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1 <br />I <br />1 <br />t <br />1 <br />1 <br />The following report describes the vegetation survey conducted by Native <br />Plants, Inc. to address the Colorado MLRD's concerns regarding vegetative <br />cover and diversity standards, as expressed in Stipulation A6 of the State <br />Draft Findings Document, dated March 14, 1983. <br />Sampling Metfiods <br />Vegetation cover was sampled within the sagebrush community type on the <br />Grand Mesa Mine permit area during July 31 and August 1, 1983. Two baseline <br />sampling areas were selected to represent this community type because of the <br />lack of sufficiently large, contiguous blocks of this type: a 1/2-acre area <br />on a west-facing, 30% slope (elevation, 6350 feet) and a 1-acre area on a <br />south-, west-, and north-facing, 5-10% sloping ridge crest (elevation, 6500 <br />feet). The mine itself is situated between 6300-6500 feet and faces all <br />aspects. Figures 1 and 2 illustrate these upper and lower sampling areas, <br />respectively. <br />Random sampling points were selected on each sampling area using an X-Y <br />coordinate grid system with 1-meter intervals. Starting coordinates were <br />obtained from a random number table. The number of sampling points selected <br />for each sampling area was proportionate to that area's contribution to <br />total sampling area acreage. <br />Cover, both total and by species, was estimated using the line-intercept <br />method. Measurements were made to the nearest centimeter along a 10-meter <br />long transect. Random orientation of each transect was achieved by using <br />the position of a watch second hand as it appeared when each sampling point <br />was reached. <br />Sample adequacy was determined using the formula: <br />' N = <br />? <br />2 <br /> (t <br />s <br />~~1 <br />' where <br /> N = minimum number of samples necessary, based on total cover estimates <br />' t = the t statistic <br />f for a 2-tailed t-test at the 80% confidence level <br />i <br />i <br />i <br />1 <br />21 <br /> or woody <br />used commun <br />es ( <br />.e., <br />. <br />) <br />t <br /> s = sample standard deviation <br />' d = 0.1 <br /> X = sample mean <br />1 <br /> <br />