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Submitted to: Ecohydrology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/8/2016 Publication Date: 6/1/2016 Citation: Flerchinger, G.N., Seyfried, M.S., Hardegree, S.P. 2016. Hydrologic response and recovery to prescribed fire and vegetation removal in a small rangeland catchment. Ecohydrology. doi: 10.1002/eco.1751. Interpretive Summary: Prescribed fire can be used as a management tool to improve habitat, control invasive weeds, and deter wildfire, but post-disturbance responses of vegetation and hydrology are not well understood. Recovery of vegetation and streamflow after a prescribed in a sagebrush ecosytem was studied. Water use by plants was reduced for a couple years after the fire until the plants had a chance to reestablish their rooting depth. Results suggest the post-fire streamflow was approximately 20% greater during the six years post-disturbance than what would have occurred without the fire. These results can be used by land managers to better assess potential effects of prescribed fire as a management tool. Technical Abstract: Prescribed fire can be used to return wild lands to their natural fire cycle, control invasive weeds, and reduce fuel loads, but there are gaps in the understanding of post-disturbance responses of vegetation and hydrology. The impact of a prescribed fire and subsequent aspen cutting on evapotranspiration (ET) and streamflow was assessed for the Upper Sheep Creek catchment, a 26-ha headwater catchment dominated by low sagebrush, mountain big sagebrush and aspen within the Reynolds Creek Experimental Watershed. The 2007 prescribed fire consumed 100% of the mountain big sagebrush and approximately 21% of the low sagebrush. The aspen, which were mostly untouched by the fire, were cut in the fall of 2008. Post-disturbance ET and vegetation recovery were related to the loss of rooting depth. ET recovered within two years on the low sagebrush area with limited rooting depth, while that on the deeper-rooted mountain big sagebrush area took four years to recover. ET from the aspen trees, which can sprout from existing roots, recovered within two years. The influence of vegetation disturbance on streamflow was assessed using both empirical time trend analysis and process-based modeling. Although both approaches suggested approximately a 20% increase in streamflow during the six years post-disturbance, results from the empirical time trend analysis were marginally significant (p=0.055) while those from the process-based modeling were not statistically significant. Marginal streamflow response can be attributed to rapid post-disturbance recovery of the aspen where most of the streamflow originates. |
