Selecting Focal Species in Ecological Network Planning following an Expert-Based Approach: A Case...

PLEASE SCROLL DOWN FOR ARTICLE

This article was downloaded by: [Battisti, Corrado]On: 28 April 2010Access details: Access Details: [subscription number 915931445]Publisher RoutledgeInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Landscape ResearchPublication details, including instructions for authors and subscription information:http://www.informaworld.com/smpp/title~content=t713437121

Selecting Focal Species in Ecological Network Planning following anExpert-Based Approach: A Case Study and a Conceptual FrameworkValerio Amici a;Corrado Battisti b

a Department of Environmental Sciences, University of Siena, Siena, Italy b EnvironmentalService—Nature Conservation Office, Rome, Italy

To cite this Article Amici, Valerio andBattisti, Corrado(2009) 'Selecting Focal Species in Ecological Network Planningfollowing an Expert-Based Approach: A Case Study and a Conceptual Framework', Landscape Research, 34: 5, 545 — 561To link to this Article: DOI: 10.1080/01426390903177268URL: http://dx.doi.org/10.1080/01426390903177268

Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf

This article may be used for research, teaching and private study purposes. Any substantial orsystematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply ordistribution in any form to anyone is expressly forbidden.

The publisher does not give any warranty express or implied or make any representation that the contentswill be complete or accurate or up to date. The accuracy of any instructions, formulae and drug dosesshould be independently verified with primary sources. The publisher shall not be liable for any loss,actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directlyor indirectly in connection with or arising out of the use of this material.

http://www.informaworld.com/smpp/title~content=t713437121

http://dx.doi.org/10.1080/01426390903177268

http://www.informaworld.com/terms-and-conditions-of-access.pdf

Selecting Focal Species in EcologicalNetwork Planning following anExpert-Based Approach: A Case Studyand a Conceptual Framework

VALERIO AMICI* & CORRADO BATTISTI***Department of Environmental Sciences, University of Siena, Siena, Italy

**Environmental Service—Nature Conservation Office, Rome, Italy

ABSTRACT In connectivity conservation and ecological network planning, the selection of focalfragmentation-sensitive species represents an a priori step. Despite their strategic role, selectionof focal species has often been carried out following non-objective approaches. If this is done,actions of planning and conservation, especially in relation to biodiversity conservation, could beineffective. We propose an expert-based approach to select focal species on the basis of sensitivityto three components of habitat fragmentation (habitat area reduction, increase of habitatisolation, increase of edge effect and landscape matrix disturbance) and of intrinsic ecologicaltraits of the species (trophic level, dispersal ability, body size, niche breadth, rarity). A case studyon terrestrial mammals of an area in Central Italy (province of Rome) shows that the speciesselected through this approach largely coincide with the species recognized in the literature asbeing fragmentation-sensitive. In this paper we present a conceptual framework to selectfocal species and to define a schematic methodology for ecological network planning andmonitoring.

KEY WORDS: Habitat fragmentation, ecological networks, focal species, sensitive species

Introduction

Habitat Fragmentation and Connectivity Conservation

Human-induced habitat fragmentation (HIHF) has been considered as a complexprocess induced by a plethora of disturbances in the landscape-scaled scenario(Fahrig, 1997, 2003; Lindenmayer & Fisher, 2007; Nichols et al., 1998). Thisprocess is one of the leading causes of loss of biodiversity, producing changes inlandscape patterns, species disruption, decrease in patch size and extinction ofsensitive animal populations (Andren, 1994; Saunders et al., 1991). HIHF can bedivided into three macro-components: i) reduction of the habitat area at patchand/or landscape scale (hereafter, AREA); ii) increase of habitat isolation, eitherfor barriers or for distance between fragments (hereafter, ISOL); iii) reduction in

Correspondence Address: Corrado Battisti, Provincia di Roma, Environmental Service—Nature

Conservation Office, via Tiburtina, 691, Rome, 00159 Italy. E-mail: [email protected]

Landscape Research,Vol. 34, No. 5, 545–561, October 2009

ISSN 0142-6397 Print/1469-9710 Online/09/050545-17 � 2009 Landscape Research Group Ltd

DOI: 10.1080/01426390903177268

Downloaded By: [Battisti, Corrado] At: 10:42 28 April 2010

the ecological suitability of the remnant fragments (e.g. habitat degradationand/or reduction of the resources available) due to the edge effect and a largenumber of different disturbances originating from the surrounding landscapematrix (hereafter, EDGE) (Andren, 1994; Fahrig, 2003). The ecological sensitivityto HIHF is a strictly species-specific trait (Ewers and Didham, 2007; Robinsonet al., 1992) and several studies have underlined that the sensitivity of a speciesto fragmentation sensu lato could be related to one or more specific macro-components of this process (AREA, ISOL, EDGE) (Ewers & Didham, 2006; Henleet al., 2004).

Recent research on connectivity conservation generally aims to mitigate the effectsof habitat fragmentation on species, communities, ecosystems and ecological pro-cesses through specific planning actions in conservation and management strategies.This is carried out with consideration of the wider repercussions on the preservationof the ecosystem and landscape patterns and processes (Bennett, 2003; Crooks &Sanjayan, 2006; Kareiva & Wennergren, 1995).

Recently, several public agencies have focused on ecological networks as a specificlandscape approach for connectivity conservation (Bennett, 1998; Jongman &Kristiansen, 2001; Jongman & Pungetti, 2004). Ecological networks are defined asnature policy plans that explicitly relate to conservation on a landscape scale(Boitani et al., 2007; Suter, 1998). These plans define a ‘system of nature reserves andtheir interconnections that make a fragmented natural system coherent, so as tosupport more biological diversity than in its non-connected form’ (Jongman &Pungetti, 2004, p. 24). Globally, more than 150 of these plans are available atdifferent scales (from local to continental scales; Bacon, 2000; Bennett, 2003; Boitaniet al., 2007; Hudson, 1991). Therefore, despite the fact that this approach is based onecological, biogeographic and conservation paradigms, there is an element ofweakness in the plans, which is the lack of specific targets and indicators (e.g., at thespecies level) established a priori to permit a multitemporal monitoring to evaluatethe effectiveness of the actions (Battisti, 2003; Boitani et al., 2007). Indeed, despiteseveral examples of ecological network plans that identify a selection of species to beutilized like indicators, these have been labelled with unclear terms (e.g., target,focal, interesting species) and their selection has been made with varying degrees ofaccuracy and objectivity (Boitani et al., 2007).

The Focal Species Approach

The use of surrogate species in landscape planning and practical conservation isrecommended although it is widely debated and criticized (Andelman & Fagan,2000; Simberloff, 1998). It has been proposed that focal species should be species-sensitive to land use change processes, human-induced disturbances and HIHF, witha function as multitasking indicators (Lambeck, 1997). Using this approach, a focalspecies is identified as the one showing the most critical requirements in terms of aspatial (in our case, AREA, ISOL) or regime disturbance (in our case, EDGE)metric. If the HIHF is considered a landscape disturbance by planners, we canidentify species that show a higher sensitivity to this process and to their macro-components (AREA, ISOL, EDGE). Using this approach in our research, we aimedto measure the effectiveness of an ecological network, selecting a set of indicators of

546 V. Amici & C. Battisti


HIHF-sensitivity and identifying the species that were more sensitive to each macro-component of the fragmentation process (i.e., AREA, ISOL, EDGE). The focalspecies approach can be defined as a shortcut for identifying management actionsrequired to meet the needs of the most vulnerable species in a landscape with respectto the processes responsible for their decline (in our case, HIHF).

The selection of a set of fragmentation-sensitive focal species (FSFS) allows thedefinition of appropriate measures for conservation and the creation of specificmonitoring actions. For instance, in a study area, the selected species will allow thedefinition of specific strategies aimed to mitigate the impacts induced from the HIHFprocess (e.g., increase of availability of suitable habitat area, increased connectivityamong habitat fragments, increase in matrix suitability and mitigation of dis-turbances from the matrix; Bennett, 2003). Furthermore, the selection of FSFS canbe useful for periodic monitoring of the planning measures. Multiple sets of theseFSFS species, defined for each of the components of habitat fragmentation, can beregarded as a ‘focal community’, whose combined needs can be used to address arange of management actions (Brooks, 2002).

How to Select Focal Species for Ecological Network Planning?

a. Summary from literatureA screening of the scientific literature to identify those species for which there isevidence of a sensitivity to HIHF and its macro-components reveals that there arethree main restrictions:

(1) Literature on HIHF-sensitivity of individual species is extremely limited innumber and is oriented to the least neglected taxa of vertebrates (birds andmammals; Andren, 1994; Bright, 1993; Opdam et al., 1994); therefore, to obtaincomplete information on the HIHF-sensitivity of a broad set of species for astudy area can be difficult, if not impossible. Moreover, the parameters used,the data obtained and findings relating to patterns and implications of theHIHF-sensitivity of species are strongly skewed towards those taxa that aremore studied;

(2) Most of the papers on the HIHF-sensitivity of individual species havebeen carried out in Northern Europe, North America and Australia(Lindenmayer & Fisher, 2007): HIHF-sensitivity is a context-specific attribute,and to extend the original results of works carried out in geographic areas thatdiffer from our study landscape contexts (i.e., the Mediterranean area) couldresult in an incorrect planning design decision;

(3) Some works from the literature referenced spatial and time scales that do notcoincide with our study area and, therefore, results are not comparable (thesensitivity can be scale-specific; Kareiva & Wennergren, 1995).

b. Context-specific oriented researchIt may be useful to select sensitive-species on the basis of data obtained from ad hocstudies in focused areas of ecological network planning (Angelstam et al., 2004;Bani et al., 2002, 2006; Lorenzetti & Battisti, 2007). Nevertheless, such research mayrequire considerable effort and financing. Moreover, in strategies promoted by

Selecting Focal Species in Ecological Network Planning 547


Public Agencies (as, e.g., Provinces or Departments), time available for landscapeplanning is limited (generally defined by laws and ranging between six months andtwo years; Selman, 2006) and carried out on a limited number of taxonomic- orecological-characterized species assemblages. Therefore, results cannot be exhaustivebecause of the low number of taxa analysed, the restriction on study length and, lastbut not least, the presence of confounding factors and autocorrelation betweenlandscape-independent variables (for example between area of fragments and theirdegree of isolation) that could locally affect the level of species-sensitivity towardsone or more macro-components of HIHF.

c. Expert-based approaches: Direct selection of fragmentation-sensitive speciesSeveral authors (e.g., Hess & King, 2002) have used the Delphi method for theselection of focal species in landscape planning, obtaining the information on thespecies to be selected through the advice of a panel of experts. This approach seemsto be useful when uncertainty is high, study time is restricted and metrics are notcomparable (Linstone & Turoff, 1975). Therefore, expert-based approaches may beused to gain an early detection of fragmentation-sensitive species in the absence ofdata from scientific literature or from field investigations.

A first stage can be to hypothesize the selection of the FSFS through an analysis ofthe responses from a panel of experts that judge the HIHF-sensitivity for eachmacro-component within a range (e.g., high, medium, low) which can then betransformed into simple numerical values (e.g., 3, 2, 1). This permits a rapidquantitative analysis, and a ranking of species-sensitivity to HIHF and for eachmacro-component (AREA, ISOL, EDGE). This approach could be difficult tooperate because of a lack of relevant expertise in the panel of experts (i.e., the HIHF-sensitivity of the species) or because literature on HIHF-sensitivity for single targetspecies could be lacking or scarce. So, the numerical scores provided by experts mayappear to be more a speculative and subjective evaluation than a true assessment offragmentation-sensitive species.

d. Expert-based approaches: Ecological-based selection of fragmentation-sensitivespeciesOwing to the chronic shortage of qualitative and quantitative data on fragmenta-tion-sensitivity found in many species within species assemblages, a direct selectionof the FSFS using an expert-based approach could prove to be difficult. Specializedresearchers of the different animal groups may not be exhaustive or correct in theirevaluation for a number of reasons: i) there are only a limited number of species thatare well-known with regard to this issue (i.e., HIHF-sensitivity); ii) when HIHF-sensitivity of a species is obtained, it is not always clear to which macro-componentof HIHF this species shows a specific sensitivity.

A selection could be based on the knowledge of species-specific ecological traitsdefined a priori, which, indirectly, may provide an indication of HIHF-sensitivityand relative macro-components (AREA, ISOL, EDGE). The ecology of manyspecies is generally better known than their HIHF-sensitivity. Therefore, an expert-based approach that assigns simple numerical values (e.g., 1: low; 4: high) could be auseful way to judge the ecological traits of a set of species, rather than trying toidentify their sensitivity toward HIHF and the macro-components of the process.



The aim of this preliminary work is to contribute to the definition of a conceptualframework and to provide a quick methodology for the selection of a set of FSFSuseful for landscape planning. Identification of the selected species may facilitatethe definition of specific strategies that are needed to mitigate the impact ofthe fragmentation process (e.g., increase of habitat size, area of the fragments,increase of connectivity among habitat fragments, increase of environmental qualityof human-made matrix; Bennett, 2003). The following is a case study that usesthis approach on terrestrial mammals present in a specific area of the Province ofRome.

A Procedure for the Selection of FSFS

An approach to the selection of FSFS can be to characterize them by identifyingecological traits that indirectly determine the intrinsic sensitivity of species to habitatfragmentation.

Several authors have identified a set of key characteristics that may facilitate anevaluation of the HIHF-sensitivity of animal species. Species: i) are rare (in terms ofabundance); ii) require habitats of large suitable size habitat areas; iii) are subject tonatural demographic fluctuations; iv) show a low reproductive potential; v) have alow dispersal ability; vi) show a high ecological specialization; vii) show a way ofutilization of environmental mosaic reduced to one or a few elements (Bright, 1993;Crooks, 2002; Haila, 1985; Henle et al., 2004).

Ewers & Didham (2006) showed how species response to HIHF and its macro-components may be related to some species-specific ecological traits. These authorsproduced a set of diagrams to show synthetic responses of species (in terms ofcategories of sensitivity: high, intermediate, low) to each of the five components ofHIHF that were selected: i) reduction in fragment area; ii) decrease of the distancefrom the edge of the fragment; iii) morphological increase of the complexity of thefragment; iv) increase of the degree of isolation; v) increase of the morphologicaland structural contrast between matrix and fragment. This response correlates,indirectly, to five ecological traits of each species, i.e. trophic level, dispersalcapacity, body size, niche breadth, rarity (in terms of numerical abundance).Therefore, if the ecological traits of a species are known, on a simplified nominalscale an evaluation of its sensitivity (high, medium, low) to each of the macro-components of HIHF can be obtained (Ewers & Didham, 2006).

On this basis, we decided to bring the five components of fragmentation listed bythese authors together with the three main macro-components (see Bennett, 2003):AREA (corresponding to component 1 of Ewers and Didham, 2006), ISOL (com-ponent 4), EDGE (components 2, 3 and 5). A new evaluation matrix was thendevised to transform the qualitative evaluations (high, medium, low) intoquantitative values (3, 2, 1). Values were assigned from 1 (corresponding to thejudgement of ‘low sensitivity’) to 2 (‘medium sensitivity’), to 3 (‘high sensitivity’).The value 0 was assigned to the absence of response to process (Table 1).

Using this approach along with a knowledge of the ecology of a species, it ispossible to obtain an indirect approximate indication of the potential sensitivityof a species to each of three macro-components of HIHF by adding the valuesobtained for each of five ecological traits considered. The range of the values



Table

1.Matrix

ofevaluationofthespecies-specificecologicaltraits(columns)

andmacro-components

ofhabitatfragmentation(adaptedfrom

Ewers&

Didham,2006)

HIH

Fmacro-

component

Trophic

level

(TL)

Dispersalability(D

A)

Bodysize

(BS)

Nichebreadth

(NB)

Rarity

(RA)

High

Interm

ediate

Low

Low

Interm

ediate

High

LargeInterm

ediate

Small

Generalist

Interm

ediate

Specialist

Rare

Interm

ediate

Spread

AREA

32

13

13

32

11

23

32

1ISOL

32

13

13

32

11

23

32

1EDGE

00

03

21

00

01

23

00

0

HIH

F:human-inducedhabitatfragmentation;AREA:reductionofhabitatsurface;ISOL:increase

ofhabitatisolation;EDGE:edgeeff

ect/matrix

disturbance);1:low

sensitivity;2:interm

ediate

sensitivity;3:highsensitivity;0:absence

oftrend.



(5–15 for macro-component AREA and ISOLATION, 2–6 for EDGE), weprovided a set of conventional threshold values beyond which the speciescould be considered as FSFS (410 for the AREA and ISOLATION, 45 forEDGE).

Further breakdown of the selected FSFS for habitat categories (for example:inland wetlands, forests, agro-ecosystems, mosaic landscapes) was carried out for thespatial scale of their populations (for example, 10–100 km2; 4100–1000; 41000).The selected FSFS is reported in Table 2, which shows the three macro-componentsof HIHF, the scale of populations, and the suitable habitat categories. Finally, asubset of FSFS was produced in relation to the scale/habitat category for eachcomponent of fragmentation (Table 3).

The selection procedure is synthesized into a conceptual scheme with nine steps(Figure 1).

A Case Study: Mammals in a Mediterranean Landscape (Central Italy)

Study Area

The study area was approximately 120 km square and is sited in the northernportion of the province of Rome (Central Italy, between 428 100 and 428 300 Northlatitude, between 128 400 and 128 600 East longitude, UTMWGS84 zone 33N). In thearea, the most evident geomorphologic feature is the Monte Soratte (691 m a.s.l.), acarbonate relief that stands prominently out of the low volcanic hills (on average100 m a.s.l.). The alluvial plain of the Tiber River (on average 36 m a.s.l.) occupiesthe eastern part of the area; this stretch consists of a broad floodplain, which is avalley excavated during the last glacial period and then filled with sediments fromrecent floods (Ventriglia, 1990).

The study area is a typical Mediterranean landscape. It includes different habitattypes:

. the Tiber Valley, characterized by rivers and small marshlands (hygrophyle andsub-hygrophyle vegetation of the alluvial plain);

. the foothills, characterized by small-scale croplands interspersed with smallwooded areas (broadleaved species with a prevalence of Quercus pubescens andQuercus cerris) and hedgerows, pseudo-steppes of grasses and annual plants(Thero-Brachypodietea habitat type);

. the area of Mount Soratte characterized by carstic limestone grassland,broadleaved forests and sclerophyllous vegetation (Alysso-Sedion albi habitattype, mixed forests with a prevalence of Quercus ilex, scrubs and woodlandcharacterized by the prevalence of Quercus ilex, Pistacia lentiscus, Phyllirealatifolia, Rhamnus alaternus and Laurus nobilis) (Provincia di Roma, 2004).

Results

In the study area, there are 27 species of native terrestrial mammals (Amori &Battisti, 2008). The values of sensitivity to each component of fragmentationwere obtained for each species on the basis of ecological traits known (Table 4).



Table

2.Example

ofmatrix

withfragmentation-sensitivefocalspecies,

components

offragmentationto

whichthey

are

sensitive,

spatialscale

of

populations(inlogarithmic

classes,in

km

2),andreference

habitatmacro-type

Species

Macro-components

ofHIH

FScales

Habitatmacrotypes

Acronym

FSFS

AREA

ISOL

EDGE

10–100

100–1000

41000

WET

FOR

AGR

MOS

...

....

x/

//

/x

x/

//

...

....

xx

/x

//

/x

/x

...

....

/x

xx

x/

/x

xx

FSFS:fragmentation-sensitive

focalspecies;

AREA:reduction

ofhabitatsurface;ISOL:increase

ofisolation;EDGE:edge

effect/matrix

disturbance;WET:inlandwetlands;FOR:forest

ecosystem

;AGR:agro-ecosystem

s;MOS:mosaic

landscape.



The threshold values defined for each component of fragmentation indicated aset of nine focal species (with a higher value than that defined as conven-tional threshold): Eliomys quercinus, Glis glis, Muscardinus avellanarius, Neomysanomalus, Neomys fodiens, Sciurus vulgaris, Martes martes, Meles meles, andMustelaputorius.

The set of selected focal species were then divided using the three macro-components of HIHF toward which they show a sensitivity, the suitable spatial scaleof populations and habitat category (Tables 5 and 6).

Discussion

This expert-based approach may facilitate the definition of sets of FSFS on the basisof the knowledge of a set of ecological traits. This approach can overcome, at least ina preliminary phase, the problem of limited data available in the literature on thesensitivity of species to HIHF. HIHF-sensitivity information obtained using anindirect ecological approach can be made more robust using available data becausethe level of knowledge of species-specific ecological traits is certainly higher whencompared to knowledge of species-specific sensitivity to HIHF. Even so, thesensitivity of a species may be difficult to define using this process, so using expertswho are specialists in a particular taxonomic group can certainly help to identify therelevant ecological traits.

The species selected as the most HIHF-sensitive can be considered as: i) FSFS forthe purposes of ecological network planning, ii) indicators for monitoring, and iii) atool to identify habitat suitability models (Crooks & Sanjayan, 2006).

This case study supports the selection of specific focal species, particularlyspecialized species such as shrews, forest micro-mammals (rodents) and carnivores

Table 3. Selection of subset of fragmentation-sensitive focal species (FSFS) divided formacro-components of fragmentation, habitat macro-types and spatial scale (logarithmic scale,in km2)

SCALE WET FOR AGR MOS

AREA10–100 Subset of FSFS100–100041000

ISOL10–100 Subset of FSFS100–100041000

EDGE10–100 Subset of FSFS100–100041000

FSFS: fragmentation-sensitive focal species; AREA: reduction of habitat surface; ISOL:increase of isolation; EDGE: edge effect/matrix disturbance; WET: inland wetlands; FOR:forest ecosystem; AGR: agro-ecosystems; MOS: mosaic landscape.



(mustelids). These species coincide with those widely known in the literature assusceptible to HIHF (e.g. shrews: Farkas et al., 1998; Peltonen & Hanski, 1991;rodents: Bright & Morris, 1994; Delin & Andren, 1999; Wauthers & Dhondt, 1992;mustelids: Kowalczyk et al., 2006; Pertoldi et al., 2001; Virgos et al., 2002; see alsoBright, 1993).

Figure 1. Conceptual framework (nine-step) for objective selection of fragmentation-sensitivefocal species for ecological network planning by an expert-based approach.



Table4.Sensitivityvalues

toeach

componentofhuman-inducedhabitatfragmentationassigned

totheterrestrialmammalsofthecase

studyareaon

thebasisoffiveselected

ecologicaltraits

HIH

Fmacro-components

AREA

ISOL

EDGE

Species

TL

DA

BS

NB

RA

tot

TL

DA

BS

NB

RA

tot

TL

DA

BS

NB

RA

tot

Crocidura

leucodon

21

12/3

17/8

22

12/3

18/9

02

02/3

04/5

Crocidura

suaveolens

21

12/3

17/8

22

12/3

18/9

02

02/3

04/5

Erinaceuseuropaeus

21

11/2

16/7

22

11/2

17/8

02

01/2

03/4

Sorexantinori

21

12/3

17/8

22

12/3

18/9

02

02/3

04/5

Sorexminutus

21

13

29

22

13

210

02

03

06

Sorexsamniticus

21

12/3

17/8

22

12/3

18/9

02

02/3

04/5

Suncusetruscus

21

12/3

17/8

22

12/3

18/9

02

02/3

04/5

Talparomana

21/3

11/2

16/9

22/3

11/2

17/9

02/3

01/2

03/5

Lepuseuropaeus

13

21/2

29/10

11

21/2

27/9

01

01/2

02/3

Oryctolaguscuniculus

11

11

37

12

11

38

02

01

03

Sciurusvulgaris

22/3

22

210/11

22/3

22

210/11

03

02/3

05/6

Apodem

usflavicollis

11

11/2

1/2

5/7

12

11/2

1/2

6/8

02

01/2

03/4

Apodem

ussylvaticus

11/3

11

15/7

11/2

11

15/6

01/2

01

02/3

Eliomysquercinus

1/2

31

32/3

10/12

1/2

31

32/3

10/12

03

03

06

Glisglis

1/2

31

32/3

10/12

1/2

31

32/3

10/12

03

03

06

Hystrixcristata

13

21

18

11

21

16

01

01

02

Microtussavii

13

11

17

11

11

15

01

01

02

Muscardinusavellanarius

1/2

31

32/3

10/12

1/2

31

32/3

10/12

03

03

06

(continued)



Table

4.(C

ontinued)

HIH

Fmacro-components

AREA

ISOL

EDGE

Species

TL

DA

BS

NB

RA

tot

TL

DA

BS

NB

RA

tot

TL

DA

BS

NB

RA

tot

Musdomesticus

13

11

17

11

11

15

01

01

02

Myodes

glareolus

11

11/2

1/2

5/7

12

11/2

1/2

6/8

03

03

06

Neomysanomalus

23

13

312

23

12

311

03

03

06

Neomysfodiens

23

13

312

23

12

311

03

03

06

Rattusnorvegicus

13

11

17

11

11

15

01

01

02

Rattusrattus

13

11

17

11

11

15

01

01

02

Martes

foina

2/3

12

22

9/10

2/3

1/2

22

29/11

02

02/3

04/5

Martes

martes

31/3

23

2/3

11/14

32/3

23

2/3

12/14

02/3

03

05/6

Meles

meles

2/3

32

21/2

10/12

32

22

1/2

10/11

02/3

02/3

04/6

Mustelanivalis

31

22

210

31/2

22

210/11

02

02

04

Mustelaputorius

31

23

2/3

11/14

32/3

23

2/3

12/14

02

03

05

Vulpes

vulpes

33

21

110

31

21

18

01

01

02

Susscrofa

13

31

19

11

31

17

01

01

02

HIH

F:human-induced

habitatfragmentation;AREA,reduction


ofisolation;EDGE:edgeeff

ect/matrix

disturbance;TL:trophic

level;DA:dispersalability;BS:bodysize;NB:nichebreadth;RA:rarity.



Table

5.Selectedfragmentation-sensitivefocalspecies(FSFS)divided

onthebasisoftheirsensitivityto

macro-components

ofhuman-induced

habitatfragmentation,ofthespatialscale

ofpopulationsandofthehabitatmacro-type

Acronym

Species

Macro-components

of

HIH

FScales

Habitatmacrotype

AREA

ISOL

EDGE

10–100

100–1000

41000

WET

FOR

AGR

MOS

ELQU

Eliomysquercinus

XX

XX

XX

GLGL

Glisglis

XX

XX

XX

MUAV

Muscardinusavellanarius

XX

XX

XX

NEAN

Neomysanomalus

XX

XX

XNEFO

Neomysfodiens

XX

XX

XSCVU

Sciurusvulgaris

XX

XX

XX

MAMA

Martes

martes

XX

XX

XMEME

Meles

meles

XX

XX

XX

XMUPU

Mustelaputorius

XX

XX

XX

HIH

F:human-induced

habitatfragmentation;AREA:reduction


ofisolation;EDGE:edgeeff

ect/matrix

disturbance;WET:inlandwetlands;FOR:forest-ecosystem

s;AGR:agro-ecosystem

s;MOS:mosaic

landscape.



Limitations

Some limitations of this approach must be underlined.The set of selected species should be subjected to a critical review because

although some ecological traits of a species may indirectly provide indications onits sensitivity to the process of HIHF or to some of its macro-components (AREA,ISOL, EDGE), there may be exceptions. Species with certain ecological charac-teristics may show a sensitivity to HIHF not in line with the responses providedby those indicated by Ewers & Didham (2006), to issues such as intra-specific(population-specific) differences or linked to specific geographical contexts. There-fore, it is important that the experts of each taxonomic group read the speciescritically. Species that are not HIHF-sensitive should be removed from the list andsensitive species not obtained following the Ewers & Didham’s procedure shouldbe added.

This approach may be affected by subjectivity in the assigning of the values:therefore, a comparison of the results from the expert process may be necessary (e.g.,with an open or closed Delphi approach) to obtain a more robust and unbiasedevaluation.

This approach doesn’t take account of possible other ecological traits thatmay induce a HIHF-sensitivity such as natural demographic fluctuations, sensitivityto the availability of resources, geographical or other types of rarity (see Yu &Dobson, 2000), so further ecological traits may need to be added to the evaluationmatrix.

Table 6. Fragmentation-sensitive focal species (FSFS) selected on the terrestrial mammalsoccurring in the case study area subdivided for macro-components of HIHF, spatial scale ofpopulations (in km2) and environmental macro-type. (See Table 5 for species abbreviations)

Spatial scale WET FOR AGR MOS

AREA10–100 NEFO, NEAN SCVU, GLGL, ELQU,

MUAV4100–1000 SCVU, GLGL, ELQU,

MAMA, MEMEMEME

41000 MUPU MUPU

ISOL10–100 NEFO, NEAN SCVU, GLGL, ELQU,

MUAV4100–1000 SCVU, GLGL, ELQU,

MAMA, MUPU41000 MUPU

EDGE10–100 NEFO, NEAN GLGL, ELQU, MUAV4100–1000 GLGL, ELQU, MAMA41000

HIHF: human-induced habitat fragmentation; AREA: reduction of habitat surface;ISOL: increase of isolation; EDGE: edge effect/matrix disturbance; WET: inland wetlands;FOR: forest-ecosystems; AGR: agro-ecosystems; MOS: mosaic landscape.



Finally, this procedure is deterministic, following the general response to theHIHF process proposed by Ewers & Didham (2006) for a wide set of animalspecies. The values are extremely generalized and those obtained for a speciesshould be used only to allow the preliminary definition of the set of focal sensitivespecies, with no implications on a hierarchy of sensitivity among species in thesame set. These values can provide a first indication; but for the selection ofthe sets of focal species, and to define a hierarchy of sensitivity (ranking amongspecies), it may be appropriate to proceed using a mixed approach (selection ofspecies based on literature; proposed expert-based approach and criticism valida-tion through field research).

Despite the limitations, in ecological network planning, the use of a set ofobjectively selected FSFS in a study area may be particularly useful for a first andrapid setting of a ‘red list’ of potential sensitive species. Future developments mayinclude a wider range of the values of sensitivity (e.g., on scales from 1 to 5), theimplementation of other taxa-specific ecological traits of species, an entry in matrixincluding altitudinal bands (other than only the spatial scales and habitat categories)and a comprehensive assessment of the sensitivity of species not only in the additivesense but also using coefficients when account may be taken of the impact on thespecies of different macro-components of HIHF.

References

Amori, G. & Battisti, C. (2008) Atlante dei Mammiferi della Provincia di Roma. Consiglio Nazionale delle

Ricerche (Rome: Province of Rome, Environmental Directorate).

Andelman, S. J. & Fagan, W. F. (2000) Umbrellas and flagships: Efficient conservation surrogates or

expensive mistakes? Proceedings of the National Academy of Sciences, 97, pp. 954–959.

Andren, H. (1994) Effects of habitat fragmentation on birds and mammals in landscapes with different

proportions of suitable habitat: A review, Oikos, 71, pp. 355–366.

Angelstam, P., Roberge, J.-M., Lohonus, A., Bergmanis, M., Brazaıtıs, G., Breuss, M., Edenıus, L.,

Kosınskı, Z., Kurlavicius, P., Larmanıs, V., Lukins, M., Mikusinski, G., Ra�cinskis, E., Srazds, M. &

Tryjanowski, P. (2004) Habitat modelling as a tool for landscape-scale conservation: A review of habitat

parameters for focal forest birds, Ecological Bulletins, 51, pp. 427–453.

Bacon P. (Ed.) (2000) ‘‘Natura 2000: rural development and ecological networks’’. Proceedings of

international seminar held in Konstancin, Poland, 15–18 December 1999, IUCN Programme Office for

Central Europe, Poland.

Bani, L., Baietto, M., Bottoni, L. & Massa, R. (2002) The use of focal species in designing a habitat

network for a lowland area of Lombardy, Italy, Conservation Biology, 16, pp. 826– 831.

Bani, L., Massimino, D., Bottoni, L. & Massa, R. (2006) A multiscale method for selecting indicator

species and priority conservation areas: A case study for broadleaved forests in Lombardy, Italy,

Conservation Biology, 20, pp. 512–526.

Battisti, C. (2003) Habitat fragmentation, fauna and ecological network planning: Toward a theoretical

conceptual framework, Italian Journal of Zoology, 70, pp. 241–247.

Bennett, A. F. (2003) Linkages in the Landscapes: The Role of Corridors and Connectivity in Wildlife

Conservation (Gland, Switzerland/Cambridge, UK: IUCN).

Bennett, G. (1998) Guidelines for the Development of the Pan-European Ecological Network. STRA-REP

98.6 (Strasbourg: Council of Europe).

Boitani, L., Falcucci, A., Maiorano, L. & Rondinini, C. (2007) Ecological networks as conceptual

frameworks or operational tools in conservation, Conservation Biology, 21, pp. 1414–1422.

Bright, P. W. & Morris, P. A. (1994) A review of the dormouse (Muscardinus avellanarius) in England and

a conservation programme to safeguard its future, Hystrix, 6, pp. 295–302.

Bright, P. W. (1993) Habitat fragmentation: Problems and predictions for British mammals, Mammal

Review, 23, pp. 101–114.



Brooks, L. (2002) The application of focal species knowledge to landscape design in agricultural lands

using the ecological neighbourhood as a template, Landscape and Urban Planning, 60, pp. 185–210.

Crooks, K. R. & Sanjayan, M. (2006) Connectivity Conservation, Conservation Biology Series 14

(Cambridge: Cambridge University Press).

Crooks, K. R. (2002) Relative sensitivities of mammalian carnivores to habitat fragmentation,

Conservation Biology, 16, pp. 488–502.

Delin, A. E. & Andren, H. (1999) Effects of habitat fragmentation on Eurasian red squirrel (Sciurus

vulgaris) in a forest landscape, Landscape Ecology, 14, pp. 67–72.

Ewers, R. M. & Didham, R. K. (2006) Confounding factors in detection of species responses to habitat

fragmentation, Biological Reviews, 81, pp. 117–142.

Ewers, R. M. & Didham, R. K. (2007) The effect of fragment shape and species’ sensitivity to habitat edges

on animal population size, Conservation Biology, 21, pp. 926–936.

Fahrig L. (1997) Relative effects of habitat loss and fragmentation on population extinction, Journal of

Wildlife Management, 61, pp. 603–610.

Fahrig, L. (2003) Effects of habitat fragmentation on biodiversity, Annual Reviews of Ecology and

Systematic, 34, pp. 487–515.

Farkas, J., Czirak, Z. & Forczek, S. (1998) Effect of the habitat fragmentation on the structure of small

mammal (Rodentia, Insectivora) communities in Kis-Balaton Natural Conservation Area, Hungary,

Opuscula Zoologica Budapest, 31, pp. 43–48.

Haila, Y. (1985) Birds as a tool in reserve planning, Ornis Fennica, 62, pp. 96–100.

Henle, K., Davies, K. F., Kleyer, M., Margules, C. & Settele, J. (2004) Predictors of species sensitivity to

fragmentation, Biodiversity and Conservation, 13, pp. 207–251.

Hess, G. R. & King, T. J. (2002) Planning open spaces for wildlife. I. Selecting focal species using a Delphi

survey approach, Landscape and Urban Planning, 58, pp. 25–40.

Hudson, W. E. (Ed.) (1991) Landscape Linkages and Biodiversity (Washington, DC: Island Press).

Jongman R. H. G. & Kristiansen, I. (2001) National and regional approaches for ecological networks in

Europe. Council of Europe Publishing, Strasbourg, France, Nature and Environment, 110, pp. 1–86.

Jongman, R. H. G. & Pungetti, G. (2004) Ecological Networks and Greenways: Concepts, Design,

Implementation (Cambridge: Cambridge University Press).

Kareiva, P. & Wennergren, U. (1995) Connecting landscape patterns to ecosystem and population

processes, Nature, 373, pp. 299–302.

Kowalczyk, R., Zalewski, A. & Jedrzejewska, B. (2006) Daily movement and territory use by badgers

Meles meles in Białowieza Primeval Forest, Poland, Wildlife Biology, 12, pp. 385–391.

Lambeck, R. J. (1997) Focal species: A multi-species umbrella for nature conservation, Conservation

Biology, 11, pp. 849–856.

Lindenmayer, D. B. & Fisher, J. (2007) Tackling the habitat fragmentation panchreston, Trends in Ecology

and Evolution, 22, pp. 127–132.

Linstone, H. A. & Turoff, M. (1975) The Delphi Method: Techniques and Applications (New York:

Addison-Wesley).

Lorenzetti, E. & Battisti, C. (2007) Nature reserve selection on forest fragments in a suburban

landscape (Rome, Central Italy): Indications from a set of avian species, Landscape Research, 32,

pp. 57–78.

Malcevschi, S. (2001) Nuovi ecosistemi e Reti ecologiche. Uomini e Parchi oggi. Reti ecologiche. Centro

Studi V. Giacomini, Quaderni di Gargnano (Gargnano, Italy), 4, pp. 94–100.

Nichols, W. F., Killingbeck, K. T. & August, P. V. (1998) The influence of geomorphological

heterogeneity on biodiversity, II: A landscape perspective, Conservation Biology, 12, pp. 371–379.

Opdam, P., Foppen, R., Reijen, R. & Schotman, A. (1994) The landscape ecological approach in bird

conservation: Integrating the metapopulation concept into spatial planning, Ibis, 137, pp. S139–S146.

Peltonen, A. & Hanski, I. (1991) Patterns of island occupancy explained by colonization and extinction

rates in shrews, Ecology, 72, pp. 1698–1708.

Pertoldi, C., Loeschcke, V., Bo Madsen, A., Randi, E. & Mucci, N. (2001) Effects of habitat fragmentation

on the Eurasian Badger (Meles meles) subpopulations in Denmark, Hystrix, 12, pp. 1–6.

Provincia di Roma (2004) Piano di Assetto della Riserva Naturale Monte Soratte. Quadro Conoscitivo.

Assessorato alle Politiche dell’Agricoltura e dell’Ambiente (Rome: Municipality of Sant’Oreste).

Robinson, G. R., Holt, R. D., Gaines, M. S., Hamburg, S. P., Johnson, M. L., Fitch, H. S. & Martino, E.

A. (1992) Diverse and contrasting effects of habitat fragmentation, Science, 257, pp. 524–526.



Saunders, D. A., Hobbs, R. J. & Margules, C. R. (1991) Biological consequences of ecosystem

fragmentation: A review, Conservation Biology, 5, pp. 18–32.

Selman, P. (2006) Planning at the Landscape Scale (Abingdon: Routledge).

Simberloff, D. (1998) Flagships, umbrellas, and keystones: Is single-species management passe in the

landscape era? Biological Conservation, 83, pp. 247–257.

Suter, W. (1998) Involving conservation biology in biodiversity strategy and action planning, Biological

Conservation, 83, pp. 235–237.

Ventriglia, U. (1990) Idrogeologia della Provincia di Roma, Vol. 3 (Rome: Abete Grafica).

Virgos, E., Tellerıa, J. L. & Santos, T. (2002) A comparison on the response to forest fragmentation by

medium-sized Iberian carnivores in central Spain, Biodiversity and Conservation, 11, pp. 1063–1079.

Wauthers, L. & Dhondt, A. A. (1992) Immigration pattern and success in red squirrels, Behavioural

Ecology and Sociobiology, 33, pp. 159–167.

Yu, J. & Dobson, F. S. (2000) Seven forms of rarity in mammals, Journal of Biogeography, 27,

pp. 131–139.



Selecting Focal Species in Ecological Network Planning following an Expert-Based Approach: A Case...

Documents

Transcript of Selecting Focal Species in Ecological Network Planning following an Expert-Based Approach: A Case...