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showed variation, either increasing slightly (Bouteloua gracilis) or decreasing significantly <br />• (Calamovilfa longifolia), and the woody shrub relative cover increased slightly. This <br />observation appears to confirm the relationship between precipitation and species <br />representation. <br />Responses of the dominant species within the reference area have been varied. Andropogon <br />hallii has maintained a constant significant presence within the reference azea since 1994, and <br />the cover of this species appears to be directly correlated with above average precipitation <br />levels during the period May through July. The eazly and limited precipitation appeazs to have <br />favored the cool season graminoids and hindered the late season growth of the tall warm <br />season grass Calamovilfa. Calamovilfa longifolia, though a warm season grass, shows <br />greater relative cover during average and wet years in the reference azea. To achieve full <br />growth, Calamovilfa appeazs to require more moisture and a longer overall favorable growing <br />season. As noted before, Bouteloua gracilis relative cover always appeazs to increase with <br />decreased overall cover values (related to decreased precipitation), asthe diminutive stature <br />of this grass is revealed when there is less canopy coverage from taller, fader species. Stipa <br />viridula, though a cool season grass, responds in the opposite mamier of Calarnovi fa, with <br />highest relative cover values during normal and dry yeazs. This season, the precipitation <br />amounts and distribution appeazed optimal for Stipa vtridula, Artemisia filifolia continues to <br />maintain a relatively constant presence in the reference area as shown by the relative cover <br />values This species appeazs largely relatively unaffected by precipitation, likely due to its <br />woody habit. <br />. 4.5.2 1995 Reclamation Areas <br />The 1995 reclamation areas have been sampled quantitatively for the last seven growing <br />seasons. A total of forty species have been encountered in vegetation sampling since 1998. Of <br />those species, eight were present in each year of the sampling. These species included five <br />perennial cool season grasses, two perennial warm season grasses, and one annual cool season <br />grass. <br />No one species has shown consistent yeazly increases in relative cover over the period of <br />sampling. However, several perennial species show stable contributions during the last seven <br />growing seasons, including Agropyron cristatum, Agropyron dasystachyum, Agropyron <br />smithii, Bouteloua gracilis, Calamovtlfa longifolia, and Oryzopsis hymenoides. The cool <br />season graminoids Agropyron cristatum and Oryzopsis hymenoides decreased in relative <br />cover this season, while Agropyron dasystachyum, Agropyron smithii, and Bromus <br />marginatus increased. Bouteloua gracilis increased in relative cover the first three years, <br />decreased slightly in 2001, increased significantly in 2002, decreased significantly in 2003, and <br />increased significantly this yeaz. Bromus tectorum relative cover decreased significantly this <br />season, revealing its sensitivity to spring precipitation and the matwation of the revegetated <br />azea. No fortis, succulents or woody plants have been encountered consistently in this <br />reclamation azea. Ambrosia psilostachyq Helianthus anrruus, and Kochia scoparia have been <br />sampled in six of seven yeazs, but with the exception of Kochia scoparia this year (7.99% <br />relative cover), none contributes significantly consistently to relative cover. <br />• <br />Coors Energy Company Page 20 <br />2004 Revegetatwn MoniWrfng Report <br />