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Habitat degradation or loss, predation by alien species, over-exploitation, climate change, pollution, emerging infectious diseases, and complex interactions among two or more factors are demonstrated or hypothesized causes of amphibian declines. Here, I review the role disease may play in amphibian declines in the GYE, but note that other causes have been identified and may be as important as or more important than disease.

Amphibian life histories are exceedingly sensitive to temperature and precipitation, and there is good evidence that recent climate change has already resulted in a shift to breeding earlier in the year for some species. There are also suggestions that the recent increase in the occurrence of El Niño events has caused declines of anurans in Central America and is linked to elevated mortality of amphibian embryos in the northwestern United States. However, evidence linking amphibian declines in Central America to climate relies solely on correlations, and the mechanisms underlying the declines are not understood. Connections between embryo mortality and declines in abundance have not been demonstrated. Analyses of existing data have generally failed to find a link between climate and amphibian declines. It is likely, however, that future climate change will cause further declines of some amphibian species. Reduced soil moisture could reduce prey species and eliminate habitat. Reduced snowfall and increased summer evaporation could have dramatic effects on the duration or occurrence of seasonal wetlands, which are primary habitat for many species of amphibians. Climate change may be a relatively minor cause of current amphibian declines, but it may be the biggest future challenge to the persistence of many species.

The western toad species complex, endemic to western North America, includes two montane species that have undergone extensive declines. These are the Yosemite toad, Bufo canorus, in the Sierra Nevada, and the southern Rocky Mountain populations of the boreal toad, B. boreas. Most declines in the Rockies appear to have occurred before 1980, but a recent episode in Rocky Mountain National Park illustrates the rapidity and severity with which populations of toads can succumb, and that the phenomenon is still occurring. Causes of these declines with experimental or observational support include increasing ultraviolet radiation, disease, or interactions among several factors. However, significant questions about the generality of each of these hypotheses remain to be answered. Regardless of the cause of past and current declines, climate change in the coming decades may create conditions that will challenge the persistence of these species and others not currently threatened.

Regardless of whether amphibian declines are due to single or multiple causes, conservation efforts in the future will need to consider multiple stressors in most cases.

The breeding phenologies of ectotherms are inextricably linked to weather, and amphibians in some temperate locations may have been breeding earlier in recent years in response to warmer spring temperatures.

Diversity of amphibians varies among wildernesses, from high in the Southeast to low in high-elevation Wilderness Areas and backcountry areas of National Parks in the western United States. Knowledge about the status of amphibians is important, because amphibians occupy important ecological niches and a high proportion of western amphibian species have undergone recent declines, often in protected habitats.

Book Review - The book is written with little technical jargon and should be accessible to any biologically literate, nonprofessional reader. I also recommend this book to professional audiences, including undergraduates and early graduate students who still harbor illusions that science proceeds the way it is described in textbooks

The documented and hypothesized causes of declines in amphibian populations fall into three categories: habitat destruction and alteration. global anthropogenic influences, and natural causes. I will not review all of these in detail because some are the subjects of other chapters in this volume. I will discuss effects of introduced predators and increasing ultraviolet radiation more thoroughly because these factors represent extremes in our ability to explain and possibly reverse declines.

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.