EAGER: Pathways to ecological generalism and the abundance-occupancy relationship in small-mammal communities

University Of Wyoming, Laramie WY

Investigators

Abstract

Understanding how small-scale experiments explain widespread patterns is a major challenge in the field of ecology. While experiments reveal mechanisms, their value is uncertain if these mechanisms cannot account for the large-scale patterns that characterize the natural world. One such common pattern is that widespread species tend to be abundant, while species with restricted distributions are often rare. This project, from an early career investigator, pursues a novel approach to determine how resource use by individuals can explain this pattern. The project will integrate experimental data collected on individuals with new models to extend individual results to populations and then to communities across large landscapes. The research will engage undergraduate students from Wyoming, who will participate in research along with Kenyan students, and leverages current NSF support by using an ongoing experiment in Kenya. Results will contribute to a reference library of savanna plants at the Smithsonian Institution that is shared with museums in Kenya. Data from this project will be publicly available. Correlations between abundance and occupancy are among the most pervasive in ecology: species with expansive distributions tend to be locally abundant, whereas those with restricted distributions tend to be locally rare. This pattern has long captivated ecologists, but proposed hypotheses to explain it have proved very difficult to test. This project pursues the resource-breadth hypotheses by focusing specifically on dietary breadth of individuals. Resource use will be quantified by sequencing fecal DNA in a species-rich guild of small, herbivorous mammals. Individual consumer-resource interactions will be integrated with estimates of fitness and population growth for constituent species in large-scale communities to discern whether ecological generalists are more abundant where they co-occur with dietary specialists and to identify the pathways through which ecological generalism is manifested in survival and recruitment rates. An ongoing herbivore exclusion experiment provides a backdrop of shifting resource dynamics across which a guild of small mammals is intensively monitored, and thus an excellent opportunity to test the resource-breath hypothesis.