THE IMPACT OF FUEL LOAD AND BURN SEASON ON THE GROWTH AND REPRODUCTIVE CAPACITY OF AN INVASIVE LEGUME, LESPEDEZA CUNEATA

Abstract

Sericea lespedeza is an invasive plant expanding its range through the grasslands of the Great Plains, displacing native grasses and reducing plant diversity. Invasive species cost the US economy billions of dollars each year. Given the historical loss of grasslands and the economic cost of invasive species, it is important to find sustainable management options. I evaluated the effect of burn season in conjunction with other common management strategies on the reduction of sericea lespedeza. We burned plots in spring, fall or unburned control, which were divided into four subplots receiving a secondary treatment of herbicide, mowing, fuel load addition, or burn only. In each subplot, biomass, stem height, stem count, and seed production were measured. Results indicate that fall burning in conjunction with mowing results in the greatest reduction of stem height, seed weight, and plant biomass. Mowing after a fall fire appears to have the greatest impact on reducing seed production. The investment in seed production was reduced from 2014 to 2015, with plants that experienced fall fire and no fire having significantly less investment in seed production than plants experiencing spring fire regardless of secondary treatment. Because sericea lespedeza is a prolific seed producer, the reduced investment in seed production is important for its control. This study shows that fall fire in conjunction with mowing treatments can significantly reduce seed production of sericea lespedeza without the use of harmful herbicides.