The spatial configuration of greenspace affects semi-aquatic turtle occupancy and species richness in a suburban landscape

Within urbanized areas, the importance of greenspaces for wildlife has been widely investigated for some animal groups, but reptiles have generally been neglected. To assess the importance of the amount, spatial distribution, and configuration of greenspaces (comprised of terrestrial and aquatic areas), we examined semi-aquatic turtle species richness in urbanized areas. In this study, we sampled turtles from 2010 to 2011 at 20 ponds, including farm (rural) ponds, ponds in urbanized environments, and golf course ponds. We used a hierarchical Bayesian species-richness model to estimate species richness and species-specific occupancy responses to three pond types (rural, golf, or urban) and four landscape measurements of greenspace (i.e., Euclidean nearest neighbor, interspersion juxtaposition, percent of landscape, and connectance), generated in FRAGSTATS. We found that probability of occupancy of four species, Kinosternon subrubrum , Trachemys scripta , Chelydra serpentina , and Pseudemys concinna increased substantially with an increase in connectance of greenspace within 500 m of each pond. When the model examining the configuration of greenspaces was analyzed, estimated species richness was greater at golf ponds as compared to either rural or urban ponds, and richness increased with increasing connectivity of greenspaces. Our results indicate that in golf course ponds can potentially support a greater diversity of semi-aquatic turtle species than rural or urban ponds and thus may be considered superior habitat in suburban environments. In addition, we suggest that maintaining connectivity of greenspaces in suburban areas is important for semi-aquatic turtles and should be considered in urban planning.