Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2006
Publication Date: 11/1/2006
Citation: Davies, K.W., Bates, J.D., Miller, R.F. 2006. Vegetation characteristics across part of the wyoming big sagebrush alliance. Rangeland Ecology and Management. 59(6):567-575. Interpretive Summary: The Wyoming big sagebrush alliance is the most extensive of the big sagebrush subspecies and provides critical habitat for many wildlife species and severs as a forage base for livestock production. This study describes cover potentials and defines distinct plant associations for relatively undisturbed Wyoming big sagebrush communities across part of its northwestern range. Vegetation cover and composition were highly variable among communities. However, variation in vegetation characteristics was reduced by forming plant associations based on dominant bunchgrass species. Comparing our results to the vegetation requirements proposed for sage-grouse suggest that the requirements exceed the ecological potential of many of the sites sampled.
Technical Abstract: The Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh) alliance is the most extensive of the big sagebrush complex in the Intermountain West. This alliance provides critical habitat for many sagebrush obligate and facultative wildlife species and serves as a forage base for livestock production. There is a lack of information that describes vegetation cover values, characteristics, diversity, and heterogeneity of the Wyoming big sagebrush alliance. This study describes vegetation cover values and defines distinct associations for intact, late seral Wyoming big sagebrush plant communities across part of its northwestern range. We sampled 107 Wyoming big sagebrush plant communities. Total herbaceous cover values were highly variable among sites with differences between sites exceeding 700%. Mean sagebrush cover was 12.3% with 90% of the sites producing 6% to 20%. Tall forb (> 18cm) cover averaged 1.9% and 90% of the sites varied between 0.2% and 5.6%. Five associations delineated by dominant perennial bunchgrass species were identified: ARTRW8 (Wyoming big sagebrush)/PSSP6 (Pseudoroegneria spicata (Pursh) A. Love, bluebunch wheatgrass), ARTRW8/ACTH7 (Achnatherum thurberianum (Piper) Barkworth, Thurber's needlegrass), ARTRW8/FEID (Festuca idahoensis Elmer, Idaho fescue), ARTRW8/HECO26 (Hesperostipa comata (Trin. & Rupr.) Barkworth, needle-and-thread), and ARTW8/PSSP6-ACTH7 (a co-dominance of bluebunch wheatgrass and Thurber's needlgrass). Our results suggest when the vegetation cover values proposed for sage-grouse are applied as requirements at or above the stand level, they exceed the ecological potential of many of the sites sampled.