Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2016
Publication Date: 4/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62325
Citation: Estell, R.E., Anderson, D.M., James, D.K. 2016. Defoliation of Flourensia cernua (tarbush) with high-density mixed-species stocking. Journal of Arid Environments. 130:62-67.
Interpretive Summary: Encroachment of woody plant species such as tarbush into grasslands is a concern for livestock producers and land managers. A study was conducted to determine the efficacy of using mixed-species stocking with cattle, sheep, and goats at high stocking rates to browse tarbush infested rangeland for short intervals. Cumulative tarbush defoliation averaged more than 70% both years. Individual shrubs varied between 0 and 100% defoliation, suggesting significant variation in palatability among individual tarbush plants. Small ruminants were able to successfully browse tarbush for short intervals, although cattle would generally not consume tarbush and had to be removed after herbaceous forage was gone.
Technical Abstract: Interest in shrub use by livestock is increasing along with the rising demands placed on rangelands worldwide. Historically, Flourensia cernua (tarbush) has increased in the Chihuahuan Desert but receives limited use by cattle. Cattle, sheep and goats co-grazed eight 0.6 ha tarbush-dominated paddocks during two periods for up to nine days during two consecutive years. Cumulative tarbush defoliation across periods and years averaged 75.6%, with a mean increase of 9.3%/day (P < 0.0001). Defoliation of individual shrubs varied from 5 to 99% in 1989 and 0 - 100% in 1990, indicating highly variable palatability among individual plants. Sheep lost 2.3 - 5.5 kg/hd (P < 0.0001) across periods and years when forced to browse tarbush. In 1989, goats gained (P . 0.0345) 0.6 kg/hd in period 1, but the gain in period 2 was not significant (P . 0.2934). During 1990, goats lost 3.1 kg/hd (P . 0.0001) across periods. High-density mixed-species stocking of small areas for short time periods resulted in extensive tarbush use, primarily due to browsing by sheep and goats. Targeted use of tarbush for short time intervals may increase use of this highly nutritious forage and potentially serve as a form of biocontrol for this shrub.