San Diego Natural History Museum--Your Nature Connection[BRCC San Diego Natural History Museum: Herpetology Department]

Birds and Mammals
Post-fire Studies

 -Species Tables
 -Species Graphs
 -Species Groupings
 -Census Routes
     Pines Fire Table
     Pines Fire Map
     Cuyamaca Map
     Cedar Fire Table
     Cedar Fire Map

 -Coastal Sage      Rodents

Field Guide

Phil Unitt
fax: 619.232.0248

Coastal Sage Scrub


Resprouting white sage (Salvia apiana) overtopped by exotic grasses.
Resprouting white sage (Salvia apiana) overtopped by exotic grasses.

Because our study plots span a gradient in abundance of exotic plants, we are able to examine changes in populations of native plants across this gradient before and after fire. The exotic herbs on our study plots, common throughout the range of coastal sage scrub, are well suited to exploit the open ground uncovered by fire or other disturbances. Thus they are expected to return rapidly to their previous abundance or even increase after a fire. Exotic plants, in large numbers, could compete with the resprouting shrubs or seedlings of native plants, as well as with the native herbs that generally flourish following fire, inhibiting native plantsí recovery. Our study will evaluate how quickly exotics return to or increase their former abundance after fire and how this change interacts with native plantsí recovery over time.


Since spring 2002, each plot has been sampled annually. On each plot we established four permanent belt transects of 50 m ◊ 1 m, between and parallel to the trap lines for rodents. During each vegetation survey we (a) count plant species richness within each belt transect; (b) estimate plant cover and height along each transect, using a point-intercept sampling method; and (c) estimate shrub densities (unburned shrubs, resprouting shrubs, and seedlings) within 12 quadrats measuring 1 m2 each along each transect. Within each 1-m2 quadrat we also visually estimate the percentage covered by exotic and native plants and count plant species richness.

Vegetation-sampling transect in burned coastal sage scrub
at Rancho Jamul Ecological Reserve.

We are currently analyzing the data. Results will follow soon.