No abstract

Context Turtles are one of the most imperilled taxonomic groups worldwide and information about population ecology is essential to species recovery. Although the spatial ecology and demography of adults of several turtle species have been well studied, little is known about early life stages. The small size, soft shell, and limited mobility of hatchling turtles may cause differences in survivorship and habitat selection compared with adults. Aims We tested the hypothesis that hatchling turtles select habitat as they move away from nests, so as to reduce the risk of predation and desiccation. Methods We examined survivorship, behaviour and habitat selection at two spatial scales in hatchling Blanding’s turtles (Emydoidea blandingii) and wood turtles (Glyptemys insculpta) in 2009 and 2010, using radio-telemetry in Algonquin Provincial Park, Ontario, Canada. In addition, temperatures of sites used by hatchlings during winter were compared with those at haphazard stations in various habitats. Key results The mortality rate was high, with 42% of E. blandingii and 11% of G. insculpta hatchlings surviving to winter; most mortality was caused by predation. Most behavioural observations for both species were of individuals hiding under cover. Both species showed evidence of macrohabitat and microhabitat selection as they dispersed from nests towards overwintering sites, and important variables in the models differed between species. Likewise, the adult stages of these two species differ in their macrohabitat specialisation. There was also evidence that hatchlings chose overwintering sites on the basis of temperature. Conclusions Despite significant differences in survivorship between hatchlings and adults, resource selection was similar between these two demographic stages, and conservation plans based on adult habitat use should simultaneously protect hatchlings. Implications Understanding habitat selection by juveniles is important for testing hypotheses about ontogenetic shifts in resource selection and for protecting habitat for species at risk.

Many animals that live in northern climates enter a state of prolonged dormancy during winter. These animals possess a suite of physiological and behavioural adaptations that minimize threats to survival while overwintering. There are three major threats to overwintering survival: metabolic and respiratory acidosis, freezing, and predation. Selection of hibernation sites should minimize these threats. We monitored dissolved oxygen, water depth, and temperature at overwintering locations of Blanding’s Turtles ( Emydoidea blandingii (Holbrook, 1838)) and at stations located haphazardly in six different habitat types over two winters in Algonquin Park, Ontario, Canada. Water depth and dissolved oxygen in overwintering sites used by turtles were similar to those measured at haphazard stations. In contrast, estimated turtle body temperatures (~0 °C) were significantly lower and less variable than water temperatures measured at haphazard stations. These data and those reported elsewhere suggest that there are two alternatives for selection of suitable hibernacula by anoxia tolerant turtles. In areas where there is periodic access to aerial oxygen, turtles select sites where ice cover may not be present for the entire winter, but in areas where ice cover restricts access to air, turtles select sites where water temperatures are close to 0 °C.