| pesticide distributions and population declines of california, usa, alpine frogs, rana muscosa and rana sierrae. | atmospherically deposited pesticides from the intensively cultivated central valley of california, usa, have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the frogs rana muscosa and rana sierrae at high elevation in the sierra nevada mountains. previous studies on these species have relied on correlations between frog population status and either a metric for amount of upwind pesticide use or limited measurements of pesticide con ... | 2011 | 21298712 |
| pesticides in mountain yellow-legged frogs (rana muscosa) from the sierra nevada mountains of california, usa. | in 1997, pesticide concentrations were measured in mountain yellow-legged frogs (rana muscosa) from two areas in the sierra nevada mountains of california, usa. one area (sixty lakes basin, kings canyon national park) had large, apparently healthy populations of frogs. a second area (tablelands, sequoia national park) once had large populations, but the species had been extirpated from this area by the early 1980s. the tablelands is exposed directly to prevailing winds from agricultural regions ... | 2004 | 15378994 |
| multiple stressors and amphibian declines: dual impacts of pesticides and fish on yellow-legged frogs. | more than 40% of earth's 5700+ amphibian species have undergone recent declines. despite the likely involvement of multiple factors in driving these declines, most studies continue to focus on single stressors. in california (usa), separate studies have implicated either introduced fish or pesticides as causal agents. to date, however, no study has simultaneously evaluated the respective roles of these two potential stressors nor attempted to assess their relative importance, information critica ... | 2007 | 17489262 |
| pathophysiology in mountain yellow-legged frogs (rana muscosa) during a chytridiomycosis outbreak. | the disease chytridiomycosis is responsible for declines and extirpations of amphibians worldwide. chytridiomycosis is caused by a fungal pathogen (batrachochytrium dendrobatidis) that infects amphibian skin. although we have a basic understanding of the pathophysiology from laboratory experiments, many mechanistic details remain unresolved and it is unknown if disease development is similar in wild amphibian populations. to gain a better understanding of chytridiomycosis pathophysiology in wild ... | 2012 | 22558145 |
| enzootic and epizootic dynamics of the chytrid fungal pathogen of amphibians. | chytridiomycosis, the disease caused by the chytrid fungus, batrachochytrium dendrobatidis (bd), has contributed to amphibian population declines and extinctions worldwide. the impact of this pathogen, however, varies markedly among amphibian species and populations. following invasion into some areas of california's sierra nevada, bd leads to rapid declines and local extinctions of frog populations (rana muscosa, r. sierrae). in other areas, infected populations of the same frog species have de ... | 2010 | 20457916 |
| introduced trout sever trophic connections in watersheds: consequences for a declining amphibian. | trophic linkages between terrestrial and aquatic ecosystems are increasingly recognized as important yet poorly known features of food webs. here we describe research to understand the dynamics of lake food webs in relation to a native riparian amphibian and its interaction with introduced trout. the mountain yellow-legged frog rana muscosa is endemic to alpine watersheds of the sierra nevada mountains and the transverse ranges of california, but it has declined to a small fraction of its histor ... | 2007 | 17918397 |
| pesticides are involved with population declines of amphibians in the california sierra nevadas. | several species of frogs and toads are in serious decline in the sierra nevada mountains of california. these species include the threatened red-legged frog ( rana aurora ), foothill yellow-legged frog ( r. boylii ), mountain yellow-legged frog ( r. muscosa ), cascades frog ( rana cascadae ), western toad ( bufo boreas ) and yosemite toad ( b. canorus ). for many of these species current distributions are down to 10% of historical ranges. several factors including introduced predators, habitat l ... | 2001 | 12805670 |