Response of planted sagebrush seedlings to cattle grazing applied to decrease fire probability

Authors: Davies, Kirk; Bates, Jonathan - Jon; Boyd, Chad

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2020
Publication Date: 8/26/2020
Citation: Davies, K.W., Bates, J.D., Boyd, C.S. 2020. Response of planted sagebrush seedlings to cattle grazing applied to decrease fire probability. Rangeland Ecology and Management. 73(5):629-635. https://doi.org/10.1016/j.rama.2020.05.002.
DOI: https://doi.org/10.1016/j.rama.2020.05.002

Interpretive Summary: After planting sagebrush seedlings, there is a need to protect them from fire because sagebrush is fire-intolerant. Grazing is likely the only tool that can be applied feasibly across the landscape to decrease wildfire probability, but there are concerns that grazing and associated activities (e.g. trampling) may negatively impact sagebrush seedlings. We investigated effects of grazing by cattle on planted sagebrush seedlings at five blocks for five years. Grazing increased sagebrush cover and reproductive efforts by almost 2-fold and had no effect on survival. This suggests that grazing favored sagebrush, a generally unpalatable shrub, recovery, likely by reducing competition from highly palatable herbaceous vegetation. Therefore, grazing can be strategically applied to reduce the probability of wildfire in areas with planted sagebrush seedlings. This is of interest to rangeland managers, wildlife managers, and restoration practitioners.

Technical Abstract: Restoration of non-sprouting shrubs after wildfire is increasingly becoming a management priority. In the western U.S., Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) restoration is a high priority, but sagebrush establishment from seed is sporadic. In contrast, planting seedlings often successfully restores sagebrush, but is expensive and time consuming. After planting, hence, there is a need to protect the investment from disturbances such as fire that will erase gains in sagebrush recovery. Grazing is likely the only tool that can be applied feasibly across the landscape to decrease wildfire probability, but there are concerns that grazing and associated activities (e.g. trampling) may negatively impact sagebrush seedlings. We investigated effects of grazing by cattle, applied as a fine fuel management strategy, on planted sagebrush seedlings at five blocks for five years. Grazing substantial reduced exotic annual grasses, large perennial bunchgrasses, and total herbaceous cover, thus achieving fuel management goals. Sagebrush cover and reproductive efforts were almost 2-fold greater in grazed compared to non-grazed areas in the final year of the study. This suggests that grazing favored sagebrush, a generally unpalatable shrub, recovery, likely by reducing competition from highly palatable herbaceous vegetation. Density of sagebrush, however, was similar between grazed and non-grazed areas. This research demonstrates that grazing can be applied to areas where sagebrush seedling were planted without deleterious effects on sagebrush survival and may substantially increase sagebrush growth and recovery of sagebrush cover. Therefore, grazing can be strategically applied to reduce the probability of wildfire in areas with planted sagebrush seedlings; thereby, protecting the investment in sagebrush recovery. With more refinement, it also appears that grazing can be utilized to accelerate the recovery of sagebrush and potentially other woody vegetation habitat by modifying the competitive relationship between herbaceous vegetation and woody vegetation.