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3.6.1.3 Plant Species Diversi <br />• <br />The third issue for Trapper Mine's reclamation program is the reestablishment of <br />an adequate plant species diversity. Species diversity is considered by most <br />plant ecologists to be the number of plant species in a particular area and the <br />manner in which the individuals are distributed. Unfortunately, precise defini- <br />tions of these concepts and how they should be measured and evaluated are not <br />well agreed on. Species diversity has in fact been the subject of intense debate <br />amongst plant ecologists for many years. <br />The Uncertainty of the Diversitv Conc <br />Even the desirability of species diversity can be questioned, depending on the <br />objectives of the post mining land use. Ranchers, farmers and other land mana- <br />gers have long recognized the value of monocultures or near moncultures as crop- <br />lands and pastureland. A great deal of effort and money have been expended to <br />reduce species diversity in favor of a single species or a few species considered <br />more suitable to the land use objectives. In contrast, some ecologists have <br />• argued that diversity is critical to provide community stability against pests, <br />diseases and climatic extremes that might eliminate a monoculture. Further, <br />plant species diversity is essential to provide a variety of niches for animals <br />and to meet the varied needs of animals. <br />Once it is assumed that species diversity is desirable, it is still an extremely <br />difficult task to define exactly what it is. McIntosh (1967) discussed a homo- <br />geneity component of species diversity and concluded diversity was maximized when <br />a large number of species were uniformly distributed. One must observe however, <br />that this would result in a total absence of ecotones which are considered to be <br />important use areas for many kinds of animals (Odum, 1971). <br />Many different concepts of the components of diversity and how they should be <br />considered have been discussed in the literature. Diversity is defined by Whit- <br />taker (1975) as the richness of species present in a community. <br />• 3-59