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

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4 PART II: STRATEGIES FOR DIVERSE RECLAMA'T'ION Physical Habitat Concerns 4. Many taxa should comprise a few percent relative abundance. Equally important to diversity are physiognomic types and their structural components. Methods by which physiognomic diversity might be formally addressed are beyond the scope of this paper, but some strategies discussed later are aimed at this facet of vegetational diversity, Due to the lack of recognizable habitat gradients and the powerful effects of initial floristics on species composition, the concept of beta diversity isn't appropriate for revegetation analysis. Local landscape diversity may be an appropriate focus of diversity, depending on the areal extent of reclamation. Regional landscape diversity is unlikely to be a focus of bond release because it extends beyond mine boundaries. We shift now from the perspective of a plant ecologist to that of a soil scierai, . To a sail scientist, the key to ensuring reclamation diversity is creating physical habitat diversity. The relation between diversity of habitat and vegetational diversity may be masked by planting wdl- adapted, stress - tolerant competitors or maximized by relying on naive propa zulee in the topsoil and seeding specialist species. In any case, habitat diversity is an integral component of integrated diversity strategies. • On a field/pasture basis, existing reclamation has achieved adequate levels ofhierarclrical richness (Table 1) and heterogeneity (Table 3, Prodgers elsewhere these proceedings). At the same time, revesetation near Colstrip is two to three times as productive as tmmined rangeland (Figure 1). If species diversity was the sole concern, we nught conclude that diversity is not a problem. While fields and pastures may have good alpha diversity, in some respects the fields are the same. Sameness has resulted because, for the most part, they were constructed in the same fashion, following the same reclamation procedures and guided or constrained by the same set of regulations. If one were to stand upon a precipice and look down on the local landscape, reclaimed and unrrnined areas would stand out in stark contrast. At Co/strip, for example, the premine landscape would be comprised of several distinct habitats, and associated with them distinctive plant communities. In contrast, revegetated fields would look pretty much the same, a single "type" or several closely allied types. We look for the forces that have shaped diverse local landscapes to inform us as to how we might proceed in creating more diverse reclaimed landscapes. Near Colstrip, sedimentary rock layers that vary in hardness, grain size, and mineralogy are the material from which the local landscape has been sculpted by forces of erosion and sedimentation over hundreds of thousands of years. Mixed communities of shrubs, subshrubs, and forbs are associated with the stark habitats of gumbo knobs. Coniferous forests occur along sandstone ridges; canopy closure is dependent on sl Shrub /grassland communities occur an sandy colluviurn below the sandstone ridges. Wa m - seaso grasses and yucca grow on soft sandstone batches, and along alluvial shrub riparian communities. Cool - season grasses dominate deep well-drained drainages are deciduous tree and drainages. The effects of climate, disturbance, and herbivory also are b but for now we focus on the enduring elements of habitat. Current reclamation strategies, dictated largely by reclamation regulations, do not re- create the diverse array of premine habitats and cannot be expected to reestablish premine landscape (physiognomic) diversity. Whether they should or not becomes more a question for politics than science. Many factors, such as climate, are entirely beyond our control. Newly reclaimed niinnesoils lack recognizable soils structure and are uniformly deep (Keck and others 1993). The spoil substratum may have higher bulk density than the overlaying soil materials (Keck and Wraith, these proceedings), 147