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COMPARISON OF VEGETATION COMMUNITIES: 1994-2001 • Direct comparison of the 2001 monitoring data for the areas sampled with that of previous years can only be undertaken for a short time period (three to four yeazs). Savage and Savage has monitored the Osgood sand reference area continuously since 1994. The 1985, 1986, and 1987 reclamation aeeas were monitored from 1994 through phase II bond release in 1998 (Savage and Savage, 1994, 1995, 1996, 1997, 1998). The 1995 reclamation areas were initially monitored in 1998. Monitoring of the 1995 reclamation areas began in 1998, while initial quantitative monitoring of the 1997 reclamation areas and 1998 reseeded or interseeded areas began in 1999. Table 12 presents comparisons of relative cover for encountered plant species within the Osgood sand reference area and the 1995, 1997, and 1998 reclaimed areas for the years 1994-2001. Within the table aze several interesting trends revealing changes in species composition at the reference and reclaimed areas. These trends aze likely attributable to the ambient precipitation regime, vegetation community development, and management of the areas and adjacent property. Osgood Sand Reference Area The Osgood sand reference area has been quantitatively sampled for vegetation cover, herbaceous production and species composition the Iast eight years. Total vegetation cover and total herbaceous production levels appear directly and tightly correlated to the yearly precipitation regime (Savage, 2000). The species composition of vegetation • communities is more reflective of the long term adaptability of the individual species comprising the community. Of the twenty-six species encountered within the Osgood sand reference azea since 1994, only five have been continuously represented from 1994 to 2001 (the Stipa species have been considered the same species). These species are Andropogon hallit, Bouteloua gracilis, Calamovilfa Jongifo/ia, Stipa viridula, and Artemisia frlifolia. These species should be considered to be the determinate core species for the reference azea. They can be categorized as a perennial deciduous woody shrub, three perennial warm season grasses, and one cool season grass. Forb presence and numbers within the reference azea are directly related to precipitation amounts. During this growing season, the five core species comprised 79.9 percent of the total relative cover of all species in the reference area. Of these species, the perennial graminoid species decreased in relative cover this season and the woody shrub relative cover increased slightly. This may be due to the increase in cool season annual grass and fort representarion in this wet year. Responses of the dominant species within the reference area have been varied. Andropogon hallii has maintained a constant significant presence within the reference azea since 1994, though the cover of this species does not appeaz directly correlated with precipitation. Bouteloua gracilis cover in the reference area appears inversely related to • precipitation amount, with the greatest relative cover coming during dry yeazs. This may -19-