Characterization of diamondback terrapin (malaclemys terrapin) nesting and nest predation at a site in northeastern usa

Diamondback Terrapin (Malaclemys terrapin) plays a keystone role in Saltmarsh ecosystems and is considered a species of conservation concern throughout its range. One major source of terrapin egg mortality is destruction of nests by nocturnal mammalian predators. Although Diamondback Terrapins are listed as State Endangered in Rhode Island, nesting ecology for the species is poorly understood at the local and regional level. To fill this knowledge gap, we identified temporal patterns of Diamondback Terrapin nesting, hatchling emergence, and nest predation during 2 y at a Rhode Island terrapin nesting site. We also used a series of trail cameras to detect and quantify the presence of nocturnal nest predators and tested a solar electric fence as a possible management solution for nest protection. Both predated nest counts and predator detections were highest during the Diamondback Terrapin nesting period, decreasing only after hatchlings began to emerge from nests. We detected Northern Raccoons (Procyon lotor) and Striped Skunks (Mephitis mephitis) more frequently than other mammalian nest predators; detections of both species were strongly correlated with observed nest predation events, suggesting that these are the main species responsible for Diamondback Terrapin nest predation at our study site. After various modifications, the electric fence succeeded in excluding raccoons from the nesting area but failed to deter skunks. An increased understanding of the dynamics of terrapin nest predation will contribute meaningfully to effective conservation of this keystone species in Rhode Island, USA, and throughout the range of the Diamondback Terrapin.