Potential Effects of Sudden Oak Death on the Small Mammal and Herpetofaunal Communities in San Luis Obispo County Coast Live Oak (Quercus agrifolia) Woodlands

Douglas J. Tempel and William D. Tietje, University of California Cooperative Extension, 2156 Sierra Way, Suite C, San Luis Obispo, CA 93401; (805) 781-5938; dtempel@co.slo.ca.us

Sudden Oak Death has the potential to greatly alter the structure and composition of California oak woodlands. In turn, wildlife communities may be highly impacted by the resulting changes in habitat structure. The pathogen has not yet been detected in San Luis Obispo County, but has recently been detected 10 miles away in Monterey County. To assess the potential impacts of the pathogen in San Luis Obispo County, we surveyed small mammals and herpetofauna at three sites located in coast live oak (Quercus agrifolia) woodlands at high risk of infection; we considered the presence of California bay (Umbellularia californica) to be an indicator of high-risk locations.

We established fifteen, 1.1-ha trapping grids with 8 × 8 dimensions. During 2003-2004 (as well as 2002 at one site), we live-trapped and ear-tagged small mammals twice per year (fall and spring) on each grid, then conducted mark-recapture analyses to estimate species abundance. During January-April of 2003 (as well as 2002 at one site), we surveyed herpetofauna using plywood coverboards; coverboards were checked every 2-3 weeks. We used the number of individuals sighted as an index of species abundance. In addition, we collected data on potentially important habitat elements within each grid—shrub cover, canopy cover, coarse and fine woody debris, tree size and composition, duff and litter layer depth, and woodrat houses. We then developed a priori regression models relating species abundance to habitat structure and selected the best model for each species using AICc values.

Back to Schedule