Road avoidance and its energetic consequences for reptiles

Roads are one of the most widespread human-caused habitat modifications that can increase wildlife mortality rates and alter behavior. Roads can act as barriers with variable permeability to movement and can increase distances wildlife travel to access habitats. Movement is energetically costly, and avoidance of roads could therefore impact an animal's energy budget. We tested whether reptiles avoid roads or road crossings and explored whether the energetic consequences of road avoidance decreased individual fitness. Using telemetry data from Blanding's turtles (Emydoidea blandingii; 11,658 locations of 286 turtles from 15 sites) and eastern massasaugas (Sistrurus catenatus; 1,868 locations of 49 snakes from 3 sites), we compared frequency of observed road crossings and use of road-adjacent habitat by reptiles to expected frequencies based on simulated correlated random walks. Turtles and snakes did not avoid habitats near roads, but both species avoided road crossings. Compared with simulations, turtles made fewer crossings of paved roads with low speed limits and more crossings of paved roads with high speed limits. Snakes made fewer crossings of all road types than expected based on simulated paths. Turtles traveled longer daily distances when their home range contained roads, but the predicted energetic cost was negligible: substantially less than the cost of producing one egg. Snakes with roads in their home range did not travel further per day than snakes without roads in their home range. We found that turtles and snakes avoided crossing roads, but road avoidance is unlikely to impact fitness through energetic expenditures. Therefore, mortality from vehicle strikes remains the most significant impact of roads on reptile populations

Body size of ectotherms constrains thermal requirements for reproductive activity in seasonal environments

Body size may influence ectotherm behaviour by influencing heating and cooling rates, thereby constraining the time of day that some individuals can be active. The time of day at which turtles nest, for instance, is hypothesized to vary with body size at both inter- and intra-specific levels because large individuals have greater thermal inertia, retaining preferred body temperatures for a longer period of time. We use decades of data on thousands of individual nests from Algonquin Park, Canada, to explore how body size is associated with nesting behaviour in painted turtles (Chrysemys picta (Schneider, 1783), small bodied) and snapping turtles (Chelydra serpentina (Linnaeus, 1758), large bodied). We found that (1) between species, painted turtles nest earlier in the evening and at higher mean temperatures than snapping turtles, (2) within species, relatively large individuals of both species nest at cooler temperatures, and relatively larger painted turtles nest later in the evening compared to smaller painted turtles. Our data support the thermal inertia hypothesis, and may help explain why turtles in general exhibit geographic clines in body size: northern environments experience more daily variation in temperature, and larger size may evolve, in part, for retention of preferred body temperature during terrestrial forays.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Conservation of herpetofauna in northern landscapes: Threats and challenges from a Canadian perspective

The scientific community is increasingly aware that many amphibian and reptile species have experienced dramatic decreases in abundance and distribution, with at least 43% of amphibian species exhibiting population declines and 19% of all reptile species threatened with extinction since 2000. Species suffer from a suite of threats including habitat destruction, alteration and fragmentation, introduced species, over-exploitation, climate change, UV-B radiation, chemical contaminants, diseases and the synergisms among them. These worldwide threats are also present in northern landscapes and in Canada in particular where 20 amphibian and 37 reptile species are listed as at-risk by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). In fact, with more than 80° in longitude and 40° in latitude, Canada presents both a diversity of northern ecosystems and a range of threats to its herpetofauna at least equal to other countries. The physical scale of Canada, its varied climate, its economic realities, and the legislative differences among levels of government and their respective mandates have long challenged traditional approaches to conservation. However, science and stewardship are leading forces in the conservation of emblematic species at risk in Canada and can serve to inform best practices elsewhere. Recent advances in data analysis and management have transformed our understanding of populations in northern landscapes. Canadian amphibians and reptiles, most of which are cold-adapted species at the northern edge of their distribution, can serve as case studies to improve modeling of population dynamics, create cogent, science-based policies, and prevent further declines of these taxa