Microsite effects on natural regeneration of anthropogenically disturbed habitats in eastern Ohio

Background/Question/Methods

Surface mining for coal is one of the most intense forms of disturbance in the Eastern Deciduous Forest in the central Appalachian region. As a result of past reclamation activities, many sites exist in a state of arrested succession, never returning to forest cover. A new reclamation approach has been proposed, the Forestry Reclamation Approach (FRA) which attempts to enhance forest recovery via reducing soil compaction. When applied as loose end dumping, the FRA creates a hummocky surface reminiscent of the microtopgraphy in old-growth forests resulting from treefall (i.e. pit and mound topography). We asked if species colonizing FRA-reclaimed mine lands exhibited microsite specificity and what abiotic factors might be driving colonization preferences. Ten 50 m transects were sampled at the Jockey Hollow Wildlife Management Area, a former surface mine in Ohio, recently reclaimed using loose end dumping. Each transect was sampled at 5, 20 and 50 m from remnant forest habitat. At each interval, a 100 m² plot was sampled for woody plant density (stems m^-2). Within the larger plot, eight 1 m² quadrats were censused for percent cover all species and included the swale, side and top microsite positions of each mound created by the end-dump reclamation process.

Results/Conclusions

Herbaceous species richness varied among mound positions with highest species richness at the intermediate slope position (P < 0.01). Herbaceous vegetation was dominated by the common mine-land reclamation species Lespedeza cuneata and Lotus corniculatus, likely dispersed from nearby older reclaimed mine land or remaining in the stockpiled topsoil seedbank. Woody species density increased with distance from remnant forest habitat (P < 0.05). Natural woody colonization was dominated by Platanus occidentalis and Populus deltoides, likely dispersed from nearby forest stands. Mound aspect was not important to plant species richness or community type but there was significantly (P < 0.05) higher total percent cover on the southwestern sides of the sampled mounds. Reclamation of these sites is targeted toward hardwood generation, but previous studies indicate that the development of the herbaceous layer may affect success of desired planted species. Further analysis will elucidate the differences in plant communities between microtopographic positions and how these community differences may be related to environmental differences existing between microsites. These results indicate that species preferentially colonize microsites at different positions along a microtopographic gradient, possibly as a result of differing abiotic conditions among those microsites.