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• 3.3 1985,1986, and 1987 Reclamation Areas <br />Total Vegetation Cover <br />Figures 9 through 12 depict the results of curve fitting to both the January-July and <br />September-July precipitation regimes and values for total vegetation cover for the 1985, <br />1986, and 1987 reclamation azeas. <br />Figure 9 depicts the closest fit curve for the January-July precipitation and cover data from <br />the older reclamation areas from 1994-1998. As with prior plotting for cover, the closest <br />fit curve is a third order polynomial. The calculated correlation coefficient is 0.8597, <br />significantly greater than that obtained when comparing January-July precipitation and all <br />reclamation areas (R2= 0.6877, Figure 2). Figure 10 depicts the best-fit curves for the <br />1985, 1986, and 1987 reclamation areas data individually. The form of the best-fit curves <br />and the correlation coefficients reveal that the curve incorporating all cover data from the <br />January-July precipitation regime and the 1985, 1986, and 1987 cover data (Figure 9) is a <br />close approximation of the results of the individual reclamation area plotting. Correlation <br />coefficients for the individual areas are close to those for the plot of all areas together. As <br />noted before, the sigmoid shape of the best-fit curves reveals inflection points at <br />approximately five and eleven inches of precipitation. This would indicate that at very low <br />precipitation levels (outside the data range), total vegetation cover would be higher than at <br />precipitation ranges between fow and six inches, and that total vegetation cover peaks at <br />• approximately 11.5 inches of precipitation. <br />Total vegetation cover and September-July precipitation for the 1985, 1986, and 1987 <br />reclamation areas is shown collectively and individually in Figures 11 and 12. The <br />collective plot reveals a third order polynomial as the best-fit curve with one inflection <br />point within the data range. A correlation coefficient of 0.9327 was obtained for this data <br />set. Individual plotting of the 1985, 1986, and 1987 reclamation areas total vegetation <br />cover and September-July precipitation shows individual correlation coefficients equal or <br />slightly higher than the collective plot with third order polynomials. As noted with the <br />January-July plots, these curves reveal inflections that indicate minimum and maximum <br />total cover values within the data set range that are not likely borne out in the natwal <br />world. <br />Total Herbaceous Production <br />The results of curve fitting for the two precipitation regimes and total herbaceous <br />production for the 1985, 1986, and 1987 reclamation areas aze found in Figwes 13 <br />through 16. <br />The plot of January-July precipitation and total herbaceous production data from 1994- <br />1998 for the 1985, 1986, and 1987 reclamation areas is depicted in Figure 13. The closest <br />fit curve is a third order polynomial with a high correlation coefficient (RZ= 0.9654). As <br />was the case with cover data, this represents a significant improvement in the explanation <br />-8- <br />