Long-Term Impacts on Macroinvertebrates Downstream of Reclaimed Mountaintop Mining Valley Fills in Central Appalachia

Abstract

Recent studies have documented adverse effects to biological communities downstream of mountaintop coal mining and valley fills (VF), but few data exist on the longevity of these impacts. We sampled 15 headwater streams with VFs reclaimed 11-33 years prior to 2011 and sampled seven local reference sites that had no VFs. We collected chemical, habitat, and benthic macroinvertebrate data in April 2011; additional chemical samples were collected in September 2011. To assess ecological condition, we compared VF and reference abiotic and biotic data using: (1) ordination to detect multivariate differences, (2) benthic indices (a multimetric index and an observed/expected predictive model) calibrated to state reference conditions to detect impairment, and (3) correlation and regression analysis to detect relationships between biotic and abiotic data. Although VF sites had good instream habitat, nearly 90 % of these streams exhibited biological impairment. VF sites with higher index scores were co-located near unaffected tributaries; we suggest that these tributaries were sources of sensitive taxa as drifting colonists. There were clear losses of expected taxa across most VF sites and two functional feeding groups (% scrapers and %shredders) were significantly altered. Percent VF and forested area were related to biological quality but varied more than individual ions and specific conductance. Within the subset of VF sites, other descriptors (e.g., VF age, site distance from VF, the presence of impoundments, % forest) had no detectable relationships with biological condition. Although these VFs were constructed pursuant to permits and regulatory programs that have as their stated goals that (1) mined land be reclaimed and restored to its original use or a use of higher value, and (2) mining does not cause or contribute to violations of water quality standards, we found sustained ecological damage in headwaters streams draining VFs long after reclamation was completed.

Specific Conductance Reduction in Valley Fill Runoff Using the Cost-Effective Sulfate Removal Process

“…Water samples collected from OF and BH were similar in composition to other sites in central Appalachia (USEPA, 2011;Clark, 2016;Timpano, 2010;Pond et al, 2014). Office Fill had the higher SC of the two sites, with an initial SC value of 2,500 µS/cm, as compared to 1,500 µS/cm at BH.…”

“…Coal mines in central Appalachia that dispose of mining spoils in valley fills have been identified as a contributor to elevated specific conductance (SC) in receiving streams (Pond et al, 2014;Timpano et al, 2010). Runoff waters from these areas, which contain elevated levels of Ca 2+ , Mg 2+ , HCO3 -, and SO4 2-, have been shown to significantly impact the benthic organisms in receiving streams.…”

Effects of Coal Mining, Forestry, and Road Construction on Southern Appalachian Stream Invertebrates and Habitats

“…Much of that activity was contour strip mining (mining exposed coal layers near ridgelines) and auguring of coal seams. In 1977, Congress passed (Pond et al 2014). …”

Macroinvertebrate and organic matter export from headwater tributaries of a Central Appalachian stream

“…This simulation suggests that leaving few or no headwater tributaries would have downstream consequences on the persistence of stream populations. Thus, intact headwaters are needed to counteract downstream extinction rates by providing constant supplies of drifting sensitive colonizers; however when present, these drifters could also affect bioassessment results by masking the detection of unabated stressors to a resident downstream assemblage especially since the fate of these sensitive colonizers is unknown (Pond et al, 2014). These tributaries are also important sites for organic matter inputs and transformation, where these products are ultimately exported to downstream consumers (Gomi et al, 2002;Wipfli & Gregovich, 2002;Meyer et al, 2007).…”

“…In this region, headwater streams harbor diverse and sensitive macroinvertebrates that are vulnerable to extirpation from regional land uses such as large-scale surface mining and streamside residential development (Pond et al, 2008;Pond, 2010;Bernhardt et al, 2012;Cormier et al, 2013;Merriam et al, 2013). In bioassessment, some evidence suggests that intact tributary streams likely contribute sensitive drifting larval colonists to impaired downstream reaches thereby increasing biodiversity and potentially lessening the perceived severity of impairment in receiving streams (Pond et al, 2014;Orlinskiy et al, 2015); others suggest that knowledge of dispersal constraints (e.g., fragmentation and lack of source populations) are critical in understanding appropriate stream restoration designs and predicting subsequent success (Parkyn & Smith, 2011;Sundermann et al, 2011;Tonkin et al, 2014). Support for these dispersal-based linkages was shown by Campbell Grant (2011) who simulated pruned (e.g., loss of headwaters through burial) versus fractal networks; when dispersal was downstream biased (drift), time to metapopulation extinction was shorter for the pruned stream network (conditions often found in upland areas of urbanized and mined landscapes) compared to a more branched, fractal network.…”