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• from 1997, the observed species density compares favorably with the values <br />of 27.7 and 33.2 species/ 100 m2 observed in the Seneca II reference areas in <br />1998 (which were themselves down by approximately the same amount from <br />1997). Mean native species density slightly exceeded that of the Seneca II <br />1994 reclaimed areas that were also assessed in 1998. <br />Sample Adequacy <br />A summary of sample adequacy calculations for the parameters of cover and <br />woody plant stem density is presented in Table 7 (Appendix 1). Although <br />there was no attempt to achieve sample adequacy during this monitoring <br />study, minimum sample size was calculated for general information. As can be <br />seen in Table 7, sample adequacy was not achieved for cover, herbaceous <br />production, or shrub density sampling. <br />Noxious Weeds <br />Of plant species observed during 1998 sampling of the 1991/1993 reclaimed <br />area, Canada thistle (Cirsium arvense, aka Breea arvensis).is listed state-wide <br />among the top ten noxious weeds (C.R.S. 1996). Downy brome (aka <br />cheatgrass, Bromus tectorum or Anisantha tectorum), .houndstongue <br />(Cynoglossum officinale), and bullthistle (Cirsium vulgare) are also listed as <br />noxious in Colorado. Canada thistle was found in about One-fifth of reclaimed <br />area samples. Downy brome was found in about half of the samples and bull <br />thistle was found in four-fifths of the 1998 samples. Houndstongue is <br />regretfully widespread in the native vegetation, and was present in two-thirds <br />of the samples. <br />r1 <br />LJ <br />tz <br />