USGS Western Ecological Research Center

Home Who We Are Where We Are What We Do Products Search Outreach Jobs Contacts

Evolutionary dynamics of a rapidly receding southern range boundary in the threatened California Red-Legged Frog (Rana draytonii)

Released: 2013
Citation:
Richmond, JQ, KR Barr, AR Backlin, AG Vandergast, and RN Fisher. 2013. Evolutionary dynamics of a rapidly receding southern range boundary in the threatened California Red-Legged Frog (Rana draytonii). Evolutionary Applications, 6(5): 808-822. doi: 10.1111/eva.12067

Populations forming the edge of a species range are often imperiled by isolation and low genetic diversity, with proximity to human population centers being a major determinant of edge stability in modern landscapes. Since the 1960s, the California red-legged frog (Rana draytonii) has undergone extensive declines in heavily urbanized southern California, where the range edge has rapidly contracted northward while shifting its cardinal orientation to an east-west trending axis. We studied the genetic structure and diversity of these frontline populations, tested for signatures of contemporary disturbance, specifically fire, and attempted to disentangle these signals from demographic events extending deeper into the past. Consistent with the genetic expectations of the ‘abundant-center’ model, we found that diversity, admixture, and opportunity for random mating increases in populations sampled successively further away from the range boundary. Demographic simulations indicate that bottlenecks in peripheral isolates are associated with processes extending tens to a few hundred generations in the past, despite the demographic collapse of some due to recent fire-flood events. While the effects of recent disturbance have left little genetic imprint on these populations, they likely contribute to an extinction debt that will lead to continued range contraction unless management intervenes to stall or reverse the process.

WERC Publication Brief for this Journal Article:
http://www.werc.usgs.gov/ProductDetails.aspx?ID=4890



The following files are related to this product:
Some files associated with this product may require the ability to read Portable Document Format (PDF) documents; the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.
FileFileSize
Richmond et al. 2013.pdf629,523 Bytes


Bookmark and Share

Share


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: webmaster@werc.usgs.gov

References to non-U.S. Department of Interior (DOI) products do not constitute an endorsement by the DOI.

* DOI and USGS link policies apply.