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EVALUATING THE EXTENT AND RELATIVE RISK OF AQUATIC STRESSORS IN WADEABLE STREAMS THROUGHOUT THE U.S.A.
Citation:
VAN SICKLE, J., J. L. STODDARD, AND S. G. PAULSEN. EVALUATING THE EXTENT AND RELATIVE RISK OF AQUATIC STRESSORS IN WADEABLE STREAMS THROUGHOUT THE U.S.A. Presented at Fifth National Monitoring Conference, San Jose, CA, May 07 - 11, 2006.
Description:
Aquatic stressors such as toxic chemicals, excess sediment, and non-native species threaten the biointegrity of stream ecosystems. The relative importance of a stressor depends both on the number of streams in which it is elevated, and on the severity of its effect when it is elevated. The Wadeable Streams Assessment (WSA), conducted by the U.S. Environmental Protection Agency's Office of Water, was designed to estimate the number of streams throughout the contiguous U.S.A. having elevated conditions for several individual stressors. We used "relative risk", a statistic widely employed in human health assessment, to assess severity the severity of each stressor's effect. Relative risk measures the strength and direction of the association between any stressor and any aquatic ecosystem response that can both be classified as being in either "least disturbed" condition or "most-disturbed (degraded) condition for each sampled stream location. We present relative extent estimates for several stressors sampled by the WSA, as well as the relative risk of degraded aquatic macroinvertebrate condition for each stressor. We estimated relative risk and relative extent for individual ecoregions as well as for the lower 48 states as a whole.