Prescribed‐fire effects on rill and interrill runoff and erosion in a mountainous sagebrush landscape

Changing fire regimes and prescribed‐fire use in invasive species management on rangelands require improved understanding of fire effects on runoff and erosion from steeply sloping sagebrush‐steppe. Small (0·5 m2) and large (32·5 m2) plot rainfall simulations (85 mm h–1, 1 h) and concentrated flow methodologies were employed immediately following burning and 1 and 2 years post‐fire to investigate infiltration, runoff and erosion from interrill (rainsplash, sheetwash) and rill (concentrated flow) processes on unburned and burned areas of a steeply sloped sagebrush site on coarse‐textured soils. Soil water repellency and vegetation were assessed to infer relationships in soil and vegetation factors that influence runoff and erosion. Runoff and erosion from rainfall simulations and concentrated flow experiments increased immediately following burning. Runoff returned to near pre‐burn levels and sediment yield was greatly reduced with ground cover recovery to 40 per cent 1 year post‐fire. Erosion remained above pre‐burn levels on large rainfall simulation and concentrated flow plots until ground cover reached 60 per cent two growing seasons post‐fire. The greatest impact of the fire was the threefold reduction of ground cover. Removal of vegetation and ground cover and the influence of pre‐existing strong soil‐water repellency increased the spatial continuity of overland flow, reduced runoff and sediment filtering effects of vegetation and ground cover, and facilitated increased velocity and transport capacity of overland flow. Small plot rainfall simulations suggest ground cover recovery to 40 per cent probably protected the site from low‐return‐interval storms, large plot rainfall and concentrated flow experiments indicate the site remained susceptible to elevated erosion rates during high‐intensity or long duration events until ground cover levels reached 60 per cent. The data demonstrate that the persistence of fire effects on steeply‐sloped, sandy sagebrush sites depends on the time period required for ground cover to recover to near 60 per cent and on the strength and persistence of ‘background’ or fire‐induced soil water repellency. Published in 2009 by John Wiley & Sons, Ltd.

[1]  Patrick E. Clark,et al.  Fire effects on rangeland hydrology and erosion in a steep sagebrush‐dominated landscape , 2008 .

[2]  Patrick E. Clark,et al.  Soil water repellency and infiltration in coarse-textured soils of burned and unburned sagebrush ecosystems , 2008 .

[3]  Stuart P. Hardegree,et al.  Runoff and Erosion After Cutting Western Juniper , 2007 .

[4]  John Wainwright,et al.  Scale relationships in hillslope runoff and erosion , 2006 .

[5]  Lee H. MacDonald,et al.  Measurement and prediction of post-fire erosion at the hillslope scale, Colorado Front Range , 2005 .

[6]  Frederick B. Pierson,et al.  Impacts of wildfire on soil hydrological properties of steep sagebrush-steppe rangeland , 2002 .

[7]  D. Marks,et al.  Long‐Term Climate Database, Reynolds Creek Experimental Watershed, Idaho, United States , 2001 .

[8]  David C. Robertson,et al.  Long‐Term Snow Database, Reynolds Creek Experimental Watershed, Idaho, United States , 2001 .

[9]  M. Johansen,et al.  Post‐fire runoff and erosion from rainfall simulation: contrasting forests with shrublands and grasslands , 2001 .

[10]  F. Pierson,et al.  Spatial and temporal effects of wildfire on the hydrology of a steep rangeland watershed , 2001 .

[11]  Lee H. MacDonald,et al.  Post‐fire runoff and erosion from simulated rainfall on small plots, Colorado Front Range , 2001 .

[12]  C. Hanson.  Characteristics of Extreme Precipitation and Associated Streamflow in the Reynold's creek Experimental watershed, Idaho , 2001 .

[13]  Peter R. Robichaud,et al.  Fire effects on infiltration rates after prescribed fire in Northern Rocky Mountain forests, USA , 2000 .

[14]  L. D. Norton,et al.  Soil erosion by surface water flow on a stony, semiarid hillslope , 1999 .

[15]  M. Inbar,et al.  Runoff and erosion processes after a forest fire in Mount Carmel, a Mediterranean area , 1998 .

[16]  L. D. Norton,et al.  Hydraulics and erosion in eroding rills , 1997 .

[17]  A. Parsons,et al.  Tracing sediment movement in interrill overland flow on a semi‐arid grassland hillslope using magnetic susceptibility , 1993 .

[18]  A. Parsons,et al.  The effect of spatial variability in overland flow on the downslope pattern of soil loss on a semiarid hillslope, southern Arizona , 1991 .

[19]  S. Morris,et al.  Forest Fire and the Natural Soil Erosion Regime in the Colorado Front Range , 1987 .

[20]  L. Debano.  Water repellent soils: a state-of-the-art , 1981 .

[21]  G. Bouyoucos.  Hydrometer Method Improved for Making Particle Size Analyses of Soils1 , 1962 .

[22]  Bessel D. van't Woudt.  Particle coatings affecting the wettability of soils , 1959 .

[23]  R. Shakesby,et al.  Wildfire as a hydrological and geomorphological agent , 2006 .

[24]  D. Neary,et al.  Fire's effects on ecosystems , 1998 .

[25]  S. Whisenant.  Changing fire frequencies on Idaho's Snake River Plains: ecological and management implications. , 1990 .

[26]  Louis W. Dekker,et al.  Water repellency in the dunes with special reference to the Netherlands , 1990 .

[27]  D. A. Woolhiser,et al.  Interrill Soil Erosion – Part II: Testing and Use of Model Equations , 1985 .

[28]  Gerald F. Gifford,et al.  Cover Allocation in Rangeland Watershed Management (A Review) , 1985 .

[29]  L. D. Meyer,et al.  Multiple-intensity rainfall simulator for erosion research on row sideslopes. , 1979 .

[30]  D. H. Knight,et al.  Aims and Methods of Vegetation Ecology , 1974 .

[31]  G. R. Foster,et al.  Transport of Soil Particles by Shallow Flow , 1972 .

[32]  Intermountain Forest,et al.  Infiltration and water repellency in granitic soils , 1971 .

[33]  D. A. Hamilton,et al.  Translocation of Hydrophobic Substances into Soil by Burning Organic Litter , 1970 .