Burning Questions: Future Research Directions in Water and Wind Erosion after Wildfire

Abstract

Wildfire activity is increasing in the western USA due to a warming and drying climate, increased human ignitions, and subsequent large-scale fire-prone grass invasions, which accelerates future wildfire occurrences. Wildfire remains one of the most prominent disturbances impacting rangeland and forested landscapes, leaving barren soils susceptible to water and wind erosion until vegetation recovery occurs or mitigation by erosion control techniques (e.g. mulch). Water erosion limits ecosystem productivity, propagates ecosystem degradation, and decreases surface water quality. Wind erosion results in airborne dust, which affects human health, reduces traffic visibility, and decreases site productivity. Here, we identify research needs related to water and wind erosion post-fire. Although a significant amount of research has been conducted on post-fire water erosion, research gaps include questions on soil water repellency, deposition, and hillslope processes. In contrast, there is a paucity of post-fire wind erosion research. We lack knowledge of 1) when, where, and how long wind erosion persists after wildfire, 2) how fire, soil, and landscape characteristics affect wind erosion, 3) how post-fire wind erosion affects ecosystem recovery (plant establishment, nutrient cycling, forage productivity), and 4) how land management actions (e.g. return to grazing, stabilization techniques, seeding) interact with wind erosion and post-fire ecosystem recovery. Both water and wind erosion research would benefit from studies that represent a wider range of plant communities and landscapes, as well as how post-fire weather, climate, and land use interact to affect site stability and vegetation recovery rates. We also present ongoing case studies that begin to address these research needs, including temporal patterns in soil and plant dynamics following wildfire and the effectiveness of fuel treatments on reducing water and wind erosion. Furthermore, while research has been conducted on post-fire wind and water erosion separately, few studies have linked the two processes. We discuss ongoing efforts to develop field instrumentation to quantify wind and water erosion and explore dynamics between the two processes utilizing two case studies in shrublands. We are also developing a rapid response team to quantify wind and water erosion immediately after wildfire. Furthering our understanding of post-fire water and wind erosion will assist land managers in determining best practices for post-fire rehabilitation efforts that reduce hazards to natural resources, property and infrastructure, and human life, while maintaining ecosystem productivity for forage and wildlife habitat.