The foothill yellow-legged frog, Rana boylii, is a stream-breeding anuran endemic to California and Oregon that has declined precipitously in recent decades. These frogs evolved in creeks and rivers flowing through a diverse set of bio-climatic regions, from relatively cool Pacific Northwest coniferous forests to warm Mediterranean scrub and oak/grassland savannahs of interior foothills of the Sierra Nevada mountains. Thus they have a wide range of temperature tolerance and behavioral adaptations to local conditions. As grazers when tadpoles and insectivores when adults, these frogs are an integral part of algal based food webs in the region's rivers. At present, R. boylii occupies less than half its historic range and absence is significantly correlated with the existence of large dams upstream. Absence is pronounced in the southern half of the range where chytridiomycosis has also been implicated as a historic cause of decline. Dam associated threats include loss of habitat when rivers are converted to lakes, mortality when extreme aseasonal variation in stream flow causes stranding and scouring of early life stages, and predation by non-native species when dam-modified flow conditions allow them to invade and proliferate. This presentation will discuss long-term monitoring and population projection modeling which indicate that recruitment bottlenecks occur when early life stages have high mortality rates due either to natural or anthropogenic causes. Techniques regarding head-starting of tadpoles, along with avoidance and mitigation measures to decrease loss of early life-stages are are under development and will be discussed as approaches to conserve this species. This lecture will also discuss a new tool for addressing ecological genomics questions: restriction site-associated DNA sequencing (RADSeq)
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