Stressor analysis approaches for endangered species assessments

Abstract

The US Endangered Species Act is legislation with the power to limit human activities that may have deleterious effects on the viability of threa- tened and endangered species of fauna and flo- ra. However, because most endangered species face multiple threats, it is often unclear whether limiting specific activities will improve the like- lihood of long-term survival, particularly when the relative importance of different stressors is uncertain. Wildlife managers responsible for pro- tecting these species face the challenge of de- termining the optimal allocation of limited funds and personnel among risk management and con- servation priorities, in the absence of a good un- derstanding of the relative importance of these stressors. We present an analytical framework that can serve as a technical basis for evaluating multiple risks to endangered species. Predictive and retrospective causal analysis applications are considered. The former address proposed pro- jects where the potential exists for adverse in- teraction between the project and an endanger- ed species. The latter involve existing projects or products for which a determination is being or has been made concerning the threats posed to an endangered species. The causal analysis me- thod described herein is a well-established pro- cedure that is widely used in other scientific fields and offers a practical and logical process through which threats to endangered species can be assessed and recovery actions prioritized.