PARENT SESSION
Oral Session 142: Mammalian Ecology.
Presiding: S Vignieri and D Berteaux
Friday, August 6, 8:30 AM to 12:00 PM, Meeting Room F 151.
Patch occupancy and spatial turnover of round-tailed muskrats in a fragmented landscape.
Schooley, Robert*,1, Branch, Lyn1, 1 University of Florida, Gainesville
ABSTRACT- Wetland species have suitable habitat that is naturally patchy and many may develop some sort of metapopulation structure. Basic models of metapopulations usually focus on two priority variables: patch area and patch isolation. Whether such an approach is adequate for most species in subdivided habitat remains an important question in spatial ecology and conservation biology. We investigated the patterns of patch occupancy and turnover of round-tailed muskrats (Neofiber alleni) in a network of >450 depression marshes in central Florida. Round-tailed muskrats are a rare species of conservation concern. We used multiple logistic regression models to identify environmental correlates of patch occupancy and of patch extinction and colonization probabilities. Muskrats occupied approximately 25% of the wetlands. Despite moderate patch turnover (18%) between two years, occupancy rates remained stable. The most important determinant of patch occupancy was habitat quality of patches, which was indexed by the cover of maidencane grass (Panicum hemitomon). Our system might be partly driven by source-sink dynamics. Patch extinctions were not spatially autocorrelated and were related to habitat quality, patch area, and recent burn history. Patch colonization was influenced by habitat quality, patch area, patch connectivity, and presence of pine plantations nearby. Hence, land-use practices in the matrix and spatial variation in habitat quality of patches affected both extinction and colonization probabilities. A simple model incorporating only patch area and isolation was not sufficient for explaining distribution patterns of round-tailed muskrats in a heterogeneous landscape.
Key words: metapopulation, wetlands, Neofiber alleni, habitat quality