Exotic grass invasion and wildlife abundance and diversity, South-Central United States

Abstract

Exotic grasses dominate rangelands in parts of the South-central United States. We reviewed the literature on the effects of exotic grasses on wildlife functional groups and species, and examined the state of the art of managing exotic vegetation in the South-central United States. In cases where researchers reported that exotic grasses reduced wildlife species abundance or diversity, the exotics were dominants in the grassland community. In a few cases, plant communities dominated by exotic grasses appeared to provide desirable habitat for a wildlife species. Giant reed (Arundo donax), for example, provided habitat for white-collared seedeaters (Sporophila torqueola) along the lower Rio Grande. Old World bluestems change soil microbial populations in a manner that inhibits colonization by native grasses. A threshold level of relative exotic grass abundance may exist below which presence of exotic grasses does not affect wildlife. The majority of peer-reviewed literature from the South-central United States on exotic grasses and wildlife is descriptive. Managers should base strategies to manage exotic grasses for wildlife on an understanding of the underlying reasons that certain wildlife species are benefited or negatively impacted by these grasses. © 2013 The Wildlife Society.