| contaminant residues and declines of the cascades frog (rana cascadae) in the california cascades, usa. | populations of cascades frogs (rana cascadae) have declined precipitously in the mount lassen area, but remain abundant in the other half of their california range in the klamath mountains. to evaluate the role of contaminants in cascade frog declines, we sampled sediment and frog tadpole tissue at 31 sites where cascades frogs had disappeared and sites where cascades frogs are still present across the lassen and klamath regions. pacific chorus frogs (pseudacris regilla) were tested and used as ... | 2012 | 22639410 |
| assessing changes in amphibian population dynamics following experimental manipulations of introduced fish. | sport-fish introductions are now recognized as an important cause of amphibian decline, but few researchers have quantified the demographic responses of amphibians to current options in fisheries management designed to minimize effects on sensitive amphibians. demographic analyses with mark-recapture data allow researchers to assess the relative importance of survival, local recruitment, and migration to changes in population densities. i conducted a 4-year, replicated whole-lake experiment in t ... | 2008 | 18680499 |
| 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 |
| the amphibian skin-associated microbiome across species, space and life history stages. | skin-associated bacteria of amphibians are increasingly recognized for their role in defence against pathogens, yet we have little understanding of their basic ecology. here, we use high-throughput 16s rrna gene sequencing to examine the host and environmental influences on the skin microbiota of the cohabiting amphibian species anaxyrus boreas, pseudacris regilla, taricha torosa and lithobates catesbeianus from the central valley in california. we also studied populations of rana cascadae over ... | 2014 | 24171949 |
| correlates of virulence in a frog-killing fungal pathogen: evidence from a california amphibian decline. | the fungal pathogen batrachochytrium dendrobatidis (bd) has caused declines and extinctions in amphibians worldwide, and there is increasing evidence that some strains of this pathogen are more virulent than others. while a number of putative virulence factors have been identified, few studies link these factors to specific epizootic events. we documented a dramatic decline in juvenile frogs in a bd-infected population of cascades frogs (rana cascadae) in the mountains of northern california and ... | 2015 | 25514536 |
| recent emergence of a chytrid fungal pathogen in california cascades frogs (rana cascadae). | the pathogenic fungus batrachochytrium dendrobatidis (bd) has been associated with global amphibian declines, but it is often difficult to discern the relative importance of bd as a causal agent in declines that have already occurred. retrospective analyses of museum specimens have allowed researchers to associate the timing of bd arrival with the timing of past amphibian declines. cascades frogs (rana cascadae) have experienced dramatic declines in northern california, but it is not clear wheth ... | 2017 | 27957606 |