DISTURBANCE ASSESSMENT AND MITIGATION OF GREAT BASIN RANGELAND
Location: Watershed Management Research
Title: Hydrologic vulnerability and risk assessment associated with the increased role of fire on western landscapes, Great Basin, USA
Submitted to: Trans American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: October 16, 2010
Publication Date: December 13, 2010
Citation: Williams, C.J., Pierson, F.B., Robichaud, P.R., Spaeth, K.E., Hardegree, S.P., Clark, P.E., Moffet, C.A., Al-Hamdan, O.Z., and Boll, J. 2010. Hydrologic Vulnerability and Risk Assessment Associated with the Increased Role of Fire on Western Landscapes, Great Basin, USA. Presented at 2010 Fall Meeting, American Geophysical Union, San Francisco, California, 13-17 December 2010.
Landscape-scale plant community transitions and altered fire regimes across Great Basin, USA, rangelands have increased the likelihood of post-fire flooding and erosion events. These hazards are particularly concerning for western urban centers along the rangeland urban-wildland interface where natural resources, property, and human life are at risk. Extensive conversion of 4-7 million hectares of Great Basin shrub-steppe to cheatgrass-dominated (Bromus tectorum) grasslands has increased the frequency and size of wildland fires within these ecosystems. Fire frequencies have increased by more than an order of magnitude and occur on 3-10 year intervals across much of the cheatgrass-dominated landscape. Extensive tree (Pinus spp. and Juniperus spp.) encroachment into wooded shrub-steppe has increased heavy fuel loads. Ladder fuels in these ecosystems promote rapidly spreading, high-intensity and severe ground-surface-crown fires. These altered fuel structures across much of the historical Great Basin shrub-steppe have initiated an upsurge in large rangeland wildfires and have increased the spatial and temporal vulnerability of these landscapes to amplified runoff and erosion. Resource and infrastructure damages, and loss of life have been reported due to flooding following recent large-scale burning of western rangelands and dry forests. We present a decade of post-fire rangeland hydrologic research that provides a foundation for conceptual modeling of the hydrologic impacts associated with an increased role of rangeland wildfires. We highlight advancements in predictive tools to address this large-scale phenomenon and discuss vital research voids requiring attention. Our geographic emphasis is the Great Basin Region, however, these concepts likely extend elsewhere given the increased role of fire in many geographic regions and across rangeland-to-forest ecotones in the western United States.