Wetland Habitat and Occupancy of the Imperiled Copper-bellied Watersnake (Nerodia erythrogaster neglecta) and Other Herpetofauna

Lauren E Hall, Purdue University

Abstract

Reptile species and populations are declining globally (Gibbons et al., 2000). Some of the main factors leading to this decline are habitat destruction and degradation, so delineation of key habitat for reptiles for protection and restoration is particularly important for reptile conservation. Long-term efforts to monitor populations are also critical if declines are to be noticed and their causes determined. One such effort involves monitoring the Northern population segment (NPS) of Copper-bellied Watersnakes, Nerodia erythrogaster neglecta, which is geographically isolated from other populations and is listed as federally threatened by the US Fish and Wildlife Service. Copperbellies are also endangered in three states in which NPS occurs (MI, OH, and IN). The objective of the current study was to use occupancy modeling as part of ongoing monitoring efforts for the NPS and build upon previous studies of habitat preferences of copperbellies. I also estimated abundance and density of copperbellies at a portion of sites in the Northern population segment’s range, and compared population parameter estimates for copperbellies to those of its more common sympatric congener, the Northern Watersnake (Nerodia sipedon sipedon). There were very few detections of copperbellies over the course of this 2 year study, resulting in low sample sizes and difficulty in ascertaining habitat effects on occupancy of copperbellies. Abundance estimates, density estimates, and occupancy estimates for copperbellies were all low, especially compared to estimates for Northern Watersnakes. Furthermore, estimates of wetland colonization rates were very low for copperbellies, but extinction rates were high. These results are alarming, but consistent with findings of previous occupancy studies done in the area (Lee & Kingsbury, 2014). Model assumptions are discussed, and recommendations for future studies and management are given.

Degree

M.S.

Advisors

Kingsbury, Purdue University.

Subject Area

Biology|Ecology|Conservation

COinS