Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/29/2000
Publication Date: 1/1/2001
Citation: DREWA, P.B., PETERS, D.C., HAVSTAD, K.M. FIRE, GRAZING AND HONEY MESQUITE INVASION IN BLACK GRAMA-DOMINATED GRASSLANDS OF THE CHIHUAHUAN DESERT: A SYNTHESIS. PROCEEDINGS OF THE INVASIVE SPECIES WORKSHOP: THE ROLE OF FIRE IN THE CONTROL AND SPREAD OF INVASIVE SPECIES. FIRE CONFERENCE 2000: THE FIRST NATIONAL CONGRESS ON FIRE ECOLOGY, PREVENTION, AND MANAGEMENT. 2001. PUBLICATION NO. 11. P. 31-39. Interpretive Summary: Interpretive summary not required.
Technical Abstract: Prior to European settlement, the Chihuahuan Desert was partly comprised of grasslands dominated by the perennial grass, black grama (Bouteloua eriopoda), as well as by other species of herbaceous vegetation. Honey mesquite (Prosopis glandulosa) was mostly abundant in adjacent lower lying areas of water runoff and intermittent streambeds. Since the late 19th century, however, cattle have been directly responsible for increased abundances and expanded distributions of honey mesquite through consumption and dissemination of seed. Additionally, a period of overgrazing and interactive effects with other factors, such as drought and small mammal herbivory, resulted in reduced abundances of black grama. As a result of decreased fuel abundance, lightning-initiated fires that likely occurred just prior and throughout the growing season have decreased in size, intensity, and frequency. Despite reductions in herbaceous fuels following gEuropean settlement, we hypothesize that fire remains effective in topkilling shrubs of honey mesquite and, in so doing, may directly interfere with its development toward reproductive maturity and its ability to set seed. Based on information from the literature and results from our research, complete kill of honey mesquite is rare. However, fire is effective in topkilling and returning shrubs to an immature life history stage. Fire remains an effective deterrent in slowing honey mesquite invasion. However, the recurrence of fire is highly contingent on the degree and rate of black grama recovery that may be determined by the timing and amount of precipitation immediately following fires, as well as the degree of livestock grazing.