Mixed-Brush Reestablishment Following Herbicide Treatment in the Davis Mountains, West Texas

Abstract

Regeneration of Mimosa biuncifera (catclaw mimosa), Acacia greggii (catclaw acacia), and associated vegetation was assessed in the following application of the herbicide tebuthiuron (1.7 kg a.i. ha-1) in the Davis Mountains, Texas. Density and foliar cover of shrubs, foliar cover of herabceous vegetation, and presence of catclaw seed banks were assessed on herbicide-treated and untreated control sites. Tebuthiuron did not completely kill catclaw shrubes, nor did it prevent shrub regeneration within six years of treatment. Regrwoth occurred from basal crowns, aerial stem sprouts, and seedling of both species. Aloysia gratissima and A. wrightii (whitebrush) were effectively eliminated by herbicide treatment and showed no indication of regeneration on treated sites. Within the herbicide treatment, Aristida sp. (perennial threeawn) and Bouteloua curtipendula (sideoats grama) had higher foliar cover, perhaps in response to shrub reductions. Catclaw seeds were not detected in the seed bank, although seedlings did emerge on treated sites, suggesting a transient seed pool. Although tebuthiuron treatment empacted vegetation composition and abundance, significant potential remains for mixed-brush communities to dominate these sites.