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Table 14 presents comparisons of relative cover for enwuntered plant species within the <br />. Osgood sand reference area and the 1995, 1997, 1998, and 1999 reclaimed areas for the <br />years 1994-2003. Within the table are several imeresting trends revealing changes in <br />species composition at the reference and reclaimed areas. These trends are likely <br />attributable to the ambient precipitation regime, vegetation community development, and <br />management of the areas and adjacent property. <br />4.5.1 Osgood Sand Reference Area <br />The Osgood sand reference area has been quantitatively sampled for vegetation cover, <br />herbaceous production and species composition the last ten years. Total vegetation cover <br />and total herbaceous production levels appear directly and tightly correlated to the <br />yearly precipitation regime (Savage, 2000). The species composition of vegetation <br />communities is more reflective of the long term adaptability of the individual species <br />comprising the community. <br />Of the twenty-eight species encountered within the Osgood sand reference area since <br />1994, only five have been continuously represented from 1994 to 2003 (the Stipa species <br />have been considered the same species). These species are Andropogon hallii, Bouteloua <br />gracilis, Calamovilfa longifolia, Stipa viridula, and Anemisia frlifolia. These species <br />should be considered to be the determinate core species for the reference area. They can <br />be categorized as a perennial deciduous woody shrub, three perennial warm season <br />grasses, and one cool season grass. Forb presence and numbers within the reference area <br />. are directly related to precipitation amounts and distribution. <br />During this growing season, the five core species comprised 813 percent of the total <br />relative cover of all species in the reference area. Of these species, the perennial <br />graminoid cool season species increased significantly in relative cover this season, while <br />the perennial warm season grasses decreased significantly, and the woody shrub relative <br />cover increased slightly. This observation appears to wnfirm the relationship between <br />precipitation and species representation. The native warm season perennial graminoids <br />appear to increase in relative cover under lower spring and winter precipitation or adverse <br />conditions while the cool season graminoids increase during greater winter and early <br />spring precipitation. <br />Responses of the dominant species within the reference area have been varied. <br />Andropogon lrallii has maintained a constant significant presence within the reference area <br />since 1994, and the cover of this species appears to be directly correlated with <br />precipitation above average precipitation levels during the period May through July. <br />Bouteloua gracilis weer in the reference area appears inversely related to precipitation <br />amount, with the greatest relative rover wming during dry years (note the 93% decrease <br />from 2002). Tlris may be related to a wmpetitive effect originating with the small size of <br />this species, wherein Bouteloua thrives when rover of larger species is reduced during dry <br />years. Calamovilfa longifolia, though a warm season grass, shows greater relative rover <br />during average and wet years in the reference area. To achieve full growth, Calamovilfa <br />n <br />U <br />CooreEn~rgyComparq Page 2t <br />2005 RevegetaUon MoniWring Report <br />