Laserfiche WebLink
the warm season grasses "shall comprise at least 50 percent of the total plant cover <br />composition." <br />Historical Data. Since no reference area sampling was performed in this evaluation, and to <br />properly evaluate vegetation trends over time, we compared data previously collected from the <br />Grassland Reference Area data collected at the Southfield Mine. <br />In sampling conducted in the fall of 1987, total plant cover on the Grassland Reference Area was <br />determined to equal 41.00 percent. Total production averaged 74.08 grams l m or 660.1 pounds <br />of air dry forage per acre. Woody plant density averaged 3.2 woody plants per 100 m or 129.5 <br />woody plants per acre. Sampling of the Grassland Reference Area in August of 1997 resulted in <br />total plant cover of 40.00 percent, and production averaged 32.55 g/1l4 m or 1,160 pounds of air <br />dry forage per acre. These data are included only to document historic trends and not in any way <br />to satisfy any of the required bond release vegetation sampling requirements but are used only to <br />make relative comparisons regarding revegetation success. Using these historic Grassland <br />Reference Area data, the revegetation success standard would be approximately 40.50 percent <br />total plant cover and production would average 25.54 g/1/4 m or 910 pounds of air dry forage <br />per acre. <br />Each of these three reclaimed areas were previously sampled in connection with reclamation <br />monitoring performed in 2006. Therefore, to document apparent vegetation trends associated <br />with these reclaimed areas, the data collected in 2010 were compared to the data collected in <br />2006. <br />Statistical Analysis of Data. As required by the Division's Vegetation Guideline, it is not <br />necessary to achieve sample adequacy for interim reclamation monitoring. However, the DRMS <br />Vegetation Guideline recommends the sampling of a minimum of 10 transects for cover, <br />production and shrub density on each reclaimed area monitored. In addition, all of the data <br />collected in this evaluation were analyzed for sample adequacy in order to determine whether the <br />data collected in this evaluation came close to the Division's requirements regarding sample <br />adequacy. The sample adequacy formulas contained in the revised regulations was used, <br />wherein a precision of 0.10 was used for cover and production and 0.15 for shrub density. <br />Results <br />Field Sampling Dates. All of the data utilized in this evaluation were collected between <br />September 13 -15, 2010. At the time of the field sampling, all of the plants were actively <br />growing and it is believed that the sampling was performed near the end of the period of <br />optimum plant growth, when the plant cover and production were near their peak. A total of 98 <br />plant species were identified in connection with this vegetation monitoring effort. A list of all of <br />the plant species encountered or observed during the field sampling efforts in this evaluation is <br />presented in Table 1, Southfield Mine Plant Species List. <br />Sample Adequacy. A statistical analysis of the data collected to characterize the plant cover, <br />5 <br />