Arguments for using population models in incidental take assessments for endangered species

Population models can be useful tools for evaluating management strategies and risks for a given species. A major, but often overlooked, component of endangered or threatened species management and recovery is the incidental take allowance of many endangered species laws. In the United States population models are seldom applied to address specific incidental take scenarios. We believe it is prudent for wildlife management agencies like the U.S. Fish and Wildlife Service to embrace explicit predictive tools to assess the possible effects of incidental take actions and to set standards for what constitutes unacceptable levels of incidental take in terms of predicted effect on population viability, recovery, and extinction. We briefly give recommendations for incorporating simulation models into jeopardy evaluations in ways that would dovetail with legislative language and provide a simple example model. Using explicit predictive models to support jeopardy determinations and incidental take decision-making would lead to transparent decisions rooted in measurable quantities such as changes in extinction probability or abundance projections.