We evaluated the effects of a lightning-initiated fire on resprouting responses of perennial grasses at the population level. Following a fire in July 1998, 25 experimental plots were established on the eastern edge of MacKenzie Flats at the Sevilleta National Wildlife Refuge. Ten of these plots were located in a Bouteloua gracilis (blue grama)-dominated site, while 15 were established in an area dominated by Bouteloua eriopoda (black grama). We evaluated basal cover of perennial grasses in systematically positioned quadrats (subsamples) within plots immediately after the fire (last week of July 1998), and in September-October 2001.
Experimental Design - Following a lightning-initiated fire in July 1998, 25 experimental plots were established on the eastern edge of MacKenzie Flats at the Sevilleta National Wildlife Refuge. Ten of these plots were located in a Bouteloua gracilis (blue grama)-dominated site, and 15 were established in an area dominated by Bouteloua eriopoda (black grama). In the former site, five of the 10 plots were established in burned areas, and the others were positioned in unburned grassland. In the latter study area, five plots were placed in burned areas, five were positioned in unburned grasslands, and the five remaining plots were located in an area that contained a mix of burned and unburned grassland vegetation.
Sampling Design - All of the plots in the Bouteloua gracilis- dominated site were 4 m x 16 m. Of the 25 plots where B. eriopoda was dominant, nine were 4 m x 16 m, and 16 were 4 m x 25 m. Regardless of site, all plots were oriented such that the long axis of each was parallel to a topographic gradient that ran east-west.
We sampled vegetation responses on two separate occasions. An initial sample was conducted immediately after the fire during the last week of July 1998, and a final sample was conducted in September-October of 2001. During each of the two sample periods, we collected data from three permanent 1 m x 1 m quadrats at the two corners and the midpoint along the north side of each plot.
Field Methods - Within each quadrat, all perennial grass clumps were identified to species and two perpendicular measurements of diameter/basal cover taken. (The first measurement was taken across the widest part of the grass clump, and the second measurement was taken perpendicular to the first.) Also, we estimated the proportion of live (i.e., green) foliage associated with each grass clump.
These metadata were supplied by Sandra Albro Rutter (firstname.lastname@example.org) and Paul Drew from Case Western University. The data are presently in an Excel file, not available to the public. The data were originally in a Word document.-- KLV