Revealing a cryptic life-history stage: differences in habitat selection and survivorship between hatchlings of two turtle species at risk (Glyptemys insculpta and Emydoidea blandingii)

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.