The Effects of Fire versus Mowing on Prairie Plant Communities
Daniel Tix, JoAnna Hebberger, Elizabeth Vaughan, Iris D Charvat
Report no. MnDOT 2003-20
The primary goals of this project are to discover management processes which benefit a restored prairie and reduce the need for prescribed burning. Moreover, because of the interdependence of the plants and soil, there is a strong focus on the soil community as a driving force of the vegetation. Consequently, our objectives were to assess the effects of manipulation (burning, mowing) on: (1) the vegetative community, (2) the belowground mycorrhizal fungal community, and (3) on soil parameters. Prescribed burning has the strongest effects on plant community composition and is the most effective method to increase aboveground plant biomass in a restored tallgrass prairie. Burning especially favors warm season grasses (WSG) and legume species, though it also favors certain annual species. Spring haying is an acceptable alternative to spring burning, though its effects are less dramatic than the burn. In particular, haying does not favor WSG as extensively and may not damage cool-season species as thoroughly as burning. Adding lime to hayed prairie may help benefit the cool-season plants, native and exotic. However, utilizing mowing instead of burning probably does not differ much from leaving the prairie untreated. The process of removing litter seems to be the most important cause of the ecosystem response to prescribed burning. Hayed plots are the most similar to burned plots in terms of soil moisture, temperature, and litter quantity. Hence, litter removal by haying will likely be a sufficient practice to replace prescribed burning at many sites.