Submitted to: Society for Range Management Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2003
Publication Date: February 2, 2003
Citation: VERMEIRE, L.T., MITCHELL, R., FUHLENDORF, S.D. PRESCRIBED FIRE EFFECTS ON GRASSHOPPER ASSEMBLAGES IN THE SOUTHERN PLAINS. SOCIETY FOR RANGE MANAGEMENT MEETING PROCEEDINGS. 2003. ABSTRACT #299. Technical Abstract: Grasshoppers (Acrididae) can have profound influences on the flora and fauna of grasslands. Severe outbreaks periodically devastate crops and forage resources. However, grasshoppers provide an important food source for many wildlife species. Given the potential impacts of grasshoppers, it is important to determine how they respond to natural disturbances, such as fire and herbivory. We selected 24, 4-ha plots 1600 m apart and assigned mid-November burn, mid-April burn, or non-burned treatments, to each with 4 replications per treatment for each of 2 years. All sites were exposed to grazing by cow-calf herds from April to September. Grasshoppers were collected with sweep nets in early August, counted, weighed, and identified to species. Species diversity was assessed by richness, evenness, Shannon-Weaver, and Simpson's indices. Total grasshopper abundance and biomass were unaffected by fire. Grasshoppers were less diverse on fall-burned plots. Diversity on spring-burned plots was intermediate and did not differ from non-burned or fall-burned plots. Of the 14 species encountered, 6 were found only on burned plots, and 4 were unique to spring burns. One rare species was unique to non-burned plots. Differences in species observed could not be explained by foraging preferences. Timing of prescribed burns, relative to biological cycles, likely played a greater role. Our results indicate alpha diversity of grasshoppers can be altered with the combined influences of prescribed fire and grazing without reductions in grasshopper abundance or biomass. Beta diversity may be increased by applying various fire treatments across the landscape.