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Reference Area No. 1 <br />RESULTS AND DISCUSSION <br />From 1998 to 2001, total vegetation cover has remained relatively stable, while grass cover has risen <br />dramatically and cover of noxious species and non - noxious forbs have markedly declined (see Figure 1). <br />Figure 1 Sutey Reference Area #1 - Absolute Cover <br />Trends; 1998 -2001 <br />50.0% <br />40.0% <br />30.0% <br />20.0% <br />1 0.0% <br />0.0% <br />i �i chi <br />Year <br />Absolute Noxious <br />Cover <br />Absolute Grass <br />C over <br />Absolute Forb <br />C ove r <br />Total Vegetation <br />C over <br />Table 1 at the end of the report lists 2001 absolute and relative cover by species and category. Table 2 <br />lists absolute and relative cover sample means by category and year; 1998 through 2001. Absolute cover of <br />noxious species declined from 6.7% to 2.2% over the course of the study, while absolute cover of perennial <br />grasses increased from 5.7% to 30.7%. The increased cover provided by perennial grasses was offset by a <br />comparable loss of perennial forbs. The reduction in perennial forb cover was largely due to the virtual <br />elimination of the low- growing weedy legume, black medic (Medicago lupulina). Black medic accounted <br />for 28% absolute cover in 1998 and, based on cover, was the dominant species in the stand by a wide <br />margin. By 2001, black medic accounted for only 0.2% absolute cover. The dominant species in 2001 was <br />Kentucky bluegrass (Poa pratensis), which had increased from 3.7% absolute cover in 1998, to 15.9% <br />absolute cover in 2001. Cover summary tables for 1998, 1999, and 2000 are included in the pertinent <br />DMG Annual Weed Sampling Report. Based on cover, the dominant noxious species throughout the <br />period of study was plumeless thistle, which declined from 6.3% absolute cover in 1998 to 1.7% absolute <br />cover in 2001. <br />The apparent decline of noxious species was real, as evidenced by the density data illustrated in Figure 2. <br />Over the course of the study, thistle density sample mean declined by 94 %, from 17.5 thistle plants per <br />square meter in 1998, to 1 plant per square meter in 2001. Houndstongue density was not estimated in <br />1998 but was in following years, and the trend for combined noxious species was similar to that for thistles <br />only, with an 87% reduction from 1999 to 2001. The various noxious thistle species were "lumped" for <br />purpose of the density estimate, due to the significant additional time expenditure that would have been <br />required to count each thistle species separately. 2001 density data is presented in Table 3, while Table 4 is <br />a summary of noxious species density sample means by year. Density data and statistics for each year of <br />the study are reported in the pertinent DMG Annual Weed Sampling Report. <br />Certain observations noted by the sampling crew and the project manager over the course of the study <br />should be noted. Cattle had grazed Reference Area #1 prior to sampling in 1999, but not in the other years. <br />3 <br />