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• numbers of species and their distribution throughout the landscape. Native vegetation <br />communities have adapted to the physical and biotic environment in macro- and <br />microdistributional patterns, resulting in patchiness, and distributions dependent on time of <br />species arrival, competition, and external environmental effects {such as flood or drought). <br />Contrasted to revegetated communities, the native communities aze old, and represent <br />later stages in vegetation community development. <br />Therein lies the conundrum. Is it reasonable to expect comparability between these two <br />dispazate types of vegetation communities? Rickliefs (1973) reports the results of <br />vegetation community successional studies as particularly variable, with reseazchers <br />reporting climax stage development ranging from twenty to forty yeazs for Colorado <br />eastern plains grasslands (Shantz, 1917) and 150 years for a forest climax (Oosting 1942). <br />A complete successional sequence from barren sand to climax forest (a primary <br />successional sequence) may require a millennium (Olson, 1958). <br />Pre-disturbance vegetation at the Keenesburg Mine consisted largely of a shrub <br />community dominated by sand sage (Artemtsia filifolia). The dominance of this shrub is <br />likely due to the long history of range grazing, the porous nature of the aeolian sandy <br />soils, and the low level of annual precipitation. The Osgood Sand Reference Area is <br />dominated by Artemisia filifolia with contributions by Stipa viridula, Calamovilfa <br />longifolia, Andropogon hallii, and Bouteloua gracilis. <br />• Since 1994, annual monitoring of the reference area and revegetated azeas has been <br />conducted (Savage and Savage 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, <br />2003, 2004). Quantitative observations of the revegetated areas reveal continued <br />development of a warm season graminoid prairie community. Reference azea observations <br />over the same period reveal ashrub-dominated community with low overall species <br />diversity. <br />Similar observations have been made over the entire period of record (1994-2005), The <br />dominant lifeforms of the reference area and the reclaimed azeas differ as does the species <br />composition. The design and implementation of the approved revegetation plan and the <br />successful results of the plan indicate that the reference azea and reclaimed azeas will not <br />develop similar vegetation communities, though the reclaimed areas are successful, as <br />determined by sampling and bond release criteria. Therefore, it is recommended that <br />several steps be taken to acknowledge the distinct differences between the reference and <br />reclaimed areas and modify the revegetation success criteria accordingly. <br /> <br />Coore EnergyCompary Keenesburg Mine t'age 3 <br />2005 Addendum to Revision of RevegetaUon 5uccesa CrKeria <br />