Mesquite (genus Prosopis; family Fabaceae) is a thorny, woody shrub or tree that inhabits many arid and semiarid regions around the world. Honey mesquite (P. glandulosa) is native to the Southern Great Plains and is found in central and West Texas, western Oklahoma, and eastern New Mexico. It has increased in density and distribution since the late 1800s. Reasons for the increase are controversial but may include livestock grazing, reduction of fire frequency, climatic change, and increased atmospheric carbon dioxide. Mesquite is widely regarded as a noxious plant because of its interference with livestock production. Control efforts since the 1930s have included herbicide, mechanical, and prescribed fire treatments. Recent research suggests the potential benefits of mesquite if managed as a low-density savanna plant. Such benefits include wildlife habitat, livestock shading, nitrogen fixation, and wood products.
Seedpods of this legume are high in soluble carbohydrates and are consumed by wildlife and domestic livestock. Germination is enhanced by animal ingestion and fecal deposition. Most initial growth is toward taproot development. Potential growth form is fewstemmed and arboreal, but destruction of aboveground tissue stimulates sprouting from meristem at stem bases and causes a multistemmed, thorny growth. Leaves are bipinnately compound, winter-deciduous, and unpalatable; flowering is monoecious.
Mesquite is adapted to a variety of soils and environments and can grow a deep taproot as well as extensive shallow lateral roots. Water use can be phreatophytic (drawing from the water table or just above it), but mesquite will also grow on shallow-water sites and tolerate droughts by minimizing transpiration. Capacity to enrich soil fertility through nitrogen fixation and canopy shading may significantly alter flora beneath canopies. Mesquite may serve as a host plant, facilitating establishment of other plant species. Generally, dense stands of mesquite reduce growth of herbaceous plants. Dense stands are thought to reduce off-site water yield, but no studies have yet verified this.
R. James Ansley Texas Agricultural Experiment Station Vernon, Texas
Brown, J. R., and S. Archer. "Woody Plant Invasion of Grasslands: Establishment of Honey Mesquite (Prosopis glandulosa var. on Sites Differing in Herbaceous Biomass and Grazing History." Oecologia 80 (1989): 19-26.
Simpson, B. B., ed. Mesquite: Its Biology in Two Desert Ecosystems. US/IBP Synthesis Series vol. 4. Stroudsberg,PA: Dowden, Hutchinson, & Ross, Inc., 1977.