Response to Herbaceous Vegetation to Aeration of a Blackbrush-Guajillo Community

Abstract

Herbaceous vegetation productivity was compared on blackbrush (Acacia rigidula)-guajillo (Acacia berlandien) dominated rangeland sites following mechanical aeration and on adjacent untreated areas. Herbaceous plant biomass was estimated by clipping vegetation in 10.8 ft2 plots. Grass and forb diversity was greater on aerated sites. Grass biomass was more than 4-fold greater on aerated sites than untreated sites. There were no differences in biomass of individual grass and forb species between treatments, with the exception of sida (Sida spp.) which produced greater yields on aerated plots. When grasses were combined into preferential rating classes, grasses of fair forage value produced greater biomass on aerated sites. Beneficial native grasses produced greater biomass and were more commonly encountered on aerated sites. Bristlegrasses (Setaria spp.) were more common on aerated sites. Invasive, introduced species such as Lehmann lovegrass (Eragrostis lehmanniana) showed no treatment effects. When pooled, forbs preferred by white­ tailed deer (Odocoileus virginianus) and cattle such as erect dayflower (Commelina erecta) and Dillens oxalis (Oxalis dillenil) were more common on treated than untreated sites. Grass productivity appears to be adequate to allow the use of pre­ scribed burning as a maintenance tool. To determine the long-term implications of brush management activities, further investigation into the effects of maintenance treatments combined with livestock grazing on herbaceous and woody vegetation is warranted.