Anthropogenic disturbance of the herpetofauna in the northeast US: Wildlife disease and habitat modification.

摘要

Herpetofauna represent striking examples of the consequences of human impact on biotic communities. They experience the full range of anthropogenically-derived stressors: habitat loss, habitat modification and degradation, pollution, collection for food and the pet trade, nuisance killings, road mortality, and disease. In this study, I examined some of the main threats faced by herpetofauna of the Northeastern United States and their implications for management of reptile and amphibians in New Jersey. I first used molecular techniques to document and assess the prevalence of two amphibian diseases, chytridiomycosis (caused by the chytrid fungus, Batrachochytrium dendrobatidis) and Ranavirus, throughout the state of New Jersey. While Bd does not seem to be a problem, Ranavirus was found at eleven sites in NJ. Next, I examined the first recorded occurrence of the American Green Tree frog (Hyla cinerea) in New Jersey to determine if its presence could be linked to a range expansion event facilitated by climate change. Toe clips were collected from both populations and partial sequences of the mitochondrial ND1 gene were used to generate a statistical parsimony network. Four haplotypes were distinguished, with all NJ haplotypes being identical to the most prevalent Delaware haplotype and the Delaware haplotypes differing by at most one base pair. These results suggest a recent movement of Delaware frogs into NJ. Finally, I examined populations of the Diamondback terrapin (Malaclemys terrapin ) in two urbanized locations of the species' range in order to determine the genetic and demographic health of these populations that live in such highly disturbed habitats. I used a fragment of the mitochondrial D-loop from terrapin blood samples to examine patterns of genetic diversity among populations of terrapins collected within Jamaica Bay (from Ruler's Bar Hassock and JFK airport), Hempstead Bay and Sawmill Creek Wildlife Management Area in the NJ Meadowlands. I show that the picture of the terrapin's demographic past is a complex one, possessing signs of a bottleneck, as well as recent expansion, and that genetic diversity of the mitochondrial D-loop is not severely reduced. Genetic data confirm what other studies have shown, that dispersal capabilities of terrapins are limited.