Individuals versus organisms versus populations in the definition of ecological assessment endpoints

Authors

  • Glenn W. Suter II,

    Corresponding author
    1. Office of Research and Development, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, MC-A130, Cincinnati, Ohio 45268
    • Office of Research and Development, U.S. Environmental Protection Agency
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  • Susan B. Norton,

    1. Office of Research and Development, U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue, NW, Washington DC 20460
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  • Anne Fairbrother

    1. Office of Research and Development, U.S. Environmental Protection Agency, 200 SW 35th Street, Corvallis, Oregon 97333
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Abstract

Discussions and applications of the policies and practices of the U.S. Environmental Protection Agency (USEPA) in ecological risk assessment will benefit from continued clarification of the concepts of assessment endpoints and of levels of biological organization. First, assessment endpoint entities and attributes can be defined at different levels of organization. Hence, an organism-level attribute, such as growth or survival, can be applied collectively to a population-level entity such as the brook trout in a stream. Second, assessment endpoints for ecological risk assessment are often mistakenly described as “individual level,” which leads to the idea that such assessments are intended to protect individuals. Finally, populations play a more important role in risk assessments than is generally recognized. Organism-level attributes are used primarily for population-level assessments. In addition, the USEPA and other agencies already are basing management decisions on population or community entities and attributes such as production of fisheries, abundance of migratory bird populations, and aquatic community composition.

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