The influence of invasive Lehmann lovegrass on two native grasses in the semi-desert grassland

Abstract

This study evaluated the influence of Lehmann lovegrass (Eragrostis lehmanniana Nees) on the densities and spatial distributions relative to mesquite (Prosopis velutina Woot.) of two native grasses, Arizona cottontop (Digitaria californica (Benth.) Henr.) and Rothrock grama (Bouteloua rothrockii Vasey), in the semi-desert grassland. Also evaluated were the affects of independent variables range site, elevation, and proportion mesquite cover on these relationships. General Linear Model analyses showed no association between Lehmann lovegrass and either the densities or the distributions of the native species. Arizona cottontop showed an affinity for mesquite cover, while Rothrock grama and Lehmann lovegrass both showed an aversion to mesquite canopy. The relationship of Rothrock grama to mesquite cover was affected by range site. The relationship of Lehmann lovegrass to mesquite cover became less averse with increasing elevation and as its density increased. These results contradict suggestions that Lehmann lovegrass is associated with declines in native grasses.