Date of this Version
Ecohydrology 9, pp. 1604–1619 (2016), DOI: 10.1002/eco.1751.
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 2 years on the low sagebrush area with limited rooting depth, while that on the deeper-rooted mountain big sagebrush area took 4 years to recover. ET from the aspen trees, which can sprout from existing roots, recovered within 2 years. The influence of vegetation disturbance on streamflow was assessed using both empirical time trend analysis and process-based modelling. Although both approaches suggested approximately a 20% increase in streamflow during the 6 years post-disturbance, results from the empirical time trend analysis were marginally significant (p = 0·055), while those from the process-based modelling were not statistically significant. Marginal streamflow response can be attributed to rapid post-disturbance recovery of the aspen where most of the streamflow originates.