My interdisciplinary, collaborative research spans taxa from frogs to grizzly bears. My mixed-methods approaches are aimed at solving a range of conservation challenges.
Foothill yellow-legged frog conservation in northern California
Foothill yellow-legged frogs are an obligate stream-breeding species that are rarely found more than a few meters from water. Native only to California and Oregon, they have declined from over half of their range. Their persistence is closely tied to the natural flow of the rivers on which they depend, and we are finding that additional factors, such as invasive species and disease, may act synergistically to spell trouble for this species. We published a portion of this work in Ecosphere.
Disease Ecology of Amphibians in Baja California, Mexico
Many parts of the world are undersampled for the often-deadly fungal amphibian pathogen, Batrachochytrium dendrobatidis (Bd). We are monitoring a suite of amphibian species throughout different habitats at a range of elevational gradients in Baja California for the fungus, and characterizing trends in its distribution and prevalence in the region. The sampling area is home to an isolated population of U.S. Endangered Species Act-listed California red-legged frogs (Rana draytonii). The first of a series of publications from this work was published in Diseases of Aquatic Organisms.
Collaborators: Anny Peralta-Garcia, Carlos Alberto Flores-López, Jorge H. Valdez Villavicencio, Cherie Briggs
Historical Grizzly Diet in California
Grizzlies are known for their varied, omnivorous diets; however, most of the research on grizzly diets in North America has focused on where the species is extant--in mountainous or boreal regions--places that are very different from California. Led by Alexis Mychajliw at the La Brea Tar Pits, this project uses stable isotope analysis of California grizzly bones archived in natural history museums. Our primary goal is to examine the diet of California grizzlies before they were extirpated from the state nearly 100 years ago, to better understand how reintroduced grizzlies may use the current California landscape nutritionally. This is a subproject of the California Grizzly Research Group at the University of California, Santa Barbara.
Collaborators: Alexis Mychajliw, Kevin Brown, Mark Page, Molly Hardesty-Moore, Peter Alagona, Scott Cooper, Zoe Welch
Detecting DNA from formalin-fixed museum specimens
Optimizing techniques is an essential component underlying ecological research. As new technologies are developed, often well-established protocols are continually used when it is possible to make changes to improve their precision. Museum specimen collections provide indispensable repositories of information that only need to be unlocked with effective technologies and refined methodologies. For this project, I tested various methods of detecting Bd DNA from formalin-fixed specimens using qPCR, and found that DNA extraction method matters--resulting in an improvement of approximately 40% over the most frequently used protocol. The results of this work were published in PLoS ONE.
Collaborators: Kathryn Richards-Hrdlicka, John LaBonte, Morgan Ball, Mary Toothman, Cherie Briggs
Southern California Amphibian Declines
California and western North America are hotspots for endemic biodiversity, and amphibians are no exception. Southern California's Mediterranean climate--characterized by cool, wet winters and warm, dry summers--makes it a unique place to examine amphibian assemblages and their responses to various stressors. Mediterranean streams in particular are highly sensitive to anthropogenic change. Many of the amphibian species native to southern California have declined substantially, but none is more stark than that of the foothill yellow-legged frog (Rana boylii), which went from very abundant to undetectable in a period of less than 10 years. For this project, I combined a series of methodologies from history and ecology, including interviews with experts and sampling of natural history collections, to examine the timing and causes of amphibian declines in southern California, including disease and rapid land use change. Results of this work were published in the journal Ecology and Evolution, and I summarized the project in a blog post.
Collaborators: Allan Pessier, Cherie Briggs