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<br /> <br />at least 3% relative cover or composition (3% is the typical lower limit for plant diversity bond release <br />evaluations). All four of those species were grasses. This reference area is located in an area that <br />exhibits "die-off" of sagebrush. It is anticipated that sage reinvasion will occur over the next several <br />years. <br />Review of Tables V11 and Chart V3 indicates that the average herbaceous production of this area in <br />2005 was 1,696 pounds per acre, oven-dry weight. Sixty-six percent (1,114 pounds per acre) of the total <br />herbaceous production is attributable to perennials, with grasses contributing 1,113 lbs./acre and forbs <br />providing 1 lb./acre. Thirty-four percent (582 pounds per acre) of the total production is attributable to <br />annuals, with grasses contributing 578 lbs./acre and forbs providing 5 lbs./acre. Noxious weeds were not <br />found in any of the sampling quadrats in this community, but were observed in the area. <br />Perusal of Tables V12 and Chart V4 indicates that the estimated woody plant density in this area <br />was 540 woody plants per acre with the shrub lifeform accounting for 100% of the total. Rubber <br />rabbitbrush was the dominant woody species with 221 plants per acre followed by basin big sagebrush at <br />198 per acre. <br />3.2.3 Study Area - Reference Area Comparability <br />Review of Table V2 indicates that the total vegetation ground cover and production for the <br />Bottomland baseline study area is comparable to the values obtained from the Bottomland reference <br />area. These comparisons of the "tabular" versus "calculated" t-statistics on Table V2 also indicate strong <br />success given the Students t-test indicated by the guidelines. A two-sided t-test for two independent <br />samples was considered appropriate and the decision rules for this test were: <br />If f* t(o.95,n1+n2-2) , conclude that the two areas are unequal, and <br />If 1* < t(o.95,n1+n2-2), conclude that the two areas are equal (for (x = 0.05). <br />The tabular t values for an a = 0.05 and n-2 degrees of freedom (d.f.) and calculation of the <br />comparison t* statistic for comparison are as follows: <br />Variable <br />Vegetation Cover <br />Production <br />COMAR CREM AOM CHAT ES, INC. <br />tabular t value <br />1.9983 <br />1.9840 <br />t* statistic <br />0.2876 <br />1.5263 <br />Page 18 <br />2005 Collom Vegetation Survey