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Résumé :
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The federally Endangered Florida Grasshopper Sparrow (FGSP, Ammodramus savannarum floridanus) is endemic to dry prairie habitat in central Florida and is currently only found at three public management areas (Avon Park Air Force Range, APAFR; Kissimmee Prairie Preserve State Park, KPPSP; and Three Lakes Wildlife Management Area, TLWMA). We analyzed long-term (1991-2008) point-count data to compare population trends of FGSPs at these management areas to determine if they function as independent populations by using Spearman's rank correlation to test for independence between annual trends. We also examined banding and resighting data to infer metapopulation structure. Populations fluctuated across years at all three sites, declining significantly at APAFR (r(s) =-0.89, P = 0.12). Previous studies indicated that sparrows in the three areas were not genetically differentiated, and two cases of dispersal between APAFR and KPPSP have been documented. However, dispersal rates among areas appear to be too low to influence demographic dynamics within individual areas. Within APAFR, FGSPs are aggregated into three spatially distinct habitat patches previously considered separate populations, but dispersal among these patches is more frequent than previously reported and population trends among these patches are correlated (r(s) >= 0.91, P
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