Ecology and conservation of the wood turtle, Glyptemys insculpta, at Delaware Water Gap National Recreation Area
I studied the ecology and population genetics of the Wood Turtle ( Glyptemys insculpta), a species threatened by extinction, at Delaware Water Gap National Recreation Area (DEWA) from 2000 to 2004. The primary goals of this research were to: (1) compare demographic and spatial attributes among aggregations of G. insculpta, (2) examine nest placement, timing of nesting, and hatching success for this species in agricultural fields, (3) examine the immediate post-emergence behavior of hatchling turtles, and (4) investigate the genetic variation and population structure of G. insculpta at DEWA. I made 1,345 captures, marked 430 adults and juveniles, and radio-tracked 30 turtles from three watersheds. Statistically significant differences among aggregations were observed for body size, age distribution, and home range size. Adult sex ratio and body condition, however, were not significantly different. Onset of the nesting season varied between years, although both seasons were of similar duration (21 days). Nest sites in 2002 had significantly more vegetation cover and higher sand content than nest sites in 2001. In addition, nest sites were significantly warmer, closer to the nearest shoreline, higher above the nearest shoreline, had less vegetation cover, and a higher sand content than random points within the nesting area, suggesting that these microhabitat variables are important for nest placement in this species. The occurrence of no development or egg infertility, embryonic death, and hatchling emergence was significantly different for eggs in 2001 and 2002. Hatchling turtles did not move directly to water upon emergence from their nests. Instead they remained terrestrial for 13 to 62 days and fed and grew prior to entering water for hibernation. While on land, they occupied sites with significantly lower air and substrate temperatures than those of adult turtles, suggesting avoidance of potential desiccation. Seven microsatellite loci revealed high allelic richness and expected heterozygosities (HE) for four G. insculpta aggregations. Population subdivision estimated as FST (&thetas;) over all loci and aggregations was not significantly different from zero and gene flow estimates (Nm) were high in all pairwise comparisons. These data suggest that G. insculpta at DEWA represent a single, genetically diverse management unit for conservation. ^
Christina Marie Castellano,
"Ecology and conservation of the wood turtle, Glyptemys insculpta, at Delaware Water Gap National Recreation Area"
(January 1, 2008).
ETD Collection for Fordham University.