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• • Vegetation Information Successional Trends and Revegetation Very limited information is available for assessing successional pathways in the natural ecosystems on this site. What revegetation has been done is limited in extent and generally quite young. As a result, describing these pathways is fairly speculative. The reclamation environment of the site will be characterized by a good annual moisture quantity and pattern (see Exhibit K -Climate). During the growing season the moisture pattems aze favorable, although it can sometimes come in less effective thunderstorms rather than slow drizzle. Severe drought periods are not common and this is reFlected in the vegetation. South facing slopes are occupied by ma~ty drought resistant species, but their compazatively high density indicates that the drought resistant capability is not commonly required except during rare dry spells. If drought was common the same species would probably be there, but the density should be lower. This indicates a favorable environment for revegetation, although certainly not ideal. Tl e ideal situation, given the existing climatic pattems, would be to have all benches face north. On the other hand, east facing benches are nearly as favorable because the wall above the bench provides shade early in the afternoon. This increases the efficiency of moisture utilization considerably and helps to increase growth rates and density. Many of the existing south facing slopes are occupied by locally dense growths of cheatgrass (Broruus tectorum). This species may become a problem in revegetation and because it is difficult to control needs to be watched closely. Careful management to keep such high impact weeds as cheatgrass out of the revegetation needs to be implemented. The revegetation environment is an ideal location fo:• such weedy species to gain a foothold and eventually dominate large areas at the expense of the desirable species. On the other hand, where most of the growth medium is composed of Fme and coarse sized particles left from mining, the ability of weeds to invade such sites is highly limited. Highly opportunistic weeds tend to prefer sites were fettility is fairly high. Mine spoil typically is not fertile and therefore favors species with low fertility requirements. In short, weeds find the mine spoil environment to be quite unfavorable. By using species that are able to grow in low and moderate fertility envirotunents as well as species that increase the fertility, eventually an environment is crer.ted that is highly favorable to long-lived grasses. This favorability helps increase the density of those species and keep out the weeds through competition. In conclusion, the existing vegetation on the site exhibits a high diversity of micrcenvirottments that translates into high diversity plant microcommunities. Although the successional pathways ~:aken to produce the existing vegetation is not evident, the existing vegetation provides many clues helpful to the revegetation program. Because the revegetation environment will mostly be a virgin envirotment, a full understanding of the natural vegetation on the south facing slopes is very helpful in designing a revegetation program. The south facing slopes, occupied mostly by the Tolman series, is scmewhat representative of the environment on the reclamation lands. Therefore, emulating what occt.rs there, with respect to all aspects of the vegetation, has a high probability of success on the quarry bem:h environment. This is not to say that the north facing slope environment should be ignored. But few sites on the quarry will exhibit that kind of environment initially and therefore taking dvection from that environment would be unrealistic. By designing a proper seed mixture based on what is observed on the south facing slopes, quarry reclamation should be successful, although not necessarily rapid revegetation. Menzer Quarry Amendment Exhibit J Page 8