Submitted to: Proceedings, XXI International Congress of Entomology
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2004
Publication Date: 10/14/2004
Citation: Branson, D. H. Responses of grasshoppers to livestock grazing: Habitat manipulation by mammalian herbivores. XII International Congress of Entomology. Abstract No. S7F108.
Technical Abstract: Little experimental work has examined the ecological interactions between livestock and grasshopper herbivores, and the effects of differing patterns of herbivory by livestock on grasshopper population dynamics have not been fully examined in western US rangelands. Grasshopper habitat manipulation in the form of livestock herbivory has been shown to impact grasshopper population dynamics. Mammalian herbivory can modify factors important for grasshoppers such as plant species composition, host plant quantity or quality, plant cover and microhabitat conditions. A multi-year cage experiment was conducted to examine how the presence, timing and intensity of sheep herbivory affected grasshopper population dynamics and vegetation. There were few initial treatment differences in grasshopper densities between the timing and intensity of sheep grazing, although grazing affected the biomass and quality of vegetation available for grasshoppers. Grasshopper population densities and community composition were assessed in pasture scale livestock grazing experiments. The results from the pasture scale studies indicate that differences in livestock grazing can affect grasshopper population dynamics, but treatment differences may not be apparent when grasshopper population densities are very low. In addition, habitat differences resulting from livestock herbivory may not occur within a single season.