Laserfiche WebLink
2005, an average precipitation year, Calamovilfa has shown less relative cover. As noted <br />before, Bouteloua gracilis relative cover always appears to increase with decreased overall <br />cover values (related to decreased precipitation), as the diminutive stature of this grass is <br />revealed when there is less canopy coverage from taller, fixller species. This season <br />Bouteloua gracilis has decreased with average precipitation. Stipa vtridula, though a cool <br />season grass, responds in the opposite manner of Calamovilfa, with highest relative cover <br />values during normal and dry years. This season, the precipitation amounts and distribution <br />appeazed optimal for Stipa viridula. Artemisia filifolia continues to maintain a relatively <br />constant presence in the reference area as shown by the relative cover values. In past years <br />this species appeared largely unaffected by precipitation, likely due to its woody habit. This <br />season, during an average precipitation yeaz, Artemisia f:lifolia has its lowest relative cover <br />since 1494. <br />4.5.2 1998 Reseeded or Interseeded Areas <br />Quantitative sampling has been undertaken in these areas for the past seven growing seasons. <br />During this time thirty-five species have been encountered. Of the species encountered, six <br />have been present all years. These species include three native perennial warm season grasses <br />(Bouteloua curtipendula (sideoats grama), Bouteloua gracilis, and Calamovilfa longifolia), <br />one introduced annual grass (Bromus tectorum), one native annual forb (Helianthus annuus, <br />(sunflower)), and one introduced annual forb (Kochia scoparia). <br />The core species of the 1998 reseeded or interseeded areas revealed increases by graminoids <br />and decreases by forbs in relative cover this growing season. Of the graminoids, the three <br />native perennial warm season grasses (Bouteloua curtipendula, Bouteloua gracilis, and <br />Calamovilfa longifolia), and the introduced annual grass (Bromus tectorum) all increased in <br />relative cover. During the 2005 season Bouteloua curtipendula increased by 21.8%, <br />Bouteloua gracilis increased by 1140.5 percent, and Calamovilfa longifolia increased by 66.5 <br />percent. )n the 2005 sampling season relative cover for the cool season annual grass Bromus <br />tectorum increased by 332.1 percent. Kochia scoparia and Helianthus annuus both <br />decreased in relative cover this season, Kochia (93.8%) and Helianthis annuus (89.3%). <br />Within the 1998 reseeded and interseeded azeas conditions were optimal for a variety of <br />grasses and unfavorable for core forb species. <br />4.5.3 1999 Reclamation Areas <br />Quantitative sampling has been undertaken in these areas for the past three growing seasons. <br />The short record of sampling precludes any observation or speculation regazding long-term <br />trends at this time. Twenty-one species were identified in 2004 and 20 species in 2005. <br />Twelve graminoids were present in 2004 and 2005, forbs decreased from nine in 2004 to <br />seven in 2005. For the first time the shrub Artemisia filifolia was recorded in the 1999 <br />reclamation azeas, this shrub is infilling from adjacent areas. <br />4.5.4 2000 Reclamation Areas <br />• Quantitative sampling has been undertaken in the 2000 reclamation azeas for the first time in <br />2005. Nineteen individual species were identified within the 2000 reclamation areas. The <br />Coors Energy Company Keenesburg Mine Page 26 <br />2005 Revegetation Monitoring Report <br />