Helen McMillan

Helen McMillan

Reduced connectivity and density of ponds, alteration of the surrounding terrestrial habitat, and changes to the chemical, physical or biological characteristics of wetlands may all be possible contributors to decreases in amphibian populations

2008 Urban Fellow

Research Topic: Effects of Urbanization on Wildlife

Faculty Advisor: David Skelly

Urbanization of New England Wetlands: Evaluating the Effects on Pond Breeding Amphibians

Urbanization often causes wetland loss and alteration, which can have significant effects on amphibian populations that utilize wetlands for breeding and adult habitat. Reduced connectivity and density of ponds, alteration of the surrounding terrestrial habitat, and changes to the chemical, physical or biological characteristics of wetlands may all be possible contributors to decreases in amphibian populations. This study evaluated these potential causes of decline on two species of tree frogs in Connecticut: the gray tree frog (Hyla versicolor) and the spring peeper (Pseudacris crucifer). I surveyed 30 ponds located along an urbanization gradient in the Salmon River watershed of eastern Connecticut during the spring/summer of 2008. Many pond characteristics, such as salinity and the presence of fish, showed clear differences with increased urbanization. In contrast to other studies, I found amphibian diversity to be highest in suburban areas, likely due to the combination of more permanent ponds that many species require and the relatively close proximity to forested areas. However the factors that best predicted amphibian density varied with each species, indicating that in order to effectively protect amphibians a variety of habitats need to be protected.