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• Density <br />Rubber rabbitbrush is the most abundant shrub in this vegetation <br />type with a density of 10,605 shrubs per acre (26,204 per hectare). Fringed <br />sage is another major component of this shrubland with a density of 6,508 <br />shrubs per acre (16,082 per hectare). Minor shrubs in order of abundance <br />are: big sagebrush, broom snakeweed, and low rabbitbrush. Winterfat also <br />occurs in this shrubland but did noT occur in any sample quadrats. See <br />Table 3.2.2-3. <br />Mean shrub heights vary from a high of 66 cm for big sagebrush <br />to a low of 23 cm for low rabbitbrush. Rubber rabbitbrush averages 57 cm <br />and fringed sage 35 cm. <br />3.2.3 Big Sagebrush shrubland <br />The Big Sagebrush shrubland vegetation type is confined to e <br />linear band between the lower elevetional limit of the Pinyon-Juniper <br />Woodland and the Sweet Jessup canal end the flat terrace west of the ranch <br />buildings. This community appears to be the climatic climax on the deep <br />loam soils of the river terraces. see photograph Figure 3,2.3-1. <br />This low shrub community is dominated by big sagebrush up to <br />1 or 1.5 meters in height, occasionally interspersed with isolated indi- <br />• viduals of mountain mahogany, serviceberry, and rubber rabbitbrush. Total <br />shrub cover is dense, estimated at 50 to 60 percent. <br />The understory herbaceous composition has been severely disturbed <br />by overgrazing. Total understory cover is estimated to range from 5 to <br />10 percent. Litter cover is low )estimated 5-10 percent), soil cover high <br />(estimated 20-30 percent), and rock cover low )estimated 0-5 percent). <br />Livestock grazing has eliminated most of the herbaceous species, <br />especially (orbs. Today, grasses ere dominant in the herbaceous understory. <br />Common species include: bluebunch wheatgrass, Indian ricegrass, junegrass, <br />squirreltaiH, and needle and thread. <br />Conspicuous fortis present ere: fleabane Eu¢e~vn punti.l~ti, <br />scarlet gilia .7pvmvp~i.~ a¢¢2Q¢ata, yellow cryptantna, and a succulent, <br />hedgehog cactus Echcnviceneu.~ Lr.i.g.lvchidia#u~. <br />The deep loamy soils of the Big sagebrusn shrubland community type <br />ere productive. Above ground net productivity for shrubs antl understory <br />herbaceous species is estimated at 1,500 pounds per acre in en average year <br />end may range to a high of 1,800 pounds per acre in a good year IRay 19801. <br />However, these figures ere for a range site in good condition. The deterio- <br />rated range at the project site would be considerably less productive. <br />• <br />-13- <br />