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recommended that several steps be taken to acknowledge the distinct differences between <br />the reference and reclaimed areas and modify the revegetation success criteria accordingly. <br />• Vegetation Cover and Herbaceous Production <br />It is recommended that a predictive mathematical model from historic precipitation, total <br />vegetation cover, and total herbaceous production data be developed to replace <br />revegetation success criteria for these two parameters from the Osgood sand reference <br />area. Two predictive equations, one for total vegetation cover and one for total <br />herbaceous production should be developed based on site specific precipitation data. <br />These predictive mathematical equations would produce expected levels of vegetation <br />cover and production for given precipitation regimes. Methodology employed could be <br />the same as proposed by Savage (2000). <br />Species Composition <br />As detailed above, the current species composition success criteria is not realistic when the <br />Osgood sand reference azea, from which this criterion was developed, cannot meet the <br />criterion. Based on statistically adequate vegetation cover data taken between 1994 and <br />2001, a new species composition success criterion should be implemented. Any criterion <br />should represent the range, number, and lifeform types of the native vegetation <br />community. The criterion proposed is, the species composition on the reclaimed area be <br />such that there aze at least four perennial species of which three are warm season perennial <br />grasses and one is a cool season perennial grass. No one component of the above four <br />• species should comprise greater than 40% relative importance nor less than 3% relative <br />importance. Relative importance will be measured by calculating relative cover of the <br />revegetation species. Vegetation species that may be used in the calculation of species <br />composition may be any plant species not defined as a noxious or prohibited plant species, <br />and may be native or introduced. <br />Management of Reference and Reclamation Areas <br />Invasion of Bromus tectorum in the native range and undisturbed areas outside the mine <br />site has been noted over the past decade. To a lesser degree, Bromus tectorum has been <br />noted in the early successional stages of revegetated aeeas at the mine site. Whether the <br />vector for dispersal is anthropogenic or natural at the mine site is not known. Control of <br />this species is necessary for continued revegetation success. The wntrolled burning of <br />non-vegetated and revegetated areas this season showed promise in controlling and <br />m;n;m;~ing Bromus tectorum growth and spread, and continuation of these and other <br />control efforts appeaz warranted for the foreseeable time. <br />If the Osgood sand reference area is to be used in future comparisons of revegetation <br />success, reduction of both Artemisia frlifo[ia and Bromus tectorum may be wattanted to <br />maintain a viable community. <br />• <br />_22_ <br />