The Otay Fire of October 2003, simultaneous with the Cedar Fire, burned 46,291 acres in southern San Diego County, including coastal sage scrub within Rancho Jamul Ecological Reserve, managed by the California Department of Fish and Game. Before the fire, Dr. Jay Diffendorfer and his students had sampled rodents and vegetation in sage scrub at 11 plots on the reserve. Nine of these plots burned in the fire; two remained unburned. We are currently studying the recovery of rodents (small mammals) and vegetation on the burned plots and comparing these patterns with those on the two original and two newly established unburned plots.
This study has two unique aspects not shared by our study of chaparral in the Cleveland National Forest: (1) the existence of extensive prefire data for the study plots and (2) plots which, before the fire, spanned a gradient in abundance of exotic plant species . Few studies of postfire recovery have substantial data preceding the fire. Without prefire data, researchers typically trade space for time by sampling burned and unburned locations, assuming that the differences between the burned and unburned sites before the fire was minimal or largely accounted for by environmental factors included in data analyses. Our prefire data eliminate the need for such assumptions and allow us to compare conditions before and after the fire directly. Because our plots encompassed a gradient of vegetation structure (from intact stands of sage scrub dominated by shrubs to stands dominated by exotic herbs), we can examine how the habitat’s condition before the fire influences patterns of recovery after the fire.