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Structural and functional characteristics of natural and constructed channels draining a reclaimed mountaintop removal and valley fill coal mine
Citation:
FRITZ, K. M., S. FULTON, B. R. JOHNSON, C. D. Barton, J. D. Jack, D. A. Word, AND R. A. BURKE. Structural and functional characteristics of natural and constructed channels draining a reclaimed mountaintop removal and valley fill coal mine. JOURNAL OF THE NORTH AMERICAN BENTHOLOGICAL SOCIETY. North American Benthological Society, Lawrence, KS, 29(2):673-689, (2010).
Impact/Purpose:
The primary objective of the research is to provide bioassessment programs the scientific tools to study headwater stream ecosystems. In particular these include: 1) standard field protocols for assessing headwater streams (including those that are intermittent); 2) appropriate index periods for field sampling in various geographic regions; 3) physical and biological indicators of hydrologic permanence; and 4) potential stressors or impairments to headwater streams.
Description:
Mountaintop removal and valley fill (MTR/VF) coal mining has altered the landscape of the Central Appalachian region in the United States. The goals of this study were to 1) compare the structure and function of natural and constructed stream channels in forested and MTR/VF catchments across ephemeral, intermittent, and perennial flow regimes; and 2) assess the relationship between litter decay and structural measures, such as the Rapid Bioassessment Protocol (RBP) habitat assessment, currently used by regulatory agencies. Specific conductance of stream water was on average 36-57x higher at perennial sites below valley fills than at perennial sites in forested catchments, whereas pH was circumneutral in both catchment types. Channel habitat and invertebrate assemblages within litterbags differed between forested streams and constructed channels in MTR/VF catchments. Invertebrate density, diversity and biomass were typically higher in litterbags from forested catchments than in MTR/VF catchments. No differences in ergosterol concentration were detected between forested and MTR/VF sites. Decay of oak leaves was slower at perennial and intermittent sites below valley fills compared to perennial and intermittent forest sites; however, there were no differences in decay rates detected between natural and constructed channels with ephemeral flow regimes. We suggest that physical rather than biological processes were driving litter decay in intermittent constructed channels based on the flashy flows, the tattered state of litterbags, and relatively low densities of shredding invertebrates at those sites. Decay rates of oak leaves were significantly related to conductivity at perrenial sites, and shredder biomass and diversity across all sites, but were not correlated with RBP scores. Land use changes associated with MTR/VF have detrimental consequences to headwater stream function that are not adequately addressed using the RBP methodology.