Long-term population ecology and movement patterns of gopher tortoises (Gopherus polyphemus) in southwest Georgia

摘要: The gopher tortoise (Gopherus polyphemus) is a keystone species of the longleaf pine (Pinus palustris) ecosystem in the coastal plain of the southeastern United States (Auffenberg and Franz 1982, Eisenberg 1983). The gopher tortoise is considered a keystone species because its burrows are known to provide habitat for over 360 commensal species, including at least 302 invertebrate species and 60 vertebrate species (Eisenberg 1983, Jackson and Milstrey 1989), as well as federally threatened species, such as the eastern indigo snake (Drymarchon couperi). Commensal species use the burrow microhabitat as refuge from fire, predators, and the effects of extreme or variable temperature events, which may increase in frequency or duration as a result of global climate change (Pike and Mitchell 2013). In addition, gopher tortoises increase understory plant diversity through habitat modification by creating colonization sites of bare mounds of soil for early successional plant species (Kaczor and Hartnett 1990), and potentially through seed dispersal (Auffenberg 1969, Boglioli et al. 2000, Birkhead et al. 2005). The geographic distribution of longleaf pine habitat in the southeastern United States has been reduced to small and highly fragmented forests covering< 3% of its pre-1880 range when it covered 40% of the region (Noss et al. 1995). The widespread loss of longleaf pine habitat and other upland habitats occupied by tortoises, along with other factors such as disease and predation, has led to an 80% range-wide decline of gopher tortoise populations (Auffenberg and