9317401 Peterson In order to evaluate two classes of food chain models (top-down and bottom-up regulation of species abundance), this project includes continued evaluation of moose and wolf population dynamics in Isle Royale National Park, Michigan, an island in Lake Superior (544 km2 in area). Also included is expanded monitoring of moose condition and vegetation status. The two food chain model classes have opposing predictions for two trophic subsystems which are evident on Isle Royale. These subsystems, attributable to differences in postglacial history, differ in forage production rate for moose, a fact that allows greater discrimination between contrasting predictions of food chain theories. Food chain models also have opposing predictions following the transformation of a three-trophic-level system into a two-trophic-level system, a change now predicted for Isle Royale because of genetic deterioration in its small wolf population. The research includes long-term aerial and ground monitoring of wolves, moose, and vegetation, recognizing the two trophic subsystems, through the expected period of wolf decline (about one decade). The proposed study, building on an unprecedented database covering the past 35 years, will provide a critical terrestrial test of predictions of food chain models, as well as contribute to a better understanding of the regulatory role of wolves in this well-characterized ecosystem.
