Vegetation Characteristics Across Part of the Wyoming Big Sagebrush Alliance
Abstract
The Wyoming big sagebrush (Artemisia tridentatassp.wyomingensis[Beetle & A. Young] S.L. Welsh) alliance is the mostextensive of the big sagebrush complex in the Intermountain West. This alliance provides critical habitat for many sagebrushobligate and facultative wildlife species and serves as a forage base for livestock production. There is a lack of information thatdescribes vegetation cover values, characteristics, diversity, and heterogeneity of the Wyoming big sagebrush alliance. This studydescribes vegetation cover values and defines distinct associations for intact, late-seral Wyoming big sagebrush plant com-munities across part of its northwestern range. We sampled 107 Wyoming big sagebrush plant communities. Total herbaceouscover values were variable among sites with differences between sites exceeding 700%. Mean sagebrush cover was 12.3% with90% of the sites producing 6% to 20% cover. Tall forb (.18 cm) cover averaged 1.9% and 90% of the sites varied between0.2% and 5.6% cover. Five associations delineated by dominant perennial bunchgrass species were identified: ARTRW8(Wyoming big sagebrush)/PSSP6 (Pseudoroegneria spicata[Pursh] A. Lo ̈ve, bluebunch wheatgrass), ARTRW8/ACTH7(Achnatherum thurberianum[Piper] Barkworth, Thurber’s needlegrass), ARTRW8/FEID (Festuca idahoensisElmer, Idahofescue), ARTRW8/HECO26 (Hesperostipa comata[Trin. & Rupr.] Barkworth, needle-and-thread), and ARTRW8/PSSP6–ACTH7 (a codominance of bluebunch wheatgrass and Thurber’s needlegrass). Our results suggest when the vegetation covervalues proposed for sage-grouse are applied as requirements at or above the stand level, they exceed the ecological potentialof many of the sites sampled.