ANTHROPOGENIC IMPACTS AND LONG-TERM CHANGES IN HERPETOFAUNAL DIVERSITY AND COMMUNITY COMPOSITION ON A BARRIER ISLAND IN THE SOUTHEASTERN UNITED STATES

We determined the impacts of human development on the herpetofauna of Kiawah Island, a barrier island in South Carolina, USA. We used drift fence arrays with pit and snake traps, cover boards, and visual encounter surveys to sample herpetofauna at twelve sites along a gradient of developmental density (low, moderate, and high) in two dominant habitats (forest and sand dune). We found the highest species richness in the low development area with 16 species, while we found 14 species in the moderate area and 13 species in the high area. We also found that abundance was the highest in the low development area with 587 individuals encountered. However, we found no statistically significant differences in richness and abundance across development areas. Diversity indices and evenness were significantly higher in the moderate and high development area when we compared them to the low development area, which we attributed to the large numbers of a few amphibian species that we found in the low development area. Community composition was fundamentally different between development areas; we encountered the largest number of families and sensitive species in the low development area. Furthermore, we found four unique species in the low development area, whereas we found one unique species in the moderate area and none in the high area. We found that species richness and abundance were significantly higher in forest habitats when compared to sand dunes, however we found two species only in the sand dunes. When we compared the results of our survey to a survey completed a few decades ago, we found that Kiawah may have lost two species but has retained 29 other herpetofaunal species and has gained two more species. We found that a variety of vegetative and environmental characteristics were important for predicting richness and abundance within each habitat. Overall, our results indicate that a mixture of various levels of development and types of habitat with certain characteristics (e.g. plant species richness, canopy cover, etc.) may have the ability to maintain the greatest herpetofaunal diversity on barrier islands.