Stressor analysis approaches for endangered species assessments

The US Endangered Species Act is legislation with the power to limit human activities that may have deleterious effects on the viability of threatened and endangered species of fauna and flora. However, because most endangered species face multiple threats, it is often unclear whether limiting specific activities will improve the likelihood of long-term survival, particularly when the relative importance of different stressors is uncertain. Wildlife managers responsible for protecting these species face the challenge of determining the optimal allocation of limited funds and personnel among risk management and conservation priorities, in the absence of a good understanding 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 projects where the potential exists for adverse interaction between the project and an endangered 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 method described herein is a well-established procedure 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.