Skills and Expertise
Research Items (6)
Diamond-backed Terrapin (Malaclemys terrapin) nests are susceptible to predation by a variety of meso-predators, predominately Raccoons (Procyon lotor). The Downing-Musgrove Causeway (DMC) leading to Jekyll Island, Georgia, USA, is a hot spot for nesting Diamond-backed Terrapins with road mortality and nest predation driving population declines. We designed and constructed artificial nest mounds with protective nest boxes to intercept female terrapins prior to accessing the causeway while simultaneously providing nest security from predators. Initial data indicated that terrapins nested on constructed nest mounds, but that predators were accessing nests within the boxes. In 2013, we used a battery and solar panel to electrify antipredator wiring that was placed along the entrances of connected nest boxes. We used time-lapse photography from wildlife cameras to document nesting terrapins and to estimate nest predation rates. We compared nest predation rates of electrified nest boxes to those without. Only one nest out of 27 was depredated in boxes with an electric wire. Conversely, 100% of known nests were depredated when no electric wire was present. We excavated nest boxes in autumn and/or spring and found high rates of egg survivorship and hatching success. The results of this study suggest that artificial nesting mounds can be used to promote recruitment of terrapins by protecting nests at local hotspots so long as proper defenses are in place.
Typhlops tasymicris was known previously from only two specimens, both immature females collected on Grenada in 1968. In June 2010, we rediscovered the species on Union Island, St. Vincent and the Grenadines, where we encountered five individuals (and captured four) on the forested slopes above Chatham Bay. The new specimens agree closely with the two previously reported individuals for all scale characters and coloration, but they differ in sizes and proportions. At least two of the new specimens are adults, but all seem to be females. This first record of a typhlopid snake in the Grenadines suggests a greater range than indicated by the earlier specimens. Although suitable habitat occurs nowhere else on Union Island, the species could occur elsewhere in the Grenadines where relatively mature forests persist. DNA sequence data clearly show a closer affinity with South American species than with any West Indian congeners.
Union Island, St. Vincent and the Grenadines (8.4 km2) has an unusually diverse reptilian fauna for such a small area, but lacks native or well-established introduced amphibians. In June 2010, we conducted a rapid assessment of 10 sites (coastal or with some variation of dry forest habitats) chosen on the basis of vegetative complexity, height and extent of canopy, and degree of human disturbance. We encountered 10 of the 15 species recorded from Union, missing only a few secretive litter-dwelling or fossorial forms and a recently introduced species for which the current status is unknown. Shannon-Weiner indices of diversity were negatively correlated with vegetative complexity, but the density of Anolis aeneus, the most frequently encountered species, was positively correlated with complexity. We supplemented the rapid assessment with visual surveys for Corallus grenadensis, an arboreal boid, smaller individuals of which feed largely on anoles. Encounter rates for C. grenadensis were not correlated with anoline densities, which we attribute to the relative paucity of both snakes and their prey on a small, dry island.