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Translocation, repatriation and relocation of wildlife are increasingly considered as methods in the management of imperiled wildlife populations. Yet, few such efforts have been studied in sufficient detail to understand demographic responses within specific life stages. We used five years of recapture data and Bayesian estimation to assess seasonal survival, movement and growth of Oregon Spotted Frogs (Rana pretiosa) relocated into created ponds at Dilman Meadow in Oregon, USA. We evaluate hypotheses specific to the relocation and elucidate aspects of R. pretiosa life history that are poorly known. The odds of survival of relocated individuals during the first year following relocation were https://0.36 times the survival odds of relocated and non-relocated frogs after one year since the relocation. Survival rate was higher for large frogs. After accounting for frog size, we found little variation in survival between ponds at Dilman Meadow. Survival was lowest for males during the breeding/post-breeding redistribution period, suggesting a high cost of breeding for males. The highest survival rates occurred during winter for both genders, and one small spring was used heavily during winter but was used rarely during the rest of the year. Individual growth was higher in ponds that were not used for breeding, and increased with increasing pond age. Our study supports other evidence that R. pretiosa use different habitats seasonally and are specific in their overwintering habitat requirements. Because frogs were concentrated during winter, predator-free overwintering springs are likely to be of particular value for R. pretiosa populations.

Book chapter that discusses specific limitations to the recovery of boreal toads from population declines in Colorado.

The chemical composition of 97 lakes and ponds in and near the Mount Zirkel Wilderness Area (MZWA) was studied during snowmelt of 1998 and 1999 to determine the magnitude of episodic acidification and the effects of acidification on amphibian reproductive success. Within the areas identified as sensitive to acidification based on granitic bedrock types, there was substantial variability in ANC that was likely related to differences in hydrologic flowpaths that control delivery of weathering products to surface waters. Many of the lakes are sensitive to acidification (summer and fall ANC< 100 eq/l), however, none of them appeared to be immediately threatened by episodic or chronic acidification. 22 ponds had minimum ANC of < 30 ueq/l, indicating that they are extremely sensitive to acidic deposition, however net acidity (ANC < 0) was not measured in any of the ponds. The lowest measured pH value was 5.4 and pH generally remained less than 6.0 throughout early summer in the most sensitive ponds, indicating that biological effects of acidification are possible at levels of atmospheric deposition measured during the study.

The amount, chemical composition, and source of dissolved organic carbon (DOC), together with in situ ultraviolet (UV-B) attenuation, were measured at 1–2 week intervals throughout the summers of 1999, 2000, and 2001 at four sites in Rocky Mountain National Park (Colorado). Eight additional sites, four in Sequoia and Kings Canyon National Park/John Muir Wilderness (California)and four in Glacier National Park (Montana), were sampled during the summer of 2000.

Our objectives in this chapter are to 1) review current information on physical stressors on amphibian population declines, 2)address the roles that changes in the physical environment could play in amphibian declines, 3) make predictions about the effects of physical stressors, and 4) determine what information is needed to evaluate the effects of physical stressors on amphibian populations.

Vernal pools are sensitive environments that provide critical habitats for many species, including amphibians. In 2005 and 2006, water samples were collected from vernal pools and adjacent flowing waters in Parks in Iowa, Washington, D.C., and Maryland, prior to and just after the local use of glyphosate. Results indicate that vernal pools and adjacent streams can be contaminated by the use of herbicides within Parks to control weeds in cropped areas or noxious or nonindigenous plants. Contamination also originates from pesticide use occurring outside Park boundaries.