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Ecological Indicators 41 (2014) 133–144

Contents lists available at ScienceDirect

Ecological Indicators

journa l homepage: www.e lsev ier .com/ locate /eco l ind

cological risk assessment of wetland ecosystems using Multi Criteriaecision Making and Geographic Information System

. Malekmohammadi ∗, L. Rahimi Blouchiraduate Faculty of Environment, University of Tehran, P.O. Box 14155-6135, Tehran, Iran

r t i c l e i n f o

rticle history:eceived 18 October 2013eceived in revised form 25 January 2014ccepted 29 January 2014

eywords:cological risk assessment (ERA)isk factorisk zoningisk management

ran – Shadegan Wetland

a b s t r a c t

Nowadays, wetlands are at risk from a wide range of stress factors. Practical application of wetlandecological risk assessment will result in a better understanding of how physical, chemical, and biologi-cal stressors impinge on wetlands and will provide a framework for prudent wetland management. Animportant aspect of wetland management is to identify ecological risks affecting the area and to develop awetland-zoning map based on those risks. This study uses a process of ecological risk assessment (ERA) toidentify stress factors and responses within the framework of an ecosystem-based approach. All potentialenvironmental factors, physical, chemical and biological need to be examined in context. This study aimsto present a systematic methodology for risk assessment and zoning of wetland ecosystems. Initially,the most important risks threatening wetlands are identified in an ecosystem-based approach. Endpointassessments are defined according to values and functions of the wetland and the ecological risks asso-ciated with these endpoints are identified. In the characteristics step, risks are analyzed according toseverity, probability and a range of consequences. A Multi Criteria Decision Making (MCDM) method is

used to prioritize these risks on the basis of experts’ opinions. Geographic Information System (GIS) isused to develop a zoning map with a combination of risk layers according to importance. Finally, manage-ment strategies are proposed to deal with the risks. The proposed methodology was applied to ShadeganInternational Wetland, located in southwestern Iran. This wetland is in the Montero list and is currentlythreatened by various risks. According to the results, high-ranking potential risks and areas with differentlevels of risk and management strategies were proposed for this wetland.

. Introduction

Wetlands are one of the three major types of ecosystem onhe Earth; they are formed through the interaction of land andater systems and provide an irreplaceable ecological service

s an ecosystem for human society (Zedler and Kercher, 2005;im et al., 2011). Wetland ecosystems have an important role

n maintaining biological diversity, they are also important foriochemical transformation, storage, production of living plantsnd animals and for decomposition of organic materials (USEPA,002; Clarkson et al., 2003). Wetlands have been exposed to aange of stress-causing alterations from activities such as dredgingnd filling operations, hydrologic modifications, pollutant runoff,utrophication, impoundment, and fragmentation by roads anditches (Klemas, 2011). These activities cause disruption to the

cological balance of animal and biotic reservoirs in wetlandsRamsar Convention Secretariat, 2004).

∗ Corresponding author. Tel.: +98 21 61113185; fax: +98 2166407719.E-mail address: malekb@ut.ac.ir (B. Malekmohammadi).

470-160X/$ – see front matter © 2014 Elsevier Ltd. All rights reserved.ttp://dx.doi.org/10.1016/j.ecolind.2014.01.038

© 2014 Elsevier Ltd. All rights reserved.

The spread of urbanization and industrialization has escalatedwetland degradation in many parts of the world, in both devel-oping and developed countries (Tiner, 1984; Holland et al., 1995;Dahl, 2000; Ralph, 2003; Zedler and Kercher, 2005). Previous stud-ies of wetland protection focused mainly on the functioning ofconstructed wetlands, ecological water demands and vegetationdevelopment (Spieles, 2005; Chen et al., 2009; Cui et al., 2009).For different kinds of wetlands, changing environmental flow isan important risk factor that needs to be considered when under-taking ecological restoration and management of water resourcesof basins (Yang and Mao, 2011). Agricultural use and industrialproduction, pesticide residues, contamination of wetlands fromchemicals outlets, change in natural habitats, over exploitationof natural resources, have caused potential risks to the wetlandecosystems. There is a need for tools to assess the ecological condi-tion of wetlands for a range of purposes, including EnvironmentalImpact Assessments (EIA), ecological reserve determinations andthe planning and monitoring of wetland management and rehabil-

itation outcomes (Kotze et al., 2012).

Recently, ecological risk assessment (ERA) has applied sev-eral tools for modeling. Ecological modeling has been used inother fields such as water quality modeling (Chau, 2007; Wu

1 i / Eco

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34 B. Malekmohammadi, L. Rahimi Blouch

nd Chau, 2006; Muttil and Chau, 2006). ERA evaluates the like-ihood of potential adverse effects on ecosystems as a resultf exposure to one or more stress factors (USEPA, 1992). Cur-ently, ecosystem-oriented models of ERA have proved efficientn evaluating structural and functional responses within a vari-ty of ecosystems to enable better environmental managementChristian et al., 2009; Chen et al., 2010, 2011). Applications ofRA include assessments that range from screening-level (qualita-ive) to detailed (quantitative) or a combination of both (i.e. tieredRA); predictive to retrospective in temporal scale; local to globaln spatial scale; and single threat to multiple threats (USEPA, 1998;urgman, 2005). ERA involves examining an area’s environmen-al conditions by means of environmental risk assessment analyseshat consider various aspects of the hazards as well as the vulnera-ility and specific environmental values of the studied area underHeller, 2006).

ERA of wetlands involves estimating potential hazards or threatsosed by stressors (chemical, physical, or biological) to bioticnd/or abiotic components of the wetland. This assessment formshe information base that drives important environmental man-gement decisions on a local, national, and international levelsorldwide. Practical application of this tool will result in a betternderstanding of how physical, chemical, and biological stressors

mpinge on wetlands and will provide a framework for prudentetland management. An important aspect of wetland manage-ent is to identify ecological risks affecting the area and to developwetland-zoning map based on those risks. Wetlands can be

iewed as complex temporal and spatial mosaics of habitats withistinct structural and functional characteristics. Because of thenique characteristics of wetlands the key stressors and receptors

n the wetlands under study should be clearly identified and, ifecessary, prioritized in order to guide the risk assessment pro-ess. Risk characterization requires an understanding of the majorxternal and internal factors regulating the operational conditionsf a wetland. Furthermore, an ecosystem-based approach involvesetermining links between these factors and identifying the way inhich stress factors affect the wetland.

Lemly (1997) examined the ERA of wetlands as a managerialool. The study developed an ecosystem-based approach towardisk assessment in freshwater wetlands. Suter (2000) presentedn argument for developing generic assessment endpoints in ERAhat measured the ecological characteristics essential for protectiongainst risks by quantification, measurement and modeling. Kellettt al. (2005) provided an analysis of ERA workshops for wetlandsf the Lower Burdekin, and recommended strategies for the exe-ution of ERA for irrigation planning and assessment. Hanson et al.2008) evaluated ecological functions of the wetlands. This projectemonstrated that assessment of wetland functions provides key

nformation for wetland environmental assessment.Wang and Cheng (2011) applied ERA in zoning of the Baiyang-

ian Basin in China. Using Geographic Information System (GIS) andemote Sensing (RS) technology, a region-wide environmental riskisualization was produced that enhanced the effectiveness of envi-onmental risk management. Zhang and Huang (2011) employedGIS-based multi-criteria method to evaluate potential nitrogen

oss at the basin level, and applied the model to the Huai Riverasin. The results helped to examine the complex responses of wet-

and systems to changes in land use under different socio-economicircumstances.

A review of previous ERA studies reveals that the most recenttudies have used structural features and functions of wetlandss valuable and important ecological features. Chen et al. (2013)

eviewed state-of-the-art models that were developed for ERA andresented a system-oriented perspective for holistic risk evalua-ion and management. They concluded that assessing ecologicalisk with system-based models at different levels of organization

logical Indicators 41 (2014) 133–144

in a combined way, presents an evolutionary step for applicationof risk evaluation in environmental management.

This study presents a systematic methodology in an ERA for wet-land ecosystems to identify stresses and responses. The methodused in this study applies all physical, chemical and biologicalstress factors affecting the environment in a semi-quantitative riskassessment approach. For this purpose, the most important envi-ronmental risks are identified. In the characteristics step, risks areanalyzed according to severity, probability and range of conse-quence. These indicators are then used to determine scope andextent of each risk. The determinations of proposed measures tobe applied in environmental control were made from gatheringexperts’ opinions. Analytical Hierarchy Process (AHP) is used toprioritize risks. A zoning map of risks threatening the wetland isdeveloped using GIS. This map identifies wetland parts according tolevel of risk to achieve optimum planning with an ecosystem-basedapproach. Finally, management strategies are proposed to deal withthese risks. The methodology has been subsequently applied toShadegan International Wetland, located in the southwest of Iran.This wetland is in the Montero list and is now threatened by variousfactors.

2. Methodology

A framework was developed for assessing the ecological risksfor wetland areas using a semi-quantitative approach. Semi-quantitative methods are used to describe the relative risk scale.For example, risks can be classified into categories like “very low”“low”, “moderate”, “high” and “very high”. In a semi-quantitativeapproach, different scales are used to characterize the likelihoodof adverse events and their consequences. Analyzed probabilitiesand their consequences do not require accurate mathematical data(Radu, 2009). In semi-quantitative methods, risk indicators and val-ues are determined according to information on real available dataas well as using judgments made by experts. Fig. 1 presents a struc-tural illustration of the methodology applied to wetland ecologicalrisk assessment. This structure was formed with a combination ofrisk assessment technique, the AHP method and the GIS tool. Themethod was according to the following steps:

Step 1: Identification of ecological endpoints and ecological risksassociated with these endpoints. In order to set the ecolog-ical endpoints, according to the International ConversationNature and Natural Resources (IUCN) booklet (Dugan,1990), the most important wetland values and functionsand the main related endpoints are identified. Assessmentendpoints are the functions and associated values that needto be protected, enhanced, or created through risk man-agement (Lemly, 1997). The focus of ecological endpointassessment is to determine ecological endpoints that arethreatened (Pastorok et al., 2002).

Step 2: Risk characterization step. In this step risks are analyzedaccording to severity, probability and consequence. A riskindex is calculated by analyzing severity, exposure andprobability (SEP) in a semi-quantitative approach with Eq.(1).

Risk = Probability of the risk × range of consequences

of risk × severity of the risk (1)

In Tables 1–4, severity, probability, range of conse-

quences and range of risks are classified from very lowto very high with scoring according to that taken from areview of related literature, engineering judgments andinformation gathered from brainstorming sessions with

B. Malekmohammadi, L. Rahimi Blouchi / Ecological Indicators 41 (2014) 133–144 135

Fig. 1. Framework of the methodology in the wetland ecological risk assessment.

Table 1Classification and scoring of the severity in the wetland ecological risk assessment.

Expected consequence Scores range Class

Destroying the integrity andexistence (5)

15–13 Very high (5)

Changes in the hydrologicalbalance and regime (4)

12–10 High (4)

Disruption of the biologicalbalances (3)

9–7 Moderate (3)

Changes in physical andchemical parameters (2)

6–4 Low (2)

Table 2Classifying range of the consequences in the wetland ecological risk assessment.

Wetland exposed area (portion of total area) Class

All of the wetland and the surrounding ecosystems Very high (5)Three quarter (¾) High (4)Half (½) Moderate (3)One quarter (¼) Low (2)Less than one quarter (¼) Very low (1)

Table 3Classifying of the probability in the wetland ecological risk assessment.

Expected probability The likelihood of theconsequence

Class

Certain (risks occurcontinuously)

Very likely Very high (5)

Common (risks occurusually)

Greater than 50% High (4)

Possible (risks may occurfrom existing risks)

Equal to 50% Moderate (3)

Likely, but are low Unlikely under normalconditions

Low (2)

Likely, but are very low Impossible or remote Very low (1)

Disruption of thebiogeochemical cycles (1)

<4 Very low (1)

a group of experts. The determined environmental risksare given a score for severity by applying an assessmentof consequences of each potential risk. Expected conse-quences are identified through assessment of the ecologicalendpoints. In Table 1, classification and scoring of the sever-ity of wetland risks are developed by cumulative impactassessment of consequences in the wetland. Summation ofnumbers in the first column is equal to 15. Classes of sever-ity are ranked from very high (5) to very low (1) and eachclass is assigned a score up to 15.

Scores evaluating the consequences of each risk are per-formed by identifying the wetland area exposed to the risk.In Table 2, classification range of consequences of risks isdone according to the wetland areas that are affected by

the risks. The probability of a wetland ecological risk isclassified according to probability of the expected conse-quence (Table 3). By applying Eq. (1), amounts are given

under normalconditions

as an evaluation of each risk. Table 4 presents the range,classification and description of risks.

Step 3: After identifying risks, they are prioritized on the basis

of their importance. This can be done according to theclassification of severity, probability and consequencesof the risk. These criteria should be valued in risk

136 B. Malekmohammadi, L. Rahimi Blouchi / Eco

Table 4Classification and description of the risks in the wetland ecological risk assessment.

Risk range Classification Description

125–101 Very high Unacceptable100–76 High Unacceptable

75–51 Moderate Acceptance withconditional control

50–26 Low Acceptable<26 Very low Negligible

assessment according to degree of importance and influ-ence. Multi-criteria Decision Making (MCDM) is used toprioritize risks and effective indicators to estimate risklevels. MCDM were applied in different EIA and ERAstudies such as Zhao et al. (2006) and Zhang et al.(2009). MCDM is a class of decision-making methodol-ogy based on the premise of assisting a decision-makerthrough the decision process via explicit formalized models(Figueria et al., 2005). Belton and Stewart (2002) and Kikeret al. (2005) presented a review of the available literatureand provide some recommendations for applying differentMCDM techniques. These include the AHP, ELimination andChoice Expressing the REality (ELECTRE), Multi AttributeUtility Theory (MAUT), Preference Ranking Organization

METHod for Enrichment Evaluation (PROMETHEE), andvarious combinations of these methods.

AHP is a theory of measurement through pairwise com-parisons that relies on the judgments’ of experts to derive

Fig. 2. Location and specification of the Shade

logical Indicators 41 (2014) 133–144

priority scales (Saaty, 2008). In this study, AHP is utilized. Ahierarchical structure of a target is used to find importantweights for each wetland ecological risk. Pair-wise com-parison matrixes in AHP are used to weight the indexesand options of the risks based on experts’ opinions. Riskprioritizing has been used to make proposals for correc-tive action to reduce risks. It should be noted that othermethods such as ELECTRE, MAUT, PROMETHEE can alsobe applied in ERA for wetlands. Each of them has theiradvantages and disadvantages as evident from a series ofregular debates in prominent journals. The advantages ofAHP over other multi-criteria methods, as often cited byits proponents, are its flexibility, intuitive appeal to thedecision-makers or experts, and its ability to check theinconsistencies in judgments (Saaty, 2000). AHP helps toelicit the complex judgments of different experts in a com-mon platform. It also ensures accuracy in the sense that ithas an inbuilt method to check the inconsistency of judg-ments. This ensures that the judgments are provided onlywith sufficient care and the error due to negligence is thusminimized (Ramanathan, 2001).

Step 4: All risk factors must be spatially modeled, they need toappear on the map as points, lines, polygons or raster mod-els. Man-made landscape features such as agricultural and

urbanized areas, tourism zones and hotels, roads, industrialareas, also surrogate indicators such as population densitycan be included as human impacts and these are deter-mined by experts and used as risk factors. The combination

gan Wetland and related basin in Iran.

i / Ecological Indicators 41 (2014) 133–144 137

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Table 5Different regions of the Shadegan Wetland (Pandam Consulting Engineers, 2002).

Shadegan Wetlandzones

Total Wildlife Refuge

Area (ha) Percent Area (ha) Percent

Freshwater 120,378 22.4 75,310 23Tidal 222,252 41.3 252,455 77Coastal (Mosa

estuary)115,978 21.6 – –

Other and marginal 79,123 14.7 – –

and change in natural habitats have directly or indirectly affectedthe wetland functions (Rahimi Blouchi, 2012). This wetland isin the Montero list and is now threatened by several risks.Despite its unique values, this wetland is now far removed from

Table 6Assessment of ecosystem functions and values of Shadegan Wetland (Behan DamConsulting Engineers, 2010, according to IUCN booklet, Dugan, 1990).

Function Values Statues ofvalues inShadeganWetlanda

Hydrologic flux andstorage

Groundwater recharge �Groundwater discharge ©Flood control and protection �

Water supply �

Biological productivity Food storage �Forest resource ©Wildlife resources �Aquatic �Forage resources �

Agricultural resources �

Historical and culturalresources

�

Biogeochemical cyclingand storage

Stabilize the shoreline/erosioncontrol

�

Sediment control/toxicmaterials

�

Protection from storm/windbreak

�

Wastewater treatment �Water quality �

Community/wildlifehabitat (ecological)

Biodiversity �Tourism/recreation �

Preservation of flora and fauna(refuge)

�

B. Malekmohammadi, L. Rahimi Blouch

of risk elements and their assigned risk parameters mayvary for each habitat in order to account for the differentways in which human activities impact on biodiversity ineach realm (McPherson. et al, 2008). Wetland zoning is usedas a management strategy done to identify areas with high-ranking risk. GIS evaluates the ecological risks of humanactivities and natural disasters, which are the main factorsthat contribute to change on wetland ecological indexes.Using the GIS tool, the zoned wetland risk map is developed.Information layers are required for the main risk factors.These layers are overlaid according to the weights obtainedfrom AHP. Weights are assigned to the layers using theRaster Calculator in Spatial Analyst functions and weightedlinear combination (WLC) is used to overlay the weights.WLC is one of the most widely used methods of Multi-Criteria Evaluation (MCE) for analysis of land suitability.It involves standardization of suitability maps, assigningweights of relative importance to the maps, and combin-ing weights and standardized suitability maps to obtain anoverall suitability score (Malczewski, 2004). WLC analysiswas based on Eq. (2).

S =∑

WiXi (2)

where S is the zoning map of the wetland, Wi is the weight oflayer i obtained from AHP, and Xi is the standard raster layeri. According to the zoning map, area zones with differentlevels of risk are determined.

tep 5: Finally, risk management strategies will be provided forhigh-risk zones. The most effective risk managementstrategies are presented within wetland basin, becausewetlands are associated and interacted with upstream anddownstream processes.

. Study area (Shadegan International Wetland, Iran)

Shadegan International Wetland is located in southwestern Iran,n Khuzestan Province, between 48◦20′–49◦20′ E longitude and0◦50′–31◦00′ N latitude. Fig. 2 shows the geographical locationnd specification of the study area. The cities of Ahwaz, Abadan,ahshahr and Shadegan are the main population centers around

he wetland. This wetland is located in the Jarahi River Delta withery flat land and low-gradient plains’ topography. The Jarahi basins located in southwestern Iran and southern parts of the Zagros

ountain Range. The basin area is about 24,310 km2. The Shadeganetland is about 537,731 ha, of which almost 61% is protected as aildlife Refuge (Environmental Protection Agency of Iran, 2010).This natural wetland has important hydrological, biological and

cological significance in terms of maintaining normal functions ofhe basin and coastal system. There are more than 100,000 waterird species with five of the world’s rare species of bird in thisetland. The unique diversity of this wetland includes plant and

nimal species specific to freshwater, brakish and saltwater envi-onments. Specifications of different parts of the Shadegan Wetlandre given in Table 5 (Pandam Consulting Engineers, 2002; Shadeganity Department of Environment, 2010). As can be seen in Fig. 2 andable 5, the Shadegan Wetland consists of three distinct parts:

1) A freshwater zone, which is located in the upper part of the wet-land. This area is fed by the Jarahi River and has lush vegetationcover.

2) A tidal zone, which is located in the southern part of the wet-

land (downstream of the Abadan-Mahshahr highway). The areais influenced by the tides of the Persian Gulf and involves multi-ple waterways (estuaries). Upstream freshwater is mixed withdownstream saltwater as freshwater passes through the land.

landsTotal 537,731 100 327,765 100

(3) The coastal zone or saltwater wetland, which includes the Per-sian Gulf coastline to at the water depth of 6 m. The Mosaestuary and several small islands are also in this area.

Wetland vegetation is a vital characteristic of such an environ-ment, it is important in terms of sustainability of the ecologicaland economic values of the wetland. The Shadegan Wetland, inaddition to its global value was granted status as Wildlife Refugeby the Iran Department of Environment. Table 5 presents fresh-water and tidal zones of the Wildlife Refuge areas in the wetland.The most significant human activities affecting the Shadegan Wet-land are those of dam construction and irrigation projects in theJarahi catchment, oil and gas platforms, industrial projects, infra-structure projects, exploitation of wetland resources and tourism.Recently, human activities such as water pollution, indiscrimi-nate exploitation of biological products of the wetland, drought

Threatened, rare, andendangered species

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a (©) absent or exceptional, (�) present, (�) common and important value ofwetland.

138 B. Malekmohammadi, L. Rahimi Blouchi / Ecological Indicators 41 (2014) 133–144

Table 7Characteristics of the risk factors in Shadegan Wetland.

Risk factor Harmful potential effects Receivers Range of consequences

Drought/low wateroccurrence

- Reduction in productivity andsurvival of the wetland- Reduction of hydrologicalstability

- All organisms in the soil andaquatic life- Humans dependent towetland

All of the wetland and thesurrounding ecosystems

High temperature and highevaporation

- Increase of chemical andbiological functions’ rates- Reduction in species richness

All organisms in aquatic life Freshwater zone

Salinity of wetland water - Reduces denitrification,biological uptake andphotosynthesis- Diminishes species richness

All organisms in the soil andaquatic life

- Freshwater zone- Tidal zones in the south ofAbadan – Mahshahr road

Sedimentation and filling - Depresses biological uptake,processing and photosynthesis- Diminishes species richness- Reduces groundwaterrecharge- Changes in sediment particlesize

All organisms in the soil andaquatic life

Freshwater zone (sedimententrance from the northernrivers)

Over exploitation ofnatural resources

- Increases erosion potential- Establishment of invasivespecies- Reduces the interception,condensation, evaporation andsurface roughness - Reducessediment stabilization

Organisms dependent tonatural resources

- Freshwater zone (The vicinityvillages)- Northeastern Wildlife Refuge

Entrance of agriculturaland livestock wastewater

- Short-term: increasesproductivity- Long-term: encouragesinvasive species, decreasesspecies

- All organisms in the soil andaquatic life- Humans dependent towetland

Freshwater zone (fromnorthern part)

Entrance of industrialwastewater

- Reduces diversity andproduction- Enhances adsorption of somechemicals- Eutrophication

- All organisms in the soil andaquatic life- Humans dependent towetland

Freshwater and tidal zones(from industries on the northand northwest)

Entrance of rural and urbanwaste water

- Diminishes habitat suitability- Reduces photo-oxidation andincreases denitrification rate

- All organisms in the soil andaquatic life- Humans dependent towetland

Freshwater and tidal zones(from central and southwest)

Oil pollution - Biological magnification- Soil pollution andcontamination of groundwater

- All organisms in the soil andaquatic life- Humans dependent towetland

- Northern boundary of theWildlife Refuge- A part of tidal zone insouthern

Change in flow regime - Reduces in water inflow- Reduces in water flowpurification

- All organisms in the soil andaquatic life- Humans dependent towetland

Freshwater zone

Change in natural habitats - Reduces groundwaterrecharge- Increases evapotranspiration- Increases concentration ofinorganic

All organisms in the soil andaquatic life in wetland

All of the wetland and thesurrounding ecosystems

Road construction - Reduces biodiversity All organisms in the soil and - Northern part

iaaa

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ds

- Disturbing hydrological flows- Reduces the water quality- Habitat loss

ts natural condition. This study aimed to identify and man-ge the most stress inducing risks that threaten the wetlandnd to maintain its ecological balance and to protect the studyrea.

. Results and discussion

Prior to modeling an ERA, it is important to identify previouslyeveloped information for the wetland under consideration in thetudy. Information from aerial photographs, historical maps and

aquatic life in wetland - North of the Wildlife Refuge

land-use documents are useful for gaining an understanding of thehistory and status of an area. It is also important to gain an under-standing of the hydrologic and geologic forces affecting a wetland.Understanding a wetland’s function and determining its values isan important part of ERA for wetlands. These function–value rela-tionships provide an important conceptual framework that can

formulate the operation’s goals and objectives.

Application of ERA methodology on the Shadegan Wetlandfirstly used important values and functions of Shadegan Wetlandto determine endpoints. Assessment of the Shadegan Wetland in

B. Malekmohammadi, L. Rahimi Blouchi / Ecological Indicators 41 (2014) 133–144 139

Table 8Results of calculation of the risks in the Shadegan Wetland.

Risk factor Severity Range ofconse-quence

Probability Risk level Importanceweight inAHP

Weightedrisk

Riskrankingnumber

Drought/low water occurrence 4 5 3 60 0.064 3.84 9High temperatures and high evaporation 2 2 5 20 0.090 1.8 12Salinity of wetland water 4 3 5 60 0.061 3.66 10Sedimentation and filling 5 2 4 40 0.056 2.24 11Over exploitation of natural resources 4 3 5 60 0.098 5.88 5Entrance of agricultural and livestock wastewater 4 3 5 60 0.072 4.32 8Entrance of industrial wastewater 4 4 5 80 0.087 6.96 3Entrance of rural and urban waste water 4 4 5 80 0.082 6.56 4Oil pollution 4 3 5 60 0.089 5.34 6

ttsbttlttatepsep

tTaticao

aT

Change in flow regime 4 5Change in natural habitats 4 5Road construction 4 3

erms of its ecosystem functions and values was done accordingo the method cited in the IUCN booklet by Behan Dam Con-ulting Engineers (Behan Dam Consulting Engineers, 2010). Theooklet includes field studies and information on environmen-al characteristics of the wetland and this information was usedo complete the IUCN checklist for values of the Shadegan Wet-and. Results of this assessment are presented in Table 6. Then,he most important ecological endpoints were identified accordingo these values and functions. All of the parameters (hydrologicalnd ecological) that were considered critical to long-term sus-ainability of the wetland were considered as possible ecologicalndpoints. Biogeochemical processes such as hydrological regime,rimary productivity (food web stability), biodiversity (abundance,pecies richness), sensitive and natural habitats, integrity andxistence of wetland, were determined as the most important end-oints.

Risks and stressors imposed on Shadegan Wetland were iden-ified in accordance with the ecological endpoints and shown inable 7. This table describes harmful potential effects, receiversnd the range of consequences for each risk factor. The most impor-ant consequences of determined by evaluation of risk factors weredentified as destroying the integrity and existence of the wetland,hanges in its hydrological balance and regime, biological imbal-nce, changes in physical and chemical parameters and disruption

f biogeochemical cycles of the wetland.

The risk factors threatening Shadegan Wetland were analyzedccording to step 2 of the methodology and are presented in Table 8.he information shown in Table 7 was used to calculate severity,

Fig. 3. Hierarchical structure of ecological r

4 80 0.099 7.92 24 80 0.12 9.6 15 60 0.082 4.92 7

probability and to determine the range of consequences for eachrisk from the step that evaluated risk analysis. According to theseverity index, drought (low water occurrence), sedimentation andover exploitation of plant resources of the wetland were evalu-ated as having the greatest level of risk (very high). Also, factors ofhigh temperatures and high evaporation were evaluated as havingthe lowest level of the risk. According to the consequence index,drought, change in flow regime and change in the natural habi-tat were evaluated as having the greatest amount of risk (veryhigh). In addition, factors of high temperatures and high evapo-ration, gradual sedimentation and filling and over exploitation ofplant resources of the wetland were evaluated as having the lowestlevel of risk (low). According to the probability index, almost all ofthe stressors have continuous impact and as such are associatedwith a very high level of risk.

Table 8 shows calculations of risk level based on Eq. (1). Resultsof risk calculation for each of the risk factors show that almost allof the risks were evaluated as having high and medium level risk.Table 8 shows the industrial wastewater outlets, rural and urbanwaste-water outlets, and changes in natural habitats that were hadthe maximum degree of risk. Also, the lowest amounts of the riskwere calculated for factors of high temperatures and high evapora-tion. Results of sensitivity analysis on the risk assessment values inTable 8 show the evaluations for elimination of the criteria ‘range

of consequence’, ‘probability’, and ‘severity’ that contribute to achange in risk level of about 31.4, 22.4, 26 and risk ranking numbersof about 91%, 41.7%, 8%, respectively. These evaluations show theimportance of considering these three criteria, especially that of

isk assessment of Shadegan Wetland.

140 B. Malekmohammadi, L. Rahimi Blouchi / Ecological Indicators 41 (2014) 133–144

Fig. 4. Risk zoning layers for risk factors in Shadegan Wetland. (a) High temperatures and high evaporation, (b) salinity, (c) over exploitation of biological resources, (d) waterpollution, and (e) change in natural habitat

B. Malekmohammadi, L. Rahimi Blouchi / Ecological Indicators 41 (2014) 133–144 141

Table 9Percentages of categories in each layer in the ecological risk zoning of Shadegan Wetland.

Category of risk Risk factor

High temperatures andhigh evaporation

Salinity ofwetland water

Over exploitation ofnatural resources

Waterpollution

Change in naturalhabitats

Final zoningmap

Very high 10.07 6.9 5.54 12 16.59 10.4High 7.67 5.9 1.05 15 8.81 11.56

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ibuPtzu

Moderate 6.37 6.22 2.Low 5.48 4.25 17.Very low 70.41 76.7 86.

range of consequence’ in wetland ecological risk assessment. Also,ariation evaluations for these three criteria show changes of upo 27% but evaluations for risk level and risk ranking number aretable. These evaluations demonstrate an acceptable level of stabil-ty in calculations of risk values in the proposed methodology for

etland ecological risk assessment. Sensitivity analysis on impor-ance of weights, based on average weights, shows that risk rankingumber is dependent on about 33.3% in terms of importanceeights.

A hierarchical structure of the ecological risks, according to thendexes of the risks (severity, range of consequences and proba-ility) is shown in Fig. 3. Information on experts’ opinions wassed to weight the criteria and alternatives of the risks through

airwise Comparison according to the hierarchical structure. Inhis study, national experts were selected from different organi-ations in the region. There was a lack of communication andnderstanding between the wetland community and those doing

Fig. 5. Ecological risk zoning ma

33 5.87 14.8830 7.82 44.0910 60.91 19.07

the risk assessment in the study region. It is essential that thoseindividuals that contribute to process of wetland ecological riskassessment have a common understanding of some basic princi-ples from both disciplines. Thus, access to experts with scientificknowledge of the area was difficult in this particular case study. Intotal, contributions from the opinions 15 experts were consideredand confirmed by the AHP Consistency Ratio. Five environmen-talists, five water resources experts, and five agricultural expertswere used in brainstorming session and to answer a questionnaire.Expert Choice software (www.expertchoice.com) was used for cal-culations of AHP weights. Final weights of AHP for the risk factorsare presented in Table 8. Risk factors were prioritized by multi-plying risk level and importance weight of each risk. Rankings of

risks are shown in the last column of Table 8, and represent thepriority of each risk factor, for the wetland. Based on these priori-ties, change in natural habitat factor was high ranking factors andsedimentation and filling factor was low ranking factors.

p for Shadegan Wetland.

142 B. Malekmohammadi, L. Rahimi Blouchi / Ecological Indicators 41 (2014) 133–144

Table 10Management strategies (control measures) for reducing effects of risk factors in Shadegan Wetland.

Risk factor Risk level Affected zone Management strategies (controlmeasures)

Category Rating

Change in natural habitats High 1 All of the wetland andsurrounding ecosystems

- Developing a legal regionalbinding guideline to prevent landuse changes- Avoid or minimize wetlanddisturbance by applying wetlandsetback regulation

Change in flow regime High 2 Freshwater zone - Allocating the minimum of waterrights- Restricting unauthorizedexploitation of the rivers,especially in drought periods- Implementation of integratedwater resources management atthe Jarahi basin

Entrance of industrialwastewater

High 3 Freshwater and tidal zones - Industrial wastewater treatment- Continuous monitoring ofwetland water quality andapplying water quality standards

Entrance of rural and urbanwastewater

High 4 Freshwater and tidal zones - Keeping the canebrakes in theentrance

Over exploitation of naturalresources

Medium 5 Freshwater zone andNortheastern of WildlifeRefuge

- Identifying the capacity of grazingand harvesting of hays and straws- Establishing buffer strips forarable lands- Developing wetland operationguidelines

Oil pollution Medium 6 Northern boundary of theWildlife Refuge and a part oftidal zone

- Insulating the oil transfer pipes

Road construction Medium 7 North part of wetland andnorth of the Wildlife Refuge

- Constructing culverts- Maintaining the wetland habitatcorridors

Entrance of agricultural andlivestock wastewater

Medium 8 Freshwater zone - Controlling the time and amountof using agricultural materials

Drought/low water occurrence Medium 9 All of the wetland andsurrounding ecosystems

- Designing a drought monitoringnetwork in the Jarahi Basin

Salinity of wetland water Medium 10 Freshwater and tidal zones - Usage of halophyte plants

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Table 8 shows changes in natural habitats, changes in upstreamow regimes (such as dam building in the catchment of Jarahi),

ndustrial wastewater outlets, rural and urban wastewater outlets,ver exploitation of natural resources of the wetland, oil pollution,gricultural and livestock wastewater outlets, road construction innd around the wetland, and drought occurrence in recent yearsere determined as the main risks threatening the Shadegan Wet-

and respectively.Based on the importance of risk factors and available infor-

ation, five layers were selected for consideration in wetlandcological risk zoning. Change in natural habitat, water pollutionby wastewater outlets), over exploitation of biological resources,alinity of wetland water, and high temperature and high evapora-ion are the layers that were developed in ecological risk zoning.

etland risk-zoning layers were produced using spatial analystools in Arc-GIS 9.3 software (Environmental Systems Researchnstitute ESRI, 2008). Each layer was reviewed, classified and rankedccording to the degree of threat that was considered for each in

elation to the habitat or species in question. Data in the past 10ears were used for developing the layers. These layers are pre-ented in Fig. 4 and explained according to the following:

- Transfer of agro-industrialcomplexes of saline drainage waterto Persian Gulf (at 6 m depth of sea)

(1) High temperature and high evaporation (Fig. 4a): due to hightemperature, the greatest influence was on the shallow parts ofthe wetland. To produce this layer, water depth in the freshwa-ter zone was used as an index. Water depth in different parts ofthe wetland varied from a few centimeters to about 3 m. Zon-ing of the wetland was done with regards to the adverse effectsof high temperature on wetland flora and fauna. Shallow partswere determined as having a high level of risk and the deepparts with lower levels.

(2) Salinity of wetland water (Fig. 4b): This map was produced fromdata on electrical conductivity of wetland water in the fresh-water zone. Electrical conductivity changed at different partsof the wetland water ranging from 1.4 to 21 dS/m. Those partswith high salinity were considered as high risk and vice versa.

(3) Over exploitation of natural resources (Fig. 4c): the likely extentof impact of the over exploitation are considered as zoningcriteria. The buffer extension in GIS software was used to pro-duce this map. The influence of distance for direct and indirect

impacts was considered at 50 and 2000 m, respectively. In loca-tions that had been over exploited, distance of the buffer zoneincreased from the centers of points, lines or polygons. Areas

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B. Malekmohammadi, L. Rahimi Blouch

with risk level ranked as very high and high were those of fresh-water wetland in the vicinity of villages due to road access roadsin those areas.

4) Water pollution (Fig. 4d): Data on source pollution and entrancepoints to the wetland were used to develop this layer. The mainsources of water pollution were those of upstream irrigationdevelopment projects, the sugar cane industry in the northernpart of wetland, petrochemical activity in Mahshahr, shipping,carbon and steel industries in Ahvaz, Maroon desalination,wastewater from surrounding cities and villages in the eastarea of freshwater wetland and burst pipes that leaked oil intothe wetland. Wastewater outlets from agricultural and live-stock farms, industrial, rural and urban areas, and oil pollutionwere considered in this layer. Due to lack of data on amountsof pollution concentrations in the wetland, sources of pollu-tion and their relative entrance points; these values were ratedaccording to experts’ opinions, judgments of engineers andinformation collected from field studies. Industrial pollution,rural and urban pollution, oil pollution, agricultural and live-stock pollution and other pollutions were rated as very high,high, moderate, low, and very low, respectively. The SpatialAnalyst interpolation was used in GIS software to produce thislayer. The Spatial Analyst interpolation was used in GIS softwareto produce this layer.

5) Change in natural habitat (Fig. 4e): This layer was preparedfrom a map of existing land-use in the wetland. Zoning wasdone according to the influence distance of change in land-use.The influence distance was determined as the spatial extentor footprint of change in the natural habitat on the wetlandand represents the maximum distance at which a feature hasa negative impact on the wetland. For example, adverse effectsof roads within the wetland’s ecological range were consideredto have a range of impact extending to 1000 m (Forman et al.,2003). The influence distances for direct and indirect impactswere considered as 200 and 1000 m, respectively. The bufferextension was used in GIS software to produce this map. Thezones that were evaluated as having very high and high levelsof risk were in areas disturbed by human activities.

Percentage of categories in each layer that were used for ecolog-cal risk zoning of the Shadegan Wetland are given in Table 9. Basedn Step 4 of the methodology, by applying importance weights fromable 8, the final ecological risk-zoning map of the Shadegan Wet-and was produced and is shown in Fig. 5. As can be seen in thisgure, the area that was evaluated with the least risk was that ofhe southern wetland in the saltwater area, probably because itas a pristine environment inaccessible to humans. Evaluationsetermined the area most at risk was the northern area of the wet-

and, a freshwater area with access roads that facilitated of humanccess to the wetland. This map enables decision makers and envi-onmental planners to regulate human activities in and around theetland.

Results of sensitivity analysis on the final risk-zoning map showhat classification of the final risk-zoning map did not changeith variation of important weights of up to 30% change, on

hese weights. These results show acceptable stability in classifi-ation of risk-zoning layers. In addition, the final risk-zoning mapas sensitive to the elimination of each layer and more sensitiv-

ty was observed for elimination of the layer representing overxploitation. Based on the results of risk analysis and the ecologi-al risk-zoning map, strategies to manage and reduce the ecological

isks of Shadegan Wetland are abstracted in Table 10. The proposedanagement strategies for the wetland were determined by the

bove-mentioned ecosystem-based approach. In Table 10, risk fac-ors were ordered according to the ranking number of each risk

logical Indicators 41 (2014) 133–144 143

from Table 8. Zones relating to each risk factor are described withregards to the risk-zone maps.

5. Conclusions

Development projects such as road construction, thermal powerplants, transmission lines, oil and petrochemicals and factoriesthreaten the life of wetlands. In order to protect and managewetlands in a sustainable way, it is necessary to reduce ecologi-cal risks that impact on the wetlands. The best approach towardapplying ERA in wetland studies is ecosystem-based management.In this study, an ecosystem-based approach was considered topresent a methodology for identifying and characterizing risks andto develop management strategies. Experts’ opinions were used toprioritize risks according to the AHP. A zoning map of the risks thatthreaten the wetland was developed using GIS.

Risk zoning is an important measure in environmental risk man-agement. It involves dividing an area into sub-areas according togeneral risk characteristics. Identifying the similarities and differ-ences of risk factors between sub-areas by making comparisonsbetween sub-areas can help to determine the most appropriateenvironmental risk management policies. The GIS that was used inthis article constitutes a powerful tool for decision-makers in con-servation to establish preferences, which need to identify humanactivities in terms of spatial interactions and other factors thatinfluence the health and viability of critical habitats and key speciesin a wetland.

ERA can provide a description of the actual situation of ecolog-ical, health status or risks that threaten wetlands. The presentedmethodology can be redeveloped to apply to different types ofwetlands to identify and manage the risks. This method focuseson identification of wetland endpoints and conservation of valuesassociated with these endpoints. This target is obtained by iden-tification of hazards/threats to values of the wetland endpoints.Results of this study for Shadegan Wetland reveal that the stress-ors inflicted on the environment of this wetland causes adverseeffects on characteristics of the wetland. Alteration in natural habi-tats, changes in the water balance of wetland, water pollution,over exploitation of biological resources, and drought are the mainstressors of this wetland. All of these factors are interrelated anddue to the complexity of wetland ecosystems, it is difficult to sep-arate the effects and consequences of these factors.

For Shadegan Wetland, management strategies are suggested onthe basis of the results of this research. Preventing change in wet-land land-use, providing sufficient water for the wetland, ensuringwater quality of the wetland, protecting biodiversity, sustainableuse of wetland resources, increasing awareness of wetland valuesand threats, and promoting public participation are the main goalsof the proposed strategies. Most threats in the study area werefound to be in the northern region and in areas of freshwater that beattributed to the existence of access roads in such areas that facil-itate increased human access to the wetland. The lowest risk zonewas identified in the southern part of the wetland in a saltwaterregion that is a pristine environment inaccessible to humans.

The key stressors and receptors in a wetland under consider-ation must be clearly identified in order to make properly targetedrisk assessment and to provide useful data. However it is very dif-ficult to assess and determine the threshold of permitted reservesof these resources and to identify stress factors in those wetlands,in which potential reserves of biological components do not haveany scientific data or documentation. Further development of the

proposed methodology can focus on risk assessment of wetlandfunctions to manage the activities that reduce capacity of the wet-land ecosystem. Assessment of wetland functions through standardquantitative risk assessment can be used to restore wetlands and

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44 B. Malekmohammadi, L. Rahimi Blouch

o improve environmental assessment programs. Quantitative riskssessment of wetlands can focus on chemical substances (such asutrients and contaminants) by only incorporating assessments ofoxicity. In this kind of assessment, indicators such as pollution con-entration at outlet points and diffusion in a wetland, the impactf wastewater on the food chain, and concentrations of metals orther pollutants in soil and water are used for making assessments.t should be noted that this study has examined major risk factorsf environmental impacts on the wetland but cumulative impactsf these risk factors have not been considered. Clearly, more workeeds to be done on the development of a holistic environmentalisk assessment for wetlands that includes qualitative and quanti-ative risk assessment approaches.

cknowledgments

The authors would like to thank the two anonymous reviewers,or their constructive comments on correction and improvement ofhe manuscript. Contributions by Ms. Azadeh Zarkar, Ph.D. studentf the University of Tehran are hereby acknowledged.

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