No abstract

Population-level responses of amphibians to forest management regimes are partly dictated by individual behavioral responses to habitat alteration. We examined the short-term (i.e., 24-hr) habitat choices and movement patterns of 3 amphibian species-southern leopard frogs (Rana sphenocephala), marbled salamanders (Ambystoma opacum), and southern toads (Bufo terrestris)-released on edges between forest habitats and recent clear-cuts in the Upper Coastal Plain of South Carolina, USA. We predicted that adult frogs and salamanders would preferentially select forest using environmental cues as indicators of habitat suitability. We also predicted that movement patterns would differ in clear-cuts relative to forests, resulting in lower habitat permeability of clear-cuts for some or all of the species. Using fluorescent powder tracking, we determined that marbled salamanders selected habitat at random, southern toads preferred clear-cuts, and southern leopard frogs initially selected clear-cuts but ultimately preferred forests. Frogs exhibited long-distance, directional movement with few turns. In contrast, toads exhibited wandering behavior and salamanders moved relatively short distances before locating cover. Southern toads and southern leopard frogs moved farther in forests, and all 3 species made more turns in clear-cuts than in forests. Habitat selection by southern toads did not vary according to body size, sex, or the environmental cues we measured. However, marbled salamanders were more likely to enter clear-cuts when soil moisture was high, and southern leopard frogs were more likely to enter clear-cuts when relative humidity and air temperature were higher in the clear-cut than in adjacent forest. Although we found evidence of reduced habitat permeability of clear-cuts for southern leopard frogs and southern toads, none of the species exhibited strong behavioral avoidance of the small (4-ha) clear-cuts in our study. Further studies of long-term habitat use and the potential physiological and other costs to individuals in altered forests are needed to understand the effects of forest management on population persistence. To reduce potentially detrimental effects of clear-cutting on amphibians in the Southeast, wildlife managers should consider the vagility and behavior of species of concern, especially in relation to the size of planned harvests adjacent to breeding sites.

No abstract

Researchers suggest that several bog turtle (Glyptemys muhlenbergii) populations in North Carolina, USA, are in decline and have few remaining individuals and low annual survival probability. Most populations are dominated by older adults with few juveniles encountered; however, the proportion of juveniles encountered in 2 populations is higher. It is unknown why the juvenile:adult ratio varies among populations. We conducted a nest monitoring study in 2016 and 2017 to test the hypothesis that sites with fewer juvenile encounters would be where nest predation was highest. We documented the fate of 272 eggs from 83 nests encountered across 7 sites in North Carolina. On average 28% of eggs hatched across all sites over both years, but we observed large variation in hatch success among sites. Predation by mesopredators and small mammals was the primary cause of nest failure. The probability of nest predation decreased with greater emergent vegetation density and increased with greater distance to the edge of the wetland. Cooler temperatures, which prolonged incubation and thus increased predation risk, may also hinder recruitment at higher elevation sites. Our observations are consistent with the hypothesis that nest predation would be highest at sites with fewer juvenile encounters. Managers concerned about low bog turtle recruitment rates should consider the role of nest predation and the potential benefits of management that increases hatch rates. © 2020 The Wildlife Society.