Wildlife numbers on excellent and good condition Chihuahuan Desert rangelands: an observation.

Abstract

Information is lacking on the influence of range condition on wildlife populations in the Chihuahuan Desert. Wildlife observations were made along transects on ranges in excellent and good ecological condition in south-central New Mexico (86% and 72% of climax vegetation remaining, respectively). Black grama (Bouteloua eriopoda Torr.) dominated the excellent condition range while the good condition range had a mixture of grasses, forbs, and shrubs. Plant species diversity was greater on the good compared to excellent condition range. Total mammal sightings/km2 during the study period were higher (p<0.05) on the good compared to excellent condition range (October 1991 through October 1992). More species of wildlife were seen on the good compared to excellent condition range. Sightings of important game species (scaled quail, mourning doves, pronghorn, desert cottontails) were higher on the good compared to excellent condition range. Lack of diversity in vegetation composition and structure appear to explain the lower wildlife sightings on the excellent condition range. Results from this study indicate that Chihuahuan Desert ranges in good ecological condition (51-75% of the climax vegetation) will better meet the needs of most wildlife species than ranges in climax or near climax range condition. Research shows grazing intensities that remove on average about 1/3 of current year's growth of key forage species (black grama) are effective in developing and maintaining range in good ecological condition in the Chihuahuan Desert.