Location: Pest Management Research Unit
Title: Effects of fall fire and livestock grazing on grasshopper populations in the Little Missouri National Grassland Authors
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 9, 2007
Publication Date: N/A
Technical Abstract: Habitat management practices such as burning or livestock grazing can influence grasshopper population dynamics and may impact the likelihood of grasshopper outbreaks. A recent study suggests that one form of grazing management can reduce rangeland grasshopper populations in the northern Great Plains. Fire can also affect grasshoppers in numerous ways. No long term replicated studies have examined the separate and interactive effects of fire and grazing on grasshopper population dynamics and vegetation. We sampled grasshopper population densities and community composition in all possible combinations of burning (burn and no-burn) and grazing treatments (twice-over rotational, season-long and no grazing). The 3 replicate blocks in the study were distinct grazing allotments on the USFS Little Missouri National Grassland in western North Dakota. Baseline sampling was conducted at all sites in 2001. Grazing treatments were initiated in the summer of 2002 and burning was conducted in October 2002. Grasshopper population densities were lower in burned plots in the 1st year following burning. Few differences in grasshopper population densities or species composition between grazing treatments were evident between 2002 and 2005. This study was conducted during a period with regionally low grasshopper densities, and the effects of grazing management on grasshopper population dynamics will likely only be evident when grasshopper population densities are increasing. In addition, changes in plant community structure from livestock grazing that might impact grasshopper population dynamics are not likely to occur immediately. Additional long-term studies are needed to examine if grazing management can be used to reduce the likelihood of grasshopper outbreaks.