Wednesday, August 8, 2007

PS 47-105: Habitat heterogeneity influences rodent abundance at Cape Canaveral, Florida, USA

Alexis A. Suazo1, Sunil Kumar2, and I. Jack Stout1. (1) University of Central Florida, (2) Natural Resource Ecology Laboratory

Habitat heterogeneity may play an important role in the distribution of rodent assemblages. Composition and configuration of habitat patches may facilitate or inhibit the movement of rodents across the landscape. For example, rodent mortality may increase at habitat edges or inhospitable habitats due to increased predation. We used 18 transect lines positioned in heterogeneous habitat of Cape Canaveral, Florida, to investigate the effect of habitat heterogeneity on the spatial distribution of beach mice (Peromyscus polionotus niveiventris), cotton mice (P. gossypinus), and cotton rats (Sigmodon hispidus).   We quantified heterogeneity in topography, landscape composition and configuration, and anthropogenic features at three spatial extents (150, 300, and 500 m radii) using geographical information system (GIS), and related it to rodent abundance to develop predictive models. We used Akaike’s Information Criterion (AIC) to select the best models from a suit of candidate multiple regression models. We found that total rodent and beach mice abundance increased with increasing distance from the beach. Topographic heterogeneity affected cotton rats and cotton mice but not beach mice abundance. Beach mice were positively associated with coastal strand vegetation and distance away from buildings. Cotton mice were negatively correlated with vegetation height and positively correlated with distance from roads, and cotton rats were positively associated with ditches and inland water bodies. At the 300 m spatial extent, the best models explained 79%, 81%, 84%, and 82% of the variation in total rodent, beach mice, cotton mice, and cotton rats abundance, respectively. Our results suggest that habitat heterogeneity affects rodent’s spatial distributions.

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