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• The dominant plant species was Bromus tectorum (cheatgrass) providing 28.93 percent <br />mean cover (52.63% relative cover). Sarcobotus vermiculatus (black greasewood) was <br />the dominant perennial species, accounting for 8.13 percent mean cover and 20.45 percent <br />relative cover. Two other species provided significant cover in the NGWRA (relative <br />cover greater than three percent); Hilaria jamesii (galleta), a native warm season grass <br />with 4.67 percent mean cover (10.12% relative cover), and Gutierrezia sarothrae (broom <br />snakeweed), a native shrub providing 2.27 percent average total cover and 5.67 percent <br />relative cover. <br />Vegetative litter (prior year's growth, dead wood, and other biologic organic material) <br />comprised 23.20 percent ground cover within the NGWItA. Baze soil comprised 18.40 <br />percent of the ground cover and rock accounted for 0.67 percent of cover encountered. A <br />significant cryptogamic crust was encountered in the NGW12A. This assemblage of <br />mosses and lichens provided 8.67 percent cover on the ground surface. <br />Herbaceous Production <br />Mean total herbaceous production of the say sampled quadrats in the NGWRA was 83.5 <br />g/m2 (744.3 lb/ac). Perennial and annual grasses and forbs were present in the production <br />sampling. No su~vtescent species were encountered during production sampling. Annual <br />grasses donnated herbaceous production, contributing 52.8 g/m2 (470.6 lb/ac) or 63.2 <br />• percent of total herbaceous production. Perennial grasses accounted for 28.0 g/m2 <br />(249.6 lb/ac) and 33.5 percent of total herbaceous production. Annual and perennial forbs <br />were nearly evenly represented and accounted for 1.5 g/m2 (13.4 lb/ac) and 1.2 g/m2 <br />(10.7 lb/ac), respectively. Total herbaceous production was quite variable with the <br />standazd deviation value approaching half the value of the population mean. <br />Woody Plant Density <br />Woody plants in the NGWRA were represented by eight species; Artemesia tridentate <br />(big sagebrush), Atriplex canescens (four-wing saltbush), Atriplex conjertifolia (shadscale <br />saltbush), Chrysothamnus nauseosus (rubber rabbitbrush), Chrysothamnus viscidijlorus <br />(rabbitbrush), Ephedra viridis (Mormon tea), Gutierrezia sarothrae, and Sorcobatus <br />vermiculatus (Table 4). Woody plant density within the NGWRA in 1999 was measured <br />at 37.32 live stems/SOrtt~ (3020 live stems/acre). Gutierrezia sarothrae was the most <br />prevalent woody plant with 18.22 live stems/SOmz (] 475 live stems/acre), with <br />Sarcobatus vermiculatus contnibuting 9.26 live stems/SOtt>2 (749 live stems acre) and <br />Atriplex confertifolia providing 4.18 live stetns/SOmz or 338 live stems/acre. The <br />remaining species contributed between 0.08 and 2.40 stems/SOrnz (6 to ] 94 live <br />stems/acre respectively). As is generally the case in shrub dominated communities in xeric <br />areas, distribution of the woody plants was patchy and variable. <br /> <br />-5- <br />