Submitted to: Bureau of Land Management
Publication Type: Government Publication
Publication Acceptance Date: 4/30/2013
Publication Date: 4/30/2013
Citation: Davies, K.W., Bates, J.D., Madsen, M.D., Nafus, A.M. 2013. Restoration of mountain big sagebrush plant communities following western juniper control. Bureau of Land Management. p.1-12. Interpretive Summary: Juniper encroachment of high elevation big sagebrush steppe has degraded wildlife habitat, reduced forage production, and increased erosion risk. Juniper can be successfully controlled with partial cutting followed by prescribed burning, but the recovery of the herbaceous understory and sagebrush may be slow. We evaluated the effectiveness of seeding perennial herbaceous vegetation and sagebrush at five sites where juniper was controlled with partial cutting and prescribed burning. Sagebrush and perennial grass density and cover were greater where they were seeded. These results suggest that seeding after juniper control can accelerate the recovery of high elevation big sagebrush steppe and provide habitat for sagebrush-associated wildlife.
Technical Abstract: Western juniper (Juniperus occidentalis ssp. occidentalis Hook) encroachment into mountain big sagebrush (Artemisia tridentata spp. vaseyana (Rydb.) Beetle) plant communities has degraded sagebrush-associated wildlife habitat, reduced livestock forage, and increased erosion and runoff risk. The loss of sagebrush as western juniper increases has exacerbated the plight of sage-grouse and other sagebrush-associated wildlife. Western juniper has been controlled with partial cutting followed by prescribed burning, but the recovery of the herbaceous component and sagebrush may be slow. We evaluated seeding perennial herbaceous vegetation and sagebrush at five sites after juniper was controlled by partial cutting and prescribed burning. Treatments were: unseeded control, seeded with a perennial herbaceous seed mix (aerial seeded), and seeded with the herbaceous seed mix plus mountain big sagebrush seed (broadcasted to simulate aerial seeding). By the third year post-treatment, perennial grass density and cover were two times greater in plots receiving the herbaceous seed mix compared to the unseeded control plots. Where sagebrush was seeded its cover and density were between 74- and 290-fold and 62- and 155-fold greater than the control and herbaceous seeded plots. By the third year after seeding, sagebrush cover was as high as 12% in some sagebrush seeded plots and between 0% and 0.4% where it was not seeded. These results indicate that aerial seeding perennial herbaceous vegetation can accelerate the recovery of perennial grasses and thus, limit opportunities for invasive plants and stabilize the site. Our results also suggest that seeding mountain big sagebrush after controlling encroaching juniper can rapidly recover sagebrush and thereby, provide habitat for sagebrush-associated wildlife.