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• The species plotted in Figure 34 represent the consistently dominant plant species of the <br />native vegetation community at the Osgood sand reference area over the eight year <br />sampling period. The species include one native woody shrub (Artemisia filifolia), three <br />native warm season grasses (Andropogon hallii, Bouteloua gracilis, and Calamovilfa <br />Inngifolia), and one native cool season grass (Slips viridula). Of the species identified <br />above that were present at least half of the yeazs sampling occurred, none contributed <br />relative cover equal to or greater than three percent for more than 40 percent of the yeazs <br />during which they were present. These species were determined to be minor species in the <br />community. <br />4.0 DISCUSSION AND RECOMMENDATIONS <br />Plotting the quantitative data from eight years of vegetation monitoring at the Keenesburg <br />Mine identified significant relationships for total vegetation cover, total herbaceous <br />production, and precipitation. The data revealed differences in the responses of the <br />Osgood sand reference area, the older reclamation azeas (1985, 1986, and 1987) and the <br />younger reclamation areas (1995, 1997, and 1998) for the vegetation parameters of total <br />vegetation cover and total herbaceous production when compared with precipitation over <br />two timeframes. Identifying and plotting species represented in the Osgood sand <br />reference area over the past eight yeazs revealed that few species and lifeforms were <br />present in significant amounts (as represented by relative cover) over that period. Of the <br />. twenty-five species encountered, only five were consistently present. <br />From this data, it is suggested that the revegetation success criteria used to judge <br />revegetation success at the Keenesburg Mine be revised for the parameters of total <br />vegetation cover, total herbaceous production, and species composition. For total <br />vegetation cover and total herbaceous production, it is proposed that predictive empirical <br />equations based on precipitation be used to develop revegetation success criteria based on <br />the expected values for each parameter. For species composition, the revegetation <br />success criterion has been modified based on the number, lifeform, and seasonality of the <br />significantly represented species over the last eight years. As a result of these changes, the <br />use of the Osgood sand reference area would be discontinued. <br />4.1 Total Vegetation Cover <br />Figure 35 provides a comparison of total vegetation cover and September-July <br />precipitation for the Osgood sand reference area and the 1985, 1986, and 1987 <br />reclamation azeas. Both curves reflect the expected increase of total vegetation cover <br />with increasing precipitation and both data sets correlate well with the best-fit curve <br />equations. Based on field observations and a review of the data from 1994 through 2001, <br />the slightly greater cover values for the reference azea result from the dominance and <br />physiognomy of Artemisia filifolia, the dominant species in the reference area. As this <br />species was not seeded into the reclamation, nor were any woody shrubs deemed <br />necessary or appropriate to meet post-mining land use goals, the cover of this species in <br />-14- <br />