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• reclaimed area. Additional shrub density plots were located randomly as previously discussed. <br /> In the two reference areas, equal numbers of cover and shrub density samples (15) were taken <br /> in each. All shrubs, including seedlings, with root crowns found within the quadrat boundaries <br /> were tabulated by species and by life stages as follows: seedling, mature, or dead. <br /> Plant Species Frequency and Density Measurements <br /> During the course of cover and shrub density sampling, all plant species occurring within the <br /> shrub density quadrats were noted as a part of each sample. Frequency for each plant species <br /> observed during sampling was calculated by dividing the number of sample transecis in which <br /> the species was observed by the total number of samples (20 in reclaimed areas, 15 in <br /> reference areas). As such, this value is more probably correctly known as "constancy." <br /> Relative vegetation cover was calculated by dividing the absoulute cover of each species by the <br /> total vegetation cover and expressing the result as a percent. <br /> The total number of species (within each lifeform) observed in each sample provide a measure <br /> • of"species density", indicating relative species richness of different areas. These measures <br /> provide an indication of progress toward return of diverse species composition to the reclaimed <br /> areas from a different perspective than is available from examination of cover data alone. <br /> Plant Species Ltstina <br /> During the course of the field work, a list of all encountered plant species (quantitatively plus <br /> incidental observations) was compiled for each reclamation area and the two reference areas. <br /> Scientific names used follow Weber and Johnston (1979); common names cited may be found in <br /> Beetle (1970), Nickerson et al. (1976), or SCS (1979). Cross reference to the substantially <br /> revised scientific nomenclature for the flora of Western Colorado, as set forth by Weber <br /> (1987), may be determined by reference to Wittman et al. (1988). Of plant species observed, <br /> only Canada thistle ( irsi um ary -ns ), Dalmation toadflax (Linnria delmati .a), and common <br /> bindweed (Convolvuls arvensis) are listed state-wide as noxious weeds (Thornton et al. 1974). <br /> Blue lettuce (Lactuca pulchella), buckhorn plantain (Plantago lanceolata), curly dock ($fix <br /> • crispus), and pennycress (Thlaspi arvense), all restricted noxious weeds in Colorado (Thornton <br /> et al. 1974) are also sparingly present at some locations in the reclaimed areas. <br /> 3 <br />