Effects of fire, grazing, and the presence of shrubs on Chihuahuan desert grasslands

TitleEffects of fire, grazing, and the presence of shrubs on Chihuahuan desert grasslands
Publication TypeJournal Article
Year of Publication2001
AuthorsDrewa P.B., Havstad K
JournalJournal of Arid Environments
Date PublishedAugust 1, 2001
Accession NumberJRN00328
ARIS Log Number116274

Responses of herbaceous and suffrutescent species to fire, grazing, and presence of Prosopis glandulosa were examined in a Chihuahuan Desert grassland in south central New Mexico. Treatments were assigned randomly to eight, 12m x 8m plots within each of two blocks. Following fires in June 1995, unfenced plots were exposed to livestock grazing over four years. Plots were established that either included or excluded P. glandulosa. Species cover and frequency were estimated before and after treatments. Perennial grass cover, primarily Bouteloua eriopoda, decreased 13% in burned plots but increased 5% in unburned areas. Conversely, perennial forb cover was 4% greater after fire. Frequency of perennial grasses and forbs decreased 30% more and increased 10% more respectively in burned than unburned areas. Further, species diversity increased 225% more following burning and was attributed to increases in evenness. In general, ,grazing had similar effects as fire, and the presence of P. glandulosa had no effect on responses of non-shrub species. Fires were conducted during near drought conditions while grazing occurred during years of precipitation equivalent to the long-term average. Precipitation immediately following fire may be critical for recovery of B. eriopoda dominated desert grasslands; relationships between fire and post-fire precipitation patterns require future investigation.