2002-07-08_GENERAL DOCUMENTS - M2002004 (3)

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• 2000 Billings Land Reclamation Symposium ENHANCING DIVERSITY THROUGH SUBSTRATE VARIABILITY Douglas E. Romig and David L. Clark' ABSTRACT Reclamation diversity continues to receive much attention in reaction to the apparent homogeneity of many reclaimed rangelands in the west. Despite improved seed mixes and topsoil handling, reclaimed minelands in New Mexico remain relatively uniform, often dominated by a few aggressive grasses and four -wing saltbush. To date, regulators and operators have primarily focused on species richness or infra- community diversity of reclaimed plant communities, presumably because it is the easiest to evaluate. In conjunction with cautious suitability guidelines for rootzone reconstruction, this has sometimes led to the reestablishment of a single shrub - grassland plant community. While there are a number of parameters that influence post -mine diversity, we believe the physical and chemical variability of soil substrates is often overlooked and vital to creating long-term landscape diversity. Native soil- landscapes exhibit a broad spectrum of physio- chemical properties that give rise to large - scale, horizontal diversity between plant communities. Through the suitability guidelines and soil salvaging operations, there is a dramatic reduction of soil variability from pre-mine soils. Moreover, baseline information is seldom fully utilized in reclamation plans to increase species diversity or landscape heterogeneity. In this review of soil handling plans at selected mine sites, we critique the regulatory constraints that guide reclamation toward uniformity. In particular, rules regarding soil substitution, topsoil redistribution, desired plant community, potentially toxic materials, and landform reconstruction need to provide more flexibility to build soil- landscapes that enhance inter- community or horizontal diversity. Opportunities to offset this decrease in the soil variability will be illustrated while considering agronomic and toxicity issues. 1 Soil Scientist and Ecologist, respectively, NM Mining and Minerals Division, 2040 S. Pacheco St., Santa Fe, NM 87505.