Attempting to restore herbaceous understories in Wyoming big sagebrush communities with mowing and seeding

Authors: Davies, Kirk; Bates, Jonathan - Jon

Submitted to: Restoration Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2014
Publication Date: 9/8/2014
Publication URL: http://handle.nal.usda.gov/10113/59735
Citation: Davies, K.W., Bates, J.D. 2014. Attempting to restore herbaceous understories in Wyoming big sagebrush communities with mowing and seeding. Restoration Ecology. 22:608-615.

Interpretive Summary: Low elevation sagebrush communities with degraded understories need to be restored to prevent exotic plant invasion, increase forage production, and improve wildlife habitat. We evaluated mowing, to reduce sagebrush dominance, followed by seeding native perennial grasses to restore the understory. Perennial grass cover and density increased, but not enough to consider the treatment successful. This treatment also increased exotic annual plants and decreased biological soil crusts. This treatment should probably not be used until research advances have improved the establishment of native perennial grasses.

Technical Abstract: Shrub steppe communities with depleted perennial herbaceous understories need to be restored to increase resilience, provide quality wildlife habitat, and improve ecosystem function. Mowing has been applied to Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle &Young) steppe plant communities to reduce sagebrush dominance to restore native herbaceous vegetation, but success has been hampered by increases in exotic annuals. Seeding native bunchgrasses after mowing may accelerate recovery and limit exotics. We compared mowing followed by seeding native bunchgrasses to mowing and an untreated control at five sites in southeastern Oregon over a four year period. Mowing and seeding bunchgrasses increased bunchgrass cover and density; however, bunchgrass cover was still relatively low (~3%) four years post seeding. Exotic annuals increased with mowing whether or not post-mowing seeding occurred. Longer term evaluation is needed to determine if seeded bunchgrasses will increase enough to suppress exotic annuals. Mowing and seeding also reduced soil biological crust more than just mowing, probably due to the added disturbance of drill seeding. Seeded bunchgrasses may have been limited by increases in exotic annuals. Though restoration of sagebrush communities with degraded understories is needed, we do not recommend mowing and seeding native bunchgrasses because this treatment produced mixed results that may lower the resilience of these communities. Before this method should be applied, research needs to improve the establishment of seeded native bunchgrasses. Alternatively, restoration practitioners may need to apply treatments to control exotic annuals and repeatedly seed native bunchgrasses.