Terrestrial habitat requirements of nesting freshwater turtles

Because particular life history traits affect species vulnerability to development pressures, cross-species summaries of life history traits are useful for generating management guidelines. Conservation of aquatic turtles, many members of which are regionally or globally imperiled, requires knowing the extent of upland habitat used for nesting. Therefore, we compiled distances that nests and gravid females had been observed from wetlands. Based on records of \u3e 8000 nests and gravid female records compiled for 31 species in the United States and Canada, the distances that encompass 95% of nests vary dramatically among genera and populations, from just 8 m for Malaclemys to nearly 1400 m for Trachemys. Widths of core areas to encompass varying fractions of nesting populations (based on mean maxima across all genera) were estimated as: 50% coverage = 93 m, 75% = 154 m, 90% = 198 m, 95% = 232 m, 100% = 942 m. Approximately 6–98 m is required to encompass each consecutive 10% segment of a nesting population up to 90% coverage; thereafter, ca. 424 m is required to encompass the remaining 10%. Many genera require modest terrestrial areas (\u3c200 m zones) for 95% nest coverage (Actinemys, Apalone, Chelydra, Chrysemys, Clemmys, Glyptemys, Graptemys, Macrochelys, Malaclemys, Pseudemys, Sternotherus), whereas other genera require larger zones (Deirochelys, Emydoidea, Kinosternon, Trachemys). Our results represent planning targets for conserving sufficient areas of uplands around wetlands to ensure protection of turtle nesting sites, migrating adult female turtles, and dispersing turtle hatchlings

Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa.

Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa

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

An enigmatic mass mortality event of Blanding’s Turtles ( Emydoidea blandingii

Mass mortality events (MMEs) can remove up to 90% of individuals in a population, and are especially damaging to population viability of long-lived species with slow life histories. Our goal was to elucidate the cause(s) of a MME of 53 Blanding’s turtles (Emydoidea blandingii (Holbrook, 1838)), a globally endangered species, in a protected area. We investigated disease, winter-kill, and depredation as potential causes of the mortality. The turtle carcasses lacked soft tissue to test for disease, so we examined tissue from co-occurring live leopard frogs (Lithobates pipiens (Schreber, 1782)) and found no evidence of ranavirus, indicating that the disease was not present at our study site. Water temperature and dissolved aquatic oxygen at known overwintering sites and sites which yielded carcasses did not differ, suggesting that winter-kill did not cause the MME. Carcass condition, comparisons to descriptions of turtle depredation events in the literature, and trail cameras paired with turtle decoys, identified potential predators within the study site, and suggested that mass depredation, enabled by low water levels and a concomitant reduction in aquatic habitat, was the most likely cause of mortality. Our study can inform conservation of the study population and the management of MMEs of long-lived species elsewhere.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