Topoedaphic unit analysis: A site classification system for reclaimed mined lands

Evaluating the success of mined land reclamation is made difficult by the multiformity of environmental conditions present following reclamation. Defining topoedaphic units for reclaimed mined land should make future evaluations rapid and accurate. In this study, properties measured were soil physical (topsoil and subsoil depth, texture, saturation percentage) and chemical (SAR, EC, pH, Ca, Na, Mg) characteristics, and topographic considerations (aspect, slope position). To define topoedaphic units we developed the following method. Principal component analysis followed by cluster and discriminant analysis were used to define topoedaphic units. Vegetation cover was then sampled within units. The aim was to establish whether vegetation properties were significantly different among topoedaphic units. When vegetation properties would not fully discriminate among topoedaphic units, topoedaphic units were redefined. The method was tested at the Glenharold Mine in North Dakota, USA. Two topoedaphic units were identified: Unit 1 restricted to upper slope positions and Unit 2 more mesic downslope positions. Topoedaphic units, defined by soil and topographic properties, were also different in terms of plant communities defined by live basal cover. We conclude that topoedaphic unit analysis or stratified sampling of topographic positions would be a more objective analysis of reclamation success.