Habitat selection, movement, and food preferences of Wood Turtles (Glyptemys insculpta) in an agri-forested landscape

Wood Turtles (Glyptemys insculpta (Le Conte, 1830)) can use agricultural fields for basking and feeding, but hayfields can be an ecological trap due to mortality associated with agricultural machinery. It is unclear if hayfields are selected habitat or simply occur adjacent to used waterways. We sought to investigate Wood Turtle habitat selection at the third- and fourth-order scales in an agri-forested landscape and quantify food abundance (berries, fungi, and gastropods–worms) among habitat types. To quantify habitat selection by Wood Turtles, we radio-tracked 23 adults from May to November of 2018. We measured habitat features at each turtle location and three random sites within 50 m. At the third order, turtles primarily selected for edge habitat and selected hayfields over forest. At the fourth order, turtles selected for low canopy cover and presence of woody debris. Earthworms (suborder Lumbricina) were abundant within hayfields, and berries and fungi were abundant in forests. Turtles abandoned hayfields at the end of July, likely due to the emergence of food within the forest. Food availability likely influences their habitat use during the season, and hayfields provide a food source that entices Wood Turtles during the prime hay harvest period, which likely increases the risk of machinery-related mortality.

Wood Turtle (Glyptemys insculpta) nest protection reduces depredation and increases success, but annual variation influences its effectiveness

Habitat loss is the leading cause of species extinctions and is especially detrimental to habitat specialists. Freshwater turtles require specific habitat types at different points in their life cycle; notably, the loss of nesting habitat has led to increased nest depredation and adult mortality. In response, conservationists have implemented nest protection and habitat restoration programs to recover declining populations. Although assumed to increase nest survival, effectiveness of these methods has not been rigorously quantified. We located Wood Turtle (Glyptemys insculpta (Le Conte, 1830)) nests in Wisconsin (USA) and conducted two analyses — logistic regression and logistic exposure — to investigate the influence of management actions and environmental factors on nest survival. The depredation rate decreased by 47% for protected nests and declined as nests aged; the success rate increased by 28% for protected nests and increased for nests in areas with fewer roads. We found high annual variation in success, and although weather variables were not predictive, likely due to their coarse scale, we posit that this inter-annual variation was driven by variation in weather conditions. Our results suggest that nest protection is effective at increasing nest survival, but future efforts should span multiple years to account for the effects of annual variation in environmental conditions.

Passive transport of Eastern Elliptio (Elliptio complanata) by freshwater turtles in New England

Dispersal of freshwater mussels (order Unionida) is primarily as glochidia on the fins and gills of host fish. Adult mussels are more sessile, generally moving short distances (<2 m/week) along lake and river beds. Between 2007 and 2016, we observed seven instances of adult Eastern Elliptio (Elliptio complanata) and one instance of a fingernail clam (Sphaerium sp.) attached to the feet of freshwater turtles in streams and ponds of New England, United States. Observations included five instances of mussels attached to Wood Turtles (Glyptemys insculpta) in Maine and Massachusetts, one instance of a mussel attached to the fingernail of an Eastern Painted Turtle (Chrysemys picta) in Massachusetts, one instance of a mussel attached to a Snapping Turtle (Chelydra serpentina) in Massachusetts, and one instance of a fingernail clam attached to the fingernail of an Eastern Painted Turtle in Massachusetts. We suggest that Eastern Elliptio may be susceptible to transport by freshwater turtles foraging in mussel beds and that transport of adult mussels by freshwater turtles could result in otherwise atypical long-distance, upstream, or overland dispersal between waterbodies.