Because recovery of the vegetation will be critical to the patterns of recovery seen among mammals we are also monitoring postfire recovery of plants. Typically, recovery of chaparral includes resprouting of some shrubs from underground root stocks and the emergence of new individuals from seeds surviving in the soil or produced by the resprouting individuals. Herbs may be particularly abundant in the first few years after fire, declining thereafter. This typical pattern, however, may vary in with the fire’s severity (e.g., Moreno and Oechel 1994), and this variation may affect mammals’ recovery.
We survey vegetation each spring on the 40 plots used for rodent surveys. On each plot we established two permanent 100 m × 1 m belt transects parallel to and 5 m away from the trap lines for rodents. During each vegetation survey we estimate (a) number of plant species (species richness) within each belt transect; (b) plant cover and height along each transect, using a point-intercept sampling method; and (c) density of resprouted shrubs and seedling within ten 1-m2 quadrats along each transect. Within each 1-m2 quadrat we also visually estimate the percentage of the quadrat covered by plants within 10 cm of the ground surface and the vertical density of vegetation to assess the relative “openness” of the habitat from the perspective of rodents.
During the first sampling period in spring 2005, we measured the smallest remaining stems of burned chamise (Adenostoma fasciculatum) to quantify the fire’s severity on each plot (Keeley 1998; Moreno and Oechel 1989). We also noted the presence of possible refugia from the fire, such as large boulders or riparian areas, on or near each plot and collected soil samples to determine soil texture.