Resilience and resistance framework predicts regional vegetation responses to shrub reduction treatments in the sagebrush ecosystem

Authors: RIGINOS, C. - Nature Conservancy; VEBLEN, K. - Utah State University; THACKER, E - Utah State University; GUNNELL, K. - Utah Division Of Wildlife Resources; Monaco, Thomas

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2022
Publication Date: 12/2/2022
Citation: Riginos, C., Veblen, K.E., Thacker, E.T., Gunnell, K.L., Monaco, T.A. 2022. Resilience and resistance framework predicts regional vegetation responses to shrub reduction treatments in the sagebrush ecosystem. Rangeland Ecology and Management. 86:35-43. https://doi.org/10.1016/j.rama.2022.10.008.
DOI: https://doi.org/10.1016/j.rama.2022.10.008

Interpretive Summary: Ecosystem resilience to disturbance and resistance to weed invasion (R&R) have recently been classified and mapped to assist rangeland managers within the big sagebrush ecosystem. However, few studies have tested whether these classifications correspond with actual outcomes of management efforts to improve R&R across a region. Thus, in this study, we related R&R levels to changes in cover 1-4 and 5-12 years after disturbances on 88 sites across Utah. Sites were treated mechanically to reduce shrub cover or burned, and most burned sites were seeded after the disturbance. As expected, perennial grass cover increased in all R&R classes relative to pre-disturbance levels, and this increase was greatest at High R&R sites. However, perennial forb cover increased only in the High R&R sites and decreased in Low R&R sites. Sagebrush showed evidence of recovery at High and Moderate R&R sites. Unexpectedly, however, annual grass cover increased slightly at High and Moderate R&R sites but decreased in the Low R&R sites. Overall, this study indicates that the R&R map is a useful tool for planning and predicting outcomes of management and that improvements are mostly needed to ensure greater perennial forb recovery and suppression of annual grasses.

Technical Abstract: Ecosystem resilience to disturbance and resistance to weed invasion (R&R) have recently been classified and mapped to assist rangeland managers within the big sagebrush ecosystem. However, few studies have tested whether these classifications correspond with actual outcomes of management efforts to improve R&R across a region. Thus, in this study, we related R&R levels to changes in cover 1-4 and 5-12 years after disturbances on 88 sites across Utah. Sites were treated mechanically to reduce shrub cover or burned, and most burned sites were seeded after the disturbance. As expected, perennial grass cover increased in all R&R classes relative to pre-disturbance levels, and this increase was greatest at High R&R sites. However, perennial forb cover increased only in the High R&R sites and decreased in Low R&R sites. Sagebrush showed evidence of recovery at High and Moderate R&R sites. Unexpectedly, however, annual grass cover increased slightly at High and Moderate R&R sites but decreased in the Low R&R sites. Overall, this study indicates that the R&R map is a useful tool for planning and predicting outcomes of management and that improvements are mostly needed to ensure greater perennial forb recovery and suppression of annual grasses.