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Integrated Environmental Assessment and Management — Volume 11, Number 4—pp. 666–673 Published 2015 SETAC
Toward a Standard Lexicon for Ecosystem Services Wayne R Munns Jr,*y Anne W Rea,z Marisa J Mazzotta,y Lisa A Wainger,§ and Kathryn Satersonk yUS Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island zUS Environmental Protection Agency, Office of Research and Development, Safe and Sustainable Water Resources Research Program, Research Triangle Park, North Carolina §University of Maryland, Center for Environmental Science, Solomons, Maryland, USA kUS Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, North Carolina
(Submitted 26 August 2014; Returned for Revision 1 November 2014; Accepted 10 February 2015)
Environmental Management
ABSTRACT The complex, widely dispersed, and cumulative environmental challenges currently facing society require holistic, transdisciplinary approaches to resolve. The concept of ecosystem services (ES) has become more widely accepted as a framework that fosters a broader systems perspective of sustainability and can make science more responsive to the needs of decision makers and the public. Successful transdisciplinary approaches require a common language and understanding of key concepts. Our primary objective is to encourage the ES research and policy communities to standardize terminology and definitions, to facilitate mutual understanding by multidisciplinary researchers and policy makers. As an important step toward standardization, we present a lexicon developed to inform ES research conducted by the US Environmental Protection Agency and its partners. We describe a straightforward conceptualization of the relationships among environmental decisions, their effects on ecological systems and the services they provide, and human well-being. This provides a framework for common understanding and use of ES terminology. We encourage challenges to these definitions and attempts to advance standardization of a lexicon in ways that might be more meaningful to our ultimate objective: informing environmental decisions in ways that promote the sustainability of the environment upon which we all depend. Integr Environ Assess Manag 2015;11:666–673. Published 2015 SETAC. This article is a US Government work and, as such, is in the public domain in the USA. Keywords: Definitions
Ecological benefits
Ecosystem services
INTRODUCTION The complex, widely dispersed, and cumulative environmental challenges currently facing society require holistic, transdisciplinary approaches to resolve. “Wicked problems” (Churchman 1967), such as the interrelated effects of global climate change on human and environmental well-being, shifts in land use patterns resulting from population growth, and anthropogenically induced changes in global biogeochemical cycles, cannot be considered narrowly by environmental policy and the science that informs it (Rea et al. 2012; Cooter et al. 2013). Rather, a holistic systems perspective, focused on sustainability and transcending disciplinary boundaries, is needed to address the full implications of our individual and collective decisions about the environment, regardless of the scale of the decision (local, national, or global) (Carpenter et al. 2009). Incorporating the perspective of sustainability into our cultural paradigm will support continued improvement in human health and well-being, as well as environmental resource protection and economic prosperity, now and in the future. In recent years, the concept of ecosystem services (ES) has become more widely accepted both as a framework that fosters
All Supplemental Data may be found in the online version of this article. * Address correspondence to [email protected] Published online 16 February 2015 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/ieam.1631
Environmental decision making
Terminology
a broader systems perspective of sustainability, and as a way to make science more responsive to the needs of decision makers and the public (Daily 1997). Understanding and making explicit the benefits people receive from nature allows for a more complete assessment of the impacts of any given management action or policy decision and should help to prevent the unintended consequences of ill-informed decisions. The ES concept arguably provides the basis for a unifying conceptual framework for the transdisciplinary approaches needed to address many of the complex and linked environmental, social, and economic problems of our time. However, a major impediment to successfully using transdisciplinary approaches in science is the misunderstandings and inconsistencies that are common and inevitable when disciplines interact. One requirement for successful transdisciplinary approaches is a common language and understanding of key concepts that provide a basis for shared meaning and understanding. Seppelt et al. (2011), based on their evaluation of 153 ES studies, assert that because of variations in the aims of the many ES studies, and therefore in the ways the concept of ES is used, it is difficult to assess the credibility of studies and also difficult for policy makers to understand and use the results obtained by them. They call for improvements in “the scientific basis for ES science’s practical implementation” (Seppelt et al. 2011). A common lexicon can help to shape ES research and facilitate understanding of research results, and is critical to achieving holistic analysis of decision impacts on sustainability. Scientists in several fields have recognized the need for standardized vocabularies to advance research, promote
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collaboration and communication, and better inform decision making, and various efforts have been made to standardize terminology. For example, Salafsky et al. (2008) under the auspices of the International Union for the Conservation of Nature (IUCN), developed a standard lexicon related to biodiversity conservation. They posited that their lexicon would facilitate communications among conservation practitioners related to problems and potential solutions, assist in identifying and cataloging threats and solutions, and help managers to set priorities and allocate resources. Like Salafsky et al. (2008), we believe that normalizing the terminology often used in discussions involving ES will help to make more transparent the meaning and value of ES in decisions of all kinds. An ES focus has been proposed in many governance contexts. In the US, for example, the President’s Council of Advisors on Science and Technology (PCAST) delivered a report in 2011 on “Sustaining Environmental Capital: Protecting Society and the Economy.” This report called for, among other things, an “increased agency use of advances in the valuation of environmental capital and ES in planning and management decisions” (PCAST 2011). Similar initiatives are underway in Europe and elsewhere (EC 2000, 2008; EFSA 2010; TEEB 2014). We anticipate that a common understanding of ES terminology can further productive conversation and action across federal agencies and partners in the public and private sectors to inform development of policy aimed at sustaining environmental capital. The primary objective of this communication is to encourage the ES research and policy communities to standardize the terminology and definitions that we use. Although we expect the lexicon of ES to continue to evolve, the definitions offered here can establish a common ground allowing natural and social scientists to communicate amongst themselves, as well as with the public and environmental decision makers. We begin by providing a short perspective on the use of the ES concept in environmental research and management, and some of the challenges to consistent definitions. We then highlight the trajectory of ES research and application at the US Environmental Protection Agency (USEPA) that provided the impetus for codifying this lexicon. Next, we describe a straightforward conceptual framework for applying the ES concept in decision making, and present our lexicon of ES terms derived largely from experiences at the USEPA. Our communication concludes with a discussion of some of the issues associated with standardization of ES terminology.
ECOSYSTEM SERVICES IN ENVIRONMENTAL RESEARCH The concept that we now recognize as “ecosystem services” is rooted in terminology that has been used by ecologists and economists for several decades. By the mid-1900s, ecologists and economists alike recognized the importance of the societal benefits derived from ecosystems, although the approaches and focuses of the 2 disciplines took somewhat different perspectives (e.g., Vogt 1948; Leopold 1949; CiriacyWantrup 1952; Clawson 1959; Krutilla 1967). In general, ecologists used a broad conception of ES, often focusing on the structure and processes (used here synonymously with functions) of ecosystems (Westman 1977; Daily 1997), whereas economists typically have focused on the outputs of
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ecosystem functions as they provide utility to society (Krutilla and Fisher 1975; Freeman et al. 2014). The ecological view, as represented by Daily’s definition of ES (Daily 1997)—“the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life”—connotes that ES are often equivalent to ecological structure and processes. Westman (1977) defines ecosystem structure as “nature’s free ‘goods’” and ecosystem functions as “nature’s free ‘services’.” This ecological view of ES is not surprising, as ecosystem structure and processes are what ecologists generally consider, and the understanding of these is crucial in managing for ecosystem goods and services (Kline 2007). However, whereas ecological typologies point out the myriad ways that ecosystem structure and processes are important, they do not always clearly define the ES that people directly interact with, value, and benefit from, and therefore are not precisely useful for unambiguous measurement of economic benefits in policy and environmental assessments. Because economic definitions generally focus on evaluating social benefits, they tend to be more precise than ecological definitions in addressing how benefits are generated from ecosystems, and in specifying the conditions necessary for comparing and summing benefits. The human benefit of a change in an ES is measured by the difference in utility (for individuals) or social welfare (for societies) caused by changes in that ES. To measure such benefits effectively, economists are typically concerned with measuring “final” goods and services that people know they value (e.g., supply of drinking water or stocks of fishable trout; Boyd and Banzhaf 2007). In contrast, the ecological view often includes what economists would term “intermediate” goods and services (Boyd and Banzhaf 2007), which are often basic ecological processes or functions (e.g., maintaining hydrologic regimes; de Groot et al. 2002) that may not immediately resonate with the public and often are challenging to quantify in a benefits assessment context. This divergence in perspectives does not immediately imply that economists do not appreciate the basic qualities and processes of natural systems that benefit people (e.g., Millennium Ecosystem Assessment’s [2005] “supporting services”), but rather that economists recognize that people have trouble making choices between desirable outcomes or activities (e.g., drinking water, fishing) and preserving or protecting a natural process (e.g., maintaining a characteristic hydrologic regime) that may seem irrelevant until its connection to their well-being is explained (e.g., hydrologic regime is needed to protect trout fishing opportunities or ensure drinking water supply). The economic view of ES combines 2 theoretical perspectives: production theory and utility theory (Freeman et al. 2014). In terms of production, ES are outputs of ecological production functions and are inputs to economic production functions (which can include both commercial production and “household” production; Bockstael and McConnell 1981). These ecological outputs either directly or indirectly affect human well-being as components of people’s utility functions. Ecological outputs may thus be inputs into economic production of other goods and services that people value (such as timber used to produce lumber), or inputs into household production of things that people directly interact with and enjoy (such as wildlife for viewing or hunting).
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In recent years, various definitions and classification systems have been proposed for communicating ES (de Groot et al. 2002; Millennium Ecosystem Assessment 2005; Boyd and Banzhaf 2007; Brown et al. 2007; Wallace 2007, 2008; Costanza 2008; Fisher and Turner 2008; Turner et al. 2008; Fisher et al. 2009; Johnston and Russell 2011; Mace et al. 2012; Nahlik et al. 2012; Pirard 2012). Many of the proposed definitions can be broadly categorized as favoring either ecological or economic viewpoints, or as providing a more general perspective that can encompass a number of viewpoints. The broadest definition of ES, “the benefits people obtain from ecosystems” (Millennium Ecosystem Assessment 2005) encompasses various viewpoints, types of value, and meanings, thus leaving its practical application open to many interpretations and unsatisfactory for environmental decision makers. Reliance on imprecise definitions can lead to studies and analyses that might intend to evaluate the same things, yet instead measure different things or measure them differently. This in turn can hinder aggregation of values across studies (e.g., as in a meta-analysis) (Bergstrom and Taylor 2006; Rosenberger and Johnston 2009) and can create problems of double counting by including the same economic impact more than once in summing the benefits (and costs) of a particular action (Boyd and Banzhaf 2007). Furthermore, definitions like the Millennium Ecosystem Assessment’s confound the goods and services actually produced by ecosystems, i.e., ES, with the benefits people receive from changes in those ES as a result of a decision or policy. Adding to the problem, definitions and classification typologies typically are proposed for specific purposes or applications, and a lexicon and typology defined for one context may not easily be applied to other contexts. We posit that a generally accepted set of definitions, applicable to situations broadly, will help to advance the value of ES concept in decision making, its application, and its communication. Here, we present a set of terminology, developed through a process of discourse among natural and social scientists, that is comprehensive and general, yet attempts to be precise enough to address many of the common misunderstandings across disciplines. Nuanced adjustments to these general definitions can be valuable to specific applications of the ES concept in unique policy or research contexts (Kline and Mazzotta 2012). For example, developing ES measures analogous to Gross Domestic Product indicators, or otherwise monitoring large-scale changes in ES over time and space, might require enhancement of our basic definitions to promote consistency (Boyd and Krupnick 2009; Nahlik et al. 2012; Ringold et al. 2013). Conversely, actions to protect or restore ecosystems can be informed by broad definitions that are meaningful to a wide array of audiences. Other applications will fall somewhere between these 2 extremes. Although the ES concept is not new to either ecology or economics, what is new about the general acceptance of the concept is the prominence of and focus on ES as an incentive for conservation of nature and as a unifying framework for transdisciplinary approaches in research, policy, and sustainability. The value of the ES concept has matured in recent years to the point where initial guidance has been offered for its use in environmental decision making (e.g., Ranganathan et al. 2008; NESP 2014). The advantages of the ES concept as a unifying transdisciplinary framework include making clear the full range of benefits provided by functioning ecosystems and the costs to them imposed by human choices, and most importantly, making transparent the tradeoffs among impacts
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on ES involved in decisions at all levels, from individual to collective, local to global. In 2007, the USEPA’s Office of Research and Development made a strategic decision to create the Ecosystem Services Research Program (ESRP) to refocus its core ecological research toward advancing the science of ES. This decision was strongly supported by the USEPA’s Science Advisory Board (USEPA SAB 2009a, 2009b) and others. This new approach directed research toward quantifying the socioeconomic value of ecosystems and how the USEPA’s decisions affected them, rather than on classical biophysical regulatory endpoints, and therefore necessitated transdisciplinary integration across the natural and social sciences. The program was structured around a number of place-based studies, tied together by cross-cutting themes such as N as a stressor, wetlands and coral reefs as key habitat types, and the basic data, models, and decision informing tools that would be needed to incorporate ES routinely in USEPA’s practices and into local to federal decisions. The rationales for this change were grounded in the need to engage USEPA decision makers and the public in issues of social well-being and equity, and to create “demand” for ecological integrity by quantifying the effects of real or potential losses created by our current decisions affecting management of ecosystems, using the language of ES. Although transdisciplinary by design, this refocusing brought to light the acute disparities in understanding and use of terminology associated with ecology, environmental economics, and the ES concept. Program ecologists, steeped in the jargon of their discipline, had difficulty grasping economic concepts of social well-being, and economists were equally challenged by ecological terms and understandings. Furthermore, when program ecologists tried to orient work toward ES outputs that would be useful for social and economic analysis, they differed in their understanding of that which would be most useful. A common basis for mutual understanding was lacking. A lexicon, developed and accepted by economists and ecologists alike, promoted the cross-disciplinary understanding of ultimate objectives required by the goals of the ESRP. As the USEPA’s research evolved to its current focus on sustainable outcomes for ecosystems, economy, and society, the ES concept has continued to be a unifying theme to help guide research objectives and production of valuable, decisioninforming knowledge. We present the ES lexicon developed for USEPA’s ESRP (Supplemental Data). It was developed through the collaboration of program participants and others, using a process of consensus-building through iterative discourse, and drew from many resources. It was informed by the conceptualization of the relationships among ecosystems and their processes, the way that humans perceive and use the outputs of those processes, and the influences and interventions of human choices (regulatory, voluntary, resource management, or otherwise) on ecosystem processes. Ultimately, the ESRP codified definitions for a wide variety of additional terms that are used in our science program. Many of these are not related directly to ES per se; rather, they encompass a broad array of natural and social science concepts. Some of these terms already are part of particular disciplines, such as environmental economics. We are not unduly attempting to standardize their use; rather we are trying to facilitate the mutual understanding of terminology by the multiple disciplines and multiple organizational contributors to ES research and policy. Although not perfect, the ESRP’s ES lexicon has served to
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move USEPA closer to the main objective described above: clear and transparent communication of ES terminology and research advancements to help inform decision making, particularly focusing on resolving communication issues among the many disciplines involved in ES research and policy. It also has served to clarify the research needed to advance ecosystem management beyond its traditional reliance on minimizing risk to biophysical regulatory endpoints independent of direct regard to their utility to the public.
A CONCEPTUAL FRAMEWORK AND STANDARDIZED TERMINOLOGY To apply the ES concept successfully, decision makers at local, regional, and national scales require the information necessary to consider the production and value of ecosystem goods and services appropriate to their decision-making processes. A key step in communicating among scientists, decision makers, and the public is common agreement on terminology. The conceptual framework offered in Figure 1 (modified from Wainger and Boyd 2009) provides a context within which to move toward a common understanding and lexicon. In this section, we highlight, further explain, provide examples illustrating some of the key aspects and terminology of this conceptual framework, and attempt to clarify some of the areas where ecological and economic terminology overlap or might be in conflict. The framework shown in Figure 1 is a simplified conceptualization depicting the most important components needed to model how ES can be evaluated by transdisciplinary teams in a decision-making context. Within this framework, several terms help to convey concepts that can clarify communications among scientists and analysts, decision makers, and the public. These represent the core of the lexicon we offer. Several points are foundational in this framework: Measures of ecological outputs and ES must be relevant, appropriate, and operational within the specific decision context. Some contexts require more precision and refinement of measures than do others. For example, a local decision associated with upgrading a water treatment facility in a particular location would likely require detailed
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specification of an ecological output such as fish abundance in an associated waterbody, and a corresponding ES such as the number of large mouth bass catchable during a fisher’s visit. Conversely, a national-level decision concerning compliance with the provisions of the Clean Water Act (CWA) could rely on broad parameters of water quality as ecological outputs, and measures corresponding generally to the CWA goals of fishable or swimmable as the important ES. The general definitions we present provide a broad and consistent vocabulary that allows for various levels of precision in measures. Further specification of those definitions can be made if necessary to enhance the level of precision, depending on the decision context. Ecological processes generally are not included in the category of ecosystem goods and services. Although there might be exceptions, generally it is the outcomes of these processes that are inputs to ES. Outcomes of ecological processes—ecological outputs in our terminology—only become ES when there is demand by people (e.g., they are important to social welfare or enter the utility functions of individuals), when quality and quantity are sufficient to warrant demand by people, and when any necessary complementary goods and services are available. For example, the ecological output of a fish population would only be considered an ES when fishers want to catch them or nature viewers want to see (or otherwise experience) them, and when the population is accessible to these uses by the presence of roads, docks, boat launches, etc. that are complementary to its use. The distinction between intermediate and final ES (see below) is critical to using ES in environmental decisions. Some ES can be both intermediate and final, depending on their ultimate use or appreciation by different people (Boyd and Krupnick 2009). Thus, knowledge of people's preferences and values is required to develop any typology or classification of ES for a particular policy or decisionmaking context. Figure 1 shows an approach to linking ecological conditions to human benefits. On the left side, the first box and arrow denote the structures, processes, and interactions of ecological
Figure 1. Conceptualization of the production of ecosystem services and ecosystem-derived benefits, and how policies and decisions affect this (modified from Wainger and Boyd 2009).
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systems that directly or indirectly yield outputs important to society. Even though all such interactions likely are important, quantifying ES benefits relies on being able to explicitly link biophysical conditions to social welfare. The first step in demonstrating benefits is to link biophysical conditions to desirable outputs via ecological production functions. The second step is to consider the demand for such outputs by location, and any necessary complementary inputs, to demonstrate that potential services are realized. The third step is to consider how changes in services affect welfare using benefit (i.e., social welfare) functions. Policy, management, and other decisions (including individuals’ behavior) determine how human actions affect ecosystems and ecological production. Ecological production functions are the focus of most environmental and resource management decisions—we limit the introduction to the environment of hazardous substances, we manage habitats and landscapes to optimize food and game production, and so on. They form the convenient “control points” that we use to achieve environmental goals. Understanding ecological production functions also permits us to target indicators of those functions—the rate of C sequestration, the number of huntable waterfowl—in ways that inform environmental management and policy.
intermediate ecosystem services proposed by Boyd and Banzaf (2007). To avoid double counting, only final ES should be included in any accounting that sums measures or values of ES. Ecosystem goods and services are outputs of ecological processes that directly (final ecosystem service) or indirectly (intermediate ecosystem service) contribute to social welfare (modified from USEPA 2006). Some outputs may be bought and sold, but most are not marketed. We do not distinguish between goods and services, although we recognize that there are conceptual distinctions between the 2. Both are contributions of nature to human well-being, and the 2 are treated identically from assessment and valuation standpoints. “Ecosystem goods and services” is often abbreviated as ecosystem services.
An ecological output is a biophysical feature, quantity, or quality that requires little further translation to make clear its relevance to human well-being (i.e., a “public-friendly” measurement or valued attribute of the ecosystem). As such, ecological outputs are the key metrics for evaluating ES. The term “output” signifies that these are the outcomes that people directly interact with and appreciate.
Not everything that nature does benefits humans directly or is valued by people explicitly. For example, the ecological interactions and processes that support a viable aquatic insect community might not provide any direct benefit to shoreline residents (insect viewing notwithstanding), and in fact might be considered a nuisance or even a public health threat (as is the case for mosquitoes). Many ecological processes go unrecognized for their ultimate contributions to human well-being. And yet, without those insect species and supporting processes, humans could not benefit from associated recreational birding and trout fishing opportunities. In this example, maintenance of the aquatic insect community is viewed as an intermediate ES (taking place in the first arrow from the left in Figure 1), with birds and fish being the final ES. The distinctions between intermediate and final ES might not always be clear-cut and certainly can change with context; people who enjoy viewing aquatic insects (e.g., dragonflies), for example, benefit directly from a viable aquatic insect community, and thus this insect community could be considered a final ES to insect watchers. It is often possible for the same ES to be both a final ES and an intermediate ES (Boyd and Banzhaf 2007; Boyd and Krupnick 2009). To distinguish final ES from intermediate ES in a particular context, some knowledge of human preferences is required (Johnston and Russell 2011; Nahlik et al. 2012; Weber and Ringold 2012). Economists include both use and nonuse (sometimes referred to as “passive use”) values in the accounting of benefits, so direct use is not always a requirement for defining a final ES. Although ecological outputs are defined as the measures that people can understand and value, not all ecological outputs are final ES. Final ES require, by definition, either active or passive use by people (i.e., demand). Furthermore, the quality of an ecological output must be sufficient to provide a beneficial service (e.g., for people to benefit from swimming, water quality must be safe for swimming), and complementary goods and services (e.g., beach access) must be available when needed for people to benefit from an ES. The term final ecosystem service determination is included in the lexicon to make these points clear.
Humans benefit from nature both directly and indirectly. To clarify this, we adopt the terms final ecosystem services and
The final ecosystem service determination (adapted from the definition of “ecoservice production function” in
The ecological production function is a description of the type, quantity, and interactions of natural features required to generate observable and measurable ecological outputs. For a simple example, the biophysical characteristics of a coastal wetland (flooding regimes, salinity, nutrient concentrations, plant species abundance, prey and predator abundance, etc.) can influence the welfareenhancing output of increased abundance of a population of watchable wading shorebirds. The terminology of “production functions” provides an analogy to economic production to better illustrate the relationships between inputs into ecological production, places to intervene to protect or enhance ecological production, and outcomes of ecological production (see Boyd and Krupnick [2009] for further explanation). Not all outcomes of ecological processes (i.e., ecological production functions) produce ES. Those that are relevant to people are termed ecological outputs. Boyd and Krupnick (2009) define ecological outputs as “meaningful biophysical outputs that do not require expert knowledge of biophysical production functions to determine their economic value. They are direct inputs to household production.” In earlier work, Boyd and coauthors used the term “ecological endpoint” in a synonymous way (Boyd 2007; Boyd and Banzhaf 2007; Wainger and Boyd 2009).
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Wainger and Mazzotta 2011), incorporates into the analysis the nonecological assessments that are needed to demonstrate existence of a final ES. It thus establishes whether an ES is actually produced, through the interactions of people with ecosystems. Three things must be evaluated: 1) whether the quality of an ecological output is sufficient to generate an ES, 2) whether demand exists for the ES by location, and 3) whether required complementary goods and services (e.g., trails, roads, homes) are available. For example, a final ecosystem service determination might consist of a quantitative or qualitative description of how a population of watchable birds (an ecological output), when combined with complementary inputs such as transportation infrastructure and demand by birders, produces a final ES. Complementary goods and services are inputs (often built infrastructure or location characteristics) that allow a good or service to be used by complementing the ecological condition. For example, complementary goods and services that allow a population of fish to become the ES of “fishable fish,” and thus to provide an opportunity for recreational fishing, will include aspects of site accessibility, such as road access, available parking, and the presence of a fishing pier, all of which make fishing at the site possible and enhance enjoyment of the activity. Finally, society receives ecological benefits, in the form of increased human well-being (i.e., utility), from their consumption of or interaction with ecosystem goods and services. Utility is the satisfaction of wants and needs obtained from the consumption or nonconsumptive use of goods and services or from passive uses such as existence value. Human well-being, broadly, is the condition of humans and society, defined in terms of the basic material and other natural resource needs for a good life, freedom and choice, health, wealth, social relations, and personal security. Social welfare is human well-being measured at some aggregate level. In the typical economic context, it is the sum of individual utility measures. Ecological benefits are the contribution to social welfare of ecosystem goods and services. In the policy and management context presented here, the term “ecological benefits” applies specifically to net improvements in social welfare that result from changes in the quantity or quality of ecosystem goods and services attributable to policy or environmental decisions (USEPA 2006). The term ecological benefit emphasizes that the benefits to people being considered are derived from improvements in ecosystems (and not to imply benefits to the ecosystem). Such benefits depend on social values, defined in terms of social welfare or human well-being. Policies and decisions connect social values to actions that affect ES.
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Policy is, generally, any statement of approach, philosophy, goal or decision. The decision-making process is one of any social and mental processes leading to the selection of a course of action among several management options or alternatives, and a decision (or management) alternative or option is a reasonable course of action or inaction to accomplish a specific goal or objective. Comparisons among decision alternatives or scenarios often involve evaluations of the ES tradeoffs—the ecosystem goods and services gained or lost as the result of selecting one option over another. One area where definitions often differ is for recreational, aesthetic, educational, or spiritual experiences (i.e., many of the “cultural ES” as defined by the Millennium Ecosystem Assessment 2005), or for risk reductions provided by ES, such as reduced risk of flood or storm surge damage to structures. In some cases, these experiences or reduced risks are referred to as ES, in others, they are referred to as benefits (Mace et al. [2012] refer to these as goods). Furthermore, some authors (Brown et al. 2007) distinguish between, for example, recreational “opportunities” and recreational “experiences” and classify recreational opportunities as ES. Using the definitions presented in our lexicon, a “recreational opportunity” would be a composite or bundled set of final ES that provide that opportunity, and a recreational experience would be the household production process by which a person transforms those ES (e.g., a water body, a stock of fish, and scenic characteristics of the site) and other inputs (e.g., boat, boat ramp, fishing rod, and fishing skill) into benefits. Often, investigators applying this approach refer to the individual ecological components (what this lexicon calls ES) as “attributes” of the ecosystem or of the opportunity (following Lancaster [1966] and Rosen [1974]). In practice, this bundled approach makes sense in many valuation and decision contexts, because it reflects how people tend to think about and value these types of experiences—in a holistic way where the various attributes or bundled services contribute collectively to make the valued experience (a day of recreational fishing) possible. A person who values a day of fishing may or may not be able to value changes in the individual ES (or attributes) that make that day possible (Weber and Ringold 2012). However, conjoint or paired comparison surveys or multi-attribute utility (MAUT) approaches are often used successfully to tease out the value of changes in the component services (or attributes) (Kiker et al. 2005).
DISCUSSION A decade has passed since the publication of the Millennium Ecosystem Assessment (2005) communicated the paramount importance of the benefits derived from nature to human well-being and sustainability. Our scientific understanding of the ways in which changes in ES can inform decision making, and how that information can be applied to the decision-making process, will improve with time and practice (Daily et al. 2009; Seppelt et al. 2011). Although the number and directions of ongoing research (and communication) efforts underway to advance ES science have increased, that advancement and its contribution to decision making continue to be hampered by the absence of generally accepted terminology and definitions.
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We are aware of other attempts to standardize the language of ES. In addition to the many definitions for individual terms offered by others (Daily 1997; King 1997; Whigham 1997; Freeman et al. 2014; Millennium Ecosystem Assessment 2005; USEPA 2006), the Willamette Partnership, a multidiscipline coalition centered in the Willamette River basin of Oregon (US) and focused in part on promoting ES markets, developed a limited glossary of terms as used by their group (Willamette Partnership 2009). We have adopted some of their definitions in our lexicon. Similarly, Pirard (2012) offered a lexicon to inform use of market-based instruments in biodiversity conservation and provision of ES. Other groups have developed or are developing glossaries for use in their individual research efforts (Harrington et al. 2010). Ringold et al. (2013), Nahlik et al. (2012), and Johnston and Russell (2011) have developed very specific definitions for selected terms to help identify biophysical indicators of final ES that can be used in monitoring efforts, and subsequently in valuation, and that facilitate a strict accounting perspective. Boyd and Banzhaf (2007) and Boyd and Krupnick (2009) focus on the need for measures that allow for aggregation or bundling of benefits, so that cumulative changes in ecosystems and the consequent changes in human well-being can be described over time or projected as a result of a suite of policy options. To accomplish this, they argue that an accounting perspective (a perspective with a set of internally consistent rules avoiding both double counting and exclusion of substantial benefits), with an emphasis on biophysical outcome measures that facilitate economic analyses, is essential. Beyond these efforts, we are unaware of other concerted efforts to standardize ES terms and their usage. Our lexicon attempts to synthesize these various efforts to provide a general and comprehensive terminology to facilitate consistent communication. Some have suggested that terminological flexibility, some degree of vagueness, and perhaps even plurality in usage, should be encouraged (Costanza 2008). We agree that definitions should be modified and tailored as is appropriate to render them most useful to specific decision-making contexts. Situational flexibility and plurality of approach make sense given the complexities of ecological-human systems and our incomplete understanding of their behaviors. Yet, standardization of terms and concepts does not preclude the use of different definitions for these terms, nor does it prevent the application of different measurement priorities, to be most responsive to specific circumstances. It does allow differences among applications to be quickly communicated and understood. In this regard, it is important to remember that there is a balance to be struck between the precision needed to maintain clarity, achieve consistency of measures across time and space, and avoid double counting, and the flexibility needed to accommodate the synergies and holistic approaches required to address the challenges of decision making affecting sustainability. Still, we argue that until the multiple disciplines necessarily involved in the science and application of the ES concept can communicate effectively with one another, advances in ES science and its use in environmental management will continue to make only halting progress. We do not assume that the lexicon presented here will be the final word regarding definitions. Indeed, we hope it is not, because the concepts of ES science continue to evolve rapidly, and new and enlightening ideas continue to emerge apace. We do believe, however, that as with any field of scientific
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endeavor, movement toward standardization of language helps to propel the science forward. We welcome challenges to these definitions and encourage honest attempts to standardize a lexicon in ways that might be more meaningful to our ultimate objective: informing environmental decisions in ways that promote the sustainability of the environmental, social, and economic system upon which we all depend. Acknowledgment—We are indebted to the conversations held among the social and natural scientists who participated in the USEPA’s ESRP and beyond. In particular, we thank J Boyd for frank discussion, P Ringold, M Weber, and D Landers for pursuing some of these issues (albeit in a direction different from that taken here), R Linthurst and I Goodman for their intellectual involvement, and R Bruins, J Darling, D Simpson, B Rashleigh, and 2 anonymous reviewers for providing critical reviews of earlier versions of this communication. Disclaimer—The views expressed in this manuscript are those of the authors and do not necessarily reflect the views or policies of the US Environmental Protection Agency. This is ORD Tracking Number ORD-003477. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
SUPPLEMENTAL DATA Terms and their definitions which collectively define the lexicon.
REFERENCES Bergstrom JC, Taylor LO. 2006. Using meta-analysis for benefits transfer: Theory and practice. Ecol Econ 60:351–360. Bockstael NE, McConnell K. 1981. Theory and estimation of the household production function for wildlife recreation. J Environ Econ Manage 8:199– 214. Boyd JW. 2007. The endpoint problem. Resources 165:26–28. Boyd J, Banzhaf S. 2007. What are ecosystem services? The need for standardized environmental accounting units. Ecol Econ 63:616–626. Boyd J, Krupnick A. 2009. The definition and choice of environmental commodities for nonmarket valuation. Discussion Paper 09–35. Washington (DC): Resources for the Future. Brown TC, Bergstrom JC, Loomis JB. 2007. Defining, valuing and providing ecosystem goods and services. Nat Resour J 47:329–376. Carpenter SR, Mooney HA, Agard J, Capistrano D, DeFries RS, Dıaz S, Dietz T, Duraiappah AK, Oteng-Yeboah A, Pereira HM, et al. 2009. Science for managing ecosystem services: Beyond the Millennium Ecosystem Assessment. Proc Natl Acad Sci USA 106:1305–1312. Churchman CW. 1967. Wicked problems. Manage Sci 14:B141–B142. Ciriacy-Wantrup SV. 1952. Resources conservation: Economics and policies. Berkeley (CA): Univ California. 395 p. Clawson M. 1959. Methods of measuring the demand for and value of outdoor recreation. Report 10. Washington (DC): Resources for the Future. Cooter E, Rea A, Dennis R, Bruins R, Schwede D. 2013. The role of the atmosphere in the provision of ecosystem services. Sci Total Environ 448:1–208. Costanza R. 2008. Ecosystem services: Multiple classification systems are needed. Biol Conserv 141:350–352. Daily GC. 1997. Nature's services: Societal dependence on natural ecosystems. Washington (DC): Island Press. 392 p. Daily GC, Polasky S, Goldstein J, Kareiva PM, Mooney HA, Pejchar L, Ricketts TH, Salzman J, Shallenberger R. 2009. Ecosystem services in decision making: Time to deliver. Front Ecol Environ 7:21–28. de Groot RS, Wilson M, Boumans R. 2002. A typology for the classification, description and valuation of ecosystem functions, goods and services. Ecol Econ 41:393–408. [EC] European Commission. 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for community action in the field of water policy (Water Framework Directive). Brussels (BE): EC. Document 32000L0060.
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Ranganathan J, Raudsepp-Hearne C, Lucas N, Irwin F, Zurek M, Bennett K, Ash N, West P. 2008. Ecosystem services: A guide for decision makers. Washington (DC): World Resources Institute. Rea AW, Davis C, Evans SA, Heninger BT, Van Houtven G. 2012. Using ecosystem services to inform decisions on U.S. Air Quality Standards. Environ Sci Technol 46:6481–6488. Ringold PL, Boyd J, Landers D, Weber M. 2013. What data should we collect? A framework for identifying indicators of ecosystem contributions to human well-being. Front Ecol Environ 11:98–105. Rosen S. 1974. Hedonic prices and implicit markets: Product differentiation in pure competition. J Polit Econ 82:34–55. Rosenberger RS, Johnston RJ. 2009. Selection effects in meta-analysis and benefit transfer: Avoiding unintended consequences. Land Econ 85:410– 428. Salafsky N, Salzer D, Stattersfield AJ, Hilton-Taylor C, Neugarten R, Butchart SHM, Colleen B, Cox N, Master LL, O'Connor S, et al. 2008. A standard lexicon for biodiversity conservation: Unified classifications of threats and actions. Conserv Biol 22:89–911. Seppelt R, Dormann CF, Eppink FV, Lautenbach S, Schmidt S. 2011. A quantitative review of ecosystem service studies: Approaches, shortcoming and the road ahead. J Appl Ecol 48:630–636. [TEEB] The Economics of Ecosystems and Biodiversity. 2014. The economics of ecosystems and biodiversity. [cited 2014 August 7]. Available from: http:// www.teebweb.org Turner RK, Georgiou SG, Fisher B. 2008. Valuing ecosystem services: The case of multi-functional wetlands. London (UK): Earthscan. [USEPA] US Environmental Protection Agency. 2006. Ecological benefits assessment strategic plan. Washington (DC): USEPA. EPA-240-R-06-001. [USEPA SAB] US Environmental Protection Agency Science Advisory Board. 2009a. Valuing the protection of ecological systems and services. Washington (DC): USEPA. EPA-SAB-09-012. [USEPA SAB] US Environmental Protection Agency Science Advisory Board. 2009b. Consultation on EPA's implementation of the Ecosystem Services Research Program. Washington (DC): USEPA. EPA-SAB-09-019. Vogt W. 1948. Road to survival. New York (NY): William Sloane Associates. 335 p. Wainger LA, Boyd JW. 2009. Valuing ecosystem services. In: McLeod K, Leslie H, editors. Ecosystem-based management for the oceans. Washington (DC): Island Press. p 92–114. Wainger L, Mazzotta M, 2011. Realizing the potential of ecosystem services: A framework for relating ecological changes to economic benefits. Environ Manag 48:710–733. Wallace KJ. 2007. Classification of ecosystem services: Problems and solutions. Biol Conserv 139:235–246. Wallace KJ. 2008. Ecosystem services: Multiple classifications or confusion? Biol Conserv 141:353–54. Weber M, Ringold P. 2012. Ecosystems and people: Qualitative insights. Environ Health Soc Bull 3:2–8. Westman WE. 1977. How much are nature's services worth? Science 197:960– 964. Whigham DF. 1997. Ecosystem functions and ecosystem values. In: Simpson RD, Christensen NL Jr., editors. Ecosystem function and human activities: Reconciling economics and ecology. New York (NY): Chapman and Hall. p 225–239. Willamette Partnership. 2009. A glossary of important terms. [cited 2012 August 30]. Available from: http://willamettepartnership.org/about-markets/ glossary
Integrated Environmental Assessment and Management — Volume 11, Number 4—pp. 666–673 Published 2015 SETAC
Toward a Standard Lexicon for Ecosystem Services Wayne R Munns Jr,*y Anne W Rea,z Marisa J Mazzotta,y Lisa A Wainger,§ and Kathryn Satersonk yUS Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island zUS Environmental Protection Agency, Office of Research and Development, Safe and Sustainable Water Resources Research Program, Research Triangle Park, North Carolina §University of Maryland, Center for Environmental Science, Solomons, Maryland, USA kUS Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, North Carolina
(Submitted 26 August 2014; Returned for Revision 1 November 2014; Accepted 10 February 2015)
Environmental Management
ABSTRACT The complex, widely dispersed, and cumulative environmental challenges currently facing society require holistic, transdisciplinary approaches to resolve. The concept of ecosystem services (ES) has become more widely accepted as a framework that fosters a broader systems perspective of sustainability and can make science more responsive to the needs of decision makers and the public. Successful transdisciplinary approaches require a common language and understanding of key concepts. Our primary objective is to encourage the ES research and policy communities to standardize terminology and definitions, to facilitate mutual understanding by multidisciplinary researchers and policy makers. As an important step toward standardization, we present a lexicon developed to inform ES research conducted by the US Environmental Protection Agency and its partners. We describe a straightforward conceptualization of the relationships among environmental decisions, their effects on ecological systems and the services they provide, and human well-being. This provides a framework for common understanding and use of ES terminology. We encourage challenges to these definitions and attempts to advance standardization of a lexicon in ways that might be more meaningful to our ultimate objective: informing environmental decisions in ways that promote the sustainability of the environment upon which we all depend. Integr Environ Assess Manag 2015;11:666–673. Published 2015 SETAC. This article is a US Government work and, as such, is in the public domain in the USA. Keywords: Definitions
Ecological benefits
Ecosystem services
INTRODUCTION The complex, widely dispersed, and cumulative environmental challenges currently facing society require holistic, transdisciplinary approaches to resolve. “Wicked problems” (Churchman 1967), such as the interrelated effects of global climate change on human and environmental well-being, shifts in land use patterns resulting from population growth, and anthropogenically induced changes in global biogeochemical cycles, cannot be considered narrowly by environmental policy and the science that informs it (Rea et al. 2012; Cooter et al. 2013). Rather, a holistic systems perspective, focused on sustainability and transcending disciplinary boundaries, is needed to address the full implications of our individual and collective decisions about the environment, regardless of the scale of the decision (local, national, or global) (Carpenter et al. 2009). Incorporating the perspective of sustainability into our cultural paradigm will support continued improvement in human health and well-being, as well as environmental resource protection and economic prosperity, now and in the future. In recent years, the concept of ecosystem services (ES) has become more widely accepted both as a framework that fosters
All Supplemental Data may be found in the online version of this article. * Address correspondence to [email protected] Published online 16 February 2015 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/ieam.1631
Environmental decision making
Terminology
a broader systems perspective of sustainability, and as a way to make science more responsive to the needs of decision makers and the public (Daily 1997). Understanding and making explicit the benefits people receive from nature allows for a more complete assessment of the impacts of any given management action or policy decision and should help to prevent the unintended consequences of ill-informed decisions. The ES concept arguably provides the basis for a unifying conceptual framework for the transdisciplinary approaches needed to address many of the complex and linked environmental, social, and economic problems of our time. However, a major impediment to successfully using transdisciplinary approaches in science is the misunderstandings and inconsistencies that are common and inevitable when disciplines interact. One requirement for successful transdisciplinary approaches is a common language and understanding of key concepts that provide a basis for shared meaning and understanding. Seppelt et al. (2011), based on their evaluation of 153 ES studies, assert that because of variations in the aims of the many ES studies, and therefore in the ways the concept of ES is used, it is difficult to assess the credibility of studies and also difficult for policy makers to understand and use the results obtained by them. They call for improvements in “the scientific basis for ES science’s practical implementation” (Seppelt et al. 2011). A common lexicon can help to shape ES research and facilitate understanding of research results, and is critical to achieving holistic analysis of decision impacts on sustainability. Scientists in several fields have recognized the need for standardized vocabularies to advance research, promote
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collaboration and communication, and better inform decision making, and various efforts have been made to standardize terminology. For example, Salafsky et al. (2008) under the auspices of the International Union for the Conservation of Nature (IUCN), developed a standard lexicon related to biodiversity conservation. They posited that their lexicon would facilitate communications among conservation practitioners related to problems and potential solutions, assist in identifying and cataloging threats and solutions, and help managers to set priorities and allocate resources. Like Salafsky et al. (2008), we believe that normalizing the terminology often used in discussions involving ES will help to make more transparent the meaning and value of ES in decisions of all kinds. An ES focus has been proposed in many governance contexts. In the US, for example, the President’s Council of Advisors on Science and Technology (PCAST) delivered a report in 2011 on “Sustaining Environmental Capital: Protecting Society and the Economy.” This report called for, among other things, an “increased agency use of advances in the valuation of environmental capital and ES in planning and management decisions” (PCAST 2011). Similar initiatives are underway in Europe and elsewhere (EC 2000, 2008; EFSA 2010; TEEB 2014). We anticipate that a common understanding of ES terminology can further productive conversation and action across federal agencies and partners in the public and private sectors to inform development of policy aimed at sustaining environmental capital. The primary objective of this communication is to encourage the ES research and policy communities to standardize the terminology and definitions that we use. Although we expect the lexicon of ES to continue to evolve, the definitions offered here can establish a common ground allowing natural and social scientists to communicate amongst themselves, as well as with the public and environmental decision makers. We begin by providing a short perspective on the use of the ES concept in environmental research and management, and some of the challenges to consistent definitions. We then highlight the trajectory of ES research and application at the US Environmental Protection Agency (USEPA) that provided the impetus for codifying this lexicon. Next, we describe a straightforward conceptual framework for applying the ES concept in decision making, and present our lexicon of ES terms derived largely from experiences at the USEPA. Our communication concludes with a discussion of some of the issues associated with standardization of ES terminology.
ECOSYSTEM SERVICES IN ENVIRONMENTAL RESEARCH The concept that we now recognize as “ecosystem services” is rooted in terminology that has been used by ecologists and economists for several decades. By the mid-1900s, ecologists and economists alike recognized the importance of the societal benefits derived from ecosystems, although the approaches and focuses of the 2 disciplines took somewhat different perspectives (e.g., Vogt 1948; Leopold 1949; CiriacyWantrup 1952; Clawson 1959; Krutilla 1967). In general, ecologists used a broad conception of ES, often focusing on the structure and processes (used here synonymously with functions) of ecosystems (Westman 1977; Daily 1997), whereas economists typically have focused on the outputs of
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ecosystem functions as they provide utility to society (Krutilla and Fisher 1975; Freeman et al. 2014). The ecological view, as represented by Daily’s definition of ES (Daily 1997)—“the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life”—connotes that ES are often equivalent to ecological structure and processes. Westman (1977) defines ecosystem structure as “nature’s free ‘goods’” and ecosystem functions as “nature’s free ‘services’.” This ecological view of ES is not surprising, as ecosystem structure and processes are what ecologists generally consider, and the understanding of these is crucial in managing for ecosystem goods and services (Kline 2007). However, whereas ecological typologies point out the myriad ways that ecosystem structure and processes are important, they do not always clearly define the ES that people directly interact with, value, and benefit from, and therefore are not precisely useful for unambiguous measurement of economic benefits in policy and environmental assessments. Because economic definitions generally focus on evaluating social benefits, they tend to be more precise than ecological definitions in addressing how benefits are generated from ecosystems, and in specifying the conditions necessary for comparing and summing benefits. The human benefit of a change in an ES is measured by the difference in utility (for individuals) or social welfare (for societies) caused by changes in that ES. To measure such benefits effectively, economists are typically concerned with measuring “final” goods and services that people know they value (e.g., supply of drinking water or stocks of fishable trout; Boyd and Banzhaf 2007). In contrast, the ecological view often includes what economists would term “intermediate” goods and services (Boyd and Banzhaf 2007), which are often basic ecological processes or functions (e.g., maintaining hydrologic regimes; de Groot et al. 2002) that may not immediately resonate with the public and often are challenging to quantify in a benefits assessment context. This divergence in perspectives does not immediately imply that economists do not appreciate the basic qualities and processes of natural systems that benefit people (e.g., Millennium Ecosystem Assessment’s [2005] “supporting services”), but rather that economists recognize that people have trouble making choices between desirable outcomes or activities (e.g., drinking water, fishing) and preserving or protecting a natural process (e.g., maintaining a characteristic hydrologic regime) that may seem irrelevant until its connection to their well-being is explained (e.g., hydrologic regime is needed to protect trout fishing opportunities or ensure drinking water supply). The economic view of ES combines 2 theoretical perspectives: production theory and utility theory (Freeman et al. 2014). In terms of production, ES are outputs of ecological production functions and are inputs to economic production functions (which can include both commercial production and “household” production; Bockstael and McConnell 1981). These ecological outputs either directly or indirectly affect human well-being as components of people’s utility functions. Ecological outputs may thus be inputs into economic production of other goods and services that people value (such as timber used to produce lumber), or inputs into household production of things that people directly interact with and enjoy (such as wildlife for viewing or hunting).
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In recent years, various definitions and classification systems have been proposed for communicating ES (de Groot et al. 2002; Millennium Ecosystem Assessment 2005; Boyd and Banzhaf 2007; Brown et al. 2007; Wallace 2007, 2008; Costanza 2008; Fisher and Turner 2008; Turner et al. 2008; Fisher et al. 2009; Johnston and Russell 2011; Mace et al. 2012; Nahlik et al. 2012; Pirard 2012). Many of the proposed definitions can be broadly categorized as favoring either ecological or economic viewpoints, or as providing a more general perspective that can encompass a number of viewpoints. The broadest definition of ES, “the benefits people obtain from ecosystems” (Millennium Ecosystem Assessment 2005) encompasses various viewpoints, types of value, and meanings, thus leaving its practical application open to many interpretations and unsatisfactory for environmental decision makers. Reliance on imprecise definitions can lead to studies and analyses that might intend to evaluate the same things, yet instead measure different things or measure them differently. This in turn can hinder aggregation of values across studies (e.g., as in a meta-analysis) (Bergstrom and Taylor 2006; Rosenberger and Johnston 2009) and can create problems of double counting by including the same economic impact more than once in summing the benefits (and costs) of a particular action (Boyd and Banzhaf 2007). Furthermore, definitions like the Millennium Ecosystem Assessment’s confound the goods and services actually produced by ecosystems, i.e., ES, with the benefits people receive from changes in those ES as a result of a decision or policy. Adding to the problem, definitions and classification typologies typically are proposed for specific purposes or applications, and a lexicon and typology defined for one context may not easily be applied to other contexts. We posit that a generally accepted set of definitions, applicable to situations broadly, will help to advance the value of ES concept in decision making, its application, and its communication. Here, we present a set of terminology, developed through a process of discourse among natural and social scientists, that is comprehensive and general, yet attempts to be precise enough to address many of the common misunderstandings across disciplines. Nuanced adjustments to these general definitions can be valuable to specific applications of the ES concept in unique policy or research contexts (Kline and Mazzotta 2012). For example, developing ES measures analogous to Gross Domestic Product indicators, or otherwise monitoring large-scale changes in ES over time and space, might require enhancement of our basic definitions to promote consistency (Boyd and Krupnick 2009; Nahlik et al. 2012; Ringold et al. 2013). Conversely, actions to protect or restore ecosystems can be informed by broad definitions that are meaningful to a wide array of audiences. Other applications will fall somewhere between these 2 extremes. Although the ES concept is not new to either ecology or economics, what is new about the general acceptance of the concept is the prominence of and focus on ES as an incentive for conservation of nature and as a unifying framework for transdisciplinary approaches in research, policy, and sustainability. The value of the ES concept has matured in recent years to the point where initial guidance has been offered for its use in environmental decision making (e.g., Ranganathan et al. 2008; NESP 2014). The advantages of the ES concept as a unifying transdisciplinary framework include making clear the full range of benefits provided by functioning ecosystems and the costs to them imposed by human choices, and most importantly, making transparent the tradeoffs among impacts
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on ES involved in decisions at all levels, from individual to collective, local to global. In 2007, the USEPA’s Office of Research and Development made a strategic decision to create the Ecosystem Services Research Program (ESRP) to refocus its core ecological research toward advancing the science of ES. This decision was strongly supported by the USEPA’s Science Advisory Board (USEPA SAB 2009a, 2009b) and others. This new approach directed research toward quantifying the socioeconomic value of ecosystems and how the USEPA’s decisions affected them, rather than on classical biophysical regulatory endpoints, and therefore necessitated transdisciplinary integration across the natural and social sciences. The program was structured around a number of place-based studies, tied together by cross-cutting themes such as N as a stressor, wetlands and coral reefs as key habitat types, and the basic data, models, and decision informing tools that would be needed to incorporate ES routinely in USEPA’s practices and into local to federal decisions. The rationales for this change were grounded in the need to engage USEPA decision makers and the public in issues of social well-being and equity, and to create “demand” for ecological integrity by quantifying the effects of real or potential losses created by our current decisions affecting management of ecosystems, using the language of ES. Although transdisciplinary by design, this refocusing brought to light the acute disparities in understanding and use of terminology associated with ecology, environmental economics, and the ES concept. Program ecologists, steeped in the jargon of their discipline, had difficulty grasping economic concepts of social well-being, and economists were equally challenged by ecological terms and understandings. Furthermore, when program ecologists tried to orient work toward ES outputs that would be useful for social and economic analysis, they differed in their understanding of that which would be most useful. A common basis for mutual understanding was lacking. A lexicon, developed and accepted by economists and ecologists alike, promoted the cross-disciplinary understanding of ultimate objectives required by the goals of the ESRP. As the USEPA’s research evolved to its current focus on sustainable outcomes for ecosystems, economy, and society, the ES concept has continued to be a unifying theme to help guide research objectives and production of valuable, decisioninforming knowledge. We present the ES lexicon developed for USEPA’s ESRP (Supplemental Data). It was developed through the collaboration of program participants and others, using a process of consensus-building through iterative discourse, and drew from many resources. It was informed by the conceptualization of the relationships among ecosystems and their processes, the way that humans perceive and use the outputs of those processes, and the influences and interventions of human choices (regulatory, voluntary, resource management, or otherwise) on ecosystem processes. Ultimately, the ESRP codified definitions for a wide variety of additional terms that are used in our science program. Many of these are not related directly to ES per se; rather, they encompass a broad array of natural and social science concepts. Some of these terms already are part of particular disciplines, such as environmental economics. We are not unduly attempting to standardize their use; rather we are trying to facilitate the mutual understanding of terminology by the multiple disciplines and multiple organizational contributors to ES research and policy. Although not perfect, the ESRP’s ES lexicon has served to
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move USEPA closer to the main objective described above: clear and transparent communication of ES terminology and research advancements to help inform decision making, particularly focusing on resolving communication issues among the many disciplines involved in ES research and policy. It also has served to clarify the research needed to advance ecosystem management beyond its traditional reliance on minimizing risk to biophysical regulatory endpoints independent of direct regard to their utility to the public.
A CONCEPTUAL FRAMEWORK AND STANDARDIZED TERMINOLOGY To apply the ES concept successfully, decision makers at local, regional, and national scales require the information necessary to consider the production and value of ecosystem goods and services appropriate to their decision-making processes. A key step in communicating among scientists, decision makers, and the public is common agreement on terminology. The conceptual framework offered in Figure 1 (modified from Wainger and Boyd 2009) provides a context within which to move toward a common understanding and lexicon. In this section, we highlight, further explain, provide examples illustrating some of the key aspects and terminology of this conceptual framework, and attempt to clarify some of the areas where ecological and economic terminology overlap or might be in conflict. The framework shown in Figure 1 is a simplified conceptualization depicting the most important components needed to model how ES can be evaluated by transdisciplinary teams in a decision-making context. Within this framework, several terms help to convey concepts that can clarify communications among scientists and analysts, decision makers, and the public. These represent the core of the lexicon we offer. Several points are foundational in this framework: Measures of ecological outputs and ES must be relevant, appropriate, and operational within the specific decision context. Some contexts require more precision and refinement of measures than do others. For example, a local decision associated with upgrading a water treatment facility in a particular location would likely require detailed
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specification of an ecological output such as fish abundance in an associated waterbody, and a corresponding ES such as the number of large mouth bass catchable during a fisher’s visit. Conversely, a national-level decision concerning compliance with the provisions of the Clean Water Act (CWA) could rely on broad parameters of water quality as ecological outputs, and measures corresponding generally to the CWA goals of fishable or swimmable as the important ES. The general definitions we present provide a broad and consistent vocabulary that allows for various levels of precision in measures. Further specification of those definitions can be made if necessary to enhance the level of precision, depending on the decision context. Ecological processes generally are not included in the category of ecosystem goods and services. Although there might be exceptions, generally it is the outcomes of these processes that are inputs to ES. Outcomes of ecological processes—ecological outputs in our terminology—only become ES when there is demand by people (e.g., they are important to social welfare or enter the utility functions of individuals), when quality and quantity are sufficient to warrant demand by people, and when any necessary complementary goods and services are available. For example, the ecological output of a fish population would only be considered an ES when fishers want to catch them or nature viewers want to see (or otherwise experience) them, and when the population is accessible to these uses by the presence of roads, docks, boat launches, etc. that are complementary to its use. The distinction between intermediate and final ES (see below) is critical to using ES in environmental decisions. Some ES can be both intermediate and final, depending on their ultimate use or appreciation by different people (Boyd and Krupnick 2009). Thus, knowledge of people's preferences and values is required to develop any typology or classification of ES for a particular policy or decisionmaking context. Figure 1 shows an approach to linking ecological conditions to human benefits. On the left side, the first box and arrow denote the structures, processes, and interactions of ecological
Figure 1. Conceptualization of the production of ecosystem services and ecosystem-derived benefits, and how policies and decisions affect this (modified from Wainger and Boyd 2009).
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systems that directly or indirectly yield outputs important to society. Even though all such interactions likely are important, quantifying ES benefits relies on being able to explicitly link biophysical conditions to social welfare. The first step in demonstrating benefits is to link biophysical conditions to desirable outputs via ecological production functions. The second step is to consider the demand for such outputs by location, and any necessary complementary inputs, to demonstrate that potential services are realized. The third step is to consider how changes in services affect welfare using benefit (i.e., social welfare) functions. Policy, management, and other decisions (including individuals’ behavior) determine how human actions affect ecosystems and ecological production. Ecological production functions are the focus of most environmental and resource management decisions—we limit the introduction to the environment of hazardous substances, we manage habitats and landscapes to optimize food and game production, and so on. They form the convenient “control points” that we use to achieve environmental goals. Understanding ecological production functions also permits us to target indicators of those functions—the rate of C sequestration, the number of huntable waterfowl—in ways that inform environmental management and policy.
intermediate ecosystem services proposed by Boyd and Banzaf (2007). To avoid double counting, only final ES should be included in any accounting that sums measures or values of ES. Ecosystem goods and services are outputs of ecological processes that directly (final ecosystem service) or indirectly (intermediate ecosystem service) contribute to social welfare (modified from USEPA 2006). Some outputs may be bought and sold, but most are not marketed. We do not distinguish between goods and services, although we recognize that there are conceptual distinctions between the 2. Both are contributions of nature to human well-being, and the 2 are treated identically from assessment and valuation standpoints. “Ecosystem goods and services” is often abbreviated as ecosystem services.
An ecological output is a biophysical feature, quantity, or quality that requires little further translation to make clear its relevance to human well-being (i.e., a “public-friendly” measurement or valued attribute of the ecosystem). As such, ecological outputs are the key metrics for evaluating ES. The term “output” signifies that these are the outcomes that people directly interact with and appreciate.
Not everything that nature does benefits humans directly or is valued by people explicitly. For example, the ecological interactions and processes that support a viable aquatic insect community might not provide any direct benefit to shoreline residents (insect viewing notwithstanding), and in fact might be considered a nuisance or even a public health threat (as is the case for mosquitoes). Many ecological processes go unrecognized for their ultimate contributions to human well-being. And yet, without those insect species and supporting processes, humans could not benefit from associated recreational birding and trout fishing opportunities. In this example, maintenance of the aquatic insect community is viewed as an intermediate ES (taking place in the first arrow from the left in Figure 1), with birds and fish being the final ES. The distinctions between intermediate and final ES might not always be clear-cut and certainly can change with context; people who enjoy viewing aquatic insects (e.g., dragonflies), for example, benefit directly from a viable aquatic insect community, and thus this insect community could be considered a final ES to insect watchers. It is often possible for the same ES to be both a final ES and an intermediate ES (Boyd and Banzhaf 2007; Boyd and Krupnick 2009). To distinguish final ES from intermediate ES in a particular context, some knowledge of human preferences is required (Johnston and Russell 2011; Nahlik et al. 2012; Weber and Ringold 2012). Economists include both use and nonuse (sometimes referred to as “passive use”) values in the accounting of benefits, so direct use is not always a requirement for defining a final ES. Although ecological outputs are defined as the measures that people can understand and value, not all ecological outputs are final ES. Final ES require, by definition, either active or passive use by people (i.e., demand). Furthermore, the quality of an ecological output must be sufficient to provide a beneficial service (e.g., for people to benefit from swimming, water quality must be safe for swimming), and complementary goods and services (e.g., beach access) must be available when needed for people to benefit from an ES. The term final ecosystem service determination is included in the lexicon to make these points clear.
Humans benefit from nature both directly and indirectly. To clarify this, we adopt the terms final ecosystem services and
The final ecosystem service determination (adapted from the definition of “ecoservice production function” in
The ecological production function is a description of the type, quantity, and interactions of natural features required to generate observable and measurable ecological outputs. For a simple example, the biophysical characteristics of a coastal wetland (flooding regimes, salinity, nutrient concentrations, plant species abundance, prey and predator abundance, etc.) can influence the welfareenhancing output of increased abundance of a population of watchable wading shorebirds. The terminology of “production functions” provides an analogy to economic production to better illustrate the relationships between inputs into ecological production, places to intervene to protect or enhance ecological production, and outcomes of ecological production (see Boyd and Krupnick [2009] for further explanation). Not all outcomes of ecological processes (i.e., ecological production functions) produce ES. Those that are relevant to people are termed ecological outputs. Boyd and Krupnick (2009) define ecological outputs as “meaningful biophysical outputs that do not require expert knowledge of biophysical production functions to determine their economic value. They are direct inputs to household production.” In earlier work, Boyd and coauthors used the term “ecological endpoint” in a synonymous way (Boyd 2007; Boyd and Banzhaf 2007; Wainger and Boyd 2009).
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Wainger and Mazzotta 2011), incorporates into the analysis the nonecological assessments that are needed to demonstrate existence of a final ES. It thus establishes whether an ES is actually produced, through the interactions of people with ecosystems. Three things must be evaluated: 1) whether the quality of an ecological output is sufficient to generate an ES, 2) whether demand exists for the ES by location, and 3) whether required complementary goods and services (e.g., trails, roads, homes) are available. For example, a final ecosystem service determination might consist of a quantitative or qualitative description of how a population of watchable birds (an ecological output), when combined with complementary inputs such as transportation infrastructure and demand by birders, produces a final ES. Complementary goods and services are inputs (often built infrastructure or location characteristics) that allow a good or service to be used by complementing the ecological condition. For example, complementary goods and services that allow a population of fish to become the ES of “fishable fish,” and thus to provide an opportunity for recreational fishing, will include aspects of site accessibility, such as road access, available parking, and the presence of a fishing pier, all of which make fishing at the site possible and enhance enjoyment of the activity. Finally, society receives ecological benefits, in the form of increased human well-being (i.e., utility), from their consumption of or interaction with ecosystem goods and services. Utility is the satisfaction of wants and needs obtained from the consumption or nonconsumptive use of goods and services or from passive uses such as existence value. Human well-being, broadly, is the condition of humans and society, defined in terms of the basic material and other natural resource needs for a good life, freedom and choice, health, wealth, social relations, and personal security. Social welfare is human well-being measured at some aggregate level. In the typical economic context, it is the sum of individual utility measures. Ecological benefits are the contribution to social welfare of ecosystem goods and services. In the policy and management context presented here, the term “ecological benefits” applies specifically to net improvements in social welfare that result from changes in the quantity or quality of ecosystem goods and services attributable to policy or environmental decisions (USEPA 2006). The term ecological benefit emphasizes that the benefits to people being considered are derived from improvements in ecosystems (and not to imply benefits to the ecosystem). Such benefits depend on social values, defined in terms of social welfare or human well-being. Policies and decisions connect social values to actions that affect ES.
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Policy is, generally, any statement of approach, philosophy, goal or decision. The decision-making process is one of any social and mental processes leading to the selection of a course of action among several management options or alternatives, and a decision (or management) alternative or option is a reasonable course of action or inaction to accomplish a specific goal or objective. Comparisons among decision alternatives or scenarios often involve evaluations of the ES tradeoffs—the ecosystem goods and services gained or lost as the result of selecting one option over another. One area where definitions often differ is for recreational, aesthetic, educational, or spiritual experiences (i.e., many of the “cultural ES” as defined by the Millennium Ecosystem Assessment 2005), or for risk reductions provided by ES, such as reduced risk of flood or storm surge damage to structures. In some cases, these experiences or reduced risks are referred to as ES, in others, they are referred to as benefits (Mace et al. [2012] refer to these as goods). Furthermore, some authors (Brown et al. 2007) distinguish between, for example, recreational “opportunities” and recreational “experiences” and classify recreational opportunities as ES. Using the definitions presented in our lexicon, a “recreational opportunity” would be a composite or bundled set of final ES that provide that opportunity, and a recreational experience would be the household production process by which a person transforms those ES (e.g., a water body, a stock of fish, and scenic characteristics of the site) and other inputs (e.g., boat, boat ramp, fishing rod, and fishing skill) into benefits. Often, investigators applying this approach refer to the individual ecological components (what this lexicon calls ES) as “attributes” of the ecosystem or of the opportunity (following Lancaster [1966] and Rosen [1974]). In practice, this bundled approach makes sense in many valuation and decision contexts, because it reflects how people tend to think about and value these types of experiences—in a holistic way where the various attributes or bundled services contribute collectively to make the valued experience (a day of recreational fishing) possible. A person who values a day of fishing may or may not be able to value changes in the individual ES (or attributes) that make that day possible (Weber and Ringold 2012). However, conjoint or paired comparison surveys or multi-attribute utility (MAUT) approaches are often used successfully to tease out the value of changes in the component services (or attributes) (Kiker et al. 2005).
DISCUSSION A decade has passed since the publication of the Millennium Ecosystem Assessment (2005) communicated the paramount importance of the benefits derived from nature to human well-being and sustainability. Our scientific understanding of the ways in which changes in ES can inform decision making, and how that information can be applied to the decision-making process, will improve with time and practice (Daily et al. 2009; Seppelt et al. 2011). Although the number and directions of ongoing research (and communication) efforts underway to advance ES science have increased, that advancement and its contribution to decision making continue to be hampered by the absence of generally accepted terminology and definitions.
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We are aware of other attempts to standardize the language of ES. In addition to the many definitions for individual terms offered by others (Daily 1997; King 1997; Whigham 1997; Freeman et al. 2014; Millennium Ecosystem Assessment 2005; USEPA 2006), the Willamette Partnership, a multidiscipline coalition centered in the Willamette River basin of Oregon (US) and focused in part on promoting ES markets, developed a limited glossary of terms as used by their group (Willamette Partnership 2009). We have adopted some of their definitions in our lexicon. Similarly, Pirard (2012) offered a lexicon to inform use of market-based instruments in biodiversity conservation and provision of ES. Other groups have developed or are developing glossaries for use in their individual research efforts (Harrington et al. 2010). Ringold et al. (2013), Nahlik et al. (2012), and Johnston and Russell (2011) have developed very specific definitions for selected terms to help identify biophysical indicators of final ES that can be used in monitoring efforts, and subsequently in valuation, and that facilitate a strict accounting perspective. Boyd and Banzhaf (2007) and Boyd and Krupnick (2009) focus on the need for measures that allow for aggregation or bundling of benefits, so that cumulative changes in ecosystems and the consequent changes in human well-being can be described over time or projected as a result of a suite of policy options. To accomplish this, they argue that an accounting perspective (a perspective with a set of internally consistent rules avoiding both double counting and exclusion of substantial benefits), with an emphasis on biophysical outcome measures that facilitate economic analyses, is essential. Beyond these efforts, we are unaware of other concerted efforts to standardize ES terms and their usage. Our lexicon attempts to synthesize these various efforts to provide a general and comprehensive terminology to facilitate consistent communication. Some have suggested that terminological flexibility, some degree of vagueness, and perhaps even plurality in usage, should be encouraged (Costanza 2008). We agree that definitions should be modified and tailored as is appropriate to render them most useful to specific decision-making contexts. Situational flexibility and plurality of approach make sense given the complexities of ecological-human systems and our incomplete understanding of their behaviors. Yet, standardization of terms and concepts does not preclude the use of different definitions for these terms, nor does it prevent the application of different measurement priorities, to be most responsive to specific circumstances. It does allow differences among applications to be quickly communicated and understood. In this regard, it is important to remember that there is a balance to be struck between the precision needed to maintain clarity, achieve consistency of measures across time and space, and avoid double counting, and the flexibility needed to accommodate the synergies and holistic approaches required to address the challenges of decision making affecting sustainability. Still, we argue that until the multiple disciplines necessarily involved in the science and application of the ES concept can communicate effectively with one another, advances in ES science and its use in environmental management will continue to make only halting progress. We do not assume that the lexicon presented here will be the final word regarding definitions. Indeed, we hope it is not, because the concepts of ES science continue to evolve rapidly, and new and enlightening ideas continue to emerge apace. We do believe, however, that as with any field of scientific
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endeavor, movement toward standardization of language helps to propel the science forward. We welcome challenges to these definitions and encourage honest attempts to standardize a lexicon in ways that might be more meaningful to our ultimate objective: informing environmental decisions in ways that promote the sustainability of the environmental, social, and economic system upon which we all depend. Acknowledgment—We are indebted to the conversations held among the social and natural scientists who participated in the USEPA’s ESRP and beyond. In particular, we thank J Boyd for frank discussion, P Ringold, M Weber, and D Landers for pursuing some of these issues (albeit in a direction different from that taken here), R Linthurst and I Goodman for their intellectual involvement, and R Bruins, J Darling, D Simpson, B Rashleigh, and 2 anonymous reviewers for providing critical reviews of earlier versions of this communication. Disclaimer—The views expressed in this manuscript are those of the authors and do not necessarily reflect the views or policies of the US Environmental Protection Agency. This is ORD Tracking Number ORD-003477. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
SUPPLEMENTAL DATA Terms and their definitions which collectively define the lexicon.
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