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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #399045

Research Project: Science and Technologies for the Sustainable Management of Western Rangeland Systems

Location: Range Management Research

Title: Long-term effects of stocking rate, year, and weather on honey mesquite canopy cover and density

item MCINTOSH, MATTHEW - New Mexico State University
item HOLECHEK, J - New Mexico State University
item Spiegal, Sheri
item CIBILS, ANDRES - New Mexico State University
item Estell, Richard - Rick
item STEELE, CAITI - New Mexico State University
item JEON, S - New Mexico State University
item Bestelmeyer, Brandon

Submitted to: Society for Range Management
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/2022
Publication Date: 2/16/2023
Citation: McIntosh, M.M., Holechek, J., Spiegal, S.A., Cibils, A.F., Estell, R.E., Steele, C., Jeon, S., Bestelmeyer, B.T. 2023. Long-term effects of stocking rate, year, and weather on honey mesquite canopy cover and density. Society for Range Management. Abstract.

Interpretive Summary:

Technical Abstract: Abiotic (precipitation, temperature) and biotic (grazing) factors are thought to be important drivers of undesirable woody shrub encroachment in arid rangelands. Woody encroachment has pervaded global rangelands over the past century, but the relative impacts of either grazing or climate are still not fully understood. We sought to evaluate the long-term (25 years; 1995-2019) effects of stocking rate (light: 25-30% and conservative: 35-40%; key forage species use rate), year, and the interaction of stocking rate by year to explore the impacts of grazing and annual weather fluctuations on percent cover and density of honey mesquite (Prosopis glandulosa), a native but invasive shrub, at the Chihuahuan Desert Rangeland Research Center (CDRRC) in southern New Mexico. Precipitation data were collected continuously at the CDRRC; temperature data were collected at the neighboring USDA-ARS Jornada Experimental Range. Drought occurred in 12 of 25 study years and mean ambient summer temperature increased from 15.1 ± 0.15 to 15.4 ± 0.27°C between the first and last 12 years of the study period. We found that stocking rate and the interaction of stocking rate by year had no effect on mesquite percent cover or density (% cover: P = 0.70; density: P = 0.10), although year had a significant effect (% cover: P < 0.01; density: P < 0.01). Mesquite canopy cover increased by 3% from 3.8 to 7.1% cover and mesquite density increased by 175% (P < 0.01) from 284 ± 53 plants*ha to 782.08 ± 35 plants*ha between the last vs first three years of the study. Our preliminary results support a growing body of literature that suggests the overriding effects of climate (increased temperatures and prolonged droughts) will continue to drive undesirable shrub encroachment on Chihuahuan Desert rangelands even when animal stocking rates are kept at historically sustainable levels.