Effects Of Livestock Grazing On Vegetation And Ground Beetles (Coleoptera, Carabidae) In A Semi-Arid Grassland

Abstract

Cattle grazing plays an important role in the structure and function of many grasslands in the western United States. This is particularly true of the semi-arid grasslands of the southwest where limited soil moisture hinders the ability of vegetation to recover following a disturbance. In these systems, grazing often impacts a wide variety of variables such as soil moisture, soil compaction, soil erosion, rate of woody plant invasion, and plant species composition. In addition to soils and vegetation, vertebrate and invertebrate grassland species are also affected as grazing alters their resource base. Grassland invertebrates in particular are highly responsive to changes in their immediate environment, making them potential indicators of changes in the environment due to grazing. Ground beetles (Coleoptera, Carabidae) have been studied as a group of insects that may reflect changes in the environment in a synergistic manner. Ground beetles therefore, may serve as indicators of a variety of changes due to livestock grazing in the semi-arid grasslands of the southwestern United States. This review provides a framework for the following two chapters. The second chapter presents the results of the vegetation analysis portion of this thesis and the third chapter presents the results of ground beetle sampling.