Vegetation succession on the surface -mined grasslands of Pike County, Indiana

摘要

In Pike County, Indiana, thousands of hectares of land were planted with non-native grasses following surface mining between 1968 and 1981. The artificial grasslands thus produced have some of the superficial appearance and functional characteristics of natural grasslands and provide habitat for numerous fauna. While normal vegetation succession in this region leads to forest communities, the severity of disturbance generated by surface mining makes the outcome of succession less certain for these sites. This research investigates the nature and status of succession processes on the surface-mined grasslands and attempts to correlate variations to reclamation processes and environmental factors.;A Geographic Information System is constructed and used in conjunction with aerial photographs to classify surface-mined grassland sites in Pike County based upon age, size and glaciation history. Mined areas where vegetation succession is not artificially controlled are identified and randomly selected quadrats on these lands are sampled. The data collected include soil pH and compaction, topographic characteristics and vegetation measurements gathered in the field. Additional data are gathered from the public records of government agencies, mine records and interviews with landowners and others.;Statistical analyses indicate that, while there is a great deal of variability in both the amount and type of woody invasion, vegetation succession in the form of woody invasion is occurring on these lands. It is apparent that, if left undisturbed, they will eventually become forested. No significant difference in terms of percent woody cover is detected between mines reclaimed under pre-Surface Mine Control and Reclamation Act (SMCRA) rules and those reclaimed after that federal law's passage in 1977. No single environmental variable is identified as having significant impact on the succession process. A greater diversity of woody species is, however, found on the post-SMCRA mines, indicating the impact of using reserved topsoil in surface-mine reclamation.