Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/14/2006
Publication Date: 5/14/2006
Citation: Pierson, F.B., Robichaud, P.R., Moffet, C.A., and Spaeth, K.E. 2006. Erosion following fire in a sagebrush ecosystem of the northern Great Basin, USA. In: Proceedings of the 14th Conference of International Soil Conservation, May 14-19, 2006, Marrakech, Morocco. (CD-ROM) Interpretive Summary: Wildfires burn millions of acres of western forest and rangeland almost every year. One of the primary impacts of these fires is the greatly increased risk of soil erosion before vegetation recovery. In this study rainfall simulation was used to measure infiltration, runoff and erosion on burned and unburned sagebrush-rangeland sites in Nevada. Increased runoff and rill erosion were increased relative to unburned sites for up to 4 growing seasons after the fire. Hydrologic consequences of fire have been closely examined in forested ecosystems, but few studies have examined impacts of wildfire on rangeland hydrology. The results of this study provide a relative measure of the increased risk of runoff and erosion, and hydrologic recovery following fire in coarse-textured sagebrush-dominated ecosystems. These data are being used to parameterize models used by USFS and BLM Burned Area Emergency Response (BAER) teams to evaluate erosion risk and to develop mitigating strategies on western rangelands that have been disturbed by fire.
Technical Abstract: Wildfire is a major ecological process and management issue on rangelands throughout the western United States. Fire can reduce infiltration and increase runoff and erosion causing reduced site productivity and offsite flooding and sedimentation. Few data are available to quantify fire-induced hydrologic impacts on rangelands or to determine how long such impacts persist. Rainfall and concentrated flow simulation methodologies were used to quantify hydrologic impacts under rangeland wildfire. Small plot-scale spatial and temporal variations in fire impacts were compared to unburned conditions. Fire impacts on infiltration, runoff and interrill erosion were localized primarily on coppice microsites directly under shrubs characterized by high surface litter accumulations. The largest and most persistent impact of fire was on rill erosion processes. The impact of fire on rill flow dynamics and erosion rates persisted for up to four growing seasons after fire.