Longer term evaluation of sagebrush restoration after juniper control and herbaceous vegetation trade-offs

Authors: Davies, Kirk; Bates, Jonathan - Jon

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2018
Publication Date: 3/10/2019
Citation: Davies, K.W., Bates, J.D. 2019. Longer term evaluation of sagebrush restoration after juniper control and herbaceous vegetation trade-offs. Rangeland Ecology and Management. 72(2):260-265. https://doi.org/10.1016/j.rama.2018.10.006.
DOI: https://doi.org/10.1016/j.rama.2018.10.006

Interpretive Summary: Restoration of sagebrush after controlling encroaching juniper with fire is needed to improve wildlife habitat. Seeding sagebrush has been suggested as a method to restore sagebrush after juniper control, but longer term evaluations are lacking. We compared seeding and not seeding sagebrush after juniper control with fire seven and eight years after seeding. Sagebrush cover averaged ~30% in sagebrush seeded plots compared to ~1% in unseeded plots eight years after seeding. Total herbaceous vegetation, perennial grass and annual forb cover was less where sagebrush was seeded. Thus, there is a trade-off with herbaceous vegetation with seeding sagebrush. Our results suggest that seeding sagebrush after juniper control can accelerate the recovery of sagebrush habitat. This information is useful for land and wildlife managers.

Technical Abstract: Degradation of shrublands around the world from altered fire regimes, over-utilization, and anthropogenic disturbance has resulted in a widespread need for shrub restoration. In western North America, reestablishment of mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) is needed to restore ecosystem services and function. Western juniper (Juniperus occidentalis ssp. occidentalis Hook) encroachment is a serious threat to mountain big sagebrush communities in the northern Great Basin and Columbia Plateau. Juniper trees can be controlled with fire, however, sagebrush recovery may be slow, especially if encroachment largely eliminated sagebrush prior to juniper control. Short-term studies have suggested that seeding mountain big sagebrush after juniper control may accelerate sagebrush recovery. Longer term information is lacking on how sagebrush recovery progresses and if there are trade-offs with herbaceous vegetation over longer time periods. We compared seeding and not seeding mountain big sagebrush after juniper control (partial cutting followed with burning) in fully developed juniper woodlands (i.e. sagebrush had been largely excluded) at five sites, seven and eight years after seeding. Sagebrush cover averaged ~30% in sagebrush seeded plots compared to ~1% in unseeded plots eight years after seeding. Thus suggesting that sagebrush recovery may be slow without seeding after juniper control. Total herbaceous vegetation, perennial grass and annual forb cover was less where sagebrush was seeded. Thus, there is a trade-off with herbaceous vegetation with seeding sagebrush. Our results suggest that seeding sagebrush after juniper control can accelerate the recovery of sagebrush habitat characteristics, which is important for sagebrush-associated wildlife. We suggest land manager and restoration practitioners should consider seeding sagebrush and possibly other shrubs after controlling encroaching trees where residual shrubs are lacking after control.