This section consists primarily of excerpts from the paper “Best Practices for Integrating Ecosystem Services into Federal Decision Making,” with a small addition from the previous version of the Federal Resources Management and Ecosystem Services Guidebook (“Bridging Indicators” by James Boyd and Lisa Wainger).

Ecological features and processes are essential for the provision of ecosystem services but are not the same as services.¹ Until there is some person somewhere who benefits from a given element or process of an ecosystem, that element or process is not a service. Benefit-relevant indicators (BRIs) are measurable indicators that capture this connection by considering whether there is demand for the service, how much it is used (for use values) or enjoyed/valued (for nonuse values), and whether the site provides the access necessary for people to benefit from the service, among other considerations.² An ecological measure can become a BRI if it is tied directly and causally to something important to people, e.g., the presence of bald eagles, which are clearly identified as important to the American public.

BRIs can also be measures of a disservice that result in lower rather than higher benefits. For example, wolves can create a disservice to ranchers who lose livestock to predation. In other cases, BRIs provide positive benefits up to a certain quantity, above which point benefits may become negative. For example, many wildlife species (for example, deer) are valued for recreational (e.g., hunting, viewing) and existence purposes up to a certain density, but at higher densities they are viewed as pests (e.g., due to damage caused to crops and landscaping). Hence, some BRIs will not have an unambiguously positive or negative impact on human welfare and may in fact simultaneously have positive impacts for some groups in society and negative impacts for other groups.

BRIs are not the only indicators that should be measured, nor do they represent the only things in nature that are valuable. They are simply indicators meant to improve the linkage between ecological analysis on the one hand and public policy, social evaluation, and lay communication on the other hand.

BRIs fulfill two important needs for ecosystem services assessments. The first is the need for indicators that are socially comprehensible, in that lay audiences can relate them clearly to their own well-being. Biophysical outcomes that are directly experienced, comprehended, and acted on are more amenable to social interpretation.

The second need is for indicators that enhance the accuracy of social evaluations. Just because lay audiences see a causal connection between an ecological outcome and their welfare doesn’t mean they will see it accurately. Accordingly, it is desirable to choose indicators that reduce the need for lay audiences, social science researchers, or both to estimate or speculate about the relationship between the indicator and the production of services. For example, it is more appropriate to ask people to assess how much they value safe drinking water than it is to ask them to assess how much they value the nutrient cycling that contributes to the quality of the water. Outcomes nearer to human experience minimize lay audiences’ need to speculate about ecological relationships and thereby lead to better, more accurate social evaluation.

A few key questions can assess if an indicator is benefit relevant.

Does the indicator reflect changes in ecological condition that are relevant to the beneficiaries?

BRIs must reflect changes in ecological condition (they must be good indicators of the ecological changes), and the changes must be relevant to people. As an example of ecological condition, marsh, reef, or mangrove habitat are all known to dampen incoming waves and, in so doing, protect coastal areas from erosion and inundation. For this service, habitat area is not the most relevant ecological metric; multiple studies have shown that the leading offshore habitat edge plays a disproportionate role in dampening waves compared with more interior acres of habitat. In this case, contiguity of offshore habitat edge is the appropriate ecological indicator to reflect a step on the causal chain for a coastal protection ecosystem services assessment.

An indicator becomes benefit relevant when it is cast in units that resonate with stakeholders as something that affects their welfare proximally (Table 1). For example, “numbers of catchable fish” is more relevant to fishers than other measures such as dissolved oxygen content in the water or an index of biotic integrity—even though water quality might directly influence fish populations. Similarly, in the causal chain connecting a change in forest management to changes in the risks of wildfire, the BRI emerges when fire behavior is translated into units directly relevant to human health (Figure 1b). Likewise, fire behavior might be translated into other BRIs connecting fire to other services of concern for various stakeholder groups such as hikers or homeowners (Figure 2). As a simple rule of thumb, if reasonably well-informed members of the beneficiary groups affected by an ecological change (e.g., those whose health is affected by airborne particulates) cannot easily understand why an indicator is relevant to their welfare, it is unlikely that the indicator is an effective BRI.

Figure 1. Differences between ecological and ecosystem services assessments and indicators

Note: Causal chains consider expected outcomes from forest fire management activities like mechanical thinning. Black text indicates an ecological assessment and indicators, red text indicates extension to an ecosystem service assessment, indicators within ovals illustrate BRIs, and blue text indicates measures of social benefit and value. The demarcation among ecology, ecosystem services, and social benefits is not absolute (the lines between categories are drawn differently by different people), as represented by the tri-colored arrow.

Figure 2. Conceptual diagram with causal chains for an ecosystem services assessment of a forest management decision

Note: This conceptual map of simplified causal chains shows possible outcomes from forest fire management activities like mechanical thinning. Black text indicates and ecological assessment and indicators, red text indicates extension to an ecosystem services assessment, and blue text indicates measures of social benefit and value.

Does the indicator capture relevant physical and institutional access constraints on the flow of the service?

Many ecological measures and indicators used in ecological assessments fulfill the first requirement of a BRI because extensive research has identified sensitive interactions in the environment of interest to people. However, a BRI must capture only those ecological components and processes that can be enjoyed or used by people for some benefit. Capturing these components and processes requires information on relevant physical or institutional limits on people’s ability to access (physically or otherwise) a benefit. For example, for the service of timber production, tree density alone is not a sufficient BRI. Physical infrastructure such as roads or features such as terrain may limit tree harvests in some areas. Separately, legal restrictions may limit physical access to areas with trees (e.g., protected areas) or regulate harvest rates or areas (e.g., through riparian buffer restrictions). A BRI must reflect these constraints so that the flow of services is not overestimated. In this case, a BRI would be the density and size of harvestable trees accessible to forest managers.

BRIs are relevant to all ecosystem services, including those with nonuse values such as existence, educational, and spiritual values. When people value the existence of an old-growth forest, a historical or culturally important place, or particular species like bald eagles or endangered tortoises, BRIs need to represent the elements that impart value to people, including the presence, quantity, quality, and sustainability of these places, habitats, or species. When species or ecosystems are protected by law, BRIs are likely to consist of well-constructed ecological metrics because laws are evidence of public interest. When a species or ecosystem is not federally protected, agencies may use BRIs to represent other types of evidence of people’s values such as conservation priorities developed by nongovernmental groups.

Alone, ecological measures may be insufficient to reflect an ecosystem service, but many are important components of causal chains that link agency actions to BRIs (see Table 1). An indicator becomes a BRI once it reflects the relevant links in a causal chain ending with the potential benefit of a service to an identifiable group of people. Choosing BRIs from links in established causal chains is critical for ensuring that a metric is specific enough to reflect the ecosystem condition causally tied to a human benefit.

Table 1. Examples of what would and would not qualify as a BRI

^a Donating to general conservation organizations is not a BRI because (1) there is no direct link between conservation donations and wolf populations—individuals may donate for reasons other than value for wolves—and (2) wolf existence is a public good—each individual can in principle obtain this benefit without paying for it—so individuals will free ride on payments made by others, and free riders will thus not be accounted for by only considering donations.

Recommended Reading

Boyd, J.W., and S. Banzhaf. 2007. “What Are Ecosystem Services? The Need for Standardized Environmental Accounting Units.” Ecological Economics 63: 616–626.

This paper describes intermediate and final ecosystem goods and services as concepts that align well with the bridging indicator concept and means-ends method described in this guidebook.

Boyd, J.W., and A. Krupnick. 2013. “Using Ecological Production Theory to Define and Select Environmental Commodities for Nonmarket Valuation.” Agricultural and Resource Economics Review 42 (1): 218–249.

This paper defines ecological endpoints (what this guidebook defines as bridging indicators) as ecological commodities for nonmarket valuation. It provides many examples and a theoretical structure for determining an ecological endpoint.

Haines-Young, R., and M. Potschin. 2009. “Methodologies for Defining and Assessing Ecosystem Services.” Report No. 14, Center for Environmental Management, University of Nottingham, Nottingham, UK.

This paper reviews approaches to classifying ecosystem services. It discusses the Millennium Ecosystem Assessment (MA) approach relative to hierarchical approaches like those used in this guidebook and concludes that the latter are probably required to produce results useful for decision makers.

Johnston, R.J., G. Macnusson, M.J. Mazzotta, and J.J. Opaluch, 2002. “Combining Economic and Ecological Indicators to Prioritize Salt Marsh Restoration Actions.” American Journal of Agricultural Economics 84(5): 1362–1370.

Although primarily an economic valuation study, this article also demonstrates methods for developing and using bridging indicators of ecological condition to assess human values.

Olander, L.P., R.J. Johnston, H. Tallis, J. Kagan, L.A. Maguire, S. Polasky, D. Urban, J.W. Boyd, L. Wainger, and M. Palmer. 2018. “Benefit relevant indicators: Ecosystem services measures that link ecological and social outcomes.” Ecological Indicators 85:1262-1272.

This paper proposes the use of a new type of indicator that explicitly reflects an ecosystem’s capacity to provide benefits to society, ensuring that ecosystem services assessments measure outcomes that are demonstrably and directly relevant to human welfare. We call these benefit-relevant indicators (BRIs) and describe a process for developing them using causal chains that link management decisions through ecological responses to effects on human well-being.

Ringold, P., J.W. Boyd, D. Landers, and M. Weber. 2013. “What Data Should We Collect? A Framework for Identifying Indicators of Ecosystem Contributions to Human Wellbeing.” Frontiers in Ecology and the Environment 11: 98–105.

This paper provides a detailed example of identifying final ecosystem goods and services (which this guidebook calls bridging indicators) and metrics for assessing them. It uses a process based on identifying beneficiaries of the goods and services.

Schiller, A., C. Hunsaker, M.A. Kane, A.K. Wolfe, V.H. Dale, G.W. Suter II, C.S. Russell, G. Pion, M.H. Jensen, and V.C. Konar. 2001. “Communicating Ecological Indicators to Decision Makers and the Public.” Conservation Ecology 5(1): 19. http://www.consecol.org/vol5/iss1/art19/.

This paper describes efforts to translate indicators of ecological condition into language appropriate for communicating with the public.

Wainger, L.A., and J.W. Boyd. 2009. “Valuing Ecosystem Services.” In Ecosystem-Based Management for the Oceans, edited by K. McLeod and H. Leslie, 92–111. Washington D.C.: Island Press.

This paper discusses alternative measures of the value of ecosystem services—ecological endpoints that capture ecosystem goods and services—that this guidebook terms bridging indicators.

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