Laserfiche WebLink
sampling. Helianthus annuus and Kochia scoparia were the major contributors to forb <br />production in 2004, both large plants in stature. As Helianthus annuus was conspicuously <br />absent from cover sampling in 2005, this partially explains the decrease in biomass <br />• production this year. <br />Major graminoid contributors to cover in the 1999 reclamation areas in 2004 lazgely <br />remained. the same in 2005. Significant forb contributors to relative cover in 2004 were <br />lacking in 2005, including Helianthus annuus, Kochia scoparia, Melilotus o~cinalis, and <br />Ambrosia psilostachya. These aze all lazge plants and robust biomass producers. <br />Based on these observations, it was concluded that the short intense pulses of precipitation at <br />certain critical growing season periods significantly affect biomass production and species <br />contributions at the Keenesburg Mine. <br />4.4 SPECIES COMPOSITION <br />The Colorado Division of Minerals and Geology considers species composition of the <br />revegetated and reclaimed azeas to be an indicator of successful vegetation establishment <br />and a diverse vegetation community. A standazd has been set by CDMG for the evaluation of <br />species composition at the Keenesburg Mine. To be judged successful, at final bond release, <br />this standazd requires that, "the species composition on the reclaimed area is such that there <br />aze at least seven perennial species of which four aze warm season grasses and one is a forb. <br />No one component of the above species should comprise greater than 40% relative <br />importance nor less than 3% relative importance. Relative importance will be measured by <br />calculating relative cover of the revegetation species. Vegetation species which may be used <br />in the calculation of species composition may be any plant species not defined as a noxious <br />or prohibited plant species, and may be native or introduced." <br />A comparison of the 2005 species composition data with the revegetation success standard <br />reveals that none of the reclamation areas or the Osgood sand reference area meet the final <br />bond release species composition success standazd. All azeas sampled lack the requisite <br />number of warm season grasses, the required perennial forb, or under- or over-representation <br />in terms of relative cover by one or more species. <br />Species presence and representation was slightly greater in the Osgood sand reference area <br />than encountered in 2004, possibly attributable to the precipitation regime favorable to eazly <br />cool season species (Table 14). The 1998 and 1999 areas each contained one fewer species, <br />than in 2004, in the case of the 1998 areas, two fewer graminoids and one added shrub, <br />whereas the 1999 areas lost two forbs and gained one shrub. <br />4.5 COMPARISON OF VEGETATION COMMUNITIES: 1994-2005 <br />Direct comparison of the 2005 monitoring data for the azeas sampled with that of previous <br />yeazs can only be undertaken for a short time period (six to seven years). Savage and Savage <br />has monitored the Osgood sand reference azea continuously since 1994. The 1985, 1986, and <br />. 1987 reclamation azeas were monitored from 1994 through Phase II bond release in 1998 <br />Coors Energy Company Keenesburg Mine Page 24 <br />2005 Revegetation Monitoring Report <br />