UNEP-WCMC technical report

Ecosystem resilience to climate change What is it and how can it be addressed in the context of climate change adaptation?

Technical report

Authors Cordula Epple, Emily Dunning Acknowledgements With thanks to Ivan Castelli and Emma Beckinsale for background work; to Keith Alverson (UNEP), Ed Barrow (IUCN), Philip Bubb (UNEP-WCMC), Barney Dickson (UNEP-WCMC), Nathalie Doswald (UNEP-WCMC), Jamison Ervin (UNDP), Val Kapos (UNEP-WCMC), Lera Miles (UNEP-WCMC), Musonda Mumba (UNEP), Andrea Sabelli (UNEP), Nik Sekhran (UNDP), Caroline Petersen (UNDP), Jason Spensley (UNEP), and Felice van der Plaat (UNEP) for comments and input; and to the German Ministry for the Environment, Nature Conservation, Building and Nuclear Safety for the funding of the project. The information shared in this document is an outcome of the Ecosystem-based Adaptation in Mountain Ecosystems Project focused on Nepal, Peru and Uganda where UNEP (UNEP-WCMC) in collaboration with partners IUCN and UNDP, undertook extensive work on Vulnerability and Impact Assessments (VIAs), to build a case for better understanding of climate resilience as it relates to mountain ecosystems. Published December 2014 Citation Epple, C., Dunning, E. 2014. Ecosystem resilience to climate change: What is it and how can it be addressed in the context of climate change adaptation? Technical report for the Mountain EbA Project. UNEP World Conservation Monitoring Centre, Cambridge. Copyright 2014 United Nations Environment Programme Photograph credits (front cover): Mount Elgon, Uganda, courtesy of Philip Bubb. The United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) is the specialist biodiversity assessment centre of the United Nations Environment Programme (UNEP), the world’s foremost intergovernmental environmental organization. The Centre has been in operation for over 30 years, combining scientific research with practical policy advice. This publication may be reproduced for educational or non-profit purposes without special permission, provided acknowledgement to the source is made. Reuse of any figures is subject to permission from the original rights holders. No use of this publication may be made for resale or any other commercial purpose without permission in writing from UNEP. Applications for permission, with a statement of purpose and extent of reproduction, should be sent to the Director, UNEP-WCMC, 219 Huntingdon Road, Cambridge, CB3 0DL, UK. The contents of this report do not necessarily reflect the views or policies of UNEP, contributory organizations or editors. The designations employed and the presentations of material in this report do not imply the expression of any opinion whatsoever on the part of UNEP or contributory organizations, editors or publishers concerning the legal status of any country, territory, city area or its authorities, or concerning the delimitation of its frontiers or boundaries or the designation of its name, frontiers or boundaries. The mention of a commercial entity or product in this publication does not imply endorsement by UNEP.

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Contents

Executive Summary ...... ii 1. Introduction ...... 1 2. Key terms, definitions and concepts for considering ecosystem resilience in the context of climate change adaptation ...... 3 3. Necessary analytical steps for including consideration of ecosystem resilience in Vulnerability and Impact Assessments and the planning of adaptation actions ...... 10 4. Possible sources of information on factors that affect the resilience of ecosystem properties and functions and the services resulting from them ...... 12 5. Conclusions ...... 20 References ...... 22 Annex ...... 25

List of tables and boxes

Tables

Table 1: : Illustrative examples of potential indicators of the resilience of ecosystem services to climate change ...... 21 B0xes

Box 1: Ecosystem functions and services...... 10

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Executive Summary

Ecosystem services are a prerequisite for human well-being. They are also a crucial asset that can help communities adapt to changes in climate. In the past, many societies around the world have developed ecosystem-based strategies for coping with climate variability and extremes. With climate change, the need for such strategies will increase. Yet ecosystems themselves will be affected by climate change, and their capacity to deliver provisioning, buffering and regulating services may decrease.

The concept of resilience is useful for assessing the likelihood that essential ecosystem services will be lost or retained, as well as for identifying ways to reduce the risk of negative impacts and avoid situations where the supply of ecosystem services cannot meet demand. The term resilience is widely used to describe the ability of a social or ecological system to maintain basic structural and functional characteristics over time despite external pressures. Resistance to fundamental change, i.e. change that alters the basic structure and function of the ecosystem into a new system, and recovery from disturbance are both mechanisms that can contribute to this ability.

However, the resilience of every system has limits. In some cases, when pressure exceeds these limits, a gradual change in the characteristics of the system will occur that is proportional to the amount of pressure leading to an altered state where function and structure are fundamentally different. In other cases, there are clear thresholds beyond which the system will undergo a marked and sometimes irreversible change, and a so-called regime shift towards a different state will take place. The predictability of such thresholds is a matter of ongoing scientific debate.

Making ecosystems resilient to the impacts of climate change has been recommended as an important component of adaptation strategies in a number of scientific and political fora, including the Conference of the Parties of the United Nations Framework Convention on Climate Change.

Still, to date few adaptation strategies set out concrete actions to maintain or enhance ecosystem resilience. One obstacle to closing this gap is the limited availability of methodological guidance and good practice examples for including consideration of ecosystem resilience in the Vulnerability and Impact Assessments (VIA) that form the basis of adaptation planning. Another is the shortage of information on the factors that affect ecosystem resilience, as well as on appropriate methods for assessing resilience to current and future climatic impacts and identifying measures that can enhance resilience where this is needed. The project "Ecosystem-based adaptation in Mountain Ecosystems" aims to address these issues.

From a methodological point of view, a first necessary step is to clarify how the concept of resilience relates to other relevant concepts used in the analytical frameworks that are applied in Vulnerability and Impact Assessments.

The most widely used analytical framework for assessing vulnerability is the one adopted by the IPCC, which describes vulnerability as a function of the exposure of a system to climate change and variation, its sensitivity, and its adaptive capacity. In relation to this framework, resilience can be considered as a wider concept integrating both sensitivity and adaptive capacity.

While the roots of the concepts of vulnerability and adaptive capacity lie in social science, the resilience concept has its origin in ecological science and was first developed in order to facilitate description and analysis of the responses of ecosystems to external factors. Making use of 'resilience thinking' and

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findings from the related literature in vulnerability assessments can therefore add value to the analysis especially when assessing the vulnerability of ecological systems and their services to society.

A more detailed discussion of the terminology surrounding resilience, vulnerability and adaptive capacity, including differences in the use of terms by different authors, is provided in the main part of this document.

It is important to note that every statement about resilience, vulnerability, sensitivity and adaptive capacity should be based on clear definitions of the 'exposed entity' (e.g. a particular societal group or ecosystem component) whose response to climate change is being described, the parameters of climate change that have been considered and the measure that has been used to assess the response of the exposed unit. In the context of adaptation strategies, identifying the possible impacts of climate change on the ability of ecosystems to provide certain desired services is likely to be a key aim of the vulnerability assessment, and this should be reflected in framing the questions.

So, for example, a vulnerability assessment for a pastoral mountain community could be designed to provide findings on a number of relevant issues such as the likely resilience of fodder production on high mountain pastures (as measured in terms of average yearly biomass production) to a projected increase in the average length of the summer dry period, or the resilience of low-income households' economic security (as measured in terms of the sustained ability to cover basic necessities) to a projected increase in the frequency of drought with associated losses of livestock. Answering this kind of clearly specified questions is more likely to produce outcomes that can guide practical adaptation actions than aiming straight for a general statement on whether 'pastoralism is resilient to climate change'.

A step-by-step explanation of how to identify the most relevant questions for a vulnerability assessment that can guide the development of ecosystem-based adaptation actions is included in another document prepared for the Mountain EbA Programme, "Guidance for Vulnerability and Impact Assessment as part of Ecosystem-based Adaptation to Climate Change".

Once the scope of the assessment has been defined, there is often a need for information on appropriate indicators of resilience, as the current knowledge base does not allow detailed projections or modelling of the responses of ecosystems to likely future changes in climate.

Where possible, information on appropriate indicators for assessing ecosystem resilience to climate change should be derived from scientific studies that have been carried out in a setting similar to the situation of interest in terms of the type of ecosystem and climatic factors considered. If necessary, this can be complemented by expert opinion based on an analysis of those features of each ecosystem that are most directly linked to the desired services (e.g. the presence of particular species or structural characteristics), and general ecological knowledge related to a) the relationship of these features with site parameters and other ecosystem characteristics, and b) the impacts of climate change and other pressures on these features. Examples of relevant types and sources of information, as well as of possible indicators, are provided in the document.

Another type of potentially useful information can be derived from a number of general hypotheses that have been put forward and discussed by various authors about factors that affect the resilience of ecosystems in general (i.e. resilience of all major characteristics of an ecosystem to a wide range of natural and anthropogenic stressors). Such hypotheses on cause-effect relationships between the state of ecosystems and their resilience have received much attention in the ecological literature. Still, there are few studies that have tested them through experiments or modelling. The difficulty of setting up ecosystem-scale experiments or models is considered to be one reason for this.

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A literature review has been carried out to examine the evidence base surrounding assumptions on the correlation between each of four general characteristics of ecosystems and the systems' resilience:

 'naturalness' (in composition and/or origin),  state of degradation and disturbance history,  fragmentation, and  biodiversity.

The literature reviewed can to some degree confirm the hypotheses about a positive or negative correlation between the four characteristics and the resilience of ecosystems, and one can conclude that they may in certain situations provide useful guidance for assessing resilience, where sufficient information is not available from other sources. However, based on the literature and common ecological knowledge, it is also clear that the validity of the hypotheses is not universal, and cautions need to be observed with regard to definitions of terms and the scope of applicability of each hypothesis. Uncritical application across a range of situations should be avoided. In the case of the biodiversity hypothesis, the possibilities for application in vulnerability and impact assessment may be further limited in practice by the common shortage of information on species diversity, and the almost complete absence of information on genetic diversity of naturally occurring species.

The same information sources that have been used to assess the resilience to climate change of ecosystems and their services can also be used to identify appropriate adaptation actions. For example, where non-climatic stressors such as overharvesting, pollution or drainage are found to have an impact on the resilience of desired ecosystem services, reducing this impact is likely to constitute a key option for adaptation.

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activities such as the sustainable management, conservation and restoration of ecosystems 1. Introduction (and their services to human populations) as part of an overall strategy to help people adapt Ecosystem services are a prerequisite for human to the adverse effects of climate change (CBD well-being. They are also a crucial asset that can AHTEG 2009, CBD Dec. X/33). help communities adapt to changes in climate. Mountain forests and wetlands, for example, The importance of ecosystem resilience for can buffer the consequences of extreme rainfall climate change adaptation has also been and drought, and the sustainable collection of recognised by Parties to the UNFCCC in their wild foods and medicines can offer additional decision 1/CP.16, which “Invites all Parties to sources of income in poor harvest seasons. In enhance action on adaptation [...] by the past, many societies around the world have undertaking, inter alia, the following: [...] developed ecosystem-based strategies for Building resilience of socio-economic and coping with climate variability and extremes, ecological systems, including through economic such as safeguarding protection forest on steep diversification and sustainable management of slopes or setting aside drought time forage natural resources” (Dec. 1/CP.16, para 14 (d)). reserves. With climate change, the need for such strategies will increase. Still, to date few adaptation strategies set out concrete actions to maintain or enhance Yet ecosystems themselves will be affected by ecosystem resilience. One obstacle to closing climate change, and their capacity to deliver this gap is the limited availability of provisioning, buffering and regulating services methodological guidance and good practice may decrease. The concept of resilience is examples for including consideration of useful for assessing the likelihood that essential ecosystem resilience in the Vulnerability and ecosystem services will be lost, as well as for Impact Assessments (VIA) that form the basis identifying ways to reduce such risks and avoid of adaptation planning. situations where the supply of ecosystem services cannot meet demand or is negatively To begin with, there is still widespread affected. uncertainty about how to interpret the concept of ecosystem resilience in the adaptation The term resilience is widely used to describe context, as the term has been used in several the ability of a social or ecological system to ways by different authors (cp. Levina et al. maintain basic structural and functional 2006). In order to facilitate its consideration in characteristics over time despite external VIA, there is a need to clarify the meaning of pressures. This use of the term acknowledges the term and how it relates to other relevant the fact that all systems undergo continual concepts used in the analytical frameworks that change, both as a result of internal processes are regularly applied in VIA, such as and in response to external factors. However, vulnerability, sensitivity and adaptive capacity. systems differ in the type and extent of their reactions to disturbances and stressors – some There is also a need for information on are more resilient than others. indicators that can be used to assess ecosystem resilience to climate change, as the current Making ecosystems resilient to the impacts of knowledge base often does not allow detailed climate change is a frequent recommendation projections or modelling of the responses of in the literature on climate change adaptation ecosystems to likely future changes in climate. and mentioned as an element in many Secondly, there is a need for guidance on how adaptation strategies. Ecosystem resilience is a to identify management options that can particularly relevant concept in the context of maintain or enhance the resilience of ecosystem-based adaptation, which is a specific ecosystems in a given situation. Finally, there is approach to adaptation that aims to use a need to develop indicators that can be used in

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monitoring the impacts of adaptation use of terms in the context of planning for interventions on the functioning of a particular ecosystem-based adaptation. ecosystem and the provision of services, and a methodology for drawing conclusions about It further explores the state of knowledge on how the resilience of the system in question the factors that affect ecosystem resilience to may have been maintained or enhanced. climate change with particular regard to the resilience of some key ecosystem services and The present document sets out the key terms the ecosystem functions that underpin them. and concepts that are relevant for analysing and Drawing on this analysis, proposals are made on describing the role of ecosystem resilience in how to address ecosystem resilience in the climate change adaptation, points out design and implementation of climate change differences in the use of these terms by various adaptation initiatives. authors and makes recommendations on the

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2. Key terms, definitions and concepts for considering ecosystem resilience in the context of climate change adaptation

Adaptation to climate change is often defined 2.1 The concept of vulnerability as as any kind of adjustment in natural or human proposed by the IPCC and other systems, in response to actual or expected climatic stimuli or their effects, which authors moderates harm or exploits beneficial A first step in adaptation planning is the opportunities (IPCC 2001, 2007). When talking elaboration of a Vulnerability and Impact about adaptation in human systems, it makes Assessment (VIA). A VIA identifies and sense to differentiate between planned and prioritizes needs for action through an spontaneous adaptation. assessment of the vulnerability of major prerequisites for human wellbeing to the likely Because of the close interactions between social impacts of climate change. There are various and ecological systems, efforts to ensure that ways of framing the questions that a societal goals can be met in the face of climate vulnerability assessment needs to ask, and it is change have to consider both types of systems important to be aware of the potential for in an integrated manner. If ecosystems are differing perspectives to avoid affected by changes in climate, their capacity to misunderstandings. This section will therefore provide services such as food production, water explore some of the basic dimensions of purification or flood control (cp. Box 1) may thinking about vulnerability, as a basis for the decrease. At the same time, societal demand for discussion that follows in section 2.2 of how the these services may increase, and adaptation concept of ecosystem resilience can be factored measures that are not well planned may expose into vulnerability assessments. ecosystems to further pressures (Paterson et al. 2008). Any overarching strategy for planned The most widely used conceptual framework for adaptation to avoid risks and exploit assessing vulnerability is the one that was opportunities to society from climate change adopted by the IPCC (2007), which defines should therefore include measures to safeguard vulnerability as the degree to which a system is or enhance key ecosystem services. susceptible to, and unable to cope with, adverse effects of climate change, including climate

Box 1: Ecosystem functions and services Ecosystem functions – The processes determining how ecosystems work. Ecosystem services – The properties of ecosystems resulting from ecosystem functions that either directly or indirectly benefit human endeavours (Hooper et al. 2005). These include: Provisioning services e.g. food, water, building materials, medicines Regulating services e.g. climate, water, pollination, pest and disease control Supporting services e.g. nutrient cycling, seed dispersal, primary production Cultural services e.g. aesthetic value, religious significance, recreation (MEA 2005)

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variability and extremes. It goes on to describe specifically aimed at assessing the vulnerability vulnerability as a function of the character, of human systems and should not be used magnitude, and rate of climate change and outside of that context. For example, Sperling et variation to which a system is exposed, its al. (2008) define vulnerability as "the sensitivity, and its adaptive capacity. characteristics of the communities that influence their ability to anticipate, cope, and This conceptual framework and the definitions adapt to climate-related hazards". UN/ISDR linked to it will form the basis for discussion in (2004) define vulnerability as "the conditions the present document. It should be noted, determined by physical, social, economic, and however, that other authors have used environmental factors or processes, which definitions of vulnerability which differ from increase the susceptibility of a community to this. the impact of hazards".

For example, a number of definitions do not When talking about the vulnerability of human include the concept of exposure, i.e. they regard systems, some authors add a fourth component vulnerability to a certain external factor as an to the IPCC framework: the “perception of risk”, inherent quality of a system that does not which affects the “willingness” to implement depend on the likelihood that the system will adaptation measures (e.g. Läderach et al. 2011). actually be exposed to this factor. This notion of vulnerability is particularly widespread in Further confusion can arise from the fact that literature from the social sciences, including some sources provide a measure of vulnerability literature referring to the vulnerability of rather than a definition. For example, UKCIP human communities to disasters (cp. Brooks (2003) state that vulnerability "refers to the 2003). In some literature sources, the concept of magnitude of harm that would result from a vulnerability is used in an even broader sense to particular hazardous event". describe the situation of societal groups that are suffering from certain disadvantages (such as Every statement about vulnerability should be lack of access to information, economic based on clear definitions of the 'exposed unit' marginalization) that are assumed to make whose vulnerability is being described (e.g. all them inherently vulnerable to a wide range of members or certain social groups within a (not clearly defined) external factors (cp. Jones community, certain species within an et al. 2004, UN/ISDR 2004). ecosystem, the flow of services from an ecosystem) and the measure of vulnerability Some of the authors who apply a vulnerability that is being used (e.g. changes in income, definition that does not include consideration mortality rates, productivity etc.). It is equally of exposure use the term 'risk' to describe the important to have a precise description of the product of vulnerability and exposure, so a exposure factor that the vulnerability 'vulnerability assessment' in the language of the assessment relates to. For example, in the IPCC would be called a 'risk assessment' under context of a climate change vulnerability this use of terms (cp. Brooks 2003, Jones et al. assessment, the climatic parameters that are 2004). considered (e.g. changes in yearly averages of temperature and precipitation vs. changes in In contrast to the IPCC definition, which can be frequency of certain types of extreme events) applied to both human and natural systems or should be named. It is impossible to assess specific components of such systems, the vulnerability without defining these three definitions used in the context of disaster variables but often the selections made are not prevention and relief, as well as definitions from explicitly stated. guidance on adaptation provided by organizations involved in development Naturally, the same need to clarify the scope cooperation (such as the World Bank) are often also applies to statements about the two 4

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inherent qualities of the exposed unit that Dawson et al. (2011), as well as Glick et al. (2011), determine its vulnerability according to the provide guidance for applying the IPCC concept IPCC framework – sensitivity and adaptive of vulnerability to species populations and capacity. develop more specific definitions of vulnerability, sensitivity and adaptive capacity The IPCC (2001, 2007) defines sensitivity as "the that are tailored to this context. The fact that degree to which a system is affected, either their explanations of sensitivity and adaptive adversely or beneficially, by climate-related capacity show some overlap (e.g. Dawson et al. stimuli". Adaptive capacity is defined as "the mention life history as a determining factor for ability of a system to adjust to climate change both characteristics) illustrates the difficulty of (including climate variability and extremes), to distinguishing between the two. However, as moderate potential damage, to take advantage long as all relevant factors are considered under of opportunities, or to cope with the one of the categories, and as long as the terms consequences" (IPCC 2001, 2007). are handled consistently throughout the scope of an assessment, this should not pose a major When talking about adaptive capacity in the problem. context of climate change, it is important to differentiate between the capacity for It is also important to note that adaptation can, spontaneous adaptation, which takes place once over time, reduce the sensitivity (and increase the system has been exposed to a change in the short-term coping capacity) of a system, climate or an extreme event, and the capacity and adaptive capacity itself can change as a for planned adaptation, which can take place result of processes within the system or both in anticipation of and in reaction to influences from outside. For example, the aspects of climate change. Capacity for planned adaptive capacity of a human system can adaptation only exists in human systems. change as a consequence of external capacity- building support, internal or external political Some authors use the term 'coping capacity' to and economic developments, or changes in the describe the capacity for short-term, state of natural resources on which the system spontaneous adaptation in reaction to a specific depends (cp. Brooks 2003). climate-related factor (e.g. an extreme weather event or a drought spell) (see Levina et al. 2006, Assessments of vulnerability that refer to a Jones et al. 2004). future point in time should therefore adopt a consistent approach as to whether or not It is not always easy to differentiate between the adaptations that take place before that time will factors that determine the sensitivity of a be taken into account. If effects of adaptation system and the factors that determine its are included in the assessment, the assumptions capacity for short-term, spontaneous made in identifying the type and extent of adaptation. This difficulty is particularly anticipated adaptations should be clearly obvious in the case of natural systems, where all spelled out. One option is to differentiate adaptations are spontaneous. For example, if between potential vulnerability (without one compares the vulnerability of different adaptation) and residual vulnerability species of grazing animals to consequences (assuming that a degree of adaptation has taken from extended periods of snow cover, the ability place). to cope with decreased access to ground-based food by a shift in grazing behaviour (e.g. A further point worth considering is the need to feeding on parts of trees and shrubs rather than draw the limits of the assessment in a way that herbs or grasses) can be considered a keeps the questions manageable but does not determinant of sensitivity as well as of adaptive disregard the complex interlinkages within and capacity. between human and natural systems, and is

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able to provide results that are useful for financial reserves to bridge periods of adversity, adaptation planning. or the degree to which the analysed community depends on the ecosystem service in question). Climate change vulnerability assessments can be limited to a simple, one-dimensional 2.2 The concept of resilience and question (e.g. assessing which coastal how it links with the IPCC settlements in a country are vulnerable to infrastructure damage from sea level rise), or vulnerability framework consider a wide range of climatic factors and possible impacts. Although resilience is a key term in literature on adaptation, its relationship to the terms used The most common type of vulnerability in the IPCC vulnerability framework has not assessments used in adaptation planning are been defined by the IPCC, and different regional or sectoral assessments, which interpretations of this relationship have been consider a range of potential impacts from put forward (cp. Levina et al. 2006, Glick et al. climate change and identify the most significant 2011). This section will examine some widely aspects that should be addressed for each used definitions of resilience and other terms region or sector. They can be thought of as that are closely related to it, before providing an 'nested' assessments, where the results of a attempt at clarification on how the concept of series of smaller assessments looking at the ecosystem resilience can be integrated into an vulnerability of individual assets or elements of assessment of vulnerability. human well-being to individual factors of climate change are brought together to form an One of the first authors who used the term overall picture. 'resilience' to describe the reactions of a system to change and disturbance was Holling (1973). The results can be presented in disaggregated Holling's paper focuses on ecological systems form, e.g. a matrix showing the vulnerability of and starts from the observation that by nature, different sectors to expected changes in these systems are continually changing, and different environmental parameters as a that the concepts of stability and equilibrium consequence of climate change. The different might not be the most appropriate for guiding aspects can also be integrated into a the management of natural resources. He vulnerability index, which allows a ranking of describes resilience as a measure of the the sectors or regions according to their 'overall' persistence of systems, and of their ability to vulnerability to climate change. However, the absorb change and disturbance and still aggregation process can lead to a loss of maintain the same relationships between decision-relevant information, and the results populations or state variables (Holling 1973). of such index-based rankings are often heavily disputed. Although the concept of resilience has since then been discussed and developed further by a Many impacts of climate change on human large number of authors (cp. Gunderson 2000, communities will be mediated through climate- Brand and Jax 2007, Benson and Garmestani related changes in ecosystems and their 2011), the basic idea of resilience as the services. Assessing the vulnerability of tendency of a system to retain certain key ecosystem functioning and services to climate properties despite changes and/or fluctuations change is therefore an essential step in in other characteristics has remained. As the assessing overall societal vulnerability. discussion has expanded beyond the discipline However, there will also be other factors of ecology in the stricter sense, a significant influencing social vulnerability which have part of the recent literature on resilience refers nothing to do with the response of ecosystems to social or social-ecological systems (e.g. to climate change (e.g. the availability of Holling 2001, Walker et al. 2004). 6

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While there is thus widespread agreement that The IPCC (2001) defines resilience as "the ability the resilience of a system can be seen in its of a social or ecological system to absorb tendency to avoid major long-term changes in disturbances while retaining the same basic basic characteristics, such as the level of structure and ways of functioning, the capacity primary productivity and the capacity to retain for self-organisation and the capacity to adapt fertile soils (in an ecological system), or the to stress and change". This definition seems to availability of adequate livelihood options and lean towards the first interpretation of health care (in a social system), there are resilience as the capacity to resist fundamental different ways of looking at the mechanisms by change. which these characteristics are maintained over time, resulting in different measures of Seeing that both resistance to change and resilience. recovery from disturbance may lead to the same long-term result, namely the persistence of According to some sources, a resilient system certain qualities of a system, for the purposes of can be recognized by the fact that it maintains a the present document both processes will be certain state despite high levels of external considered as conferring resilience. The terms pressure, i.e. that despite the pressure it 'resistance' and 'ability to recover' will be used remains within certain limits with regard to its to distinguish between the two components of basic characteristics. From this perspective, an resilience where necessary. appropriate measure of resilience would be the amount of external pressure that the system can In practice, resistance and ability to recover tolerate before shifting to a different state. may sometimes be inversely related, as the Other sources propose the view that a resilient components of systems that are characterized system is characterized by the fact that it by strong fluctuations in response to external returns quickly to the defined state if it is influences (i.e. low resistance) may have a pushed out of it by a disturbance or higher capacity to regain their former state after catastrophic event, in which case resilience disturbance (i.e. high ability to recover). Several would be measured by the time needed for authors have therefore put forward the idea recovery after experiencing a certain amount of that management regimes which aim to pressure. maintain a system in a closely defined state (i.e. managing for resistance) are likely to make the Some authors include both aspects in their system more vulnerable to substantial change definition of resilience (e.g. Alwang et al. 2001, in the long term (e.g. Holling 2001, Benson and Elmqvist et al. 2003, Cote and Darling 2010, Garmestani 2011). Miles et al. 2010), while many others apply the term resilience to only one of the two system At the same time, other authors provide properties, and some use additional terms like arguments for taking an opposite view. Based 'stability', 'resistance', 'robustness', 'recovery on the example of coral reefs and their rate' or 'ability to recover' to describe the other. resilience to damage from high water There are also some differences in the way these temperatures, Cote and Darling (2010) suggest additional terms are applied. For example, that resistance may be more important for the Holling (1973) defined stability as "the ability of continued existence of coral reefs than a system to return to an equilibrium state after recovery, as the increasing frequency of high a temporary disturbance", while Diaz et al. temperature spells will not leave enough time (2005) state that stability is "the capacity of an for recovery to take place between disturbances. ecosystem to persist in the same state", and add They therefore propose that management of that it "can be divided into two components: coral reefs should focus on increasing resistance and resilience". resistance.

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It seems plausible to assume that the relative the factor that the unit is being exposed to, and importance of resistance and ability to recover the measure that is used for determining the as mechanisms conferring resilience will in effects of exposure. If the definition of resilience reality depend on the circumstances (e.g. the is understood to include both resistance to characteristics of the system in question, as well fundamental change and the ability to recover as the degree of change and the frequency of from disturbance (as proposed in the present the disturbances that it is exposed to). document), the temporal perspective becomes an important element in determining the In any case, it is clear that both resistance and effects of exposure. the ability to recover have their limits, and the concept of 'thresholds', i.e. points beyond which For example, an assessment might aim to the qualities of a system undergo a marked and determine the resilience of smallholder farmers potentially irreversible change, has been in a certain region to effects of more frequent intensely discussed in the resilience literature droughts and use average household income as (cp. Walker et al. 2004, Levina et al. 2006, a measure. In this assessment, consideration Groffman et al. 2006). However, the changes might be given to a) whether drought has any that occur when pressures exceed the scope of significant impact on the type of farming resilience of a system need not always occur activities that are currently practised, b) suddenly or dramatically at a clearly perceptible whether short-term coping strategies are tipping point or threshold, but can in some available that will allow household income to be cases be gradual. While knowledge about the maintained within its current range during a precise limits of the resilience of ecosystems drought (e.g. by switching to a readily available would be highly desirable to inform their alternative income source), in which case management, it is rarely available and expert household income would be considered opinion combined with a precautionary resistant, and c) whether measures are available approach may provide the best possible that will allow household income to return to guidance. normal quickly (e.g. insurance that will enable farmers to endure a lost harvest, receive a quick In the context of vulnerability assessments payout and resume their activity after the using the IPCC framework, the resilience of a drought, or switching to alternative income system (or individual components or properties sources which require some time to develop), in of a system) can be considered as a combined which case there would be a strong ability to measure integrating both sensitivity and recover. adaptive capacity. Some authors who address the issue of how the concept of resilience links In an assessment of resilience referring to a to the IPCC vulnerability framework consider future point in time, changes in both resistance sensitivity to be the opposite of resistance. and the ability to recover which could result However, this direct equation appears too from adaptation strategies or other simplistic and is not recommended in this developments should also be taken into document, because depending on the account. timescales involved, both resistance and ability to recover can be seen as properties that are If applied in this way, the concept of resilience inversely related to sensitivity, and positively may avoid some of the complexities of related to adaptive capacity. distinguishing between factors contributing to sensitivity and those that contribute to adaptive It is important to keep in mind that – as with capacity. It will, however, require taking vulnerability, sensitivity and adaptive capacity - account of the temporal component of coping resilience cannot be assessed without defining with climate change impacts more explicitly. the unit whose resilience is being considered, Both of these points are considered an

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advantage in particular when assessing the even facilitating fluctuation and autonomous vulnerability of ecosystems (or selected adaptation, and maintaining certain desired ecosystem components and properties), where qualities. the distinction between sensitivity and adaptive capacity is most difficult to make and When vulnerability assessments are designed to consideration of recovery rates is of high take account of the interlinkages between importance for management. Another merit of human and natural systems (as it has been drawing on the concept of resilience is that it advocated above they should), assessing the underlines the notion that change is an resilience of those ecosystem services which are ecological necessity, and that the management most important for human wellbeing thus of ecosystems as part of an adaptation strategy becomes an essential part of the analysis. needs to strike a balance between allowing or

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3. Necessary analytical steps for including consideration of ecosystem resilience in Vulnerability and Impact Assessments and the planning of adaptation actions

In order to enable meaningful consideration of It should be noted that different stakeholders ecosystem resilience throughout the process of will have different perspectives on the value of developing an adaptation strategy (i.e. carrying specific ecosystem services, and that an out a Vulnerability and Impact Assessment and appropriate balance may need to be struck deciding on adaptation actions), a number of when selecting priorities. For example, with analytical steps need to be undertaken. regard to the continued provision of habitat for wildlife, local stakeholders and those from the To begin with, it is essential to identify those national government might prioritise different ecosystem services whose continued or species (e.g. local stakeholders might be most enhanced supply will be of importance for interested in maintaining species of economic stakeholders at different levels over the time or cultural importance, whereas the national period covered by the adaptation strategy. government might place an additional focus on Possible impacts of climate change on the species of high conservation value). demand for ecosystem services need to be taken into account. For example, where an increase in Once essential ecosystem services have been heavy rainfall events is considered likely, water determined, an assessment of their current and retention in upstream ecosystems will be a future availability, and of the extent to which service that becomes more important for this availability meets current and future inhabitants of downstream areas threatened by demand, should be included in the overall flooding. Vulnerability and Impact Assessment. This assessment should also aim to elucidate the Examples of ecosystem services that could be anticipated impacts of non-climatic pressures relevant in the context of adaptation include on service provision. provision of food, animal feed, timber, firewood and medicinal plants, regulation of the water In order to determine how climate change is cycle including flood control, water likely to influence the future availability of purification, erosion control and provision of ecosystem services, the resilience of these habitat for biodiversity 1. services to projected changes in relevant climate parameters should be assessed (see preceding sections on how ecosystem resilience links with the IPCC vulnerability framework). Both resistance and ability to recover should be 1 See Millennium Ecosystem Assessment (2005) for considered in this assessment as appropriate to the full list of provisioning, regulating, supporting and cultural services that ecosystems provide. the context. 10

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A more detailed step-by-step explanation of which affect the resilience of ecosystem how to identify the most relevant questions for functions and the services resulting from them a vulnerability assessment that can guide the is provided in Chapter 4. development of ecosystem-based adaptation actions is included in another document As a result of the consideration of ecosystem prepared for the Mountain EbA Programme, resilience in a Vulnerability and Impact "Guidance for Vulnerability and Impact Assessment, it should be possible to identify Assessment as part of Ecosystem-based areas where climate change may lead to or Adaptation to Climate Change". exacerbate a situation in which the demand for ecosystem services exceeds their availability. As has been pointed out before, assessing Where this is the case, adaptation strategies resilience will often require the selection of should include measures which can increase indicators, as it may not be possible to carry out ecosystem resilience, thus maintaining or detailed projections or modelling of the enhancing the potential for provision of responses of the ecosystems in question to ecosystem services. An example could be a case climate change. (For a discussion of available where changes in rainfall patterns with less modelling approaches and their limitations see frequent but more intense events are e.g. Glick et al. 2011). The selection of indicators anticipated in a region where soil stabilizing should be based on a clear understanding of the services provided by forest cover on hillsides are ecosystem qualities which determine the already compromised by unsustainable timber resilience of the examined ecosystem services. harvesting, and ecosystem resilience can be enhanced through an adaptation intervention In some situations this may present a challenge, which introduces a stricter community use as the required knowledge on the relationship regime, allowing natural regeneration of forest between measurable qualities of an ecosystem with some replanting activities, combined with and the resilience of the services it provides will the establishment of a community woodlot on not always be available. A discussion of unproductive agricultural land. potential sources of information on the factors

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4. Possible sources of information on factors that affect the resilience of ecosystem properties and functions and the services resulting from them

The best source of information on the determining the resilience of ecosystems. Some parameters that determine the resilience of examples of such information that may be specific ecosystem properties, functions and relevant in the context of planning for services to changes in climate are targeted ecosystem-based adaptation are described in studies that are as close as possible to the section 4.1 below. situation at hand, with regard to the type of ecosystem, ecosystem service, and anticipated A third type of potentially useful information climatic changes. Such studies can be empirical can be derived from a number of general (i.e. based on experiments or observations) or hypotheses that have been put forward and based on the modelling of ecosystem responses discussed by various authors about factors that to climate change. For example, Luo et al. affect the resilience of ecosystems in general (2010b) modelled the impacts of rising (i.e. resilience of all major characteristics of an ecosystem to a wide range of natural and temperatures and CO2 concentrations on net primary productivity in different types of anthropogenic stressors, cp. Chapin et al. 2007, mangrove ecosystems, and found that the Fischer et al. 2006; Schaberg et al. 2008; effects depended significantly on species and Laurance et al. 2011; Falkenman & Rockstrom location. In searching for relevant studies, one 2008). Such hypotheses on cause-effect should keep in mind that there are different relationships between the state of ecosystems options on the use of terminology, and that and their resilience have received much information related to resilience may be attention in the ecological literature. Still, there contained in literature referring to terms like are few studies that have tested them through vulnerability, sensitivity, susceptibility, stability, experiments or modelling. In part this is due to reliability, resistance, recovery or adaptive the difficulty of setting up ecosystem-scale capacity. experiments or models, and it is certainly no coincidence that the number of experiments Where research results of this kind are not with grassland-type systems is significantly available, useful information can often be higher than that of similar studies involving derived from more generic studies, more long-lived species, where projects which modelling/projections and widely accepted are usually of short duration can track the ecological knowledge related to the potential whole or several growth cycles of plants. impacts of climate change on the properties and functions of ecosystems that underpin certain While such general rules of thumb should types of services. The same kind of sources can always be treated with caution, if supported by also help to assess the role of other factors (e.g. plausible assumptions and sufficient evidence anthropogenic pressure, site characteristics) in they can provide useful guidance in the absence mediating these climatic impacts and thus of more specific sources of information. A

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literature review has therefore been carried out on that service, and the role of other factors in as part of the present study to examine the mediating these impacts. evidence base surrounding assumptions on the correlation between the following four general For services that depend on the presence of characteristics of ecosystems and their particular species or groups of species (such resilience: services may include provision of timber and non-timber forest products, biodiversity a) naturalness (in composition and/or conservation or aesthetic and recreational origin), values), the significant body of literature on the b) state of degradation and disturbance potential impacts of climate change on history, biodiversity, and on the factors determining c) fragmentation, and these impacts (e.g. Huntley 2007, Campbell et d) biodiversity. al. 2009, Harley et al. 2008, Glick et al. 2011) can give useful insights. For example, it is widely The methodology and results of this review are accepted that the resilience of species described in section 4.2. The following section populations to climate change will be lower at provides information relevant knowledge on the 'trailing end' of their range, i.e. that part of climate change impacts on ecosystems; the range where species are already at the limits information that is needed in assessing of their tolerance with regard to high vulnerability. temperatures or other climatic stressors that will increase with climate change (cp. Huntley 4.1 Examples of relevant 2007, Berry et al. 2003). Another commonly knowledge concerning the expected pattern is that populations of species with high fluctuation rates will be less resilient potential impacts of climate to extreme events in fragmented or naturally change on specific ecosystem isolated habitats, where the potential for properties and functions recolonisation after local extinction is low. Finally, it can be expected that populations The provision of ecosystem services can be tied whose size or fitness has been decreased by to a wide range of ecosystem properties and anthropogenic stressors (such as functions, and the relative importance of these overharvesting, pollution or habitat properties and functions for service provision degradation) will be less resilient to climate may vary. For example, provisioning services change than larger, well reproducing are normally linked to the presence of populations. Reducing other stressors is particular species or groups of species, as well therefore a frequent and well-founded as to the basic functions allowing these species recommendation in literature on adaptation to persist, such as nutrient cycling and soil options for individual species or biodiversity in formation. On the other hand, regulating general. services such as water purification and erosion For ecosystem services that depend to a large control are often more dependent on structural degree on vegetation structure and soil characteristics of an ecosystem (e.g. vegetation properties, such as erosion control, water cover and morphology of root systems) than on retention, water purification or carbon its precise species composition. sequestration, significant information related to Thinking about the ecosystem properties and the potential impacts of climate change functions that are most relevant for the (including changes in extreme weather events) ecosystem service in question can help in and the factors mediating these impacts can be identifying appropriate sources of information obtained by combining knowledge from in order to assess the impacts of climate change disciplines like biogeography, vegetation science, landscape ecology and fire ecology, as well as from dynamic vegetation models and 13

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research into the processes leading to land ecosystem characteristics considered in the degradation and desertification. For example, review were naturalness (in composition and/or knowledge about the impacts of different origin), state of degradation and disturbance grazing intensities on vegetation cover and soil history, fragmentation and biodiversity. These structure of grasslands under a range of climatic parameters were selected based on their conditions can be combined with knowledge on frequent mention in ecological literature as the influence of both factors on soil erosion to having an influence on ecosystem resilience. gain information on how grazing intensity influences the resilience of the soil retention The methodology applied in the review is service to climate change. described in the Annex to this document.

In addition to biotic and anthropogenic factors, A basic observation resulting from the literature the ecosystem properties and functions review is that the terms related to vulnerability underlying all types of ecosystem services (and and resilience are not only used in many their resilience to climate change) are also different ways, but also not always clearly influenced by a range of abiotic site parameters. defined. Often, authors talk about the resilience Examples are geological and geomorphological of ecosystems in general rather than the factors (e.g. the bedrock substrate for soil resilience of specific features, and the measures formation and slope inclination) and used to assess resilience vary widely and are not geographic location. These parameters will not always explained in detail. This adds to the be affected by changes in climate and are not difficulties in distilling general conclusions amenable to management. Still, knowledge from the wide range of case studies about the about the links between these parameters and way in which the various qualities of the potential of ecosystems to provide certain ecosystems affect the resilience of ecosystem services is important for identifying areas where services. the supply of ecosystem services can be These observations in this document are in line enhanced, or areas where there is a risk of with earlier views presented by Carpenter et al. ecosystem services not meeting demand. For (2001), who stated that the requirements for example, the parameters determining the measuring resilience were often poorly ability of soils to retain water (which in turn understood, and measures were being used that mediates resilience of vegetation to drought) had been given inadequate consideration. and soil infiltration rates (which mediate erosion risk) include abiotic parameters such as However, the literature reviewed still allows the position in the landscape, slope angle and some useful conclusions to be drawn, and these the substrate for soil formation, as well as biotic are discussed below. parameters such as plant species composition and vegetation cover (cp. Duniway et al. 2010, 'Naturalness' Nunes et al. 2009). It has been argued that ecosystems composed 4.2 Review of the evidence base of naturally occurring species are likely to be on general correlations between more resilient to climate change than selected ecosystem characteristics ecosystems whose vegetation is made up of non-native and/or planted species. This and ecosystem resilience hypothesis has been discussed most intensively with regard to forests (cp. Miles et al. 2010). As part of the preparation of this document, a literature review was carried out to look at the Although naturalness is frequently cited as a evidence base on how well selected factor affecting resilience, only a few studies characteristics of ecosystems can predict the could be found that explicitly address the resilience to climate change of their functions hypothesis. This could be partly due to the fact and/or the services derived from them. The 14

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that in reality there is often a correlation species may actually increase the resilience of between naturalness and other factors that can plantations to a range of climate-related impact on resilience, in particular biological stressors including more frequent outbreaks of and structural diversity (cp. Hawley et al. 2005; pests and diseases (cp. discussion in Miles et al. Mackey et al. 2008; Schaberg et al. 2008), so 2010). that the effects of naturalness cannot easily be isolated. Summing up, when talking about the 'naturalness' hypothesis, it seems important to Of the studies found, the majority are case clarify whether the hypothesis is applied to a studies supporting the hypothesis that more comparison of naturally growing vs. planted natural ecosystems are more resilient to climate ecosystems, or to a comparison of ecosystems change. Also, the two literature reviews composed of native vs. non-native species. included in the analysis both found more evidence in favour of the hypothesis than Despite the small number of studies found, against it (Miles et al. 2010, Thompson et al. there seems to be some support for the 2009). hypothesis that naturally growing ecosystems are more resilient to climate-related stressors However, it has to be noted that studies like storm events or rainfall variability than comparing naturally growing ecosystems to plantations. The argument that targeted planted ones can by their nature only be plantation design can increase resilience observational rather than experimental, and it deserves attention. However, it should be noted is difficult to find examples that are really that this presupposes sufficiently accurate comparable (cp. studies on resilience of natural projections of future climate, which may not be forest vs. plantations cited in Miles et al. 2010). available.

Some authors also compare the resilience of The hypothesis that ecosystems composed of plantations of native and non-native species to native species are more resilient to climate different climatic impacts. For example, Potts et change than ecosystems with a large share of al. (2006) carried out an experiment on two non-native species seems more difficult to planted monocultures of bunchgrasses, one maintain as a generic rule. with native and one with non-native species. They found that the native species were more State of degradation and resistant to rainfall pulses (more intense rainfall disturbance history events are expected in climate change) than the non-native species. Both aspects of resilience A comparatively large number of studies discuss were considered. Resilience was measured by the impacts of degradation and disturbance on looking at changes in various ecosystem fluxes, ecosystem resilience. The results of the review such as net ecosystem gas exchange (balance of underline the importance of avoiding general gross ecosystem photosynthetic and respiratory statements. There is clearly a need to take a activity) and evapotranspiration. closer look at the factors that have led to degradation and disturbance of the ecosystem While it seems reasonable to assume that native in question, as well as at the climatic factors to species are more likely to be resilient to climate which the ecosystem is expected to become variability within the current range of climatic exposed in future. When talking about conditions than non-native ones, future disturbance, the difference between natural and changes in climate may change this picture. At anthropogenic disturbance should be the same time, defining what constitutes a considered. Also, in the case of natural native species may become more difficult as disturbances, it is important to note whether species move to suitable climates in their there has been any change in disturbance adaptation to climate change. It has also been regimes over time, to which the ecosystem may argued that targeted selection of non-native be adapted. 15

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Cote and Darling (2010) discuss the impacts of Several of the studies that provide evidence on disturbance and degradation on the resilience the effects of disturbance on ecosystem of coral reefs to thermal stress, based on a resilience to climate-related stressors have review of observational evidence. They find that focussed on resilience to fire. Miles et al. (2010) reefs which have been severely degraded by discuss a number of studies which suggest that heavy disturbance from sedimentation, nutrient degradation of tropical rainforest through pollution and cyclones are likely to have low logging and previous fire events decreases resilience to thermal stress both in terms of resistance to fire, but does not decrease the resistance and ability to recover. With regard to (generally poor) rate of recovery. reefs that have been moderately disturbed, their findings are more differentiated. They note that Beeson et al (2001) modelled the impacts of fire there is growing evidence that protected or less disturbance in New Mexico forests on their degraded reefs return more quickly to their resilience to subsequent rain storms. They original state following a range of disturbances found that fire events increased overland flow (including thermal stress) than unprotected or in the rain storm simulations, showing how one more degraded reefs, i.e. they have a higher type of disturbance can have major effects on ability to recover. However, they also cite the ecosystem response to another type of evidence supporting the view that resistance to disturbance, in this case affecting the ecosystem thermal stress can be increased by a moderate service of flood regulation. level of disturbance. The explanation offered for The studies by Wittenberg et al. (2007) and this observation is that the tolerance of species Capon & Brock (2006) can serve as examples for to a non-climatic disturbance may be correlated the importance of considering natural with its tolerance to climatic impacts, and thus disturbance regimes when assessing the a moderately disturbed system will contain potential impacts of disturbance on ecosystem more stress-tolerant species. resilience. Both studies consider natural While this argument has its strengths, it seems disturbances in an ecosystem adapted to such important to note that it only holds true if disturbances (fire in a Mediterranean ecosystem tolerance to the different kinds of disturbance is and flooding in an Australian desert floodplain, indeed correlated, and if the ability of the respectively) and find that resilience is not tolerant species to contribute to continued significantly affected or even increased by these ecosystem functioning and the provision of events. ecosystem services is at least as great as that of Another issue that may be relevant in the the more sensitive species. Also, as argued context of climate change concerns the effects above, the relative importance of resistance and of disturbance on the resistance of ecosystems ability to recover for ensuring the continued to species invasions. Several authors have provision of ecosystem services will depend on argued that species immigrating by natural the circumstances, and thus increasing processes as a consequence of changes in resistance at the expense of ability to recover climate should not be considered invasive may not always be desirable. species, and this view is followed in the present Isbell et al. (2011) analysed data from a number document (see also the recommendation of studies related to the linkages between plant adopted by the Standing Committee of the Bern 2 diversity and the provision of ecosystem Convention on this topic ). However, even if services in grasslands. One conclusion that can be drawn from their analysis is that the disturbances acting on a system can be very 2 Recommendation No. 142 (2009) of the Standing different in nature, and the impacts of one Committee of the Bern Convention, adopted on 26 disturbance on species composition may well November 2009, interpreting the CBD definition of cause reduced ability to cope with another type invasive alien species to take into account climate of disturbance. change. 16

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naturally immigrating species are not Fragmentation considered, climate change is still expected to facilitate invasions of ecosystems by non-native The number of publications found that provide species that have arrived through evidence on the effects of fragmentation on anthropogenic pathways (cp. Capdevila- ecosystem resilience to climate-related factors Argüelles & Zilletti 2008). The effects of was limited. However, all of them support the colonisation by invasive species on ecosystem hypothesis that fragmentation has a negative services will depend on the characteristics of effect on resilience. both the invader and the recipient ecosystem, but may be substantial. Laurance and Williamson (2001) found that more fragmented areas of rainforest are more Gritti et al. (2006) modelled the susceptibility of vulnerable to tree mortality as a result of vegetation on five mountainous Mediterranean drought and fire. Their findings come from the islands to invasion by exotic plant species, and long-term Biological Dynamics of Forest found that more frequent disturbances (such as Fragments Project, in which forest patches of grazing and construction of roads or buildings) varying sizes were created within intact tropical cause greater vulnerability to invasion than less rainforest near Manaus, Brazil in 1979. frequent disturbances. This coincides with a Although the authors do not discuss the widely supported theory in invasion ecology. impacts of higher tree mortality rates on ecosystem services, it is clear that many Summing up, there is substantial evidence desirable provisioning and regulatory services supporting the hypothesis that ecosystem would be affected. degradation and past disturbances may lead to decreased resilience to a wide range of impacts Miles et al. (2010) cite several other studies, from climate change. However, generalisations some of which are based on the same project should be avoided, as contrary findings have area as the publication by Laurance and been encountered. Important issues that should Williamson, which demonstrate increased be considered when assessing the relevance of vulnerability of fragmented forests to wind- the disturbance/degradation hypothesis in a throw and fire. The literature review carried out concrete situation include: by Thompson et al. (2009) also came to the conclusion that more fragmented forest areas  whether the tolerance of species to the are less resilient to climate change. factor that caused degradation is likely to be positively correlated with Thrush et al (2008) looked at the recovery tolerance to the anticipated climatic aspect of resilience in a temperate estuary in impacts, New Zealand. Using species richness and  whether the observed disturbances are community composition as a measure, they actually causing degradation, or found that community recovery after artificial whether they are part of a natural destruction of the habitat was slower in more disturbance regime to which the system fragmented areas. is adapted, and Summing up, the available evidence confirms  whether the provision of desired the hypothesis that fragmentation decreases ecosystem services is dependent on the ecosystem resilience to climate change. It seems presence of particular species, and if likely that the negative effects of fragmentation yes, how these are affected by the on the ability to recover from disturbance will factors causing degradation or be most pronounced in ecosystems that are disturbance. heavily reliant on recolonisation as a means of recovery (as opposed to ecosystems in which a large share of the species has disturbance- resistant life stages, e.g. seeds or eggs). The 17

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effects of fragmentation on resistance to climate ecosystem contains a number of species that change and disturbance are likely to be highest can carry out the same functions, it is in ecosystems which have a high capacity to considered more likely that one or several of regulate their own microclimate and soil them will be able to withstand or benefit from conditions, such as forests or peatlands. the impact of change or disturbance, and the continuity of the function will be ensured. Biodiversity For example, Walker et al. (1999) examined the Among the four hypotheses examined, the effects of plant attribute diversity on resilience hypothesis that biodiversity increases resilience and ecosystem function in Australian to climate change (as well as to a number of rangelands and found that the presence of other potential sources of stress) is the one that functionally similar species favours resilience. is most intensively debated in scientific Elmqvist et al. (2003) similarly conclude from literature, and publications addressing this their literature review that the presence of issue made up the largest part of the analysed different species providing the same ecosystem literature. While the majority of studies focus function increases resistance to climate change. on effects of species diversity only, genetic, Isbell et al. (2011), in their analysis of data from structural and functional aspects of diversity are studies related to the linkages between plant also discussed by some authors. diversity and the provision of ecosystem It should be noted that the three other factors services in grasslands, find that species richness examined in this review (i.e. naturalness, played an important role for the maintenance of degradation and disturbance history, and ecosystem functions over time. They highlight fragmentation) all have an influence on that particular species promoted ecosystem biodiversity, and it is difficult to analyse each functioning in different contexts as defined by factor independently. the type of disturbance and the species combination, and point out that these context- The majority of studies found (including three dependent effects are difficult to predict. literature reviews, i.e. Miles et al. 2010, Thompson et al. 2009, Elmqvist et al. 2003) Reusch et al. (2005) examined the effects of support the biodiversity-resilience hypothesis, genetic diversity on the ability of seagrasses to but there are also a number of publications recover from periods of high water temperature, providing contradictory evidence. Most of these and found that more genetically diverse stands are based on drought experiments with a recovered more quickly. The importance of limited number of grassland species. All of the genetic diversity is also underlined by studies that did not identify a positive effect of Thompson et al. (2009) in their literature biodiversity on resilience to climate-related review, where they note that some forest types factors were focused on species diversity and of low species diversity but high genetic examined the resistance aspect of resilience. A diversity (e.g. boreal pine forests) are highly few studies that examined both resistance to resilient to disturbance. Di Falco and Chavas and recovery from climate-related stresses (2008) modelled the effects of crop biodiversity provide evidence for a positive correlation on the resilience of productivity in agricultural between biodiversity and recovery rates, but ecosystems to rainfall reduction and conclude found no such correlation between biodiversity that both diversity of crops and genetic and resistance (e.g. van Ruijven and Berendse diversity within crop species support continued 2010). productivity of agroecosystems when faced with low rainfall. Many authors who find a positive correlation between biodiversity and resilience explain Summing up, the range of the evidence found their results with the effect of functional indicates that the diversity-resilience redundancy as increasing resilience. If an hypothesis has some general validity, but 18

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exceptions to the rule need to be expected. This General assumptions about resilience based on seems to conform with common ecological measures of diversity should be used carefully sense, as the characteristics of the species (and and weighed against other available evidence. individual organisms) involved will play a role Care should also be taken to avoid comparing in determining the response of a system to a apples and pears. While the assumption that a particular stress factor, and may override effects genetically diverse temperate beech forest will of species numbers or overall genetic or be more resilient to climate-related stress than structural diversity. Based on the information a genetically impoverished one can be defended identified in the review, there is reason to based on the available evidence, comparing the assume that diversity may be a stronger diversity of a temperate beech forest to that of a predictor of the ability of a system to recover Mediterranean pine forest is not likely provide from disturbance than of its resistance. meaningful results in terms of assessing their resilience.

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climate change should be derived from scientific studies that are as close as possible to 5. Conclusions the situation at hand in terms of the type of ecosystem and climatic factors considered. As outlined in the first sections of this Where necessary, this can be complemented by document, integrating the concept of resilience expert opinion based on an analysis of the into vulnerability assessments can add value to features of each ecosystem that are most the analysis especially when considering the directly linked to the desired services (e.g. vulnerability of ecological systems and the presence of particular species, structural services they provide to society. characteristics) and general ecological Vulnerability and Impact Assessments should knowledge related to the impacts of climate ideally include the following steps: change and other pressures on these features, and on the relationship of these features with 1) Identify those ecosystem services site parameters and other ecosystem whose continued or enhanced supply characteristics. will be of importance for reaching the goals of adaptation over the timescale The four general hypotheses that were covered by the adaptation strategy; discussed above about the relationship between 2) Assess the current and future capacity naturalness, degradation and disturbance of ecosystems in the studied area to history, fragmentation and biodiversity on the one hand and the resilience of ecosystems on deliver these services, taking into the other hand are confirmed to some degree by account climate projections, the the literature reviewed. They may provide some current state of ecosystems and useful guidance for assessing resilience where pressures acting on them, and their sufficient information is not available from resilience to climate change; other sources. However, the cautions 3) Identify areas where climate change mentioned with regard to the need for clear may lead to or exacerbate a situation in definitions of terms and the scope of which the demand for ecosystem applicability of each hypothesis should be services exceeds their availability; and observed, and uncritical application should be 4) Propose adaptation measures to avoided. In the case of the biodiversity hypothesis, application may be further limited address identified problems, including by the common shortage of information on by increasing ecosystem resilience. species diversity, and the almost complete Consideration of the resilience of ecosystems absence of information on genetic diversity of and their services in climate change naturally occurring species. vulnerability assessments is often not The following table gives some illustrative straightforward due to the limited knowledge examples of indicators that could be used to base for measuring and predicting resilience. In assess the resilience of ecosystem services to many cases, proxy indicators will need to be changes in climate (note that all indicators need identified. to be checked for applicability in the actual Where possible, information on appropriate context as outlined above.) indicators for assessing ecosystem resilience to

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Table 1: Illustrative examples of potential indicators of the resilience of ecosystem services to climate change

Subject of assessment Ecosystem characteristics Possible indicators that are linked to service provision

Resilience of erosion Vegetation cover Signs of existing degradation (e.g. reduced vegetation cover or control service of mountain Density of near-surface high livestock densities) grassland to more root system Structural and species diversity intensive precipitation Abiotic factors (soil type, Presence of key species with strong soil retention capacity events slope) Abiotic factors determining general susceptibility to erosion (soil type, slope)

Resilience of erosion Vegetation cover Signs of existing degradation (e.g. reduced vegetation cover or control service of mountain Density of near-surface high livestock densities) grassland to more root system Percentage of drought-sensitive species prolonged drought periods Abiotic factors (soil type, Structural and species diversity slope) Presence of key species with strong soil retention capacity Abiotic factors determining general susceptibility to erosion (soil type, slope)

Resilience of food Habitat quality for Signs of current overhunting or other anthropogenic pressure provisioning service (game important game species Location of the site in relation to range margins of currently animals) of a forest Existence of healthy occurring and potentially immigrating game species ecosystem to temperature populations of important Isolation of the site from potential source areas for immigration rise game species of game species Location of the site in relation to range margins of dominant tree species and species providing food for important game species Diversity of species providing food for important game species

Resilience of aesthetic / Species diversity Current temperature regime in relation to temperature tolerance recreational service of a Species abundance levels coral reef to high water Structural diversity Current levels of species diversity temperatures Level of eutrophication and other degrading factors

Resilience of erosion Vegetation cover Signs of existing degradation (e.g. reduced vegetation cover or control service of mountain Density of near-surface high livestock densities) grassland to more root system Structural and species diversity intensive precipitation Abiotic factors (soil type, Presence of key species with strong soil retention capacity events slope) Abiotic factors determining general susceptibility to erosion (soil type, slope)

The same information sources that have been as overharvesting, pollution or drainage are used to assess the resilience of ecosystems and found to have an impact on the resilience of their services to climate change can also be desired ecosystem services, reducing this used to identify appropriate adaptation actions. impact is likely to constitute a key option for For example, where non-climatic stressors such adaptation.

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References

Alwang, J., Siegel, P.B., Jorgensen, S.L. 2001. Vulnerability: A View From Different Disciplines. Social Protection Discussion Paper Series. No 0115 . The World Bank, Washington, USA.

Beeson, B.C., Martens, S.N., Breshears.D.D. 2001. Simulating overland flow following wildfire: mapping vulnerability to landscape disturbance. Hydrological Processes 15, 2917-2930.

Benson, M.H., Garmestani, A.S. 2011. Can we manage for resilience? The integration of resilience thinking into natural resource management in the United States. Environmental Management.48(3), 392-399

Berry, P.M., Dawson, T.P., Harrison, P.A., Pearson, R., Butt, N. 2003. The sensitivity and vulnerability of terrestrial habitats and species in Britain and Ireland to climate change. Journal for Nature Conservation 11, 15-23.

Brand, F.S., Jax, K. 2007. Focusing the meaning(s) of resilience: resilience as a descriptive concept and a boundary object. Ecology and Society 12(1), 23.

Brooks, N. 2003. Vulnerability, risk and adaptation: A conceptual framework. Tyndall Centre for Climate Change Research, Norwich, UK.

Campbell, A., Kapos, V., Scharlemann, J.P.W., Bubb, P., Chenery, A., Coad, L., Dickson, B., Doswald, N., Khan, M.S.I., Kershaw, F., Rashid, M. 2009. Review of the Literature on the Links between Biodiversity and Climate Change: Impacts, Adaptation and Mitigation. Technical Series No. 42 Secretariat of the Convention on Biological Diversity, Montreal, Canada..

Capdevila-Arguelles, L., Zilletti, B. 2008. A perspective on climate change and invasive alien species. T- PVS/Inf (2008) 5 rev. Strasbourg, France.. 2nd Meeting of the Group of Experts on Biodiversity and Climate Change.

Capon, S.J., Brock, M.A. 2006. Flooding, soil seed bank dynamics and vegetation resilience of a hydrologically variable desert floodplain. Freshwater Biology 51, 206-223.

Carpenter, S., Walker, B., Anderies, J.M., Abel, N. 2001. From Metaphor to Measurement: Resilience of What to What? Ecosystems 4, 765-781.

Chapin, F.S., Danell, K., Elmqvist, T., Folke, C., Fresco, N. 2007. Managing climate change impacts to enhance the resilience and sustainability of Fennoscandian forests. Ambio 36, 528-533.

Cote, I.M., Darling, E.S. 2010. Rethinking ecosystem resilience in the face of climate change. PLoS Biol 8(7), e1000438.

Dawson, T.P., Jackson, S.T., House, J.I., Prentice, I.C., Mace, G.M. 2011. Beyond Predictions: Biodiversity Conservation in a Changing Climate. Science 332, 53-58.

Di Falco, S., Chavas, J.P. 2008. Rainfall shocks, resilience, and the effects of crop biodiversity on agroecosystem productivity. Land Economics 84, 83-96.

Diaz, S., Tilman, D., Fargione, J. 2005. Biodiversity Regulation of Ecosystem Services. In: Ecosystems and Human Well-being: current state and trends, Volume 1. (R. Hassan, R. Scholes, and N. Ash, Eds.) Island Press, Washington DC.

22

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Duniway, M.C., Herrick, J.E., Curtis Monger, H. 2010. Spatial and temporal variability of plant-available water in calcium carbonate-cemented soils and consequences for arid ecosystem resilience. Oecologia 163, 215-226.

Elmqvist, T., Folke, C., Nystrom, M., Peterson, G., Bengtsson, J., Walker, B., Norberg, J. 2003. Response diversity, ecosystem change, and resilience. Frontiers in Ecology and the Environment 1, 488-494.

Falkenmark, M., Rockstrom, J. 2008. Building resilience to drought in desertification-prone savannas in Sub-Saharan Africa: The water perspective. Natural Resources Forum 32 [2]. Blackwell Synergy, 93-102.

Fischer, J., Lindenmayer, D.B., Manning, A.D. 2006. Biodiversity, ecosystem function, and resilience: ten guiding principles for commodity production landscapes. Frontiers in Ecology and the Environment 4, 80-86.

Glick, P., Stein, B.A., Edelson, N.A. (ed.) 2011. Scanning the Conservation Horizon: A Guide to Climate Change Vulnerability Assessment. National Wildlife Federation, Washington, D.C. USA

Gritti, E.S., Smith, B., Sykes, M.T. 2006. Vulnerability to Mediterranean Basin ecosystems to climate change and invasion by exotic plant species. Journal of Biogeography 33, 145-157.

Groffman, P., Baron, J., Blett, T., Gold, A., Goodman, I., Gunderson, L., Levinson, B., Palmer, M., Paerl, H., Peterson, G., LeRoy Poff, N., Rejeski, D., Reynolds, J., Turner, M., Weathers, K., & Wiens, J. 2006. Ecological thresholds: the key to successful environmental management or an important concept with no practical application? Ecosystems 9(1):1–13.

Gunderson, L.H. 2000. Ecological Resilience - In Theory and Application. Annual Review of Ecology and Systematics 31, 425-439.

Harley, M., Hodgson, N. 2008. Review of existing international and national guidance on adaptation to climate change: with a focus on biodiversity issues. AEA Technology, 1-41.

Hawley, G.J., Schaberg, P.G., DeHayes, D.H., Brissette, J.C. 2005. Silviculture alters the genetic structure of an eastern hemlock forest in Maine, USA. Canadian Journal of Forest Research-Revue Canadienne de Recherche Forestiere 35, 143-150.

Holling, C.S. 1973. Resilience and stability of ecological systems. Annual Review of Ecology and Systematics 4, 1-23.

Holling, C.S. 2001. Understanding the Complexity of Economic, Ecological, and Social Systems. Ecosystems 4, 390-405.

Hooper, D.U., Chapin, F.S., Ewel, J.J., Hector, A., Inchausti, P., Lavorel, S., Lawton, J.H., Lodge, D.M., Loreau, M., Naeem, S., Schmid, B., Setala, H., Symstad, A.J., Vandermeer, J., Wardle, D.A. 2005. Effects of biodiversity on ecosystem functioning: A consensus of current knowledge. Ecological Monographs 75, 3-35.

Huntley, B. 2007. Climatic change and the conservation of European biodiversity: Towards the development of adaptation strategies. Bern Convention Standing Committee on Climate Change. Council of Europe, Strasbourg, France.

IPCC 2001. Climate Change 2001: Synthesis Report. A contribution of Working Groups I, II and III to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK.

23

Technical report

IPCC 2007. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Parry, M. L., Canziani, O. F., Palutikof, J., van der Linden, P. J., and Hanson, C. E. Cambridge University Press, Cambridge, UK. -976pp.

Isbell, F., Calcagno, V., Hector, A., Connolly, J., Harpole, W.S., Reich, P.B., Scherer-Lorenzen, M., Schmid, B., Tilman, D., Van Ruijven, J., Weigelt, A., Wilsey, B.J., Zavaleta, E.S., Loreau, M. 2011. High plant diversity is needed to maintain ecosystem services. Nature 477, 199-202.

ISDR 2004. Living with Risk: A global review of disaster reduction initiatives. Volume I UN ISDR, Geneva, Switzerland.

Jones, R., Boer, R. 2004. Assessing Current Climate Risks. In: Adaptation Policy Frameworks for Climate Change: Developing Strategies, Policies and Measures. (B. Lim and E. Spanger-Siegfried, Eds.) UNDP. Cambridge University Press, pp. 91-118.

Jorgenson, M.T., Romanovsky, V., Harden, J., Shur, Y., O'Donnell, J., Schuur, E.A.G., Kanevskiy, M., Marchenko, S. 2010. Resilience and vulnerability of permafrost to climate change. Canadian Journal of Forest Research 40, 1219-1236.

Läderach, P., Eitzinger, A., Bunn, C., Benedikter, A., Quiroga, A., Pantoja, A. and Rizo, L. 2011. Adaptation by agricultural communities to climate change through participatory and supply chain inclusive management. Methodology. CIAT: Colombia.

Laurance, W.F., Williamson, G.B. 2001. Positive feedbacks among forest fragmentation, drought, and climate change in the Amazon. Conservation Biology 15, 1529-1535.

Laurance, W.F.; Dell, B.; Turton, S M.; Lawes, M.J.; Hutley, L.B. McCallum, H., Dale, P., Bird, M., Hardy, G., Prideaux, G., Gawne, B., McMahon, C.R., Yu, R., Hero, J-M., Schwarzkopf, L., Krockenberger, A., Douglas, M., Silvester, E., Mahony, M., Vella, K., Saikia, U., Wahren, C.H., Xu, Z., Smith, B., Cocklin, C. 2011. The 10 Australian ecosystems most vulnerable to tipping points. Biological Conservation 144(5) 1472–1480.

Levina, E., Tirpak, D. 2006. Adaptation to Climate Change: Key Terms. OECD, Paris, France.

Luo, Z., Sun, O.J., Wang, E., Ren, H., Xu, H. 2010. Modeling Productivity in Mangrove Forests as Impacted by Effective Soil Water Availability and Its Sensitivity to Climate Change Using Biome-BGC. Ecosystems 13, 949-965.

Mackey, B.G., Keith, H., Berry, S.L., Lindenmayer, D.B. 2008. Green Carbon: The role of natural forests in carbon storage. Part 1. A green carbon account of Australia's south-eastern eucalypt forests, and policy implications. Australian National University Press, Canberra.

Maul, R.S., Holland, M.M., Mikel, A.T., Cooper, C.M. 1999. Resilience of forested wetlands located in the southeastern United States: Demonstration of a soil perturbation index. Wetlands.

Miles, L., Dunning, E., Doswald, N., Osti, M. 2010. Working paper: A safer bet for REDD+: Review of the evidence on the relationship between biodiversity and the resilience of forest carbon stocks. Multiple Benefits Series 10. Version 2 . Prepared on behalf of the UN-REDD Programme. UNEP World Conservation Monitoring Centre, Cambridge, UK. 1-35.

Millennium Ecosystem Assessment 2005. Ecosystems and Human Well-being: Synthesis. Island Press, Washington, D.C., USA.

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Annex Methodology of the literature review on correlations between selected ecosystem characteristics and ecosystem resilience

The review was carried out in a semi-systematic were used in a way that allowed inferences to be way, based on systematic keyword searches for drawn on resilience as defined in the present relevant publications in Web of Knowledge and document). Where authors explicitly or Google Scholar, and in addition drawing upon implicitly refer to only one of the components selected further sources including previous of resilience (i.e. resistance and ability to work carried out at UNEP-WCMC on the recover), or where contrasting evidence was factors affecting the resilience of forest carbon found concerning the two components, this was stocks (Miles et al. 2010). For the web searches, noted. a comprehensive set of search terms were used, with 36 searches carried out in total. The findings from published literature reviews were included in the analysis. To avoid bias due The relevance of all returning results was to double counting, the references cited in assessed on the basis of their title and abstract. these reviews were compared to the list of A total of 123 publications were selected for references compiled for the present document, closer analysis. A small number of articles could and the overlap was noted. not be accessed at the time of writing. If possible, these will be included in a future Studies were categorised based on the type of version of this document. evidence they contained. Experiments are considered to provide the strongest evidence, Searches were carried out for literature followed by observations (differentiated from referring to ecosystems in general and major experiments on the basis that they do not types of natural ecosystems in particular, involve human establishment or intervention), including forests, grasslands, shrublands, modelling, and finally theoretical essays. Some savannas, peatlands, rivers, and coastal and authors draw on more than one type of marine ecosystems. Publications referring to evidence; for example, a number of studies used semi-natural/agricultural ecosystems were not experimental results to feed into models (e.g. specifically searched for, but have been Maul et al 1999; Rahlao 2009; Jorgenson et al included in the analysis where they came up 2010). Publications which merely put forward during the search. hypotheses on the factors affecting resilience without referring to an evidence base were Regardless of the terminology used, all excluded from the study. publications that provide evidence related to the influence of one of the four selected Like all literature reviews of the evidence base characteristics on ecosystem resilience or the for a certain theory, this review may to some resilience of particular ecosystem properties, degree suffer from publication bias, i.e. the fact functions or services to climate change were that studies whose results do not support the included in the analysis (i.e. publications authors' original hypothesis may be less likely referring to sensitivity, vulnerability, to get published. susceptibility etc. were included if the terms

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