Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 20, 2002
Publication Date: February 2, 2003
Citation: BRANSON, D.H. THE EFFECTS OF RANGELAND FIRE ON GRASSHOPPER POPULATIONS AND VEGETATION IN A NORTHERN MIXED GRASS PRAIRIE. SOCIETY FOR RANGE MANAGEMENT MEETING ABSTRACTS. 2003. V. 56. PAPER NUMBER 30. Technical Abstract: Grassland fires have been shown to influence grasshopper community composition and population dynamics, but investigations of its effects on rangeland grasshopper population dynamics in the Northern Great Plains are lacking. Indirect effects of burning on grasshopper population dynamics are likely mediated by fire-induced changes in host plants. We examined the effect of a grassland fire in western North Dakota on grasshopper population dynamics and vegetation; with both pre- and post-fire sampling in paired burned and unburned plots. The rapidly moving fire occurred in late October, after grasshoppers had laid egg pods and died. Grasshopper population densities were significantly higher in unburned plots than in paired burned plots in 2000. In 2001, grasshopper population densities did not differ between burned and unburned plots. Although green vegetation biomass was similar between burned and unburned plots, the crude protein content of vegetation was higher in burned plots. However, the increased crude protein content of vegetation did not translate into higher grasshopper populations during the summer of 2000. Bioavailability of nitrate, as measured by ion exchange resin capsules, was also higher in burned plots during the growing season of 2000. Differences in grasshopper population densities could have resulted from vegetative changes following the fire or from increased egg mortality as a result of elevated soil temperatures during the fire.