|Title||One-Seed Juniper Sapling Use by Goats in Relation to Stocking Density and Mixed Grazing With Sheep|
|Publication Type||Journal Article|
|Year of Publication||2010|
|Authors||Utsumi, SA, Cibils, AF, Estell, RE, Baker, TT, Walker, JW|
To successfully suppress reinvasion of one-seed juniper (Juniper monosperma [Englem.] Sarg.) with goats, defoliation of newly established saplings must be enhanced to levels that eventually kill or suppress plant growth. We tested the effect of stocking density and mixed grazing with sheep as potential grazing strategies to increase utilization of one-seed juniper saplings by goats. In summer and spring, groups of 10 does (Goats alone, GA) or 5 does and 4 ewes (Mixed grazing, MG), grazed 20 x 30 m cells infested with saplings (500-533/ha; 0.8 m tall), either continuously for 6 days (Low stocking density, LD) or with daily rotation through 10x10m cells during the 6 day period (High stocking density, HD) in a block design. Frequency of saplings with light, moderate and heavy bark and foliage use, feeding activity, juniper in feces, and utilization of herbaceous vegetation were determined. Goats in HD treatment spent more time feeding on saplings, less time feeding on herbaceous forages, and tended to achieve diets with more juniper than goats in LD. Utilization of herbaceous vegetation ranged from 52 to 73% and was higher for MG than GA and for LD than HD. The MG-HD treatment resulted in highest frequency of short saplings (< 0.5m) with high percent (> 66%) of defoliated branches in summer and spring, and lowest frequency of saplings with low percent (< 33%) of debarked branches in spring. Heavy defoliation was more frequent in shorter saplings, whereas heavy debarking occurred mostly in tall saplings. The results of this study suggest that stocking density and mixed grazing stimulate feeding behaviors that increase utilization of juniper saplings by goats.