Exploring the impact of dams on genetic diversity in foothill yellow-legged frogs.

. boylii me

Above: Female and male R. boylii on rock; chin photo; Dever with former grad student Ryan Peek in the field at the middle fork of the American River; Dever at Alameda Creek with R. boylii in bag.

NPR QUEST Interview

Project Summary - Due to the overall decline in amphibian species, gathering data on existing populations is critical for their proper management. Both genetic data and a direct assessment of habitat quality will be used to assess Foothill yellow-legged frog (Rana boylii) populations from riverine watersheds in Northern California. Several questions will be addressed by the proposed study, one that is of particular interest is: Is genetic diversity greater in unregulated (without dams) river systems than in regulated (with dams) river systems for R. boylii? To answer this question, genetic diversity among subpopulations is being estimated via mitochondrial DNA and Random Amplified Polymorphic DNA (RAPD) analyses and several habitat parameters are being investigated in an effort to establish any correlations between habitat impacts and genetic diversity. These results will have important conservation applications. The maintenance of genetic diversity is of great concern because it is associated with species survival in the event of changing conditions. Preliminary results suggest a relationship exists between habitat quality and genetic diversity. The proposed study will contribute to our understanding of the specific factors involved in habitat degradation and their relationship to R. boylii declines. Collecting general population data on these and since the Foothill yellow-legged frog is listed as a species of special concern, there is a need for as much information as possible to identify existing and/or emerging problems so wise management decisions can be made.

..............rapd gel

Above: Left - One of three dams that impact the Eel river where R. boylii breeds. Right - a gel photo of RAPD data, A) lanes 1-9 are individuals collected from downstream of the dam on the Eel River; B) lanes 10-18 are individuals collected from the unregulated region of the Eel River, upstream of the dam. Note how much more variation is observable in the RAPD banding patterns for frogs living in the unregulated region (100 bp size standards on outside lanes).

Below: Left - Male R. boylii on rock; Right - One of two dams that impact the Middle Fork American river where R. boylii breeds.

frog dam

Our study sites: Regulated rivers: Middle Fork American, Rubicon; Eel River below Lake Pilsbury.

Unregulated: North Fork American, Middle Fork North Fork American, Eel River above Lake Pilsbury.

Additional Field Photos


Return to Dr. Dever's Home page