Abstract

Nest-site choice is important for species with temperature-dependent sex determination (TSD) because nest attributes determine not only incubation temperatures and therefore hatchling sex, but also performance, survivorship, and phenotype. However, suitable nesting habitat can be limited for aquatic species that nest in areas impacted by anthropogenic activities. The purpose of this study was to examine nest-site choice and nesting ecology of painted turtles (Chrysemys picta picta × C. p. marginata) inhabiting an anthropogenic wetland in south-central Pennsylvania. Visual surveys were conducted for nesting females along a perimeter dirt path and along an adjacent railway access road next to inactive fish hatchery ponds. From 2010 to 2013, we documented nest location, depth, width, temperature, canopy coverage, clutch size, and hatching success for a total of 33 nests. To address the influence of soil characteristics on nest selection, in 2016 we collected and analyzed 60 soil samples from 1) nests (with oviposition, n = 20), 2) test nests (nests aborted prior to oviposition, n = 20), and 3) randomized locations within the nesting area (n = 20). Nests were shallower than historically observed for this species and linearly aggregated north of the pond. Nests were made in soils with more coarse grains and fewer fine grains relative to test nests and random locations. Additionally, nests along the railway access road had markedly higher total carbon compared with nests on the dirt path. Although the railway may have increased solar exposure by reducing canopy coverage, this structure may also limit turtles’ access to suitable nesting habitat that could negatively impact future nest success.