Vegetation and small vertebrates of oak woodlands at low and high risk for sudden oak death in San Luis Obispo County, California.

Abstract

San Luis Obispo County contains oak woodlands at varying levels of risk of sudden oak death (SOD), caused by a fungal pathogen (Phytophthora ramorum) that in the past decade has killed thousands of oak (Quercus spp.) and tanoak (Lithocarpus densiflorus) trees in California. SOD was most recently detected 16 km north of the San Luis Obispo County line. Low-risk woodlands occupy 57 percent of the county's land area, whereas high-risk woodlands occupy only 1 percent. During 2002-2004, we collected data on vegetative structure and small vertebrate (birds, small mammals, amphibians, reptiles) abundance in both types of woodland within the county. One study site was located in low-risk habitat and two in high-risk habitat. The two high-risk sites were similar in terms of vegetative structure and wildlife, while being much different from the low-risk site. Of the 11 vegetation attributes measured, tree density, basal area, canopy cover, coarse woody debris, and litter depth were greater at both high-risk sites (P < 0.05). small mammals and amphibians were more abundant at the high-risk sites (p < 0.05), while birds and reptiles were more abundant at the low-risk site (p < 0.05). species that were notably abundant in high-risk compared to low-risk habitat included the chestnut-backed chickadee (Poecile rufescens), Steller's jay (Cyanocitta stelleri), orange-crowned warbler (Vermivora celata), dusky-footed woodrat (Neotoma fuscipes), brush mouse (Peromyscus boylii), Monterey salamander (Ensatina eschscholtzii eschscholtzii), and slender salamander (Batrachoseps spp.). Due to the scarcity and fragmented distribution of high-risk woodlands within San Luis Obispo County, these wildlife species may be severely impacted if the pathogen reaches the county.

Parent Publication

• Proceedings of the sudden oak death second science symposium: the state of our knowledge

Citation

Tempel, Douglas J.; Tietje, William D.; Winslow, Donald E. 2006. Vegetation and small vertebrates of oak woodlands at low and high risk for sudden oak death in San Luis Obispo County, California. In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 211-232