This section is made up of slightly adapted excerpts from the paper “Best Practices for Integrating Ecosystem Services into Federal Decision Making.”

Conceptual diagrams can help identify how a policy or management action can affect multiple aspects of an ecosystem and how each of the impacts on an ecosystem can have multiple impacts on social benefits. They can be useful for exploring all possible impacts to valued services. However, conceptual diagrams will likely identify too many services to be meaningfully quantified in an ecosystem services assessment. Thus, the quantitative assessment can be focused on those effects likely to be most important to the decision—often those expected to have the largest impacts on human welfare. Assessors can use a few key questions to determine which services should be included.

Does the ecosystem service fall under the legal mandates or authorities of the assessor?

Many laws, and the rules that agencies have developed to implement them, mandate an analysis of specific environmental attributes as well as social impacts, economic impacts, or both. These laws include the National Environmental Policy Act, the Clean Water Act, the Endangered Species Act, the Forest Land Policy and Management Act, and the American Indian Religious Freedom Act, among others. Any ecosystem services assessment conducted under a specific agency mandate will need to include changes to ecosystem services derived from the attributes and impacts specified in that mandate. Other regulations may also require assessments to consider services outside the assessor’s direct jurisdiction. For example, the National Oceanic and Atmospheric Association Fisheries has responsibility for managing anadromous fish, meaning that changes in ecosystem services associated with a river in which fish spawn before migrating offshore must be a consideration in decision making. In addition, these decisions may require consideration of many related services called for by other mandates from the Environmental Protection Agency, soil and water conservation districts, and water treatment facilities.

Agencies and other decision makers might not want to invest in analyzing changes to ecosystem services that are outside of their authorities. Yet, broad analysis (or at least a recognition of all affected ecosystem services, whether or not they are subsequently analyzed) can improve understanding of the potential benefits of activities and may provide an opportunity for improved collaboration across agencies and with other affected entities.

Is an impact on the ecosystem service likely to be large and strongly driven by the proposed activity?

If decision makers aim to comprehensively assess ecosystem services and potential benefits, an effect on services should be included in the assessment if the policy, decision, or action is likely to have a large impact on it, whether or not the service is the intended target of the action or required by a mandate. For example, the U.S. Forest Service broadly recognizes the importance of the national forest system in providing drinking water to communities and habitat for many aquatic and riparian species. Thus, forest plans should not only focus on direct services, such as wood production, forest species maintenance, and forest jobs, but also on the relationship between forest restoration or timber harvest actions and downstream water uses. Only if the impact of an action on a benefit-relevant indicator (BRI) is insignificant can it be safely excluded from further analysis.

When determining whether an impact on an ecosystem service is likely to be significant, the time frame of possible impacts should be matched to the time frame of the action. For example, if the decision is about placing a dam that will exist for 100 years, the magnitude of impacts on that river should be considered over the 100-year time frame. The most appropriate time scale should cover the likely impacts during the project and for the period during which effects will remain substantial.

Will the expected changes to the ecosystem service matter to many people or to groups of special concern?

Answering this question means giving consideration to the “service areas” or “servicesheds” likely to be affected and to how many and which people will be affected by likely changes in a service. A serviceshed captures the area that provides a specific ecosystem service to a specific group of people (Figure 1). Serviceshed boundaries are defined by the area that supports the biophysical production of the service, by relevant access constraints (physical and institutional) to the service, and by demand for the service within that area.¹ For example, change in the water quality of a lake popular for recreation affects people who do or would potentially visit the lake, which may include people who live outside of the watershed of the lake. In some cases, there is biophysical supply of an ecosystem service but no realized benefit. Fish abundance for recreational fishing will generate no benefit in a water body where fishing is prohibited by law, or is otherwise inaccessible for recreation (Figure 6, lake 3). If, however, the existence of a place, habitat, or species is what people care about, its condition and continuance is what matters; physical and institutional constraints preventing access do not limit the benefits being realized. In addition, the serviceshed, including all those who value the particular service, can be national or even worldwide. Servicesheds for nonuse values in particular can often span very great distances.²

Figure 1. Hypothetical serviceshed boundaries

Source: H. Tallis, C.M. Kennedy, M. Ruckelshaus, J. Goldstein, and J.M. Kiesecker, “Mitigation for One and All: An Integrated Framework for Mitigation of Development Impacts on Biodiversity and Ecosystem Services,” Environmental Impact Assessment Review 55 (2015): 21–34.

Note: The serviceshed for recreational fisheries is determined by the accessible lakes (or rivers) with harvestable recreational fish species that are within an acceptable travel time of people. Lakes 4 and 5 are outside the example serviceshed because they lack physical access or are too far away, respectively. Lake 3 is within the potential serviceshed area but is protected and so lacks legal access.

A serviceshed captures the population that will be affected and can help decision makers consider where a change in provision of a service may have a large impact on vulnerable populations or other social groups of special concern. All services do not flow to all people equally, and some decision contexts present a requirement to consider those differences. For example, Native American groups have fishing and hunting rights on all federal lands, and a NEPA assessment on such lands should capture impacts to those groups distinctly. A general BRI for commercial fishing benefits would be abundance of fish landed commercially, whereas a group-specific BRI would be abundance of fish landed by Native American groups. When such interests exist, drawing an explicit causal chain for the group of interest can be a helpful way to understand key connections and identify a group-specific BRI.

By starting with the full conceptual diagram and then selecting the critical subset of services for further analysis, practitioners acknowledge the full suite of affected ecosystem services and can be more transparent about the services that are (and are not) subsequently analyzed and the rationale for these decisions. In the next step, individual causal chains for the selected services are expanded with additional details required for analysis.

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