Population and Ecosystem Theory in Ecological Risk Assessment

Abstract

Assessments of ecological risks associated with toxic contaminant releases necessarily involve extrapolation from observed responses of simplified laboratory systems to predicted responses of complex natural systems. In this paper we evaluate the utility of population and ecosystem theory for making these extrapolations, based on: (1) the success of the theory when applied to other environmental assessment and resource management problems, and (2) the degree of scientific consensus concerning the appropriate approaches to modeling populations and ecosystems. The applications we review include fisheries management, water-quality assessment and management, and power-plant-impact assessment. We conclude that neither population nor ecosystem theory can now provide models that accurately predict the long-term ecological consequences of toxic contaminant releases. However, we show how short-term effects of toxic contaminants on fish populations can be projected by use of models employed in fisheries management. Further, we show how ecosystem theory can, in spite of its relative immaturity, make immediate contributions to understanding the qualitative responses of complex ecological systems to toxic contaminants.