Short-term changes in vegetation and soil in response to a bulldozed fireline in northern great plains grasslands

Abstract

The objectives of this study was to quantify the ecological cost of bulldozed fireline in comparison to burned and unburned sites and draw a management implications for ranchers and land owners. Vegetation cover and abundance were determined with biomass clipping and line point intercept method as separate functional groups across the bladed, burned, and unburned sites in two locations, north central and south west Montana for two years. Study area encompassed idaho fescue and bluebunch wheatgrass dominated north facing slope in Redbluff and rough fescue and bluebunch dominated grassland in Havre. After quantifying vegetation responses, top soil horizon depth, bulk density, aggregate stability and runoff and sediment yield were determined to quantify soil response to bulldozed fireline. In general, burned site did not differ from unburned site particularly by the second year after the fire. In other words fire was not detrimental to the rangeland condition. Whereas bulldozed fireline altered primary ecological processes, particularly nutrient cycle and hydrologic functioning, by mechanically removing native plant species, creating exposed bare ground which was susceptible to soil erosion and invasion of competitive non-natives.