U.S. EPA Projects:

Ecosystem Services

Combining the Ecosystem Service and Critical Load Paradigms for Resource Management and Public Policy Decision-Making
Land management and natural resource public policy decision-making in the United States increasingly relies on two resource damage/recovery paradigms: ecosystem service (ES) and critical load (CL). One well known example that is appropriate for ES and CL evaluation is  the acidification of soil and drainage water by atmospheric deposition of acidifying sulfur (S) and nitrogen (N) compounds. The basic principles of ES and CL are common, however, to a variety of air, soil, and water pollution and human land use issues. Virtually no effort to date has combined the ES and CL approaches into an overall framework that clearly documents the impacts of pollution on the environmental goods and services that benefit humans in a way that facilitates land management and public policy decision-making. In addition, there has been a lack of agreement within the scientific, economic, and public policy research communities regarding exactly what constitutes an ES and how temporal variation in ecosystem damage and recovery trajectories should be incorporated into CL calculations. E&S Environmental Chemistry is developing an integrated approach to the application of ES and CL principles for public land management and natural resource policy decision-making to facilitate adoption of an integrated ES/CL framework that is useful at the environmental science/policy interface.

Ecosystem services are, broadly speaking, the benefits that are derived by humans from nature. The term ES implicitly includes both goods (e.g., lumber provided by a healthy forest) and services (e.g., clean water provided by filtration that occurs in forest or wetland soils). The CL is the level, or load, of pollution below which significant harmful effects are not expected to occur to sensitive ecosystem elements. The CL is most commonly defined on the basis of chemical indicator dose-response functions or tipping points expressed under long-term steady-state conditions. In other words, the CL specifies the pollutant load which, when applied to the ecosystem in question for a period of years to centuries, will eventually trigger a change in a chemical indicator of biological harm at the time that the ecosystem comes into steady state with respect to that particular pollutant input level. A dynamic, as opposed to steady-state, CL can also be defined, which is specific to a particular point in time.

E&S research is helping to more closely tie these paradigms together in a way that facilitates the provision of benefits to humans from the use and enjoyment of nature’s by-products. The purpose of the E&S research is to make these connections more explicit. Management and policy options can then be examined and weighed within the context of these resource management components. Informed decisions will be rooted in consideration of multiple stressors; their causes, logistics and costs of control; and the perceived importance and/or value of impacted services.

The final report can be downloaded here.