crusoe and Alejandro Selkirk

Islands


All individuals of the feral cat population are put at risk by the techniques employed

The aerial distribution of a second-generation anticoagulant such as brodifacoum can be expected to provide an ‘initial knock-down’ of feral cats through secondary poisoning

Residential areas and their environs, and possibly other areas where livestock are present, should be excluded from aerial baiting zones. There is a risk that feral cats living in these exclusion zones will not be put at risk by the techniques employed unless special care is taken in designing and applying ground-based regimes in these areas. Baiting and trapping in and around private residences may be problematic. Any exclusions could potentially jeopardise the entire eradication

Aerial baiting, trapping, hunting with trained dogs and shooting by highly trained hunters with dogs should be used to mop up remaining feral cats, and to aid in confirming a successful eradication

Feral cats are removed faster than they can breed, at all densities

Initial knock-down using the aerial distribution of toxic baits, followed by trapping, hunting and shooting, can be expected to remove most feral cats within a few months. Efficacy in removing the last few individuals will depend on a number of factors including institutional support and hunter commitment, the consistent application and refinement of effective techniques and the ability to detect, locate and remove remaining feral cats

The risks of feral cats re-invading are near-zero

Cats typically reach new islands through deliberate introductions by people. While it is possible that cats may reach one of the Juan Fernández Islands by leaving a ship, this is unlikely and can be provided for in a biosecurity strategy

A more likely source of re-invasion, particularly on Robinson Crusoe Island, is the establishment in the wild of pet cats, or their progeny. Pet cats are typically the source of most feral cat populations on islands around the world. It will therefore be essential to secure the support of island residents, and cat owners in particular, to an agreed cat management strategy, and for associated management techniques. Only with strong community support could the risk of cats re-invading be considered ‘near-zero’

Outreach and education programs focused on the benefits of having no feral cats in the archipelago will be needed to reinforce community support. The prospects of economic benefits through the development of eco-tourism ventures focused on recovering native plants and animals following the removal of cats are also likely to strengthen community support for eradication of feral cats and other invasive species


Because the eradication of feral cats will involve a variety of aerial and ground-based approaches, it will be important that the community and other stakeholders (e.g. management agencies, donor organisations) are consulted during the planning process and their views and suggestions in relation to proposed techniques (e.g. aerial distribution of toxic baits) are incorporated

As with other eradication operations recommended in this report, we suggest local people should be employed to undertake as many tasks as possible. This will require detailed training and comprehensive support if staff with the necessary skills and motivation are to be retained

Efforts are already being taken to reduce the impacts of pet cats within San Juan Bautista, and to minimise recruitment to the feral population by de-sexing pet cats. The high level of participation by San Juan Bautista residents for the cat de-sexing program indicates there may be strong community support for eradication of the feral cat population




See Table 12



The impacts of cats are clearly recognised, as illustrated by the considerable efforts that are

already being made by a number of organisations to reduce the number of pet and stray cats

in San Juan Bautista. It is likely that institutional and donor support will be forthcoming for

the eradication of stray and feral cats, provided the issues of pet cats and their importation are

dealt with appropriately.


MODERATE–HIGH: Robinson Crusoe Island

Explanation: While a range of proven techniques are available that could potentially be

applied on both islands, the presence of domestic and stray cats in San Juan Bautista

constitutes an unknown risk that the requirement for ‘near-zero’ re-invasion risk may not be

satisfied. Our impression from talking with local residents is that there would be support for

the eradication of feral cats from Robinson Crusoe Island provided safeguards were in place

to ensure the safety of pet cats in the town. While these safeguards may present additional

risk to the project overall, we believe these risks could be managed, although there are few

precedents for this. Risks of domestic cats establishing a new feral population on Robinson

Crusoe following an eradication would vary depending on whether there was agreement to a

strategic goal that pet cats would only be permitted for a finite period, after which the entire

archipelago would be cat-free, or that pet cats were to be allowed indefinitely.

HIGH: Alejandro Selkirk Island

Explanation: There are sufficient precedents for the successful eradication of feral cats, and

sufficient people with the experience and skills necessary to advise and assist if required, to

be able to initiate the eradication of feral cats as part of a multi-species eradication operation

here with some confidence. Local residents have kept cats on Alejandro Selkirk Island in the

past, either as pets or to control rodents. JFIC, CONAF and the Fishermen’s Association have

been working towards a policy of voluntarily excluding domestic cats from Alejandro Selkirk

Island. In 2009 only one cat owner chose to bring their cat with them to the island. It seems

likely therefore that there would be strong community support for feral cat eradication on

Alejandro Selkirk Island, especially if rodents are also to be eradicated.



9.1.5 Coati

Ecology and impacts

Coatis are omnivorous animals native to mainland Latin America. They were introduced to

Robinson Crusoe Island in 1935 (Gompper & Decker 1998). Their diet generally consists of

invertebrates and fruit, supplemented by vertebrates (including carrion) when available. On

Robinson Crusoe Island they have been recorded to eat snails, insects, spiders, larvae, four-

eyed frogs and fruit, as well as the eggs, chicks and adults of various birds including pink-

footed shearwaters (Mann 1975). They have been implicated in the declines of the Juan

Fernández firecrown and pink-footed shearwater (Mann 1975; Colwell 1989; Gompper &

Decker 1998; Muñoz Pedreros et al. 2003). On one occasion, a single coati is reported to

have killed over 30 pink-footed shearwaters in one night (Bourne et al. 1992). Although they

prey on birds, coatis were not considered by Mann (1975) to be significant predators of

rodents or rabbits.

The digging behaviour of coatis is thought to have negative impacts on native vegetation and

to contribute to accelerated erosion (Sanders et al. 1982; Muñoz Pedreros et al. 2003). Coatis

are considered potential vectors of diseases such as tuberculosis, canine distemper and

Leptospira (Gompper & Decker 1998). Because they eat the fruits of invasive plants such as

blackberry and maqui (Mann 1975) coatis may also act as seed vectors for these plants.

Because of their impacts on native species Mann (1975) recommended the prompt

eradication of coatis from Robinson Crusoe Island.

Previous management

During the Holland Project control of coatis was incorporated into the rabbit control program,

with bounties being paid to hunters for coati tails. Opportunistic control measures continue,

although currently less than 20 coatis are killed each year (R. Schiller, pers. comm.).

Management options

Do nothing: Coatis will continue to damage natural values on Robinson Crusoe Island

through predation of native fauna, disturbance to native vegetation and consequent soil

erosion. They may also present a disease risk to humans and pets. If eradication efforts

target other invasive vertebrates, but not coati, the response of the coati population is

difficult to predict. Removal of potential competitors such as feral cats could cause

coatis to increase in abundance. Removal of rodents could also release coatis from

competition for prey taken by rodents, such as invertebrates. This option is hard to

envision in practice, as coati are likely bait consumers and would be controlled during

eradication of other species.

Sustained control: Coatis are currently subject to a low level of on-going control effort.

A continuation of this approach may maintain the perceived limited abundance and

distribution of this species. However, they will continue to have localised impacts and

present a potential disease risk. On-going control would require an indefinite

commitment of resources and labour.



Eradication: As coatis are native to most of their current distribution we are not aware

of any precedent for eradication of this species. However, we anticipate that eradication

would be achievable using a range of hunting and trapping techniques. We suggest an

experimental approach should be taken, with associated monitoring to ensure

techniques may be refined and improved as the operation proceeds. Eradication would

offer long-term freedom from coati impacts.

Biosecurity: We are unaware of any introductions of coati to islands apart from

Robinson Crusoe, where they were introduced deliberately. It is therefore very unlikely

that coatis would be re-introduced following eradication, either deliberately or

accidentally. It is also unlikely that coatis would be transferred from Robinson Crusoe

to other islands within the archipelago. However, comprehensive biosecurity

regulations will be required to prevent further introductions. These regulations should

also prohibit the transport of coatis between islands.


Experimental eradication of coatis from Robinson Crusoe Island by a team of eradication

specialists and trained local hunters, in collaboration with CONAF and the Municipality.


Increased survival and recruitment of native plants, large invertebrates and birds,


species with IUCN threat categories.

Reduced soil disturbance and erosion, including in seabird colonies.

Potential reduced disease risk for humans and pets.

Possible reduction in seed dispersal of invasive plants such as blackberry and maqui.

Early demonstration of the feasibility of eradicating invasive vertebrates from Robinson

Crusoe Island, resulting in likely support from the community, administrative agencies

and funding organisations for further eradications.

Increased technical and organisational capacity to perform eradications within the Juan

Fernández Archipelago.

Reduced complexity of later eradications due to the removal of a potentially-interacting

pest species.


It is recommended that the early eradication of coatis is undertaken using a range of

techniques, which will also be useful in subsequent eradications such as those of rabbits and

feral cats.



Table 19 Possible techniques for eradicating coatis from Robinson Crusoe Island.

Technique Explanation

Hunting using firearms and trained dogs

Being diurnal, gregarious and conspicuous (Gompper & Decker 1998), coatis are likely to be easily located and shot during the initial knock-down phase. Trained dogs may be useful in locating coatis, both during the day and also at night when they are resting in trees. Dogs may be particularly useful in locating solitary males, as they are presumably less conspicuous than females, which often live in large groups (Gompper & Decker 1998)

Trapping Traps are commonly used for control of raccoons (e.g. Hubert et al. 1996), which are close relatives of coatis. Similar techniques may be effective against coatis. The natural scent-marking behaviour of coatis involves anal gland secretions, possibly combined with urine (Gompper & Decker 1998). These may provide useful lures for trapping

Toxins Toxic baits can be highly effective in eradicating carnivores from islands (e.g. Phillips et al. 2005). However, there is no toxic bait currently registered for use on coati

Coatis will likely consume rodent bait and be killed. The rodent eradication could either act as an initial knockdown or as a final technique for any remnant animals depending upon timing of coati and rodent eradication campaigns

Judas animals Judas animals are effective on any social species. Individuals are captured, sterilised, fitted with radio telemetry collars, and released. They then associate with conspecifics. The Judas animals can be tracked down and any associating animals removed. This reduces search time for hunters to encounter remnant animals. The social behaviour of female coati may be exploited in this way


To our knowledge there is no precedent for either eradication or the sustained control of

coatis that could provide guidance for designing an eradication on Robinson Crusoe Island.

This will therefore be an experimental project with associated risks due to lack of prior

knowledge and proven techniques. However, techniques exist for control of the closely

related raccoon, which could be adapted for this operation. There seems to be support in the

community to remove coatis, with several having reportedly been shot by local residents. We

recommend an experimental coati eradication operation is initiated early in an integrated

invasive species management program to engage management agencies and local hunters,

and to build local eradication capacity that will benefit future operations.



Table 20 Satisfying the requirements to eradicate coatis from Robinson Crusoe Island.


All individuals of the coati population are put at risk by the techniques employed

Coatis are conspicuous animals and are therefore expected to be easily located by hunters, particularly using trained dogs

Trapping techniques have been developed for the closely-related raccoon which may be adapted for coatis

Coatis have relatively large home ranges (Gompper & Decker 1998), so it is unlikely that they will persist undetected in small areas inaccessible to hunters

The lack of precedent for coati eradication or control indicates some (probably small) risk of failure due to unforeseen difficulties. To mitigate this risk, an adaptive approach would be adopted, using expertise of experienced raccoon hunters and eradication practitioners, as well as local hunters

Coatis are removed faster than they can breed, at all densities

Coatis are usually (although not strictly) seasonal breeders, which commonly produce litters of 3–4 (maximum 7) young in captivity (Gompper & Decker 1998). They therefore have limited capacity for rapid breeding and it is likely mortality caused by hunting and trapping could exceed recruitment at all population densities

Judas animals can be expected to help remove remnant animals at a rate fast enough to exceed their recruitment potential at low densities

The risks of coatis re-invading are near-zero

Coatis reached Robinson Crusoe Island through a deliberate introduction in 1935 (Gompper & Decker 1998), and have not spread to the remainder of the archipelago. To our knowledge they have not become established on any other islands world-wide. Therefore, the risk of re-invasion following eradication is probably low

Outreach and education programs focused on the benefits of having no coati in the archipelago must garner support of island residents and coati owners. These programs coupled with appropriate regulations to prohibit deliberate reintroductions will be required


Hunting and trapping have been widely used against invasive vertebrates in the archipelago, including shooting of feral goats – and coatis. We therefore do not anticipate any resistance to the use of these techniques. It was suggested to us that there might be some reluctance to destroy all coatis captured. However, if community concerns are raised, the possibility of removing trapped coatis could be investigated, rather than euthanasing them


See Table 12


Eradication of coatis would have additional benefits as a training and capacity-building exercise, allowing local staff to develop important skills and experience in planning and implementing eradication operations before undertaking more complex eradications. These benefits would apply even in the event that coati eradication was unsuccessful

The eradication of coatis will not make it more difficult to eradicate any other invasive species, or have negative impacts on native species




Coatis have historically been targeted for control on Robinson Crusoe Island, indicating there

is likely to be support for their eradication. Donor support is likely to be forthcoming if coati

eradication is integrated with efforts to eradicate other species using similar techniques.


MODERATE

Explanation: All criteria for successful eradication of coati can potentially be met by using or

adapting existing techniques, which have been effective against species such as raccoons.

However, the lack of precedent for eradication or control of coatis introduces a degree of

uncertainty. As an intelligent species they have the ability to quickly learn to avoid removal

efforts.

9.2 Managing cattle

Cattle are not considered as an invasive species in the archipelago. They are valued as a

recreational resource for the annual rodeo on Robinson Crusoe Island, as an occasional

source of meat and, in the past, for family milk supplies. Cattle also have significant

environmental impacts in the archipelago which, in combination with other introduced

mammals, are leading to declines in biodiversity and are limiting restoration opportunities.

Balancing potentially conflicting cattle management objectives has been a sometimes

controversial feature of the management of the national park to date. We concluded that both

social and environmental objectives could be met provided there was agreement to achieve

both objectives, and a process that allowed all stakeholders to influence decisions about how

cattle should be managed. Indeed, without such a process we suggest it is unlikely any social

or environmental objectives will be achieved, or outcomes sustained from cattle management

activities. There is a prospect that if a cattle management plan could be put in place that was

supported by all stakeholders (i.e. cattle owners, the wider community and CONAF), that this

might be used as a model for resolving other conservation management issues in which the

Juan Fernández community has a stake.

We have recommended that a smaller herd of cattle be retained on Robinson Crusoe Island,

and managed in a much smaller area than is currently the case. This recommendation reflects

a compromise between the significant ecological effects of cattle, and the high social value

placed on them by the San Juan Bautista community. We concluded that the same

compromise (between ecological effects and social values) would be less appropriate on

Alejandro Selkirk Island because it would be much more difficult to manage a cattle herd on

an island which is uninhabited for several months each year. We have recommended that a

cattle management committee consisting of representatives of the main stakeholders be

established to oversee the preparation and implementation of a cattle management plan.



9.2.1 Cattle on Robinson Crusoe Island

Ecology and impacts

Cattle have been present in the Juan Fernández Archipelago since at least 1767, and possibly

since 1591 (Wester 1991). In combination with other herbivores, cattle have contributed to

the denudation of parts of Robinson Crusoe Island (Colwell 1989). This process continues.

They are having major detrimental impacts on Robinson Crusoe where they contribute to

forest fragmentation and are a major cause of accelerated erosion. Slopes are being eroded

down to thin soil or bare rock, which severely limits any potential for restoration. Although

the exact number of cattle on Robinson Crusoe is not known, it is clear it is many times larger

than the carrying capacity estimated by Cosio et al. (2003).

We observed extensive areas where accelerated erosion of shallow, friable soils was well

advanced (Figure 18). In some more accessible areas at lower elevations on Robinson Crusoe

Island, soil was virtually absent, leaving exposed rock. We would expect cattle to have

destroyed seabird burrows at some sites. Erosion at this scale is also likely to be a major

impediment to restoring plant communities.

Figure 18 Accelerated erosion on Robinson Crusoe Island.



Erosion on steep terrain such as this could also be expected to result in heavy sediment

loadings in watercourses during heavy rain, and consequent sediment deposition in coastal

areas around the islands. A discussion with a lobster fisherman in San Juan Bautista indicated

that coastal water is indeed discoloured by run-off during periods of rain, but that this clears

quickly as a result of winds and currents. Given the dependence of the Juan Fernández

economy on the inshore lobster fishery, we would expect run-off as a result of accelerated

erosion to be of some concern. Studies of lobster fisheries elsewhere have found that

sediment runoff can be harmful to the productivity of the fishery, depending on various

factors such as the particle size of the sediment and the rate at which it is carried away by

marine currents (Herrnkind et al. 1988; Booth 2001; Airoldi 2003).

Previous management

While the management plan includes provisions for managing the number and extent of the

cattle herd within the national park (CONAF 2009), these provisions are contingent on the

availability of sufficient resources. These provisions are not currently being implemented.

The Holland Project involved the erection of fences to exclude cattle from certain areas.

However, we observed cattle on both sides of fences, indicating that existing fences are not

an effective barrier. We also noted discontinuous fences, with gaps where cattle could easily

pass through. While fences can be an effective way of containing cattle, they require regular

checking and maintenance to ensure they remain stock-proof. Constructing stock-proof

fences on steep and rocky terrain, such as on Robinson Crusoe and Alejandro Selkirk Islands,

is problematic. Confining essentially feral cattle within fenced areas if food and water were in

short supply would be even more difficult. Maintaining good fences here would also require

regular commitments of labour and resources. We understand a fence has been erected to

protect a pink-footed shearwater breeding colony of a few hectares on Robinson Crusoe. We

do not know whether this has been effective, but would emphasise the need for ongoing

monitoring and maintenance if fences are to have any value in excluding livestock.

Exclosure experiments have shown that even after cattle removal other factors may delay the

recovery of pasture (Cuevas & Le Quesne 2006). This illustrates the importance of multi-

species management in which all introduced herbivores are taken into consideration, rather

than treating them in isolation. The current lack of plant recruitment is thought to be due to

the combined impacts of cattle and the high rabbit population, which have destroyed all of the

vegetation, resulting in large-scale erosion and conditions too harsh for natural revegetation

(Greimler et al. 2002). The evidence of cattle overgrazing has so far been too weak to

convince owners of the necessity to remove cattle or exclude them from forested areas

(Cuevas & Le Quesne 2006). However, the removal of cattle from most sectors has

previously been recommended as part of any long-term restoration strategy for the islands’

endemic ecosystems (Greimler et al. 2002). In other parts of the world cattle have been

shown to have significant impacts on native vegetation, soils and water quality through

browsing, grazing, soil compaction and disturbance (e.g. Belsky et al. 1999; Letnic 2004;

UNESCO 2008a). These impacts are often especially severe in and around fragmented forest

areas with encroaching weeds, and on steep, erodible slopes, such as in the archipelago.

Apart from the annual rodeo and the occasional shooting of a few individuals for meat, the

cattle on Robinson Crusoe are essentially un-managed. We understand a few cows were

milked for house supply in the past, but that this is no longer the case. Few, if any cattle are



mustered and treated for parasites or diseases. We expect that few would be given

supplementary food or supplied with water in dry periods. Wherever we saw cattle on

Robinson Crusoe (during a dry period) we noted that there was very little food available and

that stocking rates seemed to be well above the carrying capacity of available areas at that

time (May). This is supported by the observations of Mann (1975) who noted that cattle on

Robinson Crusoe were very thin due to lack of food, indicating there were too many cattle for

the island to support. We observed that many animals here were underweight and generally in

poor condition. We were told mortality has been high in drought periods in some years. Past

plans to limit the number of cattle to a small dairy herd were not put in place due to a lack of

funding to compensate cattle owners (Bourne et al. 1992).

We are aware of strongly-held views about retaining cattle in the archipelago for social and

economic reasons. There seems to be recognition within the community, however, including

the Cattlemen’s Association, that cattle numbers need to be reduced for environmental

reasons, as well as to improve herd quality. We understand Hereford bulls have been

imported to Robinson Crusoe Island as a step towards improving herd quality, and that some

owners have attempted to contain cattle within fenced areas. If both of these objectives were

achieved they may have benefits for animal welfare and farm production, as well as for

biodiversity. However, there are more than 60 owners of cattle on Robinson Crusoe Island,

including some absentee owners. Not all owners are members of the Cattlemen’s Association

and there appears to be no process for reaching agreement on management of the herd. While

it was beyond the scope of this study to assess in detail the issue of cattle impacts and

potential remedies on Robinson Crusoe, it was clear the current situation is unsustainable and

needs to change urgently.

Management options (Robinson Crusoe Island)

Do nothing: This management option would lead to continued severe environmental

degradation and further limits to restoration opportunities. While other herbivores such

as rabbits and feral goats are also contributing to environmental degradation, cattle are

likely to be major contributors at some sites. Even with the removal of other invasive

mammals, cattle will continue to cause irreversible damage to the island through

accelerated erosion. We note also that unrestricted access by livestock is not consistent

with the management objectives of a biosphere reserve (UNESCO 2008b). Doing

nothing, involving current ‘hands-off’ farming practices, is unlikely to lead to any

improvement in herd quality, to enhance meat or milk production, or to add to the

recreational values of the herd.

Sustained control: Cattle could be restricted to designated areas by fencing. This would

require considerable commitment of resources, both for the initial construction and the

on-going maintenance of fences. The numbers of cattle would also have to be limited in

accordance with the carrying capacity of the designated areas, as dictated by good

animal husbandry and pasture management practices. These designated areas could

constitute ‘transition areas’ (UNESCO 2008b) within the biosphere reserve. Under this

strategy there is potential that cattle may continue to be available to meet recreational

and other social objectives.

Eradication: Eradication from both Alejandro Selkirk and Robinson Crusoe Islands

would represent the optimal outcome for restoration of natural ecosystems. However, in

view of the high cultural value placed on cattle on Robinson Crusoe, in particular, we



concluded an eradication objective here would be unacceptable and inappropriate. We

have recommended below, however, that all cattle be removed from Alejandro Selkirk

Island, recognising that maintaining (and containing) a cattle herd there would be even

more difficult than on Robinson Crusoe.


Recognising the cultural value of cattle on Robinson Crusoe Island, we suggest controlling

their numbers and limiting their distribution is an appropriate objective. Cattle could be

confined to a fenced area in the vicinity of Villagra where the annual rodeo is held. The

number of cattle held within the designated area should be determined by community needs

balanced with the carrying capacity of the area based on good animal husbandry and pasture

management practices. The spread of cattle to many parts of Robinson Crusoe suggests that

retaining a herd here represents a significant compromise to the national park’s management

objectives. Such a compromise should be based not only on recognition of the community’s

needs, but also on an understanding of the environmental costs and risks in retaining cattle

within the park.

In addition to reducing the environmental impacts cattle are causing, we suggest there is also

a pressing need to put in place good animal husbandry and pasture management practices if a

cattle herd is to be maintained on Robinson Crusoe Island. We recommend a cattle

management committee consisting of representatives of CONAF, cattle owners and the wider

community is established to prepare and oversee the implementation of a cattle management

plan for the archipelago. This plan should set out both conservation and farming objectives. It

should prescribe the size of the herd and the location and extent of fenced grazing areas,

along with herd management, animal husbandry and pasture management practices to be

applied. It will be important for CONAF to take the lead in initiating this process, and in

seeing it is effectively applied.


Improved herd quality and sustainable farming practices.

Continued availability of a cattle herd for the annual rodeo, and as an occasional source

of meat.

Development of an effective and accepted process for resolving management objectives

where conflicting objectives must be considered.

Reduced erosion, soil compaction and sediment runoff, possibly leading to increased

productivity of the lobster fishery.

Extensive recovery of forest and grasslands.

Improved survival of rare and threatened plants, leading to population increases and,

eventually, down-grading and perhaps de-listing of species with IUCN threat

categories.

Reduced destruction of seabird burrows, including the threatened pink-footed

shearwater.

Reduced weed seed dispersal.



Management techniques

It is beyond the scope of this study to identify mechanisms by which reduction of the cattle

herd on Robinson Crusoe Island might be achieved. This will require extensive consultation

with cattle owners and other community representatives. Suggestions might include CONAF

securing ownership of all cattle, thereby enabling a consistent and effective management

program. The acquisition of the cattle herd by CONAF is identified as a priority in the park

management plan (CONAF 2009). Unless CONAF takes the lead in resolving this situation

we predict it will only worsen and become more difficult to resolve in the future. Several

cattle owners commented to us that their interests were in improving the quality of the herd.

They believed reducing the numbers of cattle on the island would be important in achieving

this objective. A more closely managed breeding system would facilitate this goal. A process

for annual cattle censuses is required to ensure that limits on cattle numbers are observed and

that any cattle outside designated areas are quickly removed. Compulsory marking of cattle

(e.g. using ear tags) may help to facilitate this. The development of a cattle management plan

and its oversight by a cattle management committee including key stakeholders could be a

positive step forwards in resolving not only the cattle issue, but also other potential conflicts

between park management objectives and community needs.


The main risk associated with managing cattle is a potential lack of community support due

to the social values placed on these animals. Cattle management should not proceed without

significant support from the community. Further research to tease apart the effects of cattle

and other herbivores may help to assure some stakeholders that management is required. We

do not believe, however, that such research is necessary in order to make urgent decisions to

reduce cattle impacts.

Anticipated costs

Maintaining a herd and limiting the numbers and distribution of cattle on Robinson Crusoe

Island will involve the construction and indefinite maintenance of stock-proof fencing. There

will also be ongoing labour costs involved in animal husbandry, pasture management and in

conducting an annual census to ensure that the herd does not exceed the agreed numbers. It is

possible that compensation may need to be paid to cattle owners in return for reducing cattle

numbers.


The impacts of cattle on Robinson Crusoe Island are recognised in the park management plan

(CONAF 2009), and institutional support to reduce these impacts could be expected at

regional and national levels. However, in recognition of the importance of cattle to Robinson

Crusoe residents it will be necessary to ensure local support is obtained for any herd

reduction and improvement strategy.



Feasibility of controlling cattle on Robinson Crusoe Island

MODERATE

While there seems to be support for reducing cattle numbers and improving the quality of the

Robinson Crusoe herd, extensive discussion will be required to resolve how this might be

achieved. Any control program here will need to be based on agreed principles, strong

leadership and consistent support from CONAF, and the engagement and support of key

stakeholders.

9.2.2 Cattle on Alejandro Selkirk Island

Ecology and impacts

While cattle impacts (browsing of native vegetation and trampling of soils) are also evident

on Alejandro Selkirk Island, their effects are not as pronounced here compared to Robinson

Crusoe – although we visited Selkirk during a wetter time of the year (December) when more

fodder was available. The absence of rabbits from Alejandro Selkirk is clearly reflected in

more vigorous growth of grasses and other plants compared to Robinson Crusoe. It appeared

to us that cattle numbers were much lower.

Previous management

We understand cattle are occasionally killed for meat on Alejandro Selkirk, including taking

meat back to Robinson Crusoe. We understand some residents of Alejandro Selkirk have

asked that a small number of cattle be retained here as an emergency food supply. In 2009

CONAF began negotiations with owners to limit cattle on Alejandro Selkirk Island to three

head per household. The intention is to maintain a maximum of 50 cattle on the island (I.

Leiva, pers. comm.).

Management options

Do nothing: This management option would lead to continued degradation of

ecosystems and further limits to restoration opportunities. Even with the removal of

other invasive mammals cattle will continue to cause significant damage through

accelerated erosion and trampling of soil and vegetation. Maintaining the current

situation could lead to excessive numbers of cattle, and increased environmental

impacts. Unless good farming practices are applied it is likely that herd quality will be

poor, limiting its value as a meat supply.

Sustained control: Cattle could be contained within fenced ‘transition areas’ on

Alejandro Selkirk, as recommended for Robinson Crusoe (see above). This would

involve significant commitments of resources and entail considerable risk (that

containment is not sustainable). The lack of human presence on Alejandro Selkirk

Island for several months each year would present additional difficulties in containing

the cattle herd within fenced areas, and ensuring their needs are met.



Eradication: The eradication of the cattle from Alejandro Selkirk Island would remove

their impacts (defoliation, accelerated soil erosion and compaction), allowing for

enhanced regeneration of native vegetation. It would negate any need for ongoing effort

and costs in maintaining fences, and avoid associated risks that containment will not be

achieved. If goats were also eradicated important opportunities would be created for the

restoration of ecosystem function and recovery of threatened flora and fauna. The

removal of all cattle from Alejandro Selkirk would mean local residents would not be

able to use cattle here as an emergency food supply.


We have recommended that a small herd of cattle be retained on Robinson Crusoe Island, in

recognition of their social values. It is unclear to us whether cattle have the same social value

on Alejandro Selkirk Island. We have observed that retaining a cattle herd on Alejandro

Selkirk would involve even greater risks than on Robinson Crusoe, because Alejandro

Selkirk is not permanently inhabited. We suggest consideration be given to local people

removing all the cattle from Alejandro Selkirk, perhaps over several years. Thereafter a

managed cattle herd could be retained on Robinson Crusoe alone to meet the needs of both

communities.

Because of the value placed on cattle in the archipelago we recommend a cattle management

committee is established, with representatives from cattle owners, the wider community and

CONAF. The roles of this committee would be to prepare and oversee the implementation of

a cattle management plan for the archipelago, and to facilitate a process through which

agreed cattle management policies may be supported and implemented.


Development of an effective and acceptable process through which all stakeholders

may influence decisions about cattle in the archipelago, and can contribute to their

management.

Reduced environmental impacts, including improved survival of threatened species.

Restoration opportunities, in the absence of browsing and trampling mammals, are

created.

Management techniques

To be determined once a cattle management plan has been prepared.


See 9.2.1 above.




See 9.2.1 above.

Feasibility of removing all cattle from Alejandro Selkirk Island

MODERATE

There are no technical reasons why cattle could not be removed from Alejandro Selkirk

Island.

9.3 Managing other species

9.3.1 Horse

Ecology and impacts

Although populations of feral horses have had severe environmental impacts in other parts of

the world (e.g. Dobbie et al. 1993), only a small number of horses and mules are present in

the archipelago. On Robinson Crusoe a small number of horses are largely restricted to the

areas around San Juan Bautista and Villagra. Some residents commented that they would like

to see horses better controlled in town, as their gardens and greenhouses had previously been

raided by horses. Although these animals are unlikely to be having severe environmental

impacts, it is likely they contribute to the erosion of tracks, consume native plants and act as

seed vectors for weeds such as murtilla.

Management options

Do nothing: Horses will continue to contribute to erosion, to spread the seeds of

invasive plants, and be a nuisance around town. Owners will continue to keep horses as

they see appropriate.

Sustained control: By restricting the grazing of horses to fenced areas, their impacts on

soil and vegetation, and their ‘nuisance value’ may be reduced.


Horses are of high value for transporting people and goods, and their continued presence on

Robinson Crusoe Island is clearly desirable. We expect many horses here are also valued as

companion animals. However, we suggest the grazing of horses should be confined to

designated areas where they do not contribute to erosion or act as seed vectors for invasive

plants. This may require the construction of fences and, possibly, the provision of

supplementary food, as they will no longer be able to forage as widely as they do currently.

Horses may be confined in the same or adjoining fenced pasture areas on Robinson Crusoe as

cattle. A limit to the number of horses which may be kept on both islands should also be

agreed by the community and CONAF.



Two mules are present on Alejandro Selkirk Island, for use in transporting materials around

the island. Similar containment provisions and an agreement to a limit to numbers should also

be applied to Alejandro Selkirk.


Erosion will be reduced on the slopes above San Juan Bautista and the likelihood that

weeds will spread beyond the designated containment zone around the town will also

be reduced.

The nuisance value of some horses will be reduced.

Horses will remain as a conservation asset, rather than become a conservation pest

Feasibility

Although containing horses within fenced areas is logistically achievable, it is possible some

horse owners may not support these measures. Community support for any objectives to

control horses may be contingent on dialogue and agreements in relation to other

conservation objectives.

9.3.2 Austral thrush

Ecology and impacts

The austral thrush (or ‘zorzal’) is a native of the Chilean mainland, and probably arrived in

the Juan Fernández Archipelago some time before 1830. It is not known whether the species

reached the islands naturally or with human assistance (Hahn et al. 2005). Today it occurs

throughout most habitats on Robinson Crusoe and Alejandro Selkirk Islands, reaching high

densities in some habitat types (Hahn et al. 2005). The thrush feeds on the fruits of invasive

plants such as blackberry, maqui and murtilla (Skottsberg 1953) and has been implicated in

spreading these weeds across much of the archipelago (Cuevas & van Leersum 2001).

Thrushes also prey on the eggs and chicks of hummingbirds, but are not thought to be a major

source of mortality (E. Hagen unpublished data). No data are currently available on the

thrush’s potential role as a seed disperser of native plants.

Previous management

Thrushes were hunted as part of the Holland Project, apparently reducing their localised

abundance by around 50%. They are still hunted recreationally, and for food, and there is

interest within CONAF and SAG in controlling or eradicating their populations (Hagen

2010).

Management options

Do nothing: Thrushes will continue to aid in the spread of invasive plants by dispersing

their seeds, and to prey on the eggs and chicks of hummingbirds.



Sustained control: On-going control could be effective in reducing and maintaining the

impacts of thrushes at acceptable levels. However, control would require an indefinite

commitment of effort and resources and involve the application of new approaches and

techniques.

Eradication: Thrushes are widely distributed across Robinson Crusoe and Alejandro

Selkirk Islands. We are not aware of any precedent for eradication of this species, nor

are there proven control techniques which might be adapted to a thrush eradication

project in the archipelago. An experimental control project might lead to the

development of effective eradication techniques, and greater confidence that

eradication might be achievable.

Biosecurity: Given that thrushes are widely viewed as undesirable in the archipelago, it

is unlikely there would be any deliberate introduction in the future. As with all species,

there will be a need for biosecurity protocols to prevent unintentional introductions,

especially if a management program was initiated. Since it is possible that the thrush

reached the archipelago naturally, the possibility of natural reinvasion cannot be

discounted.


At present too little is known about the ecology of thrushes in the archipelago, the nature of

the threats they pose, or of possible methods for their removal to justify either eradication or

control at this time. There is also doubt as to whether this species was introduced to the

archipelago or arrived naturally. We recommend further research into their impacts as

predators and seed dispersers, perhaps including intensive localised removal experiments.

Once a clearer understanding has been gained of thrush ecology and impacts, and removal

techniques have been refined, consideration may be given to larger-scale control or perhaps

eradication. Regardless of its impacts, eradicating the species may not be considered

appropriate if it arrived naturally on the islands and was not introduced by humans.


Increased knowledge of the ecology and environmental impacts of the austral thrush in

the archipelago.

Reduced mortality of nesting hummingbirds as a result of targeted control of thrushes.


With the exception of hunting, which has previously been used in an attempt to control

thrushes in the archipelago, we are not aware of any techniques that have been used

effectively to control thrushes. However, techniques used for other birds may be able to be

adapted. With further research and trials it is possible techniques such as trapping, netting and

poisoning may prove effective.




We are unaware of any precedent for eradication of the austral thrush, or of a suitable range

of methods that could be used to attempt eradication. We therefore anticipate that an attempt

at eradication at this time would carry a high risk of failure.

Table 21 Satisfying the requirements to eradicate austral thrushes from Robinson Crusoe and Alejandro

Selkirk Islands.


All individuals of the thrush population are put at risk by the techniques employed

Apart from hunting, we are not aware of any techniques that have been used to remove austral thrushes. Given the wide distribution and reportedly high densities of the species in the archipelago, it is unlikely all individuals could be targeted by hunting

Thrushes are removed faster than they can breed, at all densities

Although it is conceivable hunting may remove thrushes rapidly over a small area, it is unlikely to do so over an area as large as Robinson Crusoe or Alejandro Selkirk Islands. Thrushes may also become difficult to locate at low population densities

The risks of thrushes re-invading are near-zero

It is not known whether thrushes reached the Juan Fernández Archipelago naturally or with human assistance. The risk of re-invasion is therefore difficult to assess. However, deliberate introduction is unlikely, and the risk of accidental introduction could be minimised through appropriate biosecurity measures


As thrushes have been subject to lethal control in the past, and continue to be hunted by locals, it is unlikely that there would be any objections to the use of lethal measures against this species


The role of austral thrushes as a weed seed disperser is clearly recognised, and there is interest within CONAF and SAG in removing them. It is therefore likely that institutional support would be forthcoming for their eradication

Benefits outweigh costs The nature and extent of the impacts caused by austral thrushes (for example, their role as nest predators of other birds) are not clearly understood. Their role as a disperser of native and endemic plants is also not well understood. Therefore, it is difficult to assess the benefits of their eradication. The lack of any precedent for their eradication also makes the costs of such an operation difficult to predict


The austral thrush is recognised as a seed vector for invasive plants, and there is interest

within CONAF and SAG in controlling or eradicating the species. We therefore anticipate

that institutional and funding support will be available for research into the species’ ecology

and possible methods of control or eradication.




LOW

Explanation: Due to the wide distribution of the austral thrush in the archipelago, the lack of

precedents for their eradication elsewhere, and limited techniques available for the removal

of populations, we conclude the feasibility of eradicating them here is low. However, this

assessment could be revised following further research and trials.

9.3.3 Four-eyed frog

Ecology and impacts

The four-eyed frog is native to mainland Chile and Argentina, where it eats invertebrates and

a small amount of vegetation (Díaz-Páez & Ortiz 2003). It can be found in both natural and

altered habitats (Veloso et al. 2008). The timing and circumstances of its arrival in the Juan

Fernández Archipelago are unknown, but Mann (1975) noted that numbers of this frog

appeared to increase considerably in the archipelago in the two years between his visits, and

that it may have contributed to increasing the abundance of coatis, which prey on the frogs.

Management options

Do nothing: No ecological impacts of this species have been recorded, suggesting that

no management may be necessary. However, it is possible that this species has impacts

on local invertebrate populations. Its numbers may also increase if coatis are eradicated.

Monitoring and research would allow more informed judgements on the impacts and

appropriate management of this species.

Sustained control: At present there is insufficient evidence of harm caused by the four-

eyed frog to justify control measures.

Eradication: There are no known methods for eradicating this species or evidence to

suggest eradication is justified at this time.

Biosecurity: Comprehensive biosecurity regulations will be required to prevent the

introduction of exotic species, including further four-eyed frogs, to the archipelago.


CONAF could monitor the abundance and distribution of four-eyed frogs and conduct

research into their ecology and impacts in the archipelago, but we consider this to be a low

priority. There is currently no evidence that they are having negative impacts, and little

justification for active management.




Improved knowledge of the ecology and any impacts of the four-eyed frog.

Feasibility

LOW

Explanation: There is no evidence of environmental impact, no precedents for effective

management, and no proven management techniques available which may be applied to this

species in the archipelago.

9.3.4 House sparrow

Ecology and impacts

House sparrows have a wide range of negative impacts in areas where they have been

introduced. They displace native birds from nesting sites, consume crops and ornamental

plants, and are known vectors of 29 diseases affecting people and livestock (Clergeau et al.

2004; Fagerstone 2007). For example, by polluting water supplies, they can transmit giardia

and cryptosporidium (Chilvers et al. 1998). They are rated as one of the top species for

invasive potential in California (Smallwood & Salmon 1992). Clergeau et al. (2004) called

for the eradication of a small, localised population of house sparrows from Guadeloupe Island

in the Lesser Antilles. However, local authorities did not regard sparrows as a priority and did

not attempt eradication. Sparrows have since spread throughout the island and appear to

compete with endemic birds (P. Clergeau, pers. comm.).

Sparrows have been present on Robinson Crusoe Island since 1943. It is believed that until

recently the birds were restricted to the vicinity of San Juan Bautista, but since the tsunami in

February 2010 they have dispersed more widely (Hagen 2010). They are now found on

higher ground, closer to forested areas, possibly increasing the risk that they will spread into

the national park (J. Meza, pers. comm.). Sparrows aid the spread of invasive plants on

Robinson Crusoe Island by acting as a seed vector (CONAF 2009). Given their aggressive

behaviour towards other birds elsewhere, it is likely they also displace native birds such as

the Juan Fernández firecrown (Hagen 2010). In North America sparrows attack native bird

species, push eggs and nestlings from nests and chase adults. Two of the four most common

birds attacked by sparrows are wrens and robins (Barrows 1889 cited in Anderson 2006).

Juan Fernández tit-tyrants are a Robinson Crusoe island endemic and may potentially also be

impacted by house sparrows. Sparrows were present on Alejandro Selkirk Island, but were

reportedly eliminated by 1994 (Hahn et al. 2009; H. González, pers. comm.).



Previous management

Although the presence of sparrows is recognised as undesirable (CONAF 2009), there have

been no attempts to manage their populations on Robinson Crusoe Island (Hagen 2010).

Management options

Do nothing: Sparrows may pose a health risk to humans, and possibly displace native

birds such as the Juan Fernández firecrown and tit-tyrant. They may also continue to

help in the spread of invasive plants by dispersing their seeds. There will be a continued

risk that sparrows will spread beyond San Juan Bautista to invade the national park.

The likelihood and ecological implications of such a spread are unknown.

Sustained control: Trapping, netting and shooting could be effective in reducing and

maintaining sparrow impacts at acceptable levels. However, control would require an

indefinite commitment of effort and resources, and a better understanding of their

impacts. As long as sparrows are present there will be some risk that they will spread

beyond their current, restricted distribution, possibly with negative consequences for

native biodiversity.

Eradication: Sparrows are believed to have a localised distribution in the archipelago,

being confined to San Juan Bautista and its environs. If surveys confirmed a single,

localised population there might be merit in undertaking an eradication.

Biosecurity: Sparrows were deliberately transported to the archipelago by people (Hahn

et al. 2005). The isolation of the islands means that sparrows would be very unlikely to

reach them unassisted. Provided there was community support to keep the archipelago

sparrow-free, biosecurity regulations would be needed to prevent sparrows being

reintroduced deliberately. Surveillance would also be required to detect any accidental

introductions. Outreach programs may also be needed to ensure cage bird breeders

understand the implications of introducing sparrows following their eradication.


Sparrows have not yet become established on Robinson Crusoe Island, except for a restricted

area around San Juan Bautista. Early eradication is advisable in such situations, before the

species becomes widespread and therefore more difficult to manage (Clergeau et al. 2004).

However, there is currently insufficient information to justify the effort involved in

eradicating sparrows. Furthermore, there is insufficient knowledge to undertake an

eradication with a high degree of confidence. Research into sparrow distribution, behaviour

and impacts on Robinson Crusoe Island should be undertaken, along with trials to improve

confidence in eradication techniques. In particular, it is important to determine whether

sparrows have negative impacts on the Juan Fernández firecrown and Juan Fernández tit-

tyrant. Depending on the outcomes of these initial investigations, a sparrow eradication plan

could be prepared for implementation. The Municipality and CONAF should take the lead in

conducting surveys and research.




Definitive information about where sparrows occur, including where they nest and

roost.

Better understanding of sparrow behaviour and impacts, as well as their vulnerability to

control or eradication techniques.

Sparrow removal techniques developed and refined.

Possible Eradication techniques

After more information has been gathered on the distribution and impacts of sparrows,

eradication may become a high priority. We have noted below a range of techniques which

may possibly be used.

It is expected that a combination of methods and some testing and refinement of suitable

techniques would be required before sparrow eradication is attempted. The effectiveness of

some methods may decline over time, as sparrows learn to avoid them (Bednarczuk et al.

2009; 2010). This emphasises the importance of using a variety of techniques in an adaptive

management approach.

Table 22 Possible techniques for eradicating house sparrows from Robinson Crusoe Island.


Trapping

McGregor and McGregor (2008) successfully reduced numbers of sparrows using a combination of trapping and removal of structures that provided harbour to the birds. They also describe in detail a design for an effective trap

Trapping was also the most successful method in removing large numbers of sparrows on Round Island, Mauritius (Bednarczuk et al. 2009; 2010)

Poisoning Poisoning with alpha-chloralose is effective against sparrows (Nelson 1994) if they can be enticed to feed on poisoned baits (Bednarczuk et al. 2009; A. Woolnough pers. comm.). This method can be particularly effective if the birds are accustomed to being fed by humans. Pre-feeding with a non-toxic version of the bait can help to increase feeding rates so that subsequent toxic baiting will be more effective (Nelson 1994). Recordings of sparrow calls can also be used to attract birds to the bait (Bednarczuk et al. 2009; 2010). However, the use of poison would require careful consideration of potential imapcts on non-target bird species (A. Woolnough, pers. comm.). We do not know if bird toxicants are registered in Chile for agricultural or domestic use

Netting Mist netting was used by Bednarczuk et al. (2009, 2010), although this method was less effective than trapping and therefore discontinued. However, mist nets may provide an additional method to target birds that survive other techniques

If communal roost sites can be identified or if large numbers of birds can be attracted to a bait, drop-nets may also be effective (K. Campbell unpublished data)

Shooting As a follow-up to other methods, remaining individual sparrows may effectively be removed by shooting with a .22 air rifle or a .22 rifle with a silencer (A. Woolnough, pers. comm.). Bednarczuk et al. (2009, 2010) removed 11 sparrows in one week using a shotgun at roosting and nesting sites. They report that shooting is likely the only way to remove the last individuals of a sparrow population



Opportunistic shooting of sparrows when they came into town areas on Alejandro Selkirk Island apparently led to the extirpation of the species there (H. González, pers. comm.)

Electronic devices such as image intensifiers and infra-red cameras may be useful in detecting remaining sparrows

Nest destruction Bednarczuk et al. (2009, 2010) destroyed a small number of nests and humanely killed any chicks present. The nests were not re-established. Most nests on Round Island were inaccessible, limiting the usefulness of this technique. However, nest destruction may be effective where nests are more accessible

Spray with surfactant at communal roosts

Although we are not aware of this technique having been used for sparrows, spraying with a mixture of water and surfactant has been effective in removing other communally-roosting birds (Heisterberg et al. 1987). The spray is applied while the birds are roosting, reducing the insulation capacity of their feathers and causing them to die of hypothermia


Assuming the Robinson Crusoe Island sparrow population is confined to San Juan Bautista

and its environs, there are reasonable prospects that eradication could succeed. While there

are no examples of successful sparrow eradications (Bednarczuk et al. 2009), a range of

techniques is available which may be adapted and applied here.

If poison is used to kill sparrows, there may be some risk of non-target impacts on native

birds. The risk of non-target poisoning can be minimised by using a bait that is not attractive

to native birds, by monitoring birds that feed on the baits or by placing baits in a manner to

exclude other species. On Robinson Crusoe Island the only non-target birds that may

consume a grain bait are feral pigeons, austral thrushes and domestic chickens. The effects of

alpha-chloralose are easily reversed if birds are treated soon after ingesting the poison

(Morriss 2009).

It is possible that predation by rodents and kestrels is limiting the spread of sparrows into the

national park. If rodents are eradicated sparrows may spread throughout the island and

increase in numbers, making them much harder to eradicate.

Table 23 Satisfying the requirements for eradication of house sparrows from Robinson Crusoe Island.


All individuals of the sparrow population are put at risk by the techniques employed

While there is no precedent for sparrow eradication, a range of techniques have been used effectively for control. Provided surveys confirm that the sparrow population is confined to San Juan Bautista and its environs, and trials indicate that effective detection and removal is feasible, it is possible that all individuals may be put at risk

Sparrows are removed faster than they can breed, at all densities

Initial knock-down of the majority of sparrows may be achieved when sparrows are communally roosting (if indeed, as suggested to us, they do roost communally here), or when they are nesting

There is potential to lure sparrows to food sources, such as seed tables, where they may be trapped, netted or shot

The risks of sparrows re-invading are near-zero

While they are good dispersers, it is extremely unlikely that sparrows could reach the archipelago unassisted. They are more likely to be introduced deliberately as cage birds, or accidentally on vessels or in cargo



Capacity building and community support objectives of any eradication mounted against sparrows would need to be promoted in outreach programs. Regulations would also be required to underpin biosecurity measures


Because any eradication of sparrows would require the support of virtually all residents, and the active participation of some, it will be essential that most residents are supportive of the techniques that are to be used. If some residents are not supportive assurances will be required to ensure their lack of support will not lead to any actions being taken which might jeopardise the success of the operation


While we do not anticipate sparrow eradication would require significant resourcing, we suggest it would still need the declared support of the Municipality to proceed. In addition to leading the process of community consultation and project planning we would expect the Municipality to play a lead role in coordinating survey and research activities and supporting the engagement of local residents. It would also play important roles in creating and implementing biosecurity measures

Benefits outweigh costs As the impacts of sparrows on Robinson Crusoe Island have not been studied, it is difficult to assess the benefits of their eradication. However, in keeping with the precautionary principle, there may be benefit in eradicating sparrows before they potentially become widespread on the island


There is recognition that sparrows represent a threat to biodiversity on Robinson Crusoe

Island, and of their potential to spread beyond their currently restricted distribution and

invade the national park. However, there is some risk that stakeholders and donors may not

see sparrow eradication as a priority, as was the case in the Lesser Antilles (Clergeau et al.

2004). We would not expect management agencies or funders to prioritise sparrow

eradication over other invasive vertebrate eradications recommended in this report.


MODERATE

Explanation: We expect surveys to confirm that sparrows in the archipelago are confined to

San Juan Bautista and its environs. There are obvious advantages in targeting an invasive

species which is confined to a relatively small and accessible area. At this stage, however, the

lack of relevant precedents leads us to conclude there is only a moderate prospect of success

currently. We would expect this assessment to improve following surveys and research.

9.3.5 Feral pigeon

Ecology and impacts

Feral pigeons have been present on Robinson Crusoe and Santa Clara Islands for several

centuries, having reportedly been introduced by pirates (Mann 1975). Observations from

January to March suggested pigeons ate mainly seeds of milk thistle, as well as some grass

seeds (Mann 1975). They are also seed vectors for invasive plants such as blackberry, maqui



and murtilla (CONAF 2009). As they are able to travel 20 km between roosting and feeding

sites (Morriss 2009), pigeons are presumably distributed across most of Robinson Crusoe and

Santa Clara Islands. Due to this dispersal ability these two islands must be considered

together as a single eradication unit, not as separate populations. Pigeons are not kept or

maintained by island residents, and exist only in the feral state in the national park.

Feral pigeons are a serious agricultural pest, causing extensive crop damage and economic

losses (Witmer et al. 2007). They are also vectors of human diseases (Murton et al. 1972).

They harbour 60 different human pathogens, and there are records of seven of these being

transmitted from pigeons to humans (Haag-Wackernagel & Moch 2004).

Previous management

Feral pigeons are occasionally hunted for food on Robinson Crusoe Island, but hunting

pressure is low and no attempt has been made to reduce pigeon populations in the archipelago

(Hagen 2010).

Management options

Do nothing: Feral pigeons will continue to pose a potential risk to human health, and to

spread seeds of invasive plants.

Sustained control: On-going control efforts may hold feral pigeons at low densities.

They will continue to be weed seed vectors, however, and to present a disease risk to

humans. On-going control would require an indefinite commitment of resources and

labour.

Eradication: Although we are not aware of any attempts to eradicate feral pigeons,

populations have been controlled in various places around the world. A range of lethal

control methods are available, which may be adapted for eradication in the archipelago.

Biosecurity: Pigeons were probably intentionally introduced to the Juan Fernández

Archipelago. Biosecurity measures would need to be in place to prevent any further

introductions before eradication could be considered.


Further information about feral pigeon distribution, behaviour and impacts in the archipelago

should be gathered by CONAF as a matter of priority. This could inform decisions about

possible eradication.


Definitive information about where feral pigeons occur, including where they nest and

roost.

Better understanding of pigeon behaviour and impacts, as well as their vulnerability to

control or eradication techniques.

Pigeon removal techniques developed and refined.



Possible Eradication techniques

Further research and testing of techniques will be required before a pigeon eradication

program could be initiated with a high degree of confidence. We have noted below, however,

a range of techniques which may possibly be used if eradiation is to proceed. As in the case

of sparrows, a combination of methods would likely be required, and techniques may need to

be tested and refined.

Table 24 Possible techniques for eradicating feral pigeons from Robinson Crusoe and Santa Clara Islands.


Trapping

Multiple-capture cage traps have been used effectively to catch pigeons. Traps should be left open and baited with grain for a one-week pre-feeding period before being set (Morriss 2009)

Drop nets have not been used on pigeons to our knowledge but could be used for capturing large groups in a single event if targeted and pre-baited during a period of low naturally available foods

Traps may incorporate sentinel birds which assist in attracting other pigeons

Poisoning Pigeons may be poisoned with alpha-chloralose (Murton et al. 1972; Morriss 2009). This method may be effective for targeting pigeons and sparrows simultanelously. Bait must be monitored as some birds are not killed but merely stupefied, and must then be euthanased. However, this has the advantage that any non-target birds that consume bait may be revived. It is uncertain if any toxicant is registered for pigeons in Chile

Shooting Shooting with shotguns or rifles is an effective way to remove pigeons (Morriss 2009)

The last wary pigeons could be removed with aerial shooting by shotgun from a helicopter, which would allow easy access to cliff areas

Removal of food sources Removal of all food sources is not realistic (Morriss 2009) However, control of invasive plants that provide food for pigeons (e.g. blackberry, murtilla and maqui) may help to reduce pigeon numbers and make remaining birds more likely to consume toxic baits

Egg oiling or pricking If their eggs are removed, pigeons will rapidly lay new ones. However, if the eggs are rendered inviable by coating them with paraffin or corn oil, or by pricking a small hole in them, the parents will continue to try to incubate the eggs. This method can require year-round effort, and is only useful if sufficient nests can be located and accessed (Morriss 2009). As pigeons nest on the numerous cliffs on Robinson Crusoe and Santa Clara this method would be difficult to implement

Natural predation Juan Fernández kestrels are known to kill pigeons on the wing. At high densities a few mortalities can be compensated for by the breeding rate of the population. However, once at low densities, predation events may facilitate the eradication of remnant individuals


We are unaware of any precedent for eradicating feral pigeons. They have been effectively

controlled, however, at many sites and a range of techniques are available which may be

adapted for eradication purposes here. There may be some risk to non-target birds from the



use of toxins to eradicate pigeons. The use of alpha-chloralose, however, may involve

manageable risks (Section 9.3.4).

Table 25 Satisfying the requirements to eradicate feral pigeons from Robinson Crusoe and Santa Clara

Islands.


All individuals of the pigeon population are put at risk by the techniques employed

While there is no precedent for pigeon eradication, various techniques are available for pigeon control. Trials of proposed methods should be carried out to determine whether they are likely to place all individual pigeons at risk

Pigeons are removed faster than they can breed, at all densities

Large numbers of pigeons can be rapidly removed by shooting, trapping and poisoning. Average clutch size is two eggs, and a pair typically raises two or three broods per year (Morriss 2009). It is likely that pigeons can be removed much more rapidly than they can breed when they are in large numbers and easily detected. Success will depend on being able to detect and remove the last remaining individuals. This may be problematic, especially in less accessible areas such as sea cliffs

The risks of pigeons re-invading are near-zero

It is unlikely that pigeons could reach the archipelago unless introduced deliberately. Provided there was community support for the eradication and biosecurity measures are in place, there is little risk of re-invasion


As pigeons are currently hunted by locals, it is unlikely that there would be any objections to the use of lethal measures against this species


Pigeons are recognised as a threat to the biodiversity of the Juan Fernández (CONAF 2009). It is therefore likely that institutional support would be forthcoming for their eradication

Benefits outweigh costs As the impacts of feral pigeons in the archipelago have not been studied in detail, it is difficult to assess the benefits of their eradication. Uncertainty as to the effectiveness of eradication techniques means that costs are also difficult to predict at this stage


Pigeons are regarded as a threat due to their role as a seed vector for invasive plants in the

Juan Fernández Archipelago. However, the extent of their impacts is unknown. It is likely

there may be institutional support for their eradication after additional research on their

distribution, impacts and possible methods of removal.


MODERATE

Explanation: A range of control methods could potentially be adapted for eradication here.

However, due to the lack of any precedent for pigeon eradication, there is uncertainty about

its achievability on Robinson Crusoe and Santa Clara Islands. In recognising the threats

pigeons pose in the archipelago, there may be merit in undertaking experimental localised



control to develop and refine techniques. This work may lead to a subsequent eradication

proposal.

9.3.6 European (yellow-jacket) wasp

Ecology and impacts

European wasps were first detected in San Juan Bautista in 2001 (H. González, pers. comm.),

and are thought to have arrived with goods imported from the mainland. They rapidly spread

across Robinson Crusoe Island, reaching high densities in some areas. The wasps are most

active during summer and have a number of impacts on humans and wildlife. Wasps are

known to forage on Santa Clara Island; however, it is believed they are unable to establish

there due to a lack of fresh water (H. González, pers. comm.). In addition to their powerful

sting, which can be dangerous to humans, they also consume and spoil food (Hagen 2010).

Due to their carnivorous nature they may also be a threat to native invertebrates and

vertebrates such as pink-footed shearwaters (JFIC unpublished data). This possibility is

supported by the impacts of European wasps elsewhere in the world. For example, in New

Zealand they have moderate to strong impacts on a wide range of native invertebrates and

nestling birds. They may also have indirect effects on nutrient cycling and pollination

(Brockerhoff et al. 2010). Wasps consume a large biomass of invertebrate prey and may

compete for food with insectivorous birds (Harris 1991).

Previous management

In 2003 SAG and local residents attempted a control program for European wasps, placing

poison baits across Robinson Crusoe Island. However, this approach was labour-intensive

and was discontinued after a short time (Hagen 2010). Baiting using the toxin fipronil has

been used successfully to control European wasps in New Zealand (Harris & Etheridge

2001).

The parasite Sphecophaga vesparum has had moderate success as a biological control agent

for European wasps on the Chilean mainland. However, there are concerns regarding the non-

target effects of the introducing this agent to the archipelago (H. González, pers. comm.).

This parasite was also introduced to New Zealand for biological control of European wasps

but was unsuccessful (P. Cowan, pers. comm.).

Management options

Do nothing: Wasps will continue to present a threat to human safety, and possibly to

native animals. Native plants may also be affected indirectly through interruption of

pollination.

Sustained control: Although baiting over the entire island may be labour intensive, an

alternative is to conduct on-going baiting operations in priority areas. This approach

can be very effective for European wasps (D. Ward, pers. comm.).

Eradication: As European wasps are widespread on Robinson Crusoe Island, it is

unlikely that eradication will be feasible.



Biosecurity: Preventing European wasps from reaching Alejandro Selkirk Island is

recognised as a high priority (Hagen 2010). Biosecurity measures, including

contingency plans for rapid response in the event of an incursion, would greatly reduce

the risk of wasps establishing on Alejandro Selkirk Island.


We recommend that biosecurity measures be developed and implemented urgently to prevent

the spread of European wasps to Alejandro Selkirk Island from Robinson Crusoe. Biosecurity

measures should be developed and enforced by relevant agencies (e.g. CONAF, SAG and the

Municipality). Further research on biological control should be supported by SAG. A

contingency plan for rapid response in the event of wasps being detected on Alejandro

Selkirk should also be developed. Consideration should also be given to placing permanent

grids of baits to control wasps in priority areas where their impacts are most severe.


Reduced risk of European wasps becoming established in Alejandro Selkirk Island.

Reduced numbers and impacts of wasps in priority areas subject to baiting.

9.3.7 Cottony cushion scale

Ecology and impacts

Infestations of cottony cushion scale were detected in San Juan Bautista in 1999 and were

distributed widely through the town by 2003 (Hagen 2010). This species causes damage to

trees by sucking their sap.

Previous management

The Vedalia ladybeetle was introduced in 2004 as a biological control agent. This measure

has been successful in reducing cottony cushion scale to very low densities (Hagen 2010).

However, there are emerging problems with other species of cushion scales present on the

island (H. González, pers. comm.).

Management options

Sustained control: Biological control has achieved sustained control of cottony cushion

scale in San Juan Bautista.

Eradication: It is unlikely that eradication efforts are necessary as cottony cushion

scale is being effectively controlled by the biological control agent.

Biosecurity: The spread of cottony cushion scale within the archipelago may be

prevented by effective biosecurity measures.




We recommend biosecurity measures be developed and implemented to prevent the spread of

cottony cushion scale and other invasive species within the archipelago. Biosecurity measures

should be developed and enforced by relevant agencies. Regular monitoring is required of

this and other species of cushion scales.

9.3.8 Argentine ant

Ecology and impacts

Argentine ants are listed as one of the world’s worst invasive species (Lowe et al. 2000).

They out-compete native ants and prey on other native invertebrates in many parts of the

world, often with flow-on effects for processes such as plant seed dispersal, pollination and

soil nutrient cycling. Argentine ants can also form mutualistic relationships with other pests

such as cottony cushion scale, causing both species to increase in abundance (D. Ward, pers.

comm.). They can also kill nestling birds and compete for food with some vertebrates (Harris

2002). Argentine ants are also a pest to humans, causing food spoilage, inflicting painful bites

and potentially spreading disease (Harris 2002).

Within the Juan Fernández Archipelago Argentine ants occur on Robinson Crusoe and

Alejandro Selkirk Islands, where their distribution appears to be expanding. The timing of

their arrival on the islands is unknown, but they are believed to have been present at least

since 1990 (Ingram et al. 2006). The species has formed dense populations, expanding

outwards from San Juan Bautista, Puerto Inglés and Rada la Colonia, and is regarded as a

potential threat to native plants and animals (Ingram et al. 2006). Argentine ants have been

recorded visiting endemic plants and collecting nectar without facilitating pollination

(Bernardello et al. 2002), thereby depleting plant reserves and potentially competing for nectar

with the critically endangered Juan Fernández firecrown (M. López-Calleja, unpublished data).

There are no native ants in the Juan Fernández Archipelago.

Previous management

Ingram et al. (2006) called for measures to restrict the spread of Argentine ants, but offered

no suggestions as to how this might be achieved. However, chemical control using toxins

such as fipronil may possibly be used (Harris 2002; Stanley 2004). There are currently no on-

going monitoring or control efforts in place for Argentine ants in the archipelago (Hagen

2010).

Management options

Do nothing: Argentine ants will likely continue to spread, potentially increasing their

impacts on native plants and animals. They may also invade Santa Clara Island where

they are not yet present.

Sustained control: The spread of Argentine ants could be confined using baits, thus

restricting their impacts to the areas already infested. Baiting in priority areas may also

reduce the ants to very low densities locally.



Eradication: Eradication would be the preferred option for a new incursion. However,

given current knowledge and techniques eradication is unlikely to be achievable for the

widespread, established populations of Argentine ants in the archipelago.

Biosecurity: The risk of Argentine ants invading Santa Clara Island may be reduced by

developing and enforcing biosecurity measures within the archipelago. In the event of

an incursion being detected on Santa Clara, immediate action would be required to

eradicate the ants.


We recommend surveys to confirm the distribution of Argentine ants in the archipelago. If

they are confirmed to be absent from Santa Clara Island, biosecurity measures should be

established to prevent them from reaching and becoming established there. Biosecurity

measures should be developed and enforced by relevant agencies.

Following surveys to map their current distribution, any further spread of Argentine ants may

be contained by baiting. Consideration should also be given to on-going baiting in areas

where ant impacts are of most concern. Further research is also required into the

environmental impacts of Argentine ants in the archipelago.


The restoration of Santa Clara Island may be achieved more rapidly and easily in the

absence of Argentine ants.



10 Multi-species eradications and anticipated costs

We recommend combining multiple animal eradications into four coordinated operations:

Rodents, feral cats and feral goats on Alejandro Selkirk Island

Feral goats on Robinson Crusoe Island

Rodents, rabbits and feral cats on Robinson Crusoe Island

Experimental eradication of coatis, house sparrows and feral pigeons

The costs of these multi-species programs will be much lower than the cost of treating each

species separately. This is because some eradication methods will simultaneously target more

than one species, and the removal of some species will aid the subsequent eradication of

others (e.g. removing rodents and rabbits will make feral cats easier to eradicate).

It is not possible to provide accurate costs for the projects and actions recommended in this

report. This will only be possible once detailed operational plans have been prepared which

set out specific tasks, roles and timeframes. Some ‘ballpark’ estimates of overall costs can be

derived, however, based on the costs of similar projects undertaken elsewhere. These

estimates are provided here as an indication for consideration by management agencies,

potential donors and other participants. Typically, such organisations require some

preliminary indication of ballpark costs as they consider their support for a project. It is

important to note that there may be a significant difference between the estimate provided

here and actual costs once detailed plans have been prepared.

10.1 Rodents, feral cats and feral goats on Alejandro Selkirk Island

We estimate that this campaign will cost approximately US $6.15M over a 12-month

implementation period.

10.2 Feral goats on Robinson Crusoe Island

A ballpark estimate of costs for this operation, including planning, is US $1.7M over three

years. The experimental eradication of coatis (see Section 9.1.5) would also be included in

these costs.

10.3 Rodents, rabbits and feral cats on Robinson Crusoe Island

This multi-species campaign is expected to cost around US $7.6M over a period of two years.

10.4 Experimental eradications: coatis, sparrows and pigeons

Due to the lack of precedents for eradicating coatis, house sparrows and feral pigeons, we

recommend that these operations proceed as experimental eradications. These should be

approached in several stages:



Collect information on biology and possible methods of removal for each species

Address knowledge gaps with targeted research and field observations

Conduct field trials of specific methods

Develop an eradication plan and secure support and funding

Implement the eradication plan within an adaptive management framework, collect and

regularly analyse operational data

Report on the lessons learned from the eradication attempt.

At the conclusion of each step, the feasibility of eradication should be re-assessed in the light

of the new information gathered. If eradication is not judged to be feasible at any stage, the

operation should not proceed to the next step.

We recommend that coatis be the first to be targeted for experimental eradication, and that

this is undertaken in conjunction with the eradication of feral goats from Robinson Crusoe

Island. The experimental eradications of feral pigeons and house sparrows should be

attempted before rodent eradication on Robinson Crusoe Island. In this way, small numbers

of remaining birds may be removed during the aerial baiting for rodents.

Although initial research will require some expenditure, it will be less expensive than a failed

eradication attempt, and will increase the chances of successful eradication. As the research

and trial phases of the experimental eradication procedure are completed, it will be possible

to estimate more accurately the risks, costs and benefits of proceeding with eradication.

10.5 Risks and their management

Some risks are specific to the management of certain species, or to the use of particular

techniques, and are dealt with in the individual species sections above. However, there are

some categories of risk that are broadly applicable to eradication programs and we discuss

these here. The following table is not a comprehensive list of anticipated risks and potential

risk management procedures. It is presented here to provide some indication of the types of

risks which may need to be managed when eradicating of invasive vertebrates from the

archipelago. More detailed lists will be prepared as part of operational planning.



Table 26 Some risks involved in eradication programs, and ways in which these risks may be managed.

RISK CATEGORY SPECIFIC RISKS RISK MANAGEMENT

Operational risks Field accidents

Weather disruptions

Equipment failure (e.g. helicopters)

Poor quality assurance on baits and toxicants

Comprehensive planning / Appropriate safety training / Good field equipment (e.g. boots, hand-held radios)

Appropriate provisions in plans and budgets (flexibility) / Use appropriate weather forecasting / Use local knowledge

Use only experienced crews and appropriate equipment / Ensure appropriate safety standards and operating procedures are rigorously applied

Ensure best-practice methods are used for quality assurance / Use suppliers with proven reliability

Outcome risks Objectives and targets not achieved

Perverse outcomes, e.g. weeds proliferate after removal of herbivores

Restoration targets not met

Non-target species impacts not acceptable

Use best-practice techniques, followed by a confirmation phase, on-going surveillance and biosecurity measures

Use proven techniques, with advice and support from experienced operators / Manage and monitor weeds, starting before eradication operation begins

Establish outcome monitoring (including baselines) / Keep restoration targets under review / Undertake research to refine targets / Initiate research to predict ecological, social and economic outcomes

Conduct non-target risk assessments to predict risks / Allow management authorities to determine if risks acceptable / Conduct mitigation actions to offset unacceptable risks / Involve experts in planning and implementation of mitigation actions / Pro-active public relations campaign

Institutional risks Insufficient skilled and motivated staff

Poor governance / management

Prioritise support and training of project staff / Ensure field staff share in achievements and successes / Appropriate remuneration

Establish governance structures and mechanisms at the outset / Consistently and transparently apply project management procedures



Financial risks Funding support not forthcoming

Budgeted costs exceeded

Funding support withdrawn

Identify potential funders (government/non-government, Chile/international) / Engage potential funders early, including seeking their feedback on this feasibility study

Use approved financial management procedures including regular audits

Ensure funding bids are realistically budgeted and linked to project plans / Keep funders informed, including regular reports to meet their information needs

Political risks Community support withdrawn

International support not forthcoming

Animal rights/welfare groups express opposition

Establish dialogue with stakeholder groups and identify their needs early in the project development process / Maintain dialogue and meet stakeholder information needs (e.g. regular reports) / Ensure openness and honesty in communications with stakeholders /Retain as much flexibility as possible to respond to new information and emerging needs

Ensure international profile from the outset (e.g. presentations at international conferences and workshops) / Ensure key international donors are aware of the project and funding opportunities.

Ensure animal welfare issues are appropriately addressed in project planning / Ensure appropriate ethical standards in manipulating animals are consistently applied



11 Restoration activites

A goal of all the invasive species management actions recommended here should be to

protect and restore the ecological integrity of indigenous ecosystems of the archipelago. Once

seed predators and herbivores are under control or have been eradicated, methodologies

established and capacity built in Phase 2, it should become increasingly possible to carry out

active restoration projects beyond the initial management sites. This will remain complicated

on Robinson Crusoe Island due to severe erosion and lack of soil, but on Alejandro Selkirk

we foresee this as increasingly feasible. While for these two islands, active restoration of

larger areas is a longer-term goal, a start can be made on Santa Clara Island, which is already

free of the major impediments to restoration.

11.1 Santa Clara Island

Santa Clara Island provides a good case study for ecological restoration. Following intensive

management action the island is now free of all invasive mammals. Fortunately, the most

invasive alien plants present in the archipelago never established on Santa Clara, and those

alien plants that are present may be helping stabilise the soil. Remnant populations of native

plants are beginning to recover. However, seeds of native plants on Santa Clara are scarce,

and while there is regeneration from the few remaining individuals on the island, the process

is slow.

There is historical evidence of the presence of a low forest cover on Santa Clara Island

dominated by Dendroseris litoralis, Chenopodium sanctae-clarae, Erigeron fernandeziana,

and Wahlenbergia berteroi (Johow 1896). Across the archipelago this vegetation type has

been almost completely destroyed by invasive herbivores. The successful removal of these

herbivores during the Holland Project and the absence of the worst transformer weed species

from Santa Clara Island provide an opportunity for its ecological restoration. This process has

begun naturally, but because of spatially limited seed banks it is likely to take a very long

time without further intervention. The likelihood of new weed incursions to the island means

it is necessary to accelerate the restoration process with supplementary planting.

A simple management action such as establishing focal areas to be planted with native plants

(Table 27) across the island will help increase the speed of recovery. This, in turn, will help

establish a plant community more resilient to weed incursion, and one that also helps stabilise

the soil. This project could become an important focus for community involvement in active

restoration, but will need to be preceded by efficient quarantine measures to prevent the

inadvertent introduction of any new invasive species. See Appendix 3 for more details.



Table 27 Feasibility of restoration on Santa Clara Island.


Technical Santa Clara is already restoring itself, and has no major weeds or herbivores

Due to small founder populations, regeneration is very slow, allowing for dominance by weeds

Restoration planting could present biosecurity risks as plants and materials are moved from Robinson Crusoe to Santa Clara

Propagation techniques for all native endemic species are not yet known

Identify key areas and species for planting with natives to act as foci for more rapid restoration

Develop a specific plant propagation program for Santa Clara

Develop and implement an inter-island quarantine program

Further research is needed on propagation of native species

Social General awareness of success story of Santa Clara

Little active involvement by community

Involvement of the community in the replanting program

Institutional CONAF have the infrastructure to propagate large numbers of native plants

Nursery management standards will have to be improved and training undertaken

Staff training in nursery management and large-scale production

Economic Dedicated staff in plant production exists

Staff often involved in other tasks

Allocation of funds to allow dedicated nursery manager

An outline for a Santa Clara Island Restoration Plan is provided in Appendix 3.

11.1.1 Recommendations for Santa Clara Island

A Santa Clara restoration plan should be prepared as soon as possible.

A biosecurity program should be established for the island before any restoration

program begins.

An intensive planting program is recommended for selected sites on Santa Clara. These

replanted sites would act as seed sources to accelerate future regeneration.

11.2 Robinson Crusoe Island

Following the removal of threats from the intact indigenous remnant plant communities on

Robinson Crusoe Island through site-led management, restoration planting may be required to

buffer and improve long-term viability of forest remnants, to re-introduce extirpated species,

and to bolster populations of rare or threatened species. Outside these priority sites, and even



with the removal of invasive herbivores and seed predators, we believe that restoration in the

short-term is not achievable in many areas due to a lack of soil, shade and water. Exotic

species naturalising into these areas (e.g. Acaena argentea) may act as ecological stepping

stones that will assist with the creation of more receptive environments for future restoration

planting of indigenous species in the longer term.

There is a need to involve the community in restoration activities and in education programs

in the archipelago. Restoration planting is a good way to generate community support for

conservation. Initiation of several of these projects in easily accessible locations would be

both important and achievable, given past successes at Plazoleta el Yunque. Species that

could be used in restoration planting are listed in Table 28.

Table 28 Species that could be used in restoration plantings on Robinson Crusoe Island.

Species Common name

Histriopsis incisa -

Ugni selkirkii Murtilla de Juan Fernández

Juania australis Palma chonta

Sophora fernandeziana Leña dura

Myrceugenia fernandeziana Luma

Coprosma pyrifolia Peralillo

Dendroseris marginata -

Gunnera peltata Pangue

Fagara mayu Naranjillo

Boehemeria excelsa Manzano

Rhaphithamnus venustus Juan Bueno

Haloragis masatierrana -

Cyperus reflexus Morcacho

Ochagavia elegans -

11.2.1 Recommendations for Robinson Crusoe Island

Prepare a restoration plan incorporating ecological and social goals, to guide longer-

term restoration activities on Alejandro Selkirk Island.

Establish baseline monitoring to detect changes in response to the management applied

and to alert managers to the need for further interventions (e.g. weed control).

Engage residents in management activities and ensure they remain well informed.

Small-scale restoration actions should be undertaken near the town (e.g. a continuation

of the Plazoleta program started during the Holland Project) or at easily accessible sites

(e.g. Villagra) to increase community involvement and community ‘ownership’ of

conservation activities and outcomes.



Time-frame

This work is not as urgent as protection of priority sites or biosecurity work. However,

restoration planning could commence any time in the next few years. The restoration of Santa

Clara Island should be an initial 5-year project.

Resources

Capital

Improved nursery infrastructure (including dedicated area for Santa Clara Island

restoration project)

Biosecurity room on Santa Clara Island

Hardening-off nursery on Santa Clara Island

Improved accommodation facilities on Santa Clara Island

Operating

Spades, plant production

Slow-release fertiliser

Staff

Coordinating project manager for all restoration work

Planting could be carried out by dedicated staff or community

Responsibilities

CONAF, SAG and community groups

11.3 Alejandro Selkirk Island

Although there are fewer eroded hill slopes with exposed soil and/or bare rock than on

Robinson Crusoe, the effects of burning, browsing and grazing are also evident on Alejandro

Selkirk. In addition to removing invasive herbivores, restoration activities may need to be

focused on restoring native plant communities at critical sites. Steeper head-catchments

(riparian protection) and key habitats for threatened plants and animals (species recovery) are

examples of sites which might be identified in a restoration plan where replanting or other

restoration activities may need to be undertaken. We have recommended that buffer planting

to protect and expand forest areas should be initiated at selected sites during the capacity

building phase. In addition to species recovery objectives (rayadito, firecrown, endangered

plants) these activities may lead to new and better restoration approaches and techniques to

be applied subsequently. In addition to natural increases in native invertebrate and bird

populations following the removal of invasive competitors and predators, consideration may



also be given to re-introducing birds such as ground-nesting and burrowing seabirds to

replace extirpated species, or to expand existing colonies. Important advances have been

made in developing successful seabird translocation techniques. It was suggested to us that

there may even be justification for re-introducing the firecrown to Alejandro Selkirk.

11.3.1 Recommendations for Alejandro Selkirk Island

Prepare a restoration plan incorporating ecological and social goals, to guide longer-

term restoration activities on Alejandro Selkirk Island

Establish baseline monitoring to detect changes in response to the management applied

and to alert managers to the need for further interventions (e.g. weed control)

Engage residents in management activities and ensure they remain well informed

Time-frame

The development of longer-term restoration plans for all three islands is urgent, starting with

Santa Clara. The establishment of baseline monitoring programs which will allow progress

towards restoration goals to be measured, and for ecological changes to be detected and

interpreted will also be important.

Resources

Staff

Coordinating project manager for all restoration work

Responsibilities

CONAF, SAG and community groups

12 Suggested timing of management activities

Many of the recommended actions in this report are inter-related. While some are short-term, others will need to be carried out indefinitely.

Below, we present a suggested sequence for recommended operations on each island. We emphasise that the suggested order of vertebrate

eradications below is contingent on all the operations being carried out simultaneously, or in quick succession. For example, if eradication of

cats is not carried out soon after the removal of goats on Alejandro Selkirk Island, the recovery of vegetation caused by goat removal could make

cat eradication much more difficult. The precise order and timing of operations will need to be determined by detailed operational planning.

Institutional capacity building, including training local people so that they can effectively contribute to management projects and ongoing

activities, will be important. Planning should involve extensive consultation with stakeholders and the community.

Table 29 Time frame for the major actions recommended in this report.

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

RC, AS, SC Establish and enforce biosecurity plan

RC, AS

Commence eradication of potentially

invasive weeds within the eradication zone

RC, AS

Containment of introduced plants within

the containment zone

RC, AS Site-led weed control

SC

Prepare and implement Santa Clara

Restoration Plan

RC

Eradication of feral goats and experimental

eradication of coatis

RC

Reduce distribution and numbers of cattle

in line with agreed plan

AS

Following agreement from island residents,

remove all cattle

RC Experimental eradication of house sparrows

RC, AS Experimental eradication of feral pigeons

AS

Eradication of rodents, feral cats and feral

goats

RC

Eradication of rodents, rabbits and feral

cats

Key: Planning, trials, consultation, capacity

building

Implementation

Confirmation

Year 4 Year 5 Year 6 Continue

IndefinitelyIsland(s) Action

Year 1 Year 2 Year 3

As discussed in Table 15, the timing of aerial baiting operations must be carefully planned to maximise effectiveness and minimise risk to non-

target species. Conducting baiting operations outside the breeding season of seabirds helps to minimise disturbance to the birds, and also ensures

that baits are available to the target species at a time when availability of other food sources (i.e. nesting birds and their eggs) is low. This

maximises the chances of target species consuming a lethal quantity of bait. Table 30 shows the timing of annual breeding for seabirds in the

Juan Fernández Archipelago, while Figure 19 shows the average monthly precipitation. Baiting operations should be designed using such

information.

Table 30 The breeding phenology of seabirds in the Juan Fernández Archipelago. (Courtesy of M. McKown and C. Wolf).

Common Name Species Island Nov. Dec. Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct.

Kermadec petrel Pterodroma neglecta Robinson Crusoe

Pink-footed shearwater Puffinus creatopus Robinson & Santa Clara

Juan Fernandez petrel Pterodroma externa Alejandro Selkirk

Stejneger's petrel Pterodroma longirostris Alejandro Selkirk

DeFilippe's petrel Pterodroma defilippiana Santa Clara

White-bellied storm petrel Fregetta grallaria segethi Santa Clara

KEY

At colonies

Egg laying / Incubation

Hatching

Chick rearing

Fledging

Figure 19 Average monthly precipitation in the Juan Fernández Archipelago. (Figure courtesy of M. McKown and C. Wolf).



13 Acknowledgements

We are sincerely grateful to the community of San Juan Bautista for their support and

hospitality, and for enthusiastically sharing with us their knowledge of their islands. We

thank the Municipalidad de Juan Fernández, CONAF and SAG for their generous

contributions of time and resources. Special thanks are due to the following people who

participated in discussions and site visits with us, and whose knowledge and views were

invaluable:

Mayor Leopoldo González, Felipe Paredes, Christian López, Daniel González, Scheila

Recabarren, Ramón Schiller, Danilo Arredondo, Bernardo López, Guillermo Araya, Oscar

Chamorro, Manuel Tobar, Jorge Angulo, Mascimiliano Recabarren, Alfonso Andaur, Hernán

González, Alexis Yañez Diaz, Juan Carlos Recabarren, Daniella Matta, Juan Carlos Ordenes,

Rosamaría Recabarren, Paola González, Juan Ramón Chamorro, Ronaldo Contreras, Patricia

Pereira, Miloska Rojas, Jacqueline Vergara, Johanna Hobart, Pablo Manriquez, Olivia

Chamorro, Christina Muena, María Elena Martínez, Julio Figueroa Silva, Ana Ponce, Julio

Figueroa, Javiera Meza, Santiago Huaiquinao, Cecilia González, Aurora Espinoza, Leonel

Sierralta, Sofia Guerrero, Gloria Rojas, Miguel Stutzin, Cecilia Smith, Philipe Danton and

Simon Haberle.

We are grateful also to V. Tatayah (Mauritian Wildlife Foundation), P. Clergeau (Institut

National de la Recherche Agronomique, France), P. Warren (Department of Conservation,

New Zealand), S. Arico (UNESCO), A. Woolnough (Department of Agriculture and Food,

Western Australia), M. McKown and C. Wolf (JFIC), and P. Fisher (Landcare Research) for

sharing information that was valuable in the preparation of this report. Chris Smuts-Kennedy

also provided information and advice.

Sincere thanks to J. Parkes, P. Cowan, D. Ward, L. Hayes and A. Byrom (Landcare

Research) and Brad Keitt and Hugo Arnal (Island Conservation) for constructive comments

on drafts of the report, and to Anne Austin, Kathryn O’Halloran and Allison Kerr for editing

and formating.



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Appendix 1: The feasibility study team and the peer-review process

Feasibility study team A seven-person team of international invasive species specialists formed the core of the

feasibility study team. The team members have collective expertise in managing and

eradicating invasive plants and animals, as well as experience of conservation in Chile.

Table A1. Composition and roles of feasibility study team

Team member Agency Roles

Alan Saunders Landcare Research, NZ Team Leader; Project oversight

Technical inputs (animals)

Al Glen Landcare Research, NZ Technical inputs (animals)

Karl Campbell Island Conservation, Chile Technical oversight (animals) Liaison & logistics

John Sawyer Consultant, New Zealand Technical oversight (weeds)

Rachel Atkinson Consultant, UK/Chile Technical inputs (weeds)

Hernán Torres

Erin Hagen

Consultant, Chile

Consultant, Chile

Facilitation & liaison

Technical advice

Alan Saunders Alan has been involved in ecological management for almost 40 years, and is currently

Manager of Invasive Species International, a subsidiary of Landcare Research, New Zealand.

He has been involved in species recovery and island restoration projects in New Zealand and

internationally, and has provided advice and expertise to a number of eradication projects.

Al Glen Al has over 15 years experience in research and management of invasive species. He has

specialist knowledge in carnivore ecology and ecological interactions between pest animals.

Al has advised various governments on managing communities of native and invasive

animals. He is currently a Postdoctoral Researcher at Landcare Research, New Zealand.

Karl Campbell Karl has over 13 years experience in island restoration in Latin America. He has pioneered

advanced techniques in pest animal eradication, and successfully overseen field operations

for the world’s two largest island restoration projects on Isabela and Santiago Islands. He is

currently a Senior Project Manager with Island Conservation.

John Sawyer John has more than 18 years experience in management of invasive environmental weeds and

recovery of threatened species. He has worked extensively on habitat protection and

ecological restoration in New Zealand including the Chatham Islands. John works as a

Supervisor and Plant Ecologist for the Department of Conservation, New Zealand.



Rachel Atkinson Rachel has over 8 years experience in managing invasive and conserving threatened plant

species and in ecosystem restoration on islands including the Galápagos, Mauritius and the

UK.

Hernán Torres Hernán has over 30 years experience of conservation management in Latin America and the

Caribbean. He has specialised in ecosystem planning and management and has advised

various governments and international organisations. He is currently Director of Torres

Asociados Limitada, his own consultancy firm in Chile.

Erin Hagen Erin has 9 years of experience working with local islanders to investigate and address

influences of introduced species on threatened avifauna of the Juan Fernández Archipelago.

She is currently a Project Ecologist with Oikonos, and a co-director of the Juan Fernández

Islands Conservancy.

The peer-review process A draft of this report was peer-reviewed by senior scientists within Landcare Research (John

Parkes, Phil Cowan, Lynley Hayes and Darren Ward) and Island Conservation (Brad Keitt

and Hugo Arnal), all of whom have extensive experience in island eradications and

management of invasive species. The comments and suggestions of these reviewers were

incorporated before the report was officially approved by the Science Leader of Wildlife,

Ecology and Epidemiology in Landcare Research, Andrea Byrom.



Appendix 2: Itinerary

Trip 1: Robinson Crusoe and Santa Clara (May 2010)

16 May 2010: Santiago

Discussion of terms of reference for the feasibility study

Initial briefing

17 May: Robinson Crusoe Island

Walk from airport to San Juan Bautista

Familiarisation with the island and the impacts of invasive species

18 May: Robinson Crusoe Island

Briefing from local advisor

Meeting with CONAF and SAG staff

Meeting with Mayor and Council

19–26 May: Robinson Crusoe and Santa Clara Islands

Site visits to various locations on Robinson Crusoe and Santa Clara Islands

Meetings with representatives of the Cattlemen’s Association, Fishermen’s

Association and SAG

Meetings and informal discussions with community members and Councillors

Review of relevant documents in the CONAF library

27 May: Viña del Mar

Meeting with CONAF Regional Director and staff

Review of relevant documents and files held in the CONAF Regional Office

28 May: Santiago

Meeting with Head of Sub-department for Wildlife and Regional Head (Valparaiso)

of Section for Natural Resources, SAG

Meeting with Departmental Head and staff of the Department for Protection of

Natural Resources, CONAMA

Meeting with Head of Department of Botany, Chilean National Museum of Natural

History



29 May: Santiago

De-brief

Trip 2: Alejandro Selkirk Island (December 2010)

5 December 2010: Santiago

Briefing for second trip

6 December: Robinson Crusoe

Flight to Robinson Crusoe Island

Boat trip to Alejandro Selkirk Island (overnight)

7 December: Alejandro Selkirk Island

Initial field inspection

Meeting with island residents in evening


Field trips, escorted by local residents and CONAF & SAG staff





Departed for Robinson Crusoe Island in early evening

11 December: Robinson Crusoe Island – Santiago

Arrived at Robinson Crusoe Island

Visit to CONAF & nursery inspection

Flight; Robinson Crusoe – Santiago

12 December: Santiago

De-brief


Meetings; SAG (Santiago & Viña del Mar)




Meetings; UNDP & NZ Embassy

Departure



Appendix 3: Possible outline of a Santa Clara Island Restoration Plan

Introduction Feral goats and rabbits were successfully eradicated from Santa Clara Island as part of the

Holland Project (1997–2003). Santa Clara is now free of all invasive mammals. Because of

the lack of mammalian predators the island is the main breeding site for many birds and

should be the subject of a restoration program (Bourne et al. 1992). Eradication is

increasingly being used as an important step in the restoration of island ecosystems around

the world. While it can be assumed that goats and rabbits were eradicated from Santa Clara as

a step towards restoring the island’s ecological values, we found no reference to such a

restoration goal. Ideally a restoration plan would be prepared before management was

undertaken. The process of preparing such a plan could allow a long-term vision for the

island to be declared, for agreement to be reached about appropriate management goals and

for necessary commitments to be discussed by key stakeholders. In addition to providing a

basis for more detailed planning, even a very brief restoration plan could also allow for

measures to be identified through which progress may be monitored and on-going

management improved. Restoration plans have also been used by donor agencies to inform

their decisions about funding restoration activities.

Even though important steps towards its restoration have already been taken (that is, the

eradication of goats and rabbits) the preparation of a Santa Clara Island Restoration Plan

would be both timely and useful. The process of preparing this plan could be used to develop

further capacity within organisations with relevant mandates. In addition to identifying an

agreed long-term vision, a Santa Clara Island Restoration Plan might also set out goals

relating to such issues as restoring vegetation (replanting?), recovering extirpated birds (re-

introductions?), baseline monitoring parameters (e.g. soil movement, seabird usage) and

biosecurity (quarantine and surveillance measures). Perhaps most importantly, a restoration

plan for Santa Clara Island would be available as a basis for consistent institutional and

funding support being provided. This would enhance the prospects of long-term goals being

achieved and sustained. It might also be used as a model for the preparation of a more

comprehensive restoration plan for the entire Juan Fernández Archipelago.

Restoration plans can be very brief – perhaps just a few pages. They can be prepared quickly,

provided all key stakeholders are engaged and able to influence goals and objectives. There is

no template for these plans – their content will depend on local and anticipated

circumstances, and on the expressed needs of key stakeholders. We have suggested a few

headings (below), with brief explanations, which a Santa Clara Island Restoration Plan might

contain. We would be happy to offer further comment and advice if appropriate.

Vision What will the island be like 50 years (or 500 years) from now? Based on our knowledge of

what it was like before human modification, what ecological attributes would we be hoping

to restore? While objectives and even longer-term goals might change as more information is

obtained, vision statements are less likely to change.



Goals What will need to be achieved to make progress towards our vision? If the vision involves

Santa Clara being extensively forested, for example, what, if anything, needs to be done to

facilitate the re-establishment of native vegetation? How will we minimise the risk of

invasive species such as goats or weeds establishing and jeopardising our restoration vision?

Ideally there will be social and economic goals, as well as ecological ones. Goals should be

strategic (What do we want to achieve?), rather than tactical (How will we achieve it?).

Management objectives What activities will need to be undertaken to achieve the goals? Objectives ideally should be

specific and measurable. One objective, for example, might be: ‘A plant nursery is

established on the island by December 2012 and is being maintained by CONAF in which

locally-sourced seed stock is being propagated for a planned island revegetation program.’

Performance measures What parameters will we use to measure progress towards our objectives, and goals? An

anticipated incremental increase in forest cover, for example, might be used to develop some

performance measures for a revegetation goal. The number of seeds collected and seedlings

planted may also be useful measures of relevant objectives.

Resources, effort and costs Until detailed operational plans are prepared which set out tasks, responsibilities and

timelines it is difficult to identify specific resourcing needs and costs. Indicative ‘ballpark’

estimates of project costs can be made, however, based on rough assessments of necessary

resources and effort required. ‘Ballpark’ cost estimates can be useful to management agencies

and donor institutions in determining the nature and level of any support they may provide in

order to achieve declared goals.



Governance How a project will be managed, and by whom are important considerations which should be

determined early in the planning process. While organisations may have different

requirements, clear project governance including provisions for accountability and

transparency will be important.


Appendix 4: Weed species for eradication from Robinson Crusoe Island

Species Family Common name

(English)

Common name (Spanish) Islands Feasibility and Notes

Agave americana Agavaceae Century plant, agave Agave RC HIGH Depending on distribution

Anredera cordifolia Basellaceae Madeira vine Enredadera de mosquito, Parra de Madeira

RC MEDIUM

Arum italicum italicum

Araceae Italian arum RC HIGH

Arundo donax Poaceae Giant reed RC HIGH

Bryophyllum pinnatum

Crassulaceae Air plant, Life Plant, Miracle Leaf

Hoja del aire RC MEDIUM Potential conflict with user

Buddleja globosa Loganiaceae Orange ball tree Matico RC HIGH

Canna indica Cannaceae Indian shot RC HIGH

Chasmanthe aethiopica

Iridaceae Chasmanthe, Cobra lily RC HIGH

Chusquea culeou Poaceae Matorral de colihue, Caña Coligüe

RC HIGH

Colocasia esculenta Araceae Taro Papa china RC HIGH

Cortaderia selloana Poaceae Pampas grass RC HIGH

Cupressus sempervirens

Cupressaceae Mediterranean cypress, Common cypress, Italian cypress.

Ciprés RC HIGH

Erigeron karvinskianus

Asteraceae RC HIGH

Fuchsia magellanica Onagraceae Fuchsia Chilco RC HIGH

Genista monspessulana

Fabaceae Montpellier broom Teline RC MEDIUM

Hedera helix Araliaceae Ivy Hiedra RC MEDIUM

Hedychium flavescens

Zingerbaraceae Yellow ginger RC MEDIUM

Ilex aquifolium Aquifoliaceae Holly Muerdago RC HIGH

Jasminum polyanthum

Oleaceae Jasmine RC HIGH

Kalanchoe blossfeldiana

Crassulaceae Mother of millions RC MEDIUM

Lantana camara Verbenaceae Curse of India, Lantana Supirrosa RC HIGH

Lardizabala biternata

Lardizabalaceae Zabala fruit Coquil, voqui blanco RC LOW Potential conflict as sweet fruit highly prized

Leonotis ocymifolia Lamiaceae Lions tail RC HIGH

Ligustrum japonicum Oleaceae Japanese privet Ligustrino, Ligustro RC LOW Unlikely to be possible as widely used for hedges

Lonicera japonica Caprifoliaceae Japanese honeysuckle Madreselva RC HIGH

Lupinus polyphyllus Fabaceae Large-leaved lupin, Russell lupin

RC HIGH

Nephrolepis exaltata Nephrolepidaceae

Sword fern Helecho RC MEDIUM

Opuntia ficus-indica Cactaceae Prickly-pear Tuna RC MEDIUM Potential conflict as has a use

Parietaria judaica Urticaceae Asthma weed, Spreading pellitory

RC MEDIUM

Passiflora caerulea Passifloraceae Blue passion flower RC HIGH

Phoenix canariensis Arecaceae Phoenix palm, Canary Island date palm

Palma de Canarias RC LOW Potential conflict as highly ornamental

Pittosporum Pittosporaceae Karo Pitosporo RC HIGH


crassifolium

Pittosporum tenuifolium

Pittosporaceae Black matipo Pitosporo RC HIGH

Pittosporum undulatum

Pittosporaceae Sweet pittosporum Pitosporo RC HIGH

Psidium cattleianum Myrtaceae Strawberry guava Guayaba RC LOW Potential conflict as fruit highly valued

Robinia pseudoacacia

Fabaceae False acacia Falsa acacia RC HIGH

Schinus molle Anacardiacaee Pepper tree Molle RC HIGH

Sporobolus indicus Poaceae Smut grass RC HIGH Only seen in one garden – if this is correct then eradication is feasible

Tecoma (Podranea) ricasoliana

Bignoniaceae Pink trumpet vine, Port St John creeper

RC HIGH

Tradescantia fluminensis

Commelinaceae Wandering willie RC–AS MEDIUM

Watsonia borbonica borbonica

Iridaceae Bugle lily RC HIGH

Watsonia meriana Iridaceae Bugle lily RC HIGH

Xanthium spinosum Asteraceae Bathurst bur Abrojo RC–AS HIGH

Appendix 5: Weed species for eradication from Alejandro Selkirk Island

Species Family Common name (English) Common name (Spanish) Islands Feasibility and Notes

Acacia melanoxylon Fabaceae Australian blackwood Aromo RC–AS HIGH

Ailanthus altissima Simaroubaceae Tree of heaven AS

HIGH (although concern about its benefit as a wind break)

Carpobrotus edulis Aizoaceae Ice plant Doca RC–AS HIGH (only present on 2 cliff faces)

Crocosmia crocosmiiflora Iridaceae Montbreccia Patas de gallo RC–AS HIGH

Cupressus macnabiana Cupressaceae Macnab cypress Ciprés RC–AS HIGH (this species may not still be present)

Eucalyptus globulus Myrtaceae blue gum Eucalipto RC–AS MEDIUM (it is used as firewood for barbecues, and occasionally for lobster traps)

Pinus radiata Pinaceae Monterrey pine Pino insigne RC–AS

MEDIUM (At most 2 individuals, but one is a very large beautiful tree in the village)

Psidium cattleianum Myrtaceae Strawberry guava Guayaba RC–AS HIGH (one plant recently introduced)

Ricinus communis Euphorbiaceae castor oil plant Higuerilla RC–AS HIGH (this may already not exist)

Salix babylonica Salicaceae Weeping willow Sauce llorón RC–AS HIGH


Appendix 6: Weed species for containment on Robinson Crusoe Island

Species Family Common name (English) Common name (Spanish)

Islands Feasibility and Notes

Acacia dealbata Fabaceae Silver wattle Aromo RC–AS HIGH Provides food for hummingbird

Acacia melanoxylon Fabaceae Australian blackwood Aromo RC–AS HIGH Provides food for hummingbird

Amaryllis belladonna Amaryllidaceae Naked lady, Belladonna lily

Belladonna RC MEDIUM – widespread

Delairea odorata (Senecio mikaniodes)

Asteraceae German ivy Senecio RC MEDIUM – widespread

Eucalyptus globulus Myrtaceae Blue gum Eucalipto RC–AS HIGH

Ipomoea indica Convolvulaceae Blue morning glory RC MEDIUM – harder to detect

Olea europea Oleaceae Olive Oliva RC HIGH

Paraserianthes (Albizia) lophantha

Fabaceae Brush wattle, Albizia, Cape wattle, Stink bean

Peorilla RC HIGH Provides food for hummingbird

Pinus pinaster Pinaceae Maritime pine Pino RC HIGH

Pinus radiata Pinaceae Monterrey pine Pino insigne RC–AS HIGH

Vinca major Apocynaceae Large periwinkle Hierba donzella RC MEDIUM – harder to detect

Zantedeschia aethiopica Araceae Arum lily Cala RC–AS MEDIUM

Appendix 7: Weed species for site-led control at high priority sites

Alejandro Selkirk Island

Species Family Common name (English) Common name (Spanish)

Islands Feasibility and Notes

Aristotelia chilensis Elaeocarpaceae Chilean wineberry Maqui RC–AS HIGH

*Rubus ulmifolius Rosaceae Blackberry Zarzamora RC–AS HIGH

*Ugni molinae Myrtaceae Chilean guava Murtilla RC–AS HIGH

*Depending on their distribution, which is so far not known


Robinson Crusoe Island

Species Family Common name (English) Common name (Spanish) Islands Feasibility and Notes

Acaena argentea Rosaceae Bidibid Amores secos RC–AS HIGH

Acaena ovalifolia Rosaceae Bidibid Cadillo RC–AS HIGH

Anthoxanthum odoratum Poaceae Sweet vernal grass, Holy grass, Vanilla grass, Buffalo grass

RC–AS HIGH

Aristotelia chilensis Elaeocarpaceae Chilean wineberry Maqui RC–AS HIGH

Conium maculatum Apiaceae Hemlock RC–AS HIGH

Cupressus goveniana Cupressaceae Gowen cypress Ciprés RC HIGH

Cupressus macnabiana Cupressaceae Macnab cypress Ciprés RC–AS HIGH

Cupressus macrocarpa Cupressaceae Monterry cypress Ciprés RC HIGH

Dactilis glomerata Poaceae Cocksfoot RC HIGH

Galium aparine Rubiaceae Cleavers RC–AS MEDIUM – hard to detect

Pittosporum eugenioides Pittosporaceae Lemon wood RC HIGH

Rubus ulmifolius Rosaceae Blackberry Zarzamora RC–AS MEDIUM – hard to detect

Rumex acetosella Polygonaceae Sheep’s sorrel Vinagrillo RC–AS HIGH

Solanum nigrum Solanaceae Black nightshade RC HIGH

Sorghum halepense Poaceae Johnson grass Grama china RC MEDIUM – hard to detect

Ugni molinae Myrtaceae Chilean guava Murtilla RC–AS HIGH



Appendix 8: Glossary

Term Definition for the purposes of this document

Areas Verdes The group employed by the Municipality of Juan Fernández to

manage public parks and gardens

Adaptive management An iterative process of making management decisions, monitoring

the outcomes and, if necessary, modifying the management approach

if monitoring suggests that optimal outcomes are not being achieved

AvesChile Unión de Ornitólogos de Chile. A non-profit organisation promoting

the study and conservation of Chilean birds and their environments

Biodiversity The diversity of natural phenomena, including genes, species,

ecosystems and ecological processes

Cat, domestic Cats living in close association with humans, who provide all of

their needs for survival. These cats often hunt live prey, but do not

need to do so to survive (Moodie 1995)

Cat, feral Feral cats live in the wild, forming breeding populations that are not

dependant on humans (Moodie 1995)

Cat, stray Stray cats generally live around human settlements where they

obtain some resources such as food or shelter, but are not owned by

humans (Moodie 1995)

CONAF

CONAMA

Corporación Nacional Forestal

Comisión Nacional del Medio Ambiente

Domestic cat See Cat, domestic

Endemic An endemic species (or group of species) is one which is native to a

particular area and occurs nowhere else

Feral cat See Cat, feral

Introduced Introduced species are species that have been transported to the area

in question (either deliberately or inadvertently) by humans.

Introduced species, may be harmful, neutral or beneficial to humans

and the environment (Low 2007)



Invasive Invasive species are introduced species that have spread beyond their

point of introduction, having adverse impacts on humans and/or the

environment

JFIC Juan Fernández Islands Conservancy

Rada la Colonia The settlement on Alejandro Selkirk Island, inhabited by lobster

fishermen and their families from October through May each year

SAG Servicio Agrícola y Ganadero

San Juan Bautista The town in Cumberland Bay, Robinson Crusoe Island

Managing invasive species Juan Fernández Archipelago

Documents

Transcript of Managing invasive species Juan Fernández Archipelago