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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #250926
Title: Plant Community and Soil Environment Response to Summer Fire in the Northern Great Plains

Author
item Vermeire, Lance
item CROWDER, JESSICA - State Of Wyoming
item WESTER, DAVID - Texas Tech University

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2010
Publication Date: 1/24/2011
Citation: Vermeire, L.T., Crowder, J.L., Wester, D.B. 2011. Plant Community and Soil Environment Response to Summer Fire in the Northern Great Plains. Rangeland Ecology and Management. 64:37-46.

Interpretive Summary: Fire is a keystone process in many ecosystems, especially grasslands. However, documentation of plant community and soil environment responses to fire is limited for semiarid grasslands relative to that for mesic grasslands. Replicated summer fire research is lacking, but much needed because summer is the natural fire season and the period of most wildfires in the western U.S. We evaluated summer fire effects on soil temperature, soil moisture, aboveground biomass, root biomass and functional group composition for two years in semiarid cool-season grass-dominated northern Great Plains. Following pre-treatment measures, four 1.9-ac sites were burned during August for comparison with non-burned sites and the experiment was repeated the next year on adjacent sites to assess weather effects. Soils were about 0.9oF cooler on burned sites in the first experiment and similar in the second. Burned sites were consistently 1% drier than non-burned sites. Litter was reduced by fire, but did not account for changes in soil moisture because differences occurred before the growing season. Current-year aboveground biomass and root biomass were similar between treatments, indicating productivity was resistant to summer fire. Perennial cool-season grasses increased in dominance with positive biomass responses to fire for all but the bunchgrass, needle-and-thread, and a reduction of annual grasses. Perennial warm-season grasses were unaffected by summer fire. Needle-and-thread was resilient, with biomass on burned sites equaling non-burned sites the second growing season. Biomass was more responsive to precipitation than fire and the fire-induced changes in species composition suggest exclusion of fire may be a greater disturbance than summer fire.

Technical Abstract: Fire is a keystone process in many ecosystems, especially grasslands. However, documentation of plant community and soil environment responses to fire is limited for semiarid grasslands relative to that for mesic grasslands. Replicated summer fire research is lacking, but much needed because summer is the natural fire season and the period of most wildfires in the western U.S. We evaluated summer fire effects on soil temperature, soil moisture, aboveground biomass, root biomass and functional group composition for two years in semiarid C3-dominated northern Great Plains. Following pre-treatment measures, four 0.75-ha sites were burned during August for comparison with non-burned sites and the experiment was repeated the next year on adjacent sites to assess weather effects. Soils were about 0.5oC cooler on burned sites in the first experiment and similar in the second. Burned sites were consistently 1% drier than non-burned sites. Litter was reduced by fire, but did not account for changes in soil moisture because differences occurred before the growing season. Current-year aboveground biomass and root biomass were similar between treatments, indicating productivity was resistant to summer fire. Perennial C3 grasses increased in dominance with positive biomass responses to fire for all but the bunchgrass, Hesperostipa comata, and a reduction of annual grasses. Perennial C4 grasses were unaffected by summer fire. H. comata was resilient, with biomass on burned sites equaling non-burned sites the second growing season. Biomass was more responsive to precipitation than fire and the fire-induced changes in species composition suggest exclusion of fire may be a greater disturbance than summer fire.