PARENT SESSION
Oral Session # 43: A. Insect Ecology I; B. Traditional Ecological Knowledge.
Presiding: E Borer and SP Yanoviak
Wednesday, August 6. 8:00 AM to 11:30 AM, SITCC Meeting Room 105.

Grasshopper abundance and species richness resulting from fire, topography and ungulate grazing in tallgrass prairie.

Joern, Anthony¹, ¹ University of Nebraska-Lincoln, Lincoln, NE, USA

ABSTRACT- How does the abundance and species richness of common insect herbivores respond to fire, topography and large ungulate grazing, major drivers in determining the structure and function of tallgrass prairie? I evaluated grasshopper species (Acrididae) from Konza Prairie to test the habitat heterogeneity hypothesis that predicts species diversity and overall abundance will increase with increased structural heterogeneity and number of plant species. Grasshopper species richness and abundance at Konza Prairie increased in response to grazing by bison, but fire interval and topographic effects had little impact in this study. Habitat structure and heterogeneity were positively related to both grasshopper species richness and overall abundance. However, densities of common individual grasshopper species differed significantly with regard to effects of fire, grazing and topography. Abundances of some species are very responsive to bison grazing, while other species are not. Densities in these latter species reflect responses to fire interval, but in different ways. Clearly, it is important to evaluate responses at both species and community levels to understand the significance of major system drivers in tallgrass prairie to important insect consumers. Results will be discussed with respect to managing tallgrass prairie for promoting insect biodiversity and conservation.

Key words: Grazing, Grasshoppers, Fire, Konza Prairie