1 Ecosystems a n d Human Well-Being A Manual for Assessment Practitioners EDITED BY NEVILLE ASH, HERNÁN BLANCO, CLAIR BROWN, KEISHA GARCIA, THOMAS HENRICHS, NICOLAS LUCAS, CIARA RUADSEPP-HEANE, R. DAVID SIMPSON, ROBERT SCHOLES, THOMAS TOMICH, BHASKAR VIRA, AND MONIKA ZUREK
4 A Manual for Assessment Practitioners
6 Ecosystems and Human Well-being A Manual for Assessment Practitioners Neville Ash Hernán Blanco Claire Brown Keisha Garcia Thomas Henrichs Nicolas Lucas Ciara Raudsepp-Hearne R. David Simpson Robert Scholes Thomas P. Tomich Bhaskar Vira Monika Zurek Washington Covelo London
7 Copyright 2010 Neville Ash, Hernán Blanco, Claire Brown, Keisha Garcia, Thomas Henrichs, Nicolas Lucas, Ciara Raudsepp-Hearne, R. David Simpson, Robert Scholes, Thomas P. Tomich, Bhaskar Vira, and Monika Zurek All rights reserved under International and Pan-American Copyright Conventions. No part of this book may be reproduced in any form or by any means without permission in writing from the publisher: Island Press, 1718 Connecticut Avenue NW, Suite 300, Washington, DC 20009, USA. Island Press is a trademark of The Center for Resource Economics. Library of Congress Cataloging-in-Publication Data Ecosystems and human well-being : a manual for assessment practitioners / Neville Ash... [et al.]. p. cm. Includes bibliographical references and index. ISBN (pbk. : alk. paper) ISBN (cloth : alk. paper) 1. Human ecology. 2. Ecosystem management. 3. Biodiversity. I. Ash, Neville. GF50.E '4 dc Printed on recycled, acid-free paper Manufactured in the United States of America
8 Contents ix xi xiv xvi Foreword Preface Acknowledgments Acronyms and Abbreviations Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Index Assessing Ecosystems, Ecosystem Services, and Human Well-being Neville Ash, Karen Bennett, Walter Reid, Frances Irwin, Janet Ranganathan, Robert Scholes, Thomas P. Tomich, Claire Brown, Habiba Gitay, Ciara Raudsepp-Hearne, and Marcus Lee Stakeholder Participation, Governance, Communication, and Outreach Nicolas Lucas, Ciara Raudsepp-Hearne, and Hernán Blanco Conceptual Frameworks for Ecosystem Assessment: Their Development, Ownership, and Use Thomas P. Tomich, Alejandro Argumedo, Ivar Baste, Esther Camac, Colin Filer, Keisha Garcia, Kelly Garbach, Helmut Geist, Anne-Marie Izac, Louis Lebel, Marcus Lee, Maiko Nishi, Lennart Olsson, Ciara Raudsepp-Hearne, Maurice Rawlins, Robert Scholes, and Meine van Noordwijk Assessing State and Trends in Ecosystem Services and Human Well-being Robert Scholes, Reinette Biggs, Cheryl Palm, and Anantha Duraiappah Scenario Development and Analysis for Forward-looking Ecosystem Assessments Thomas Henrichs, Monika Zurek, Bas Eickhout, Kasper Kok, Ciara Raudsepp-Hearne, Teresa Ribeiro, Detlef van Vuuren, and Axel Volkery Assessing Intervention Strategies R. David Simpson and Bhaskar Vira
10 Foreword Commissioned by the United Nations Secretary General in 2000, and completed in 2005, the Millennium Ecosystem Assessment (MA), based on the findings of 34 sub-global assessments carried out in a diverse set of ecosystems in sites around the world, provides a state-of-the-art appraisal of the condition and trends in the world s ecosystems and the services they provide. The MA presents compelling evidence that underlines the urgency and necessity of restoring, conserving, and sustainably managing our ecosystems. Most important, the assessment shows that, with appropriate actions, it is possible to reverse the degradation of many ecosystem services over the next 50 years. By providing invaluable information to policy makers, the MA seeks to help ensure that the required changes in current policy and practice undertaken will be evidence based and informed by the best available scientific analysis. This manual, Ecosystems and Human Well-being: A Manual for Assessment Practitioners, allows for the wider adoption of the MA conceptual framework and methods. The manual, which contains numerous case studies of best practice, offers a practical guide for undertaking ecosystem assessments and includes tools and approaches that can assess options for better managing ecosystems. UNEP and UNDP, working together with other partners, are committed to promoting sustainable development and ensuring the protection of our planet. By stimulating future ecosystem assessments, based on the proven methodologies of the MA, it is our hope that this manual will provide the knowledge needed to develop appropriate and effective policies and strategies to ensure that the earth s ecosystems and their vital services are restored and preserved. Our very livelihoods depend on this. Achim Steiner, Executive Director United Nations Environment Programme (UNEP) Helen Clark, Administrator United Nation Development Programme (UNDP) ix
12 Preface The Millennium Ecosystem Assessment The Millennium Ecosystem Assessment (MA) was called for by the United Nations Secretary-General Kofi Annan in 2000 in his report to the UN General Assembly, We the Peoples: The Role of the United Nations in the 21 st Century. The MA was carried out between 2001 and 2005 to assess the consequence of ecosystem change for human well-being, by attempting to bring the best available information and knowledge on ecosystem services to bear on policy and management decisions. The MA established the scientific basis for action needed to enhance the conservation and sustainable use of ecosystems and their contribution to human well-being. The MA was in part a global assessment, but to facilitate better decision making at all scales, 34 regional, national and local scale assessments (or sub-global assessments) were included as core project components. Since the release of the MA, further subglobal assessments have started. What are ecosystems and ecosystem services? An ecosystem is a dynamic complex of plant, animal and micro-organism communities and the nonliving environment interacting as a functional unit. The conceptual framework for the MA assumes that people are integral parts of ecosystems. The MA Report itself focuses on linkages between ecosystems and human well-being, in particular on ecosystem services, which are the benefits that people obtain from ecosystems. Ecosystem services include the following: Provisioning services, such as providing food, water, timber and fibre; Regulating services, such as the regulation of climate, floods, disease, wastes and water quality; Cultural services, such as offering recreational, aesthetic, and spiritual benefits; and Supporting services, such as soil formation, photosynthesis, and nutrient cycling. What is ecosystem assessment? An ecosystem assessment provides the connection between environmental issues and people. An assessment of ecosystem services needs to consider both the ecosystems from which the services are derived and also the people who depend on and are affected by changes in the supply of services, thereby connecting environmental and development sectors. Assessments play numerous roles in the decision-making process, including responding to decision makers needs for information, highlighting trade-offs between decision options, and modeling future prospects to avoid xi
13 xii Preface unforeseen long-term consequences. They inform decisions by providing critical judgment of options and uncertainty and through synthesizing and communicating complex information on relevant issues. They are also of value through the process they involve, engaging and informing decision makers long before final assessment products are available. Thus, decision makers including those whose goals and actions are focused on people, society, and economics can benefit from examining the extent to which achieving their goals depends on ecosystem services. Assessments can provide credible and robust information on the links between ecosystems and the attainment of economic and social goals. Why is this Manual needed? This Manual makes the methods of the MA and associated sub-global (local and regional) assessments widely accessible. While the MA is the most comprehensive assessment of ecosystems carried out to date, there are other related assessment processes such as Global Environment Outlook (GEO), Global International Waters Assessment (GIWA), Intergovernmental Panel on Climate Change (IPCC), Land Degradation Assessment in Drylands (LADA), International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD) and World Water Assessment. Lessons learned from these assessments supplement the best practice of ecosystem assessment identified through the MA. The publication of this Manual aims to encourage more assessments at scales which are relevant to policy and decision makers. Why use this Manual? The Manual is intended to be a how to guide for undertaking ecosystem assessments. The Manual contains detailed guidance on conceptual frameworks, assessing status and trends of ecosystems, developing and using scenarios, assessing policy options, and the process for establishing, designing and running an ecosystem assessment, including communications and outreach. The priority audience for the Manual are individuals who are responsible for designing and carrying out environmental or developmental assessments, and individuals responsible for building capacity for ecosystem assessments, either through structured training (such as through developing curricula relating to ecosystem services and development) or assistance in conducting assessments on the ground. New and emerging ecosystem assessment practitioners should use this Manual to: Familiarize themselves with the concept of ecosystem assessment; Understand how and why an ecosystem assessment can benefit decision making at their scale of interest and what steps are involved; Improve capacity to undertake an assessment where the need for one has already been identified; and Act as a guide for practitioners who are undertaking an assessment to obtain more background information and identify sources of potential assistance with challenging areas.
14 Preface xiii Experienced ecosystem assessment practitioners should use this Manual to: Update and complement their knowledge and skills in ecosystem assessment; Serve as a basis for dialogue on methods for ecosystem assessment to improve the shared knowledge base on this approach; and Train new and emerging ecosystem assessment practitioners in an applied or classroom setting. This Manual complements other related resources such as the Ecosystem Services: A Guide for Decision-makers, prepared by WRI and others (which focuses on how the findings of ecosystem assessments can be used), and the UNEP-GEO assessment training modules (which cover a much broader institutional State of the Environment reporting process).
15 Acknowledgments Authors of the Millennium Ecosystem Assessment (MA) were the recipients of the Zayed International Prize for the Environment prize in honor of His Highness Sheik Zayed Bin Sultan Al Nahyan, President of the United Arab Emirates and Governor of Abu Dhabi. On agreement of the Board of the MA, a significant portion of these funds was allocated to the production of this Manual. Financial support for the Manual was also provided by the UK Department for Environment, Food and Rural Affairs. The support of the following institutions enabled the participation of lead authors in compiling this Manual: IUCN, Switzerland; RIDES, Chile; The Cropper Foundation, Trinidad and Tobago; National Environmental Research Institute, Denmark; European Environment Agency (EEA), Denmark; Secretariat of Environment and Sustainable Development, Argentina; McGill University, Canada; Council for Scientific and Industrial Research, South Africa; National Center for Environmental Economics, USA; University of California, Davis, USA; University of Cambridge, UK; FAO, Italy; and United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), UK. In addition to the lead authors, contributions to the Manual were provided by Alejandro Argumedo (Asociacion Andes), Ivar Baste (UNEP), Karen Bennett (WRI), Esther Camac (Association IXACAVAA for Indigenous Development and Information), Anantha Duraiappah (UNEP), Bas Eickhout (Netherlands Environment Assessment Agency), Colin Filer (Australian National University), Kelly Garbach (University of California, Davis), Helmut Geist (University of Aberdeen), Habiba Gitay (World Bank Institute), Kasper Kok (University of Wageningen), Frances Irwin (WRI), Anne-Marie Izac (Consultative Group for International Agricultural Research), Louis Lebel (Chiang Mai University), Marcus Lee (The World Bank), Walter Reid (David and Lucile Packard Foundation), Maiko Nishi (United Nations University), Meine van Noordwijk (World Agroforestry Centre), Lennart Olsson (Lund University), Cheryl Palm (Columbia University), Janet Ranganathan (WRI), Maurice Rawlins (The Cropper Foundation), Teresa Ribeiro (European Environment Agency), Axel Volkery (European Environment Agency), and Detlef van Vuuren (Netherlands Environment Assessment Agency). All of the MA authors and review editors who contributed to this manual through their contributions to the MA itself, upon which this manual is based, are acknowledged. The MA process included a total of 34 sub-global assessments (SGAs) from around the world. These assessments analyzed the importance of ecosystem services for human well-being at local, national, and regional scales. The experience of the team involved in carrying out or coordinating SGAs also contributed to the content reflected in the manual. xiv
16 Acknowledgments xv The Manual Chapter Review Editors provided valuable guidance and input: John Agard (University of West Indies); Yolanda Kakabadze (Fundación Futuro Latinoamericano), Richard Norgaard (University of California, Berkeley), David Stanners (European Environment Agency), Dan Tunstall (WRI) and Tom Wilbanks (Oak Ridge National Laboratory). Many individuals reviewed drafts of the Manual and provided critical review comments: Heidi Albers (Oregon State University), Salvatore Arico (UNESCO), Jan Bakkes (Netherlands Environmental Assessment Agency), Karen Bennett (WRI), Reinette Biggs (Stockholm Resilience Institute), Traci Birge (UNEP DEWA), Steve Carpenter (University of Wisconsin), David Cooper (Secretariat for the Convention on Biological Diversity), Steven Cork (EcoInsights), Anantha Duraiappah (UNEP), Paul Ferraro (Georgia State University), Max Finlayson (Charles Sturt University), Inger Heldal (Norad Norwegian Agency for Development Cooperation), Bente Herstad (Norad Norwegian Agency for Development Cooperation), Robert Höft (Secretariat for the Convention on Biological Diversity), Frances Irwin (WRI), Annekathrin Jaeger (EEA), Christian Layke (WRI), Marcus Lee (UNEP, now World Bank), Markus Lehmann (Secretariat for the Convention on Biological Diversity), Jock Martin (EEA), Connie Musvoto (CSIR), Gerald Nelson (University of Illinois at Urbana-Champaign), David Niemeijer, Cheryl Palm (The Earth Institute, Columbia University), Bely Pires, Janet Ranganathan (WRI), Walter Reid (David and Lucile Packard Foundation), Belinda Reyers (CSIR), Dale Rothman (International Institute for Sustainable Development), Frederik Schutyser (EEA), Albert van Jaarsveld (National Research Foundation, South Africa), Hans Vos (EEA), Rodrigo Victor, Ernesto Viglizzo, Angela Wilkinson (James Martin Institute, Oxford University), Sven Wunder (CIFOR), Kakuko Nagatani Yoshida (UNEP Regional Office for Latin America and the Caribbean) and the participants in the first meeting of sub-global assessment practitioners held in Kuala Lumpur, April Translation of the manual into French was sponsored by the UNDP/UNEP Poverty and Environment Initiative. The Spanish translation was sponsored by the European Environment Agency. UNEP-WCMC coordinated the preparation and publication of the manual. Thanks go to Claire Brown, Matt Walpole, Philip Bubb, and Jessica Jones for their efforts. Keisha Garcia from the Cropper Foundation was hosted as a fellow at UNEP-WCMC and advanced the manual during her tenure and beyond. Linda Starke s expert eye to the text as copyeditor has been an invaluable contribution.
17 Acronyms and Abbreviations AC AKST AR4 ASB ATEAM BBOP CA CBA CBD CEA CEC CEO CFCs COP CRP DAC DDP DfID DPSIR EC EEA GDP GEO GIS GIWA GNI HIPC HWB IAASTD IEA ILO IMF INRM IPCC IPU Advisory Committee agricultural knowledge, science and technology Fourth Assessment Report (for the IPPC) the Alternatives to Slash-and-Burn Program Advanced Terrestrial Ecosystem Analysis and Modelling the Business Biodiversity Offset Program California Agroecosystem Assessment cost-benefit analysis Convention on Biological Diversity cost-effectiveness analysis Cation exchange capacity chief executive officer Chlorofluorocarbons Conference of the Parties Conservation Reserve Program Development Assistance Committee Dahlem Desertification Paradigm U.K. Department for International Development Drivers-Pressures-States-Impacts-Responses the European Commission European Environment Agency Gross Domestic Product Global Environment Outlook Geographic Information System Global International Waters Assessment Gross National Income Heavily Indebted Poor Countries Human Well-Being International Assessment of Agricultural Science and Technology for Development International Energy Agency International Labour Organization International Monetary Fund Integrated natural resource management intergovernmental panel on climate change Inter-Parliamentary Union xvi
18 Acronyms and Abbreviations xvii ITU IUCN JIU LADA LDCs LLDA LUCC MA MBIs MCA MDGs NGO ODA ODP OECD PES PNG PPP PRELUDE PSR SAfMA SDM SEWA SPM SRES STEEP drivers ToR UN UNAIDS UNCCD UNCTAD UNDP UNEP UNESCO UNFCCC UNICEF UNSD UPLB U.S. WHO WRI WTO International Telecommunication Union International Union for Conservation of Nature Joint Inspection Unit Land Degradation Assessment in Drylands Least Developed Countries Laguna Lake Development Authority Land-Use/Cover Change Programme Millennium Ecosystem Assessment market-based incentives multi-criteria analysis Millennium Development Goals nongovernmental organization Official Development assistance Ozone depletion potential Organisation for Economic Co-operation and Development payments for ecosystem services Papua New Guinea purchasing power parity PRospective Environmental analysis of Land Use Development in Europe Pressure State Response Southern Africa Millennium Ecosystem Assessment summary for decision makers Self-Employed Women s Association summary for policy makers Special Report on Emissions Scenarios social-cultural, technological, economic, environmental, and political driving forces terms of reference United Nations The Joint United Nations Programme on HIV/AIDS United Nations Convention to Combat Desertification United Nations Conference on Trade and Development United Nations Development Programme United Nations Environment Programme United Nations Educational, Scientific and Cultural Organization United Nations Framework Convention on Climate Change United Nations Children s Fund United Nations Statistic Division University of the Philippines Los Baños United States of America World Health Organisation World Resources Institute World Trade Organisation
20 1 Assessing Ecosystems, Ecosystem Services, and Human Well-being Neville Ash, Karen Bennett, Walter Reid, Frances Irwin, Janet Ranganathan, Robert Scholes, Thomas P. Tomich, Claire Brown, Habiba Gitay, Ciara Raudsepp-Hearne, and Marcus Lee What is this chapter about? This chapter provides an overview of the process and components of scientific assessments that have as their focus or include within their scope the connections between ecosystems and people. It introduces ecosystem services as the link between ecosystems and human well-being and therefore as the focus of assessing the consequences of ecosystem changes for people. The chapter introduces and highlights the relationship between the various components of assessment. In doing so, it provides an introduction and roadmap to the subsequent chapters of the manual. 1.1 Introduction Section s take-home messages This manual can be used as a whole document, or individual chapters can help assessment practitioners who are looking for guidance on particular aspects of the process. Assessments are not just about the findings. Getting the process right, from the early stages of design through to the communication of findings, is essential in order to have an impact. This manual is a stand-alone how-to guide about conducting an assessment of the consequences of ecosystem change for people. However, the manual also relates closely to other recent publications, particularly Ecosystem Services: A Guide for Decision Makers (WRI 2008), which presents methods for public-sector decision makers to use information on ecosystem services to strengthen economic and social development policies and strategies. This manual can be used as a whole document, or individual chapters can help assessment practitioners who are looking for 1
21 2 A Manual for Assessment Practitioners guidance on particular aspects of the process. The manual builds on the experiences and lessons learned from the Millennium Ecosystem Assessment (MA) global assessment and from over 30 ongoing or completed sub-global assessment initiatives at a range of scales, including local, national, and regional assessments. (See www. MAweb.org for further details on the MA and the various follow-up activities currently under way.) It also includes insight and experiences gained from a wider range of assessment activities focused on ecosystem services. The chapter begins with an overview of such assessments what they are and why they are useful and then provides a summary of the step-by-step process for conducting an assessment. Drawing on both theory and best practice from the field and on a range of global and sub-global assessments, the chapter highlights the importance not just of the findings of an assessment but also of the process itself. Getting the process right, from the early stages of design through to the communication of findings, is essential in order to have an impact on the intended audience. This manual has been written to support integrated ecosystem assessment practitioners. However, it is essential that the assessment practitioner also understand the decision-making context in which the study is being conducted and into which the findings may be taken on board. As such, the chapter concludes with a short section on how assessments can be considered in the context of the decision-making process and how the focus and impact of an assessment will depend on what stage an issue is in its policy life cycle. Subsequent chapters in the manual elaborate on the material presented here and address key aspects of the assessment process: engaging stakeholders; developing and using a conceptual framework; conducting assessments of conditions and trends in ecosystems, their services, and human well-being; developing scenarios of change for ecosystems, their services, and human well-being; and assessing responses or interventions that aim to improve the management of ecosystems for people. Figure 1.1 outlines the main contents and layout of this manual, and shows how key sections of the manual relate. 1.2 How to improve decision making using ecosystem assessments Section s take-home messages An ecosystem services assessment can help build a bridge between the development and environmental communities by providing credible and robust information on the links between ecosystem management and the attainment of economic and social goals. As improvements are made in describing and valuing the benefits of ecosystem services, decision makers can better understand how their actions might change these services, consider the trade-offs among options, and choose policies that sustain the appropriate mix of services. Successful assessments share three basic features: they are credible, legitimate, and relevant to decision makers needs. People everywhere depend on ecosystems for their well-being. Ecosystems are the source of obvious necessities such as food and fresh water, but they also provide
22 Assessing Ecosystems, Ecosystem Services, and Human Well-being 3 Figure 1.1. Contents and layout of the manual. less obvious services such as flood protection, pollination, and the decomposition of organic waste. The natural world provides spiritual and recreational benefits as well. These and other benefits of the world s ecosystems have supported the extraordinary growth and progress of human societies. Yet the Millennium Ecosystem Assessment found that the majority of ecosystem services are in a state of decline and can no longer be taken for granted. Ignoring the links between ecosystems and human well-being in public and private decision making puts at risk our ability to achieve long-term development goals. An assessment of ecosystem services provides the connection between environmental issues and people. Thus, decision makers including those whose goals and actions are focused on people, society, and economics can benefit from examining the extent to which achieving their goals depends on ecosystem services (see Table 1.1). Reconciling economic development and nature is challenging because they have traditionally been viewed in isolation or even in opposition, and the full extent of humanity s dependence on nature s benefits, or ecosystem services, is seldom taken into account by development or environmental communities. An ecosystem services
23 Table 1.1. Linking development goals and ecosystem services Goal Health Natural hazard protection Adaptation to climate change Freshwater provision Environmental conservation Dependence on ecosystem services Ecosystem services such as food production, water purification, and disease regulation are vital in reducing child mortality, improving maternal health, and combating diseases. In addition, changes in ecosystems can influence the abundance of human pathogens, resulting in outbreaks of diseases such as malaria and cholera and the emergence of new diseases. Increasingly, people live in areas that are vulnerable to extreme events such as floods, severe storms, fires, and droughts (MA 2005:443). The condition of ecosystems affects the likelihood and the severity of extreme events by, for example, regulating global and regional climates. Healthy ecosystems can also lessen the impact of extreme events by regulating floods or protecting coastal communities from storms and hurricanes. Climate change alters the quantity, quality, and timing of ecosystem service flows such as fresh water and food. These changes create vulnerabilities for those individuals, communities, and sectors that depend on the services. Healthy ecosystems can reduce climate change impacts. Vegetation provides climateregulating services by capturing carbon dioxide from the atmosphere. Ecosystem services such as water and erosion regulation, natural hazard protection, and pest control can help protect communities from climate-induced events such as increased floods, droughts, and pest outbreaks. Ecosystems help meet peoples need for water by regulating the water cycle, filtering impurities from water, and regulating the erosion of soil into water. Population growth and economic development have led to rapid water resource development, however, and many naturally occurring and functioning systems have been replaced with highly modified and human-engineered systems. Needs for irrigation, domestic water, power, and transport are met at the expense of rivers, lakes, and wetlands that offer recreation, scenic values, and the maintenance of fisheries, biodiversity, and long-term water cycling. Conservation projects often only consider a few benefits of nature s preservation. An ecosystem services framework can help build support for these projects by clarifying that their success provides multiple ecosystem services and therefore is linked to the achievement of other development goals. If a protected area, for example, can be shown to have additional benefits such as providing biochemicals for pharmaceuticals, its creation is more likely to be supported.
24 Assessing Ecosystems, Ecosystem Services, and Human Well-being 5 Table 1.1. continued Goal Dependence on ecosystem services Food production Poverty reduction Energy security Ecosystems are vital to food production, yet there is pressure to increase agricultural outputs in the short term at the expense of ecosystems long-term capacity for food production. Intensive use of ecosystems to satisfy needs for food can erode ecosystems through soil degradation, water depletion, contamination, collapse of fisheries, or biodiversity loss. The majority of the world s 1 billion poorest people live in rural areas. They depend directly on nature for their livelihoods and well-being: food production, freshwater availability, and hazard protection from storms, among other services. Degradation of these services can mean starvation and death. Investments in ecosystem service maintenance and restoration can enhance rural livelihoods and be a stepping stone out of poverty. Many renewable energy sources, such as biofuels or hydroelectric power, are derived from ecosystems and depend on nature s ability to maintain them. Hydropower, for example, relies on regular water flow as well as erosion control, both of which depend on intact ecosystems. Source: WRI assessment can help build a bridge between the development and environmental communities by providing credible and robust information on the links between ecosystem management and the attainment of economic and social goals. This can mean the difference between a successful strategy and one that fails because of an unexamined consequence, for example for a freshwater supply, an agricultural product, a sacred site, or another ecosystem service (see Box 1.1). Undertaking an ecosystem services assessment and taking the findings into account in policies and action can improve the long-term outcome of decisions. As improvements are made in describing and valuing the benefits of ecosystem services, decision makers can better understand how their actions might change these services, consider the trade-offs among options, and choose policies that sustain the appropriate mix of services. A range of assessment initiatives in recent years have focused on various aspects of ecosystem services. Box 1.2 provides an overview of the main recent and ongoing global assessment initiatives; further resources and background information on ecosystem services can be found in the Additional Resources section at the end of this chapter. An assessment of ecosystem services needs to consider both the ecosystems from which the services are derived and also the people who depend on and are affected by changes in the supply of services, thereby connecting environmental and development sectors. Assessments play numerous roles in the decision-making process, including responding to decision makers needs for information, highlighting trade-offs between decision options, and analyzing ecosystems to avoid unforeseen long-term consequences. They inform decisions through providing critical judgment