Effects of fire on kangaroo rats in the San Joaquin Desert of California

Fire can alter ecological communities, particularly those that are not fire-adapted, such as desert communities. We examined the effects of fire on rodent communities in the San Joaquin Desert of central California. Of particular interest were the effects on kangaroo rats (Dipodomys spp.) including 2 rare species, the giant kangaroo rat (D. ingens) and the short-nosed kangaroo rat (D. nitratoides brevinasus). Lightning caused multiple fires in arid scrub habitat in western Kern County in 1993. We trapped rodents at 7 sites along paired transects, with one transect in a burned area and one in a nearby unburned area. We conducted 5 trapping sessions from July 1993 to November 1995. Kangaroo rat abundance trends were similar between burn and control transects across the sessions. We also compared abundance of giant kangaroo rats between a trapping grid in an area subjected to controlled burning and a grid in a nearby unburned area on the Carrizo Plain in eastern San Luis Obispo County. Abundance trends were similar between the burned and unburned grids, although kangaroo rat numbers were maintained on the burn site over several sessions compared to the unburned site. We did not detect any adverse effects to kangaroo rat abundance from fire in the 2 study areas. Sheltering in burrows and storing seed underground may mitigate the effects of fire on kangaroo rats. Also, fire may actually benefit kangaroo rats by reducing groundcover density, thereby improving their mobility and predator detection. We do not recommend fire as a management strategy, however, because burning may adversely impact other species, kill shrubs, and erode air quality in a region where the air is chronically polluted.