Restoring the sagebrush component in crested wheatgrass dominated communities

Authors: Davies, Kirk; Boyd, Chad; NAFUS, ALETA - Oregon State University

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2013
Publication Date: 8/2/2013
Citation: Davies, K.W., Boyd, C.S., Nafus, A.M. 2013. Restoring the sagebrush component in crested wheatgrass dominated communities. Rangeland Ecology and Management. 66(4):472-478.

Interpretive Summary: Crested wheatgrass plant communities have limited diversity and provide low quality habitat for wildlife until sagebrush reestablishes. However, sagebrush reestablishment is often slow because crested wheatgrass is competitive with sagebrush seedlings and seed sources may be limited. We evaluated broadcast seeding and plant seedling sagebrush with varying levels of crested wheatgrass control with glyphosate. About 70% of the planted sagebrush seedlings survived, even without crested wheatgrass control, but sagebrush largely failed to establish where it was broadcast seeded. Sagebrush plants were larger with higher levels of crested wheatgrass control. Our results suggest that planting sagebrush seedlings may be used to increase the diversity of crested wheatgrass plant communities and improve wildlife habitat.

Technical Abstract: Monotypic stands of crested wheatgrass (Agropyron cristatum [L] Gaertm. and Agropyron desertorum [Fisch.] Schult.), an introduced grass, occupy vast expanses of the sagebrush steppe. Efforts to improve habitat for sagebrush-associated wildlife by establishing a diverse community of native vegetation in crested wheatgrass stands have largely failed. Instead of concentrating on a diversity of species, we evaluated the potential to restore the foundation species, Wyoming big sagebrush (Artemisia tridentata spp. wyomingensis [Beetle & A. Young] S.L. Welsh) to these communities. We investigated the establishment of Wyoming big sagebrush into six crested wheatgrass stands (sites) by broadcast seeding and planting seedling sagebrush across varying levels of crested wheatgrass control with glyphosate. Planted sagebrush seedlings established at high rates (~70%), even without crested wheatgrass control. However, most attempts to establish sagebrush by broadcast seeding failed. Only at high levels of crested wheatgrass control did a few sagebrush plants established from broadcasted seed. Sagebrush density and cover were greater with planting seedlings than broadcast seeding. Sagebrush cover, height, and canopy area were greater at higher levels of crested wheatgrass control. High levels of crested wheatgrass control also created an opportunity for exotic annuals to increase. Crested wheatgrass rapidly recovered after glyphosate control treatments; suggesting multiple treatments may be needed to effectively control crested wheatgrass. Our results suggest that planting sagebrush seedlings can structurally diversify monotypic crested wheatgrass stands to provide habitat for sagebrush-associated wildlife. Though this is not the full diversity of native functional groups that previously occupied crested wheatgrass stands, it is a substantial improvement over other efforts that have largely failed to alter these plant communities. We also hypothesize that planting sagebrush seedlings in patches or strips may provide a relatively inexpensive method to facilitate sagebrush recovery across vast landscapes where sagebrush has been lost.