Surface mining for coal has altered thousands of hectares of natural areas into landscapes often dominated by exotic herbaceous and woody plant species. Since the US Surface Mining Control and Reclamation Act (SMCRA) of 1977, reclamation after coal extraction has been mandated and must include re-vegetation efforts. Such efforts have often included the planting of cool season grasses and nitrogen-fixing plants, including the invasive shrub Elaeagnus umbellata (autumn olive). In this study, we evaluate vegetation species richness, cover, and dominance in grasslands of The Wilds, a large-scale conservation center located on 3,700 hectares of mine land in southeastern Ohio, twenty five years post-reclamation. Furthermore, we examine changes in vegetative cover before and after removal of the invasive shrub, E. umbellata. Within each of twelve 200m x 200m (4ha) study plots, two 50m x 20m subplots were randomly established and then further divided into 10 modules arranged in a 2 x 5 array with four intensively sampled modules. Vegetation plots were surveyed June-July, 2007 and again July-September, 2009. All vascular species were recorded using the North Carolina Vegetation Survey (NCVS) protocol and using an improved method, ‘occurrence weighted cover’ (OWC).
Results/Conclusions
Overall, we sampled 79 different species across all twelve plots in 2007. We evaluated the efficacy of our sampling protocol using two common, incidence-based richness estimators, which indicated that a slightly greater number of species likely exist in the study location [Chao II: 112 (± 17 S.E), and Jackknife II: 118]. Species richness among the 12 plots varied from a low of 11 to a high of 33. Species diversity was estimated using the Shannon Diversity Index (H´), which ranged from a low of 1.04 to a high of 1.78 with a mean of 1.49 (± 0.07 SE). Evenness of species distribution varied however, as the most species rich plots did not always attain the greatest H´ score. Simpson’s Index values indicated that the increased richness in some of the plots resulted from additional rare species, with a few highly abundant species still providing the majority of the plant cover. Currently, we are examining changes in the vegetative community post-E.umbellata removal. Initial data suggests that, without attempts to assist native species immediately after disturbance, other aggressive non-native species quickly colonize the disturbed area. The findings represent important information on reclaimed mine land more than two decades post-reclamation, and have important implications for invasive species management.
