9424566 Doak Habitat degradation is frequently cited as one of the most important causes of species endangerment and extinction. Almost all plans for the recovery of endangered species, or any of the compromise plans that try to protect a species while still allowing some development emphasize population monitoring as a means of gauging the health of threatened populations. However, the ability of monitoring to measure impacts of gradual habitat degradation on long-term population viability has rarely been addressed. This research will develop source-sink models with varying levels of biological and spatial complexity to explore the effects of habitat degradation on short-term population growth and long-term viability. General models will be developed and explored, as well as more specific models linked to two well-studied species of conservation interest that face effects of habitat degradation: Yellowstone grizzly bears and sea otter populations in Alaska and California. Models will be used to investigate both the effects of habitat degradation - especially the existence of time lags in population responses - and the abilities of different monitoring strategies to detect these responses in a timely fashion. In addition, by fitting models of varying complexity to these systems, the level of model complexity and the type of field data needed to adequately detect responses to habitat degradation will be addressed, as well as the robustness of these predictions. This research will not only give a better scientific understanding of the effects of habitat degradation, but will also improve the incorporation of monitoring data into the process of management and policy decision-making.
