2002-07-08_GENERAL DOCUMENTS - M2002004 (2)

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Other Scales of Diversity Noss (1990 as reproduced in West 1993) distinguished four levels of biodiversity, with notes an composition, structure, function, inventory, and monitoring_ His regional landscape diversity has been discussed; his ecosystem- community level, despite the nomenclatural ambiguity, is closely allied with Whittaker's alpha diversity. Noss identifies two finer levels of diversity. A focus on species populations, perhaps in deference to wildlife ecologists, forces us to consider whether plant populations and ultimately species composition matter in reclamation. Finally, there is a genetic level. In the final analysis, evolutionary processes take place at the population level where genotype selection occurs. Fortunately, we are unaware of work done to investigate genetically based ecological differentiation in populations arising from mining revegetation. Units for Assessing Diversity To a large extent, diversity indices are attempts to give mathematical expression to our intuition. Botanists are predisposed to immediately conceive diversity in terms of flora. Laypersons and perhaps a good many other orgardsms are likely to look past species and see physiognomy. Physiognomy refers to the gross appearance of a kind of vegetation, ignoring its taxonomic composition. Diversity can be measured using broader taxa (hierarchical diversity) or growth - forms, although like species, growth-forms do not differ equally. Vegetation diversity may be distinguished from species diversity on this basis (Bonham and others, 1980). Elsewhere in these proceedings, Prodgers evaluated some redaination factors using a number of vegetation diversity measurements including hierarchical diversity. The coefficient of determination for species and genera richness was 0.88, so evaluating both was hardly worth the effort. The r for species or genera versus families was a little Iess than 0.5. Growth -form ricimess and taxonomic groupings were less related (r < 0.2). Sindelar (1980) found revegetated communities to have about half the richness of native rangeland and considerably lower heterogeneity, in part due to reliance on introduced species that tended to restrict diversity through competitive dominance. par more recent reclamation, that is no longer the case. Table 1 compares richness of fields (uniform soils and seeding) and pastures (sets of contiguous fields) at Western Energy's Rosebud 1fiine to several semmatural types sampled in unmined areas elsewhere in eastern Montana, In Table 1, ricitness is defined as the number of taxa in sample sets unequal in number but with species area curves indicating adequate floristic inventories. The richness of fields compares favorably to a simple blue grarna/westem wheatgrass community. Species and genera richness of pastures falls within the range of more complex native types, but family richness lags. Structure is the natural complement to composition. Structure refers to the measured and described elements of physiognomy. In physiognomy, the emphasis rests on the overall appearance of vegetation, regardless of its floristic composition. Whereas composition uses species units, structure uses life - forms, which may be grouped into synusias (i.e., a ref nerriart of the "layer" concept, groups of life forms, or subdivisions of physiognomy). The proportion of lifteforms deterorines a plant community's physiognomy. Many animals depend upon the structure oftheir habitat. MacArthur (1964), for example, found that bird speces diversity was accurately predicted by foliage height diversity. This type of functional relationship should guide how structural classes are defined. For the animal ecologist, synusia like those used by MacArthur (herbaceous ground cover, shrubs, and small trees 2 -25 feet tall, etc.) might be best. For the plant ecologist, the building blocks of growth -forms (e.g., Raunlciaer's 1934) may be most appropriate. From a physiognomic viewpoint, most coal revegetation would be classed as grassland, steppe, or scrub types (following the types identified by Daubennmire 1968 p. 251). The addition of a forest or 145