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The Future of Healthy Ecosystems
DefrEFRAefraa Horizon Scanning Project
CTHS 0303/CT 20603SD0306
Draft FinalRevised final report August OctoberDecember 20020054
Raffaelli, D., White, P.C.L., , Perrings, C.A., Smart, J.S. and A. Renwick
Environment Department
University of York
Correspondence: Dave Raffaelli,
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Project Code & Title:
SD0306 The Future of Healthy Ecosystems
Representatives of the Parties:
Prof. Dave Raffaelli (Contractor Representative)
Environment Department
University of York
Dr Sara Webster (Secretary of State’s Representative)
Defra
Room 201 Cromwell House Dean Stanley Street Westminster London
Project Dates:
Commencement: 1st March 2004
Completion: 31st August 2004
Final draft: October 2004
Revised final report OctoberDecember 2005
Total Project Costs: £51,432 excl. VAT
Total Staff Input per Grade: 2 PDRA @ 0.5 year
Original objectives:
1. Review key indicators and definitions of ecosystem health
2. Identify ecological goods and services associated with different indicators and evaluate their socio-economic significance
3. Critically review the modelling approaches available
4. Assess the potential of higher level metrics and measures that can be used as possible common currencies and identify knowledge and data gaps which might impinge on horizon scanning
Milestone / Target Date / Title01/01 / 01/06/04 / Review the key indicators and definitions of ecosystem health
02/01 / 01/06/04 / Identify the socio-economic significance of different indicators
03/01 / 01/07/04 / Critically review the modelling approaches available for predicting changes in key indicators
04/01 / 31/08/04 / Assess potential for common currencies and identify knowledge gaps
Executive Summary & Recommendations
1. In the context of global climate change, understanding and monitoring the function and performance of ecosystems over time is of critical importance.
2. A greater emphasis on environmental sustainability, an accompanying recognition of the scarcity of natural resources and increasing concern regarding human impacts on the environment have focused attention on the concept of ‘ecosystem health’ as a method by which such issues might be addressed.
3. This Defra Horizon Scanning Project critically examines the concept of ecosystem health and makes recommendations as to how the concept might be implemented within the UK context.
4. A number of different approaches have been used to assess ecosystem health. These include biological, ecological and biophysical indicators and indices derived by direct measurement, as well as structural, functional and system-level metrics derived from ecological and/or economic models of managed ecosystems.
5. The application of such indicators to assess the health of agricultural, forest and aquatic ecosystems is described within the UK, Europe and elsewhere.
6. Our review suggests that purely biological or biophysical assessments do not capture the complexity of managed ecosystems with a significant societal component, such as agricultural landscapes. Approaches which incorporate ecological, economic and societal components, such as The Holistic Ecosystem Health Indicator (HEHI), have more potential in this respect.
7. A new holistic approach, Monitoring Ecosystem Health by Trends Analysis (MEHTA), is developed here.
8. MEHTA analyses changes in indicators which reflect the status of a set of environmental, ecological, financial, human and social capital stocks which are vital for the provision of products of social and economic relevance within managed ecosystems. MEHTA uses historical data to evaluate the rate and direction of changes in these capital stocks with respect to desired critical thresholds.
9. The potential and limitations of the MEHTA approach are illustrated for the North York Moors National Park and the catchment of the River Ythan in Aberdeenshire.
10. Our analyses have identified scale mis-match across space and time, and limited data availability as issues of concern. Further research is required to resolve these issues.
11. Our key recommendations for policy makers, such as Defra, are as follows. Whilst the present Defra sustainability indicators make an effort to reflect ecological, environmental and social dimensions, there is need to develop approaches which enable these and other measures to be combined in suites or bundles of sustainability metrics appropriate for particular systems over a range of spatial scales, in order to deliver a more holistic assessment of the health of those systems. This will require: research funding to develop the novel statistical and numerical tools required; consultation with stakeholders about acceptable limits, thresholds and targets; and agreed changes (where appropriate) in the kinds of metric data routinely collected by statutory bodies as well as the storage and management of such data in order to ensure their availability to those charged with assessing ecosystem health.
12. In conclusion, understanding and assessing ecosystem health is important because ecosystem health underpins sustainable development. An holistic assessment technique such as MEHTA provides a formal mechanism through which society’s views on ecosystems and the environment can be incorporated into the assessment process.
CONTENTS
1 Introduction 1
1.1 Purpose 1
1.2 Objectives 1
1.3 Methods 2
1.4 Structure of the report 2
1.5 Acknowledgements 3332
2 Origins and development of the ecosystem health concept 3
2.1 Ecosystem health and the ecosystem approach to conservation 3
2.2 Ecosystem health and sustainable development 4443
2.3 Relationship of ecosystem health to Quality of Life counts and the UK Biodiversity Action Plans 4
3 Definitions of ecosystem health 5554
4 Approaches to assessing ecosystem health 6
4.1 Costanza’s index of ecosystem health 6
4.2 Structural and functional indicators 67
5 Indicators and indices derived from direct measurement 9
5.1 Ecological indicators 9
5.2 Multimetric indices 9
5.3 Issues with biological monitoring and indicators 10
6 Using models to assess ecosystem health 11
6.1 Odum’s conjectures and mass-balance approaches 1111111110
6.2 Adaptive cycles and resilience 13
6.3 System-level metrics from mass balance models 14141413
6.4 Mass-balance measures and ecosystem health: a case study of the Ythan estuary, Aberdeenshire 16161615
6.5 Model-based approaches to ecosystem management from ecological economics, environmental economics and resource economics 17171716
7 Application of these different approaches for evaluating the health of terrestrial and aquatic systems 18181817
7.1 Agroecosystem health 18181817
7.1.1 Biological monitoring in agroecosystems 18
7.1.2 Indicators of biodiversity in agroecosystems 20202019
7.1.3 Population and community ecological parameters as indicators of change in agroecosystems 21212120
7.1.4 Means-based and effect-based indicators of environmental impact in agroecosystems 21212120
7.1.5 Direct and surrogate indicators in agroecosystems 22222221
7.1.6 Historical development of agroecosystem indicators in Europe 22222221
7.1.7 Historical application of agroecosystem indicators within England 25252524
7.2 Forest ecosystem health 25252524
7.2.1 Monitoring forest ecosystems 27272726
7.2.2 Indicators of forest health 27272726
7.2.3 Indicators of forest health in Britain 27272726
7.3 Aquatic Ecosystem ecosystem health 28282827
7.3.1 Physical and chemical indicators of aquatic ecosystem health 30303029
7.3.2 Biotic indicators of aquatic ecosystem health 30303029
7.3.3 Multimetric biotic indices 30303029
7.3.4 Methods used to assess aquatic ecosystem health in Britain 31313130
8 Interdisciplinary indicators of ecosystem health 32323231
8.1 The HEHI approach 32323231
8.2 MEHTA (Monitoring of Ecosystem Health throughby Trends Analysis): an alternative interdisciplinary indicator 33333332
8.2.1 Analysing indicator data 35353534
8.3 Contrasts with the HEHI approach 36363635
9 Application ofHow the MEHTA approach might be applied 37373735
9.1 Case Study 1: The North York Moors National Park 37373735
9.1.1 Indicators of natural and man-made capital stocks 38383836
9.1.2 Analysis and results 39393937
9.1.3 Conclusion 43434340
9.2 Case Study 2: The Ythan catchment in Aberdeenshire 44444441
9.2.1 Indicators of natural and man-made capital stocks 45454542
9.2.2 Analysis and results 46464643
9.2.3 Conclusion 48484845
10 Data resolution and availability 48484845
10.1 Spatial resolution 48484845
10.2 Temporal resolution 50505047
10.3 Data availability 52525249
111 Conclusions and recommendations 52525249
11.1 Is the ecosystem health concept valuable? 52525249
11.2 Operational approaches to assessing ecosystem health 53535350
11.3 What is the appropriate spatial extent for ecosystem health assessment? 53535350
11.4 Data availability and accessibility 53535350
11.5 Gaps in knowledge 54545451
11.6 Summary of key findings and recommendations 54
References 5255
LIST OF TABLES
Table 4.2 / General criteria for assessing ecosystem health (Xu & Mage, 2001) / 7
Table 6.1 / Odum’s 24 attributes of development through ecological succession (Odum, 1969) / 11
Table 7.1 / Twelve different agroecosystem evaluation methods (after van der Werf and Petit (2002)) / 18
Table 7.2 / Proposed ecological parameters to monitor changes in agroecosystems (Buchs et al., 2003) / 20
Table 7.3 / State and pressure indicators selected by ELISA (after Wascher, 2000) / 22
Table 7.4 / Indicators related to agricultural practice, proposed by the PAIS (LANDSIS g.e.i.e. et al., 2000) / 23
Table 7.5 / Factors that contribute to forest health (after Percy, 2002) / 25
Table 7.6 / Indicators designed and used by the UK Forestry Commission (Forestry Commission, 2002) / 27
Table 7.7 / Ecological indicators used to assess structural, functional and system-level determinants of ecosystem health (after Xu et al. 2001) / 28
Table 9.1 / Summary of trends in indicators of natural and man-made capital stocks in managed ecosystems within the NYMNP / 38
Table 9.2 / Summary of trends in indicators of natural and man-made capital stocks in the Ythan catchment / 43
LIST OF FIGURES
The adaptive cycle of ecosystem behaviour (From Gundersen and Holling, 2002)
/ 13Fig 8.1 / Structure of the Holistic Ecosystem Health Indicator (HEHI) used by Aguilar (1999) in tropical managed systems in Costa Rica / 32
Fig 8.2 / Assessing ecosystem health by determining trends and safety margins for individual indicators of the status of environmental, ecological, financial, human andhuman and social capital stocks within a managed ecosystem. The MEHTA (Monitoring Ecosystem Health by Trends Analysis) approach / 34
Fig 9.1 / Actual and predicted number of visitor days (million) within the North York Moors National Park showing 95% upper and lower confidence intervals for individual predictions / 39
Fig 9.2 / Actual and predicted breeding bird survey index from the Grampian region showing 95% upper and lower confidence intervals for individual predictions / 44
Fig 10.1a / Spatial resolution of different indicator datasets for the North York Moors National Park / 46
Fig 10.1b / Spatial resolution of different indicator datasets for the Ythan catchment / 47
Fig 10.2a / Temporal resolution of different indicator datasets for the North York Moors National Park / 48
Fig 10.2b / Temporal resolution of different indicator datasets for the Ythan catchment / 48
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1 Introduction
1.1 Purpose
The need to understand and quantify ecosystem behaviour and condition has come to the forefront of environmental policy due to a greater emphasis on environmental sustainability and an accompanying recognition of the scarcity of natural resources, such as water, soil and biological diversity. Increasing concern regarding human impacts on the environment and the possibility that some human-induced changes in ecological systems may be irreversible has also focused attention on ways in which such changes can be assessed and, if possible, reversed or avoided. From the policy maker’s perspective, the concern is not only in terms of the possible extent of these problems, but also the likelihood of their occurrings occurrence and the timeframe over which they may operate. In the context of global climate change, understanding the functioning of ecosystems, and how their health and performance can be measured and monitored over time is of critical importanceThe need to understand and quantify ecosystem behaviour and condition has come to the forefront of environmental policy due to a greater emphasis on environmental sustainability and an accompanying recognition of the scarcity of natural resources, such as water, soil and biological diversity. Increasing concern regarding human impacts on the environment and the possibility that some human-induced changes in ecological systems may be irreversible has also focused attention on ways in which such changes can be assessed and, if possible, avoided. From the policy maker’s perspective, the concern is not only in terms of the possible extent of these problems, but also the likelihood of their occurrence and the timeframe over which they may operate. In the context of global climate change, understanding the functioning of ecosystems, and how their health and performance can be measured and monitored over time is of critical importance. This need has also been highlighted recently by the recommendations of the Millennium Assessment: ecosystem performance and human activity and well-being are inseparable.
At this stage, it is worth rehearsing some definitions for the reader. The term “ecosystem” has a long history in ecology and many definitions. Here, we adopt the perspective of the Convention on Biodiversity which defines ecosystem as ….” a dynamic complex of plant, animal and micro-organism communities and their non-living environment interacting as a functional unit.” (Article 2 of the convention), and in order to accommodate the ecosystem approach to biodiversity conservation (see below) the recognition that “humans, with their cultural diversity, are an integral component of ecosystems”. Our definition of an ecosystem thus combines the natural and human elements present, referred to as the natural and social capital stocks which provide the services from which humans benefit. Ecosystem services can be provisioning (e.g. food, fresh water, fuel wood, genetic resources), regulating (e.g. pest control, pollination, flood control) or cultural (e.g. spiritual, aesthetic, educational, symbolic). An ecosystem is healthy if it is able to maintain those flows of services which underpin human well-being as well as its resilience to perturbations.
One approach to the issue of assessing the ability of an ecosystem to continue to deliver services is is problem is through the concept of “ecosystem health”, a field dominated to date by North American researchers, and which understandably emphasises North American ecosystems and environmental policy. This report builds on this previous work and assesses the potential of the ecosystem health concept for monitoring change in the UK landscape, in particular the extent to which health assessment can be linked to an ecosystem’s ability to produce marketed and non-marketed products which are of socio-economic value, and how sustainability might be related to the continued capability to deliver such products.