Linking the Distribution of an Invasive Amphibian (Rana catesbeiana) to Habitat Conditions in a Managed River System in Northern California

Linking the Distribution of an Invasive Amphibian (Rana catesbeiana) to Habitat Conditions in a Managed River System in Northern California
Terra E. Fuller1,2,*, Karen L. Pope1, Donald T. Ashton1, Hartwell H. Welsh Jr.1
Article first published online: 14 JUL 2010
2010 Society for Ecological Restoration International. Published 2010. This article is a US Government work and is in the public domain in the USA
Restoration Ecology, Volume 19, Issue 201, Pages 204-213 March 2011
How to Cite
Fuller, T. E., Pope, K. L., Ashton, D. T. and Welsh, H. H. (2011), Linking the Distribution of an Invasive Amphibian (Rana catesbeiana) to Habitat Conditions in a Managed River System in Northern California. Restoration Ecology, 19: 204-213. doi: 10.1111/j.1526-100X.2010.00708.x
Author Information
1 USDA Forest Service, Pacific Southwest Experiment Station, Redwood Sciences Laboratory, 1700 Bayview Dr., Arcata, CA 95521, U.S.A.
2 Department of Wildlife, Humboldt State University, Arcata, CA 95521, U.S.A.
*Correspondence: Terra E. Fuller,
*Correspondence: T. E. Fuller, email tfuller@dfg.ca.gov
Publication History
Issue published online: 2 MAR 2011
Article first published online: 14 JUL 2010

Abstract
Extensive modifications of river systems have left floodplains some of the most endangered ecosystems in the world and made restoration of these systems a priority. Modified river ecosystems frequently support invasive species to the detriment of native species. Rana catesbeiana (American bullfrog) is an invasive amphibian that thrives in modified aquatic habitats. In 2004-2005 we studied the distribution of bullfrogs along a 98-km reach of the Trinity River below the Lewiston Dam to identify habitat characteristics associated with bullfrogs and to recommend actions to reduce their prevalence in the system. We also examined native amphibian distributions relative to bullfrogs and disturbance regimes. We used regression techniques to model the distribution of bullfrogs in relation to environmental conditions. Models assessing breeding habitat outperformed models assessing bullfrog presence. Top-ranked predictor variables of bullfrog distribution included water depth, percent !
rooted floating vegetation, and river km. Most breeding sites of bullfrogs were relict mine tailing ponds or inactive side channels created during restoration activities in the 1990s. Native species were more common in the lower reach where habitats were less modified, in contrast to the distribution of bullfrogs that dominated the upper, more modified reach. To control bullfrogs along a managed river, we suggest reducing the suitability of breeding sites by decreasing depth or reducing hydroperiod and increasing connection with the active river channel. Current management goals of restoring salmonid habitat and returning the river to a more natural hydrologic condition should aid in control of bullfrogs and improve conditions for native amphibians.