MARYLAND'S ANURAN POPULATIONS: ARE THEY AT RISK FROM ANTHROPOMORPHIC IMPACT

Abstract

From 1999 to 2003, roadside frog chorus surveys were conducted across the state of Maryland by volunteers per the North American Amphibian Monitoring Program protocol. The data generated was used to test the hypothesis that more anuran species are present in habitats with lower anthropomorphic impact. In other words, I predicted that more frog species would inhabit undeveloped areas compared to developed areas and agricultural areas. Statewide there was trend in anuran species diversity compared to land use. Anurans marginally preferred agricultural areas. Only one species, Rana virgatipes, significantly preferred undeveloped areas. It should be stressed that this study does not imply or support that agricultural wetlands are beneficial to all anurans. Only that a greater diversity of anurans were observed at the agricultural sites monitored in this study. Indeed the data for R. virgatipes suggests that some species were negatively impacted by agricultural land use. The populations of thirteen Maryland anuran species (R. catesbeiana, R. clamitans, R. palustris, R. sylvatica, R. virgatipes, R. sphenocephala, Bufo americanus, Acris crepitans, Pseudacris crucifer, P. feriarum, Hyla cinerea, Gastrophryne carolinensis, and Scaphiopus holbrookii) were stable during this study. Detection rates of two species, H chrysoscelis I versicolor and B. fowleri, increased over the course of this study. The remaining three species of Maryland anurans (R. pipiens, P. brachyphona, and H gratiosa) were not detected in this study.