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J <br />35 <br />difference: their species composition (diversity) is slightly different as are <br />the successional trends by which they reached their present situation. <br />Treatment 2 favors a stand high in legume composition which is very desirable <br />since all plants will benefit from a perpetual source of nitrogen. The major <br />drawback is a community with a low density of shrubs due to their inability to <br />compete with these nitrogen-fixers. The nitrogen and excelsior amended plots <br />support increased shrub growth, but again forb growth limits the productivity <br />of the shrub life form to little more than that occurring on Treatment 2. <br />The forb growth occupying Treatments 5 and 6 (nitrogen + excelsior) have <br />mixed advantages when viewed against those established on Treatment 2: better <br />overall diversity than Treatment 2 but less legumes which may reduce treatment <br />performance somewhat in the future as nitrogen becomes limiting and until more <br />nitrogen-fixers can establish. Finally, Treatments 3 and 4 supported the best <br />overall mixture of species, with higher levels of nitrogen improving growth <br />slightly. With time, these subplots may also experience some species shifting <br />as nitrogen is lost from the site and legumes move in to replace high nitrogen <br />dependent plants. At any rate Treatments 2-6 will most likely achieve similar <br />communities in the long run with a moderate grass component, a higher number <br />of fortis dominated by legumes, a few shrubs, and an ever decreasing number of <br />invaders as the stand closes. <br />Fertilization (at least phosphorus and potassium) appears necessary to <br />establish a stand of vegetation that exhibits a biomass and cover somewhat <br />compatible with the Reference Areas (Figures 6 and 7). Density is higher in <br />the test plot than in the native vegetation (Figure 8), but these values will <br />decrease as plants mature and competition for limited resources becomes more <br />dramatic. At this point in time Treatment 2 appears to hold the most economical, <br />yet still satisfactory, approach for revegetating the dolomite waste materials, <br />