Laserfiche WebLink
been present in all yeazs. These species include one perennial warm season grass <br />{Calamovi fa longtfolia), one perennial cool season grass (Oryzopsis hymenoides), one <br />• annual grass (Bromus tectorum), one perennial native forb (Ambrosia psilostachya), one <br />biennial forb (Melilotus officinalis), one native annual forb (Helianthus anrruus), and one <br />introduced annual forb (Kochia scoparia}. Three new species were encountered in 2000, <br />and three have been present during the last two yeazs, Agropyron smithii, Bromus <br />marginatus and Nuttallia rruda. <br />In the 1997 reclamation areas, Calamovilfa dongtfolia, Oryzopsis hymenoides and <br />Ambrosia psilostachya had higher relative cover values during the dry 2000. This may be <br />due to a competitive effect or other unknown effect on these species. Kochia scoparia <br />and Helianthus anrruus have both decreased in relative cover over the last three yeazs. <br />This may indicate a maturing of the vegetation community and a replacing of the <br />pioneering early seral species. Melilotus o~cinalis is an opportunistic species that <br />responds duectly to precipitation. The new species encountered last year represent <br />perennial species of more mature vegetation communities. <br />1998 Reseeded or Interseeded Areas <br />Quantitative sampling has been undertaken in these azeas for the past three growing <br />seasons. During this time twenty-seven species have been encountered, seven of them new <br />this season. Of the species encountered, twelve have been present all years. These species <br />include four perennial warm season grasses (Andropogon hallii, Bouteloua cur[ipendula, <br />Bouteloua gracilis, and Calamovilfa longifolia), three perennial cool season grasses <br />• (Agropyron smithii, Oryzopsis hymenoides, and Stipa viridula) one annual grass (Bromus <br />tectorum), one perennial native forb (Ambrosia psilostachya), one native annual forb <br />(Helianthus annuus), and two introduced annual forbs (Kochia scoparia and Sisymbrium <br />altissimum). <br />Of the species present in all years, Agropyron smithit and Ambrosia psilostachya have <br />consistently increased in relative cover. Andropogon hallii, Bouteloua curtipendula, and <br />Calamovilfa longtfolta, all warm season graminoids, and Stipa viridula, a cool season <br />grass, have greater relative cover during dry conditions. Bouteloua gracilis relative cover <br />is not directly correlated with precipitation, as noted above, while Bromus tectorum <br />growth is. Remaining species aze opportunistic forbs responding to precipitation or the <br />opening of space in burned azeas. <br />RECOMMENDATIONS <br />Long term monitoring of the Osgood sand reference area and reclaimed areas at the <br />Keenesburg Mine reveals significant differences between the reference azea and the <br />reclaimed azeas. The dominant lifeforms of the reference area and the reclaimed areas <br />differ as does the species composition. The design and implementation of the approved <br />revegetation plan and the successful results of the plan indicate that the reference area and <br />• reclaimed azeas will not develop similar vegetation communities, though the rec]aimed <br />azeas aze successful, as determined by sampling and bond release criteria. Therefore, it is <br />-21- <br />