Impacts of emerging infectious disease on wildlife populations have been identified as major drivers to global species declines and extinctions, with considerable conservation efforts focused on mitigating these threats in wild populations. In particular, amphibians have been disproportionately affected by disease. Chytridomycosis, caused by a fungal pathogen Batrachochytrium dendrobatidis (Bd), has been identified as the culprit to collapses of hundreds of amphibian species worldwide. One perennial example of this decline is in the Mountain Yellow-Legged Frog species complex (Rana sierrae and Rana muscosa) (MYLF) that inhabit the high alpine lakes and streams of the Sierra Nevada of California. Having vanished from more than 90% of their historical range within the last few decades, Sequoia-Kings Canyon National Parks (SEKI) contain the largest remaining populations of MYLF categorized by rebounding and severe die-off population dynamics. Subsequently, SEKI is a primary contributor for frog translocations and recovery efforts. However, given limited knowledge of the genetic structure and variation of MYLF, researchers and managers have been restricted in translocations of frogs due to avoiding the introduction of novel genotypes to sub-populations. To address this issue, we developed a population genetic study within SEKI of MYLF that included sampling locations encompassing 48 drainage basins across four major drainages (San Joaquin, Middle Fork Kings, South Fork Kings, and Kern). Using a custom assay, we used genetic material from non-invasive swab samples to sequence 48 genomic regions across 400 swab samples to analyze the distribution of genetic variation across SEKI.
Results/Conclusions:
We were able to successfully produce a swab dataset of 1447 SNPs across the targeted genomic regions. Results concluded that there are three main populations clusters separated by the four major drainages. Middle Fork Kings and South Fork Kings populations showed less genetic discontinuity (FST=0.08), proving ambiguous as compared to previous genetic work which split the species. Middle Fork Kings and San Joaquin had little differentiation across drainages (FST=0.02). Current work is addressing demographic processes such as ongoing rates of gene flow, landscape barriers to gene flow, and historical census sizes among populations to provide information for conservation goals. Finally, we are identifying sub-populations that hold high genetic potential for translocations and anti-fungal treatments to mitigate Bd across MYLF range.