Submitted to: Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2008
Publication Date: 1/22/2009
Citation: Davies, K.W., Bates, J.D., Johnson, D., Nafus, A. 2009. Influence of Mowing Artemisia tridentata ssp. wyomingensis on Winter Habitat for Wildlife. Environmental Management. 44:84-92.
Interpretive Summary: Mechanical treatment of Wyoming big sagebrush is commonly implemented to improve wildlife habitat and increase forage production for livestock. Information is generally lacking describing the impacts of mechanical thinning treatment on stand structure, sagebrush recovery, and nutritional quality of sagebrush leaves. Sagebrush stand characteristics and leaf nutritional quality were measured in mid-winter on zero-, two-, four-, and six-year old fall applied mechanical (mowed at 20 cm height) treatments and compared to adjacent untreated (control) areas. Mowing compared to the control decreased sagebrush cover, density, canopy volume, canopy elliptical area, and height. All sagebrush structural characteristics were recovering, suggesting that the impacts of mowing are not long-term. Sagebrush leaf tissue nutritional quality appears to be greater in the mowed compared to control treatments in two-, four-, and six-year post-treatment time interval plots. These results demonstrate that mowing Wyoming big sagebrush plant communities can increase stand structural complexity and the nutritional quality of sagebrush leaves. This information will be useful to land and wildlife managers.
Technical Abstract: Mowing is commonly implemented to Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh (Wyoming big sagebrush) plant communities to improve wildlife habitat, increase forage production for livestock, and create fuel breaks for fire suppression. However, information detailing the influence of mowing on winter habitat for wildlife is lacking. This information is crucial because many wildlife species depended on A. tridentata spp. wyomingensis plant communities for winter habitat and consume significant quantities of Artemisia during this time. Furthermore, information is generally limited describing the recovery of A. tridentata spp. wyomingensis to mowing and the impacts of mowing on stand structure. Stand characteristics and Artemisia leaf tissue crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were measured in mid-winter on zero-, two-, four-, and six-year old fall applied mechanical (mowed at 20 cm height) treatments and compared to adjacent untreated (control) areas. Mowing compared to the control decreased Artemisia cover, density, canopy volume, canopy elliptical area, and height (P < 0.05), but all characteristics were recovering (P < 0.05). Mowing A. tridentata spp. wyomingensis plant communities slightly increase the nutritional quality of Artemisia leaves (P < 0.05), but simultaneously result in up to 20 years of decrease in Artemisia structural characteristics. Because of the large reduction in A. tridentata spp. wyomingensis for potentially 20 years following mowing, mowing should not be applied in Artemisia facultative and obligate wildlife winter habitat. Considering the decline in A. tridentata spp. wyomingensis dominated landscapes, we caution against mowing these communities.