Restoring the sagebrush biome

The sagebrush biome, once covering over 500,000 square kilometers of western North America, has shrunk to about half its original size due to a variety of disturbances, including wildfire, human infrastructure, and invasive species. To reduce sagebrush decline, resource managers are often tasked with the management of large, expensive restoration projects, like aerial re-seeding or on-the-ground drill seeding of burned sagebrush habitat. Despite the costs of these projects, research has shown they have varying success across landscapes; sometimes restoration efforts are effective, and other times they are not. 

Estimating restoration efficacy

Restoration of degraded sagebrush habitat requires knowledge of the factors leading to its local decline and an understanding of the efficacy of different sagebrush restoration practices, which can vary depending on local environmental conditions. In this study, researchers leveraged data on habitat disturbance, vegetation cover, soil moisture, and on-the-ground resource management projects from across the sagebrush landscape to evaluate the individual and combined influences of a) restoration treatments and b) environmental conditions on sagebrush recovery.

Range-wide projections of sagebrush recovery

Results of this study include range-wide estimates of restoration potential and sagebrush recovery across the sagebrush biome. Broadly, researchers found that restoration effectiveness and probability of sagebrush recovery varied greatly across the biome, depending on local environmental conditions and restoration treatment. The researchers break down four major takeaways:

1. Sagebrush seeding and seedling planting facilitated sagebrush recovery, particularly in drier areas, and ground-based seeding methods were generally more effective than aerial seeding.
2. Co-seeding native grasses was more likely to improve sagebrush recovery in drier sites, whereas co-seeding introduced grasses may increase sagebrush cover in moister sites. However, seeding introduced grasses could be counter-productive for restoring sagebrush in dryer sites.
3. Initial vegetation cover (such as the amount of living sagebrush or perennial grasses) influenced future sagebrush establishment and subsequent cover trends, and could therefore determine success of restoration treatments.
4. Repeated wildfires inhibited sagebrush recovery but sagebrush seeding treatments could overcome this effect to some extent, improving trajectories over natural recovery.

Overall, these projections can be used to guide strategic conservation efforts and prioritize restoration efforts to areas most likely to benefit from restoration action.