Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2011
Publication Date: 11/14/2011
Citation: Williams, C.J., and Pierson, F.B. 2011. Hydrologic and Erosional Impacts Associated with an Increased Role of Wildland Fire on Western Rangelands. In: Abstracts of the Association for Fire Ecology Interior West Conference, November 14-17, 2011, Snowbird, UT.
Technical Abstract: Landscape plant community transitions across the Great Basin and Intermountain West have altered fire regimes and present large-scale consequences relative to rangeland hydrology. Extensive conversion of Great Basin shrub steppe to annual grasslands has increased fuel continuity and the frequency, size, and severity of wildfires within these systems. Densely stocked persistent woodlands and wooded shrublands have experienced an increased frequency of large, high severity fires resulting in part to greater fuel loading. The increased role of fire amplifies the spatial and temporal exposure and vulnerability of these landscapes to greater runoff and erosion. Greater temporal exposure ensures significant runoff and long-term soil loss from frequently occurring low interval storms (1-10 yr events) and increases the likelihood that susceptible conditions will occur during less frequent, more damaging flood-generating storms. Historical accounts of post-fire flooding, resource damage and loss of human life further demonstrate the potential risks associated with an increased frequency and severity of wildland fire. This study explores the hydrologic impacts of large-scale plant community transitions and an increased role of wildland fire on western rangelands. Potential fire effects on rangeland hydrologic vulnerability are presented through a review of published field studies from semi-arid rangelands and woodlands and xeric forest communities. A conceptual framework for evaluating post-fire hydrologic response and risk is presented. Our geographic focus is the Great Basin and Intermountain West, but the concepts presented are likely applicable across the western US where ongoing plant community transitions have increased the role of wildland fire.