Wind and Water Erosion Potential of Fire-Affected Soils: Immediate and Short-Term Effects in a Desert Ecosystem

The increase in fires in arid and semi-arid parts of the Southwest U.S. has important implications for runoff and sediment management, and for the stewardship of soil-contaminated sites throughout the region. This study was initiated to examine the effects and duration of fire on wind and water erodibility on shrubland sites analogous to those on the Nevada National Security Site. Quantification of wind erosion was conducted with a portable wind tunnel analog and a small, portable rainfall simulator. Data collected on a Coleogyne ramosissima (blackbrush)dominated site indicated post-fire windblown emissions were higher on burned compared to unburned areas, and on vegetative understory soils compared to interspace soils. By 24 months after the fire, these effects were near pre-burn levels. Water erosion, as measured by runoff response and sediment yield, was unaffected by the fire. The same measurements at a Pinus spp. (pinyon)/Artemisia spp. (sagebrush) shrubland site indicated elevated responses in the potential for both wind and water erosion 12 months after a fire. Amounts of airborne particulate material and sediment were higher from vegetative understory soils than interspace soils, while runoff was more prevalent on interspace than understory soils. These differences in wind emission and runoff data highlight the complex relationship between fire and erosion in shrubland ecosystems.