Vegetation structure and the habitat specificity of a declining North American reptile: A remnant of former landscapes

Abstract

Although all species provide some spatial information about past environments, remnant populations of habitat specialists can serve as biological legacies and natural archives of historical landscapes. The endangered longleaf pine ecosystem is home to an array of imperiled fauna that specialize on the habitat. Often referred to as pine savanna, the ecosystem was characterized by longleaf pine ( Pinus palustris), but included an array of open-canopy habitats within a grassland matrix dominated by a variety of tree species. In this study, we used a coarse scale of description to quantify habitat associations of a declining reptile, the eastern diamondback rattlesnake ( Crotalus adamanteus), historically associated with pine savannas of the southeastern United States. We made cross-scale habitat comparisons and controlled for land use and geographic variability. Habitat models of within home range and microhabitat selection indicated that the species was associated with an open-canopy savanna community structure. We identified the eastern diamondback rattlesnake as a remnant of the historical southeastern savanna, which is important for species conservation and broader management of the southeastern savanna community. Given their longevity and habitat specificity, remnant eastern diamondback rattlesnake populations are biological legacies of the southeastern savanna community and act as a surrogate for the prioritization of land conservation. Thus, the species’ presence provides spatial information that can be used by conservationists to identify habitats that have high restoration potential, and also increases the probability that other species associated with pine savanna occur locally.