Abstract
Introduced populations of species pose one of the greatest threats to the persistence of native species. Documentation of distribution, range expansion and habitat use of introduced populations are key components of developing effective management strategies for the control and eradication of invasive species. In 2006 and 2007, we surveyed four islands in Biscayne National Park for nests to evaluate the presence of red-bellied squirrels (Sciurus aureogaster) and the distribution and index of dispersion of their nests in the Florida Keys archipelago within the Atlantic Ocean. Red-bellied squirrels were initially introduced to Elliott Key, Florida, USA in in 1938. We documented evidence of squirrels on two additional islands, Sands Key and Old Rhodes Key, which adds to concerns of spread of this introduced squirrel to areas with endangered endemic insular mammals. Squirrel nests were documented only in mixed-hardwood forest, and nests had a clumped distribution within this forest type. Range expansion was a chief concern to the National Park Service, as continued spread could result in squirrels exiting the park, and prompted management action. Understanding nest site selection and distribution was critical for developing an eradication strategy for the introduced population of red-bellied squirrels from south Florida.
We thank Associate Editor Boris Kryštufek and two anonymous reviewers for their comments and suggestions to improve the paper. Rosa R. Jessen, Courtney J. Conway and William J. Matter all provided useful comments on early drafts of this manuscript. Funding and support from the Florida/Caribbean Exotic Plant Management Team and the University of Arizona was greatly appreciated. We thank Richard Curry, Shelby Moneysmith, Todd Kellison, Max Tritt, Jim Chadwick, Sergio Martinez and Vicente Martinez of the National Park Service for their support of this project and survey effort. Special thanks to Zach Koprowski, Nate Gwinn, Kate Pasch, Brett Pasch, Claire Zugmeyer, Seafha Blount, Pedro M. Chavarria and Rebecca Lechalk for their assistance in the field. We thank Melissa Merrick for her assistance with GIS, map design and statistical analyses.
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