Effects of large-scale wildfire on carnivores in San Diego County, California

Type: report

Article abstract: We investigated the role of large-scale wildfires on the relative abundance of carnivores at two study areas within San Diego County of southern California, 1) Santa Ysabel Open Space Preserve and 2) Rancho Jamul Ecological Reserve-Hollenbeck Canyon Wildlife Area. In October and November of 2003, large-scale fires burned approximately 130,000 ha of San Diego County. To assess fire impacts on local carnivore communities, we collected data using two sampling techniques, 1) track surveys with baited scent stations and 2) remotely triggered camera stations. Sampling prior to the fires was conducted between May 2001 and June 2003, while post-burn sampling was conducted between August 2006 and September 2007. We calculated the relative abundance of carnivore species for each track transect and camera station, comparing pre-burn and post-burn abundance indices. Fifteen medium to large mammal species were detected across Santa Ysabel and Rancho Jamul at track transects and camera stations. We detected 11 native species including mountain lion (Puma concolor), mule deer (Odocoileus hemionus), coyote (Canis latrans), bobcat (Felis rufus), badger (Taxidea taxus), gray fox (Urocyon cinereoargenteus), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), spotted skunk (Spilogale gracilis), opossum (Didelphis virginiana), and long-tailed weasel (Mustela frenata). We also detected four species typically associated with humans including, domestic cow (Bos taurus), domestic horse (Equus caballus), domestic dog (Canis familiaris), and domestic cat (Felis catus). Ten of the native species (badger excluded) and two human-associated species (domestic horse and domestic dog) were documented within both study sites. Within Santa Ysabel and Rancho Jamul, we found little evidence that the 2003 wildfires affected the relative abundance of the carnivore species for which we gathered sufficient data. Most of the species we studied seemed capable of persisting in the patchwork of unburned and burned habitats resulting from these wildfires. In addition, the effects of the fires were likely short term for most carnivore species. We did not begin post-burn monitoring until nearly three years after the wildfires of 2003, by which time we likely missed the more dramatic immediate responses to wildfire. Overall, we suspect the indirect effects of wildfires, such as changes in habitat suitability and predator-prey dynamics, were largely responsible for the mi

Number of pages: 41

Authors: Turschak, Greta; Rochester, Carlton; Hathaway, Stacie; Stokes, Drew; Haas, Chris; Fisher, Robert N.;

Year: 2010

Prepared for: Sarah, Pierce;

Prepared by: U.S. Geological Survey, Western Ecological Research Center;

Keywords: carnivores; Hollenbeck Canyon Wildlife Area; Rancho Jamul Ecological Reserve; Santa Ysabel Ranch Open Space Preserve; wildfires;

Species: American badger; Mountain lion; California bobcat; Southern mule deer