Great Basin Naturalist


Plant species richness, density, and frequency were quantitatively examined within Pogonomyrmex rugosus (seed-harvester ant) nest discs and at various distances from nest discs in a Larrea tridentata–Ambrosia dumosa (creosote bush–white bursage) shrubland in southern Nevada. Woody vegetation at and near the edge (perimeter) of nest discs showed decreased species richness, density, and frequency compared with vegetation in adjacent reference areas (nonnest; 4 m beyond discs). Four of 17 species were found with significantly lower density and frequency on nest discs than at greater distances from the nest. Thirteen of 17 species were not found on nest discs at all. Species richness, density, and frequency were significantly and negatively correlated with distance from nests. Woody vegetation was sparse and less variable in composition when occurring at discs and edges of discs. Local disturbances caused by P. rugosus nests may largely alter immediate surrounding vegetation in the L. tridentata–A. dumosa shrubland of southern Nevada.