Practical postfire sagebrush shrub restoration techniques

Abstract

Wildfire is increasing in frequency and size in the western United States with climate change and invasive species such as cheatgrass. This increase is also causing an increase in the need for restoration techniques, especially in low-elevation, arid shrublands. Sagebrush shrublands are home to the threatened Gunnison sage-grouse and can take decades, if not longer, to recover after fire. We investigated management-friendly restoration techniques aimed at increasing sagebrush cover in a sagebrush system important to Gunnison sage-grouse and impacted by fire in western Colorado. We tested several restoration techniques that could be replicated in management actions to mitigate stressors on sagebrush recruitment, specifically herbivory by large ungulates, water limitation, and competition with other plants. We found that sagebrush grew and survived better when planted as transplanted seedlings versus seeds, when planted in areas where herbicide had been applied versus when vegetation was removed by hand tools, and when caged to prevent herbivory than when not caged. Surprisingly, providing supplementary water did not improve sagebrush transplant growth or survival over use of a microsite (small structure made of wood collected from the burn scar). Constructed microsites were meant to provide protection from wind, retain moisture, and provide shade. Overall, our results indicate that if sagebrush seedlings are provided shelter and structure, then survival can approach natural (not planted) rates and sagebrush can be successfully established in low-elevation sites.