Reclamation Highlights: Native tree survival and growth are improved with less competitive groundcover. Of the variables evaluated in this study, selection of favorable mine soil materials was most influential in improving native tree survival and growth. Invasive species are less abundant where native trees are well established.

Appalachian (eastern USA) coal surface mines fracture geologic materials, causing release of both major ions and trace elements to water via accelerated weathering. When elevated above natural background, trace elements in streams may produce adverse effects on biota via direct exposure from water and sediment and via dietary exposure in food sources. Other studies have found elevated water concentrations of multiple trace elements in Appalachia's mining-influenced streams. Except for Se, trace-element concentrations in abiotic and biotic media of Appalachian mining-influenced streams are less well known. We analyzed environmental media of headwater streams receiving alkaline waters from Appalachian coal mines for eight trace elements (Al, As, Cd, Cu, Ni, Sr, V, and Zn) and assessed the potential consequent ecological risks. Streamwater, particulate media (sediment, biofilm, leaf detritus), and benthic macroinvertebrates (primary consumers, secondary consumers, crayfish) were sampled from six mining-influenced and three reference streams during low-flow conditions in two seasons. Dissolved Cu, Ni, and Sr were higher in mining-influenced streams than in reference streams; Ni, Sr, and Zn in fine sediments and Ni in macroinvertebrates were also elevated relative to reference-stream levels in samples from mining-influenced streams. Seasonal ratios of mining-influenced stream concentrations to maximum concentrations in reference streams also demonstrated mining-influenced increases for several elements in multiple media. In most media, concentrations of several elements including Ni were correlated positively. All water-column dissolved concentrations were below protective levels, but fine-sediment concentrations of Ni approached or exceeded threshold-effect concentrations in several streams. Further study is warranted for several elements (Cd, Ni, and Zn in biofilms, and V in macroinvertebrates) that approached or exceeded previously established dietary-risk levels. Environ Toxicol Chem 2023;42:2651-2665. © 2023 SETAC.

Global salinization of freshwaters is adversely affecting biotic communities and ecosystem processes. We reviewed six decades (1960-2020) of literature published on animal responses to increased salinities across different taxonomic and ecological contexts and identified knowledge gaps. From 585 journal articles, we characterized 5924 responses of mol-lusks, crustaceans, zooplankton, non-arthropod invertebrates (NAI), insects, fishes, and amphibians to salinization. In-sects and fishes were the most studied taxa; Na+ and Cl- were the most studied ions-. Collectively, concentrations of the ions examined typically spanned five orders of magnitude. Species' invasiveness was a key motivation for studying mollusks, crustaceans, and fishes; threats of urbanization and road salts were key motivations for studying NAI, zooplankton, and amphibians. Laboratory studies were more common than field studies for most taxa. Focal life stages in laboratory studies varied widely but juveniles and adults were represented similarly in field studies. Studies of mol-lusks, NAI, and crustacean focused on adults; studies of zooplankton, insects, fishes, and amphibians focused on juve-niles. Organismal-and population-level responses measuring solute uptake, internal chemistry, body condition, or ion concentrations predominated laboratory studies; population-and assemblage-level responses measuring abundance, spatial distribution, or assemblage composition predominated field studies. Negative responses to salinization predom-inated but positive and unimodal responses were apparent across all taxa and organizational levels. Key topics for fur-ther research include a) salinity responses by more taxa, b) responses to especially toxic ions (i.e., potassium, bicarbonate, sulfate, magnesium), c) mechanisms causing positive and unimodal responses, d) traits underpinning re-sponses, e) effects transcending organizational levels, f) ion-specific response thresholds, and g) interactions between salinity and other stressors. Our review suggests inter-taxa variation in sensitivity to salinization reflects occurrence of certain biological traits, including gill-breathing, semi-permeable skin, multiple life stages, and limited mobility. We propose a traits-based framework to predict salinization sensitivity from shared traits. This evolutionary approach could inform management aimed at preventing or reducing adverse impacts of freshwater salinization.

Many ecosystems are losing biodiversity, raising concern for the services they provide. However, the extent of loss is uncertain, especially for diverse insects, because of incomplete sampling. Modeling techniques for estimating upper bounds on diversity are needed to assess benthic freshwater insect abundances, taxa richness, and diversity because some species are declining at alarming rates while others are increasing. In central Appalachian streams of the U.S.A., aquatic insect communities have lost diversity following salinization caused by mining activities. However, the number of taxa observed are dependent upon sampling effort. Incomplete sampling could misrepresent biodiversity and functional losses. Our goal was to use taxon sampling curves to estimate sampling effort required to maximize the probability of accurate benthic macroinvertebrate characterization in dominant riffle habitats of headwater streams. We collected 5 to 10 quantitative benthic macroinvertebrate samples in each of six, first-order streams in the central Appalachian region. For our single-habitat, mesoscale approach, we predicted: (1) macroinvertebrate taxa richness would be the most robust indicator of salinization response compared to diversity, evenness, and density, (2) less sampling effort would be needed to capture taxonomic richness in salinized streams compared to reference streams, and (3) response diversity would also be lower in salinized streams because select trait states would be represented by fewer taxa. Results suggested nominally lower taxa richness, evenness, and diversity in some salinized streams but not in all despite greater or more variable within-stream densities. Nonetheless, sampling effort required to characterize macroinvertebrate communities did not differ between reference and salinized streams, though uneven within-stream taxa distributions corresponded with greater sampling effort requirements for complete characterization. Benthic macro invertebrate community characteristics were different where higher densities and richness of small-bodied and fast-developing taxa were more common in salinized streams. Response diversity depended on trait states. For example, only about five shredder taxa were represented in salinized streams compared to eight taxa in reference streams. Despite some indication of lower response diversity across some functional feeding groups, more than five samples were needed for robust comparisons. Taxon and trait-based sampling curves suggest that greater overall sampling effort is needed and equal samples per stream was critical for complete diversity assessments regardless of the level of mining-induced salinization. Model-based sampling curves can serve as a tool to assess upper bounds on diversity metrics and sample-effort rigor.

The Appalachian coalfield occurs within the eastern United States (US). This mountainous landscape is formed from natural dissection of sedimentary geologic strata with interbedded seams of coal and serves as headwaters for multiple rivers. The region’s natural ecosystems, with a primary vegetation of mostly deciduous forest, are among the non-tropical world’s most biodiverse. After first humans arrived more than 10,000 years ago, the first Europeans came to Appalachia as fur trappers and traders; agriculturalists and merchants came soon after. The region’s diverse forests and richmineral resources supported economic development as settlements expanded and populations grew. Coalmining began in themid-1700s to supply commercial and residential users. Large-scale timber harvesting and coal mining stimulated railroad expansion in the mid-1800s, which improved transportation linkages to more populated areas and further increased coal demand. The American nation’s industrial development increased usage of iron and steel, further expanding coal demands. Coal was essential to American electrification during the twentieth century. With numerous and thick coal seams accessible by both surface and underground mines, Appalachia was the US’s primary coal-producing region from the 1800s through the 1970s. Appalachian coal mining has influenced the region’s landscapes, forests, water, and people over more than two centuries.

Appalachian coal mining provided the lifeblood of energy for a century of expanding industrial development in America. Now, coal production in Appalachia has declined to levels not seen since the late 1800s. Coal's legacy is stamped on Appalachia's mined landscapes and remains imprinted on Appalachia's coal-mining communities, and these impacts will influence land, water, and people into the 21st century, environmentally as well as economically and socially. We call on local, state and national leaders to recognize the challenges ahead for Appalachia's coal-producing communities and people; to promote economic development, education, and health in these areas; and to encourage greater chances for expansion of economic opportunities and quality of life for residents.

For more than a century, the coal-mining industry has been a major economic force and employer in the Appalachian region of eastern USA. As national and global energy economies experience rapid change, Appalachian mining is declining in a way that appears permanent. Coal mining, however, has left its mark on the region's lands, waters, and people. Most mined lands have soils, plant and wildlife communities that differ from those present in the region's existing native forests and are not used for economically valued purposes. Non-native plants are prominent on many former mine sites. Mined areas typically produce waters with elevated geologic-origin pollutants, major ions and trace elements, and support biotas differing from those present in waters flowing from the region's native forests. Human communities also reflect the region's mining history, as economic, education, and human-health indicators in intensive coal-mining areas lag those elsewhere in the region. These effects are evident as coal-mining declines to levels last seen in the late 19th century and with little prospect of recovery. As the people of the Appalachian coalfield look to the future, they do so while bearing that legacy. Here, we describe the condition of Appalachia's resources as they have been influenced by mining. We also look to the future by presenting opportunities for conversion of the region's extensive mined lands to beneficial uses and offering our perspective on prospects for Appalachia's coal-mined areas.

Benthic macroinvertebrate community assessments are used commonly to characterize aquatic systems and increasingly for identifying their impairment caused by myriad stressors. Yet sampling and enumeration methods vary, and research is needed to compare their abilities to detect macroinvertebrate community responses to specific water quality variables. A common assessment method, rapid bioassessment, uses subsampling procedures to identify a fixed number of individual organisms regardless of total sample abundance. In contrast, full-enumeration assessments typically allow for expanded community characterization resulting from higher numbers of identified organisms within a collected sample. Here, we compared these two sampling and enumeration methods and their abilities to detect benthic macroinvertebrate response to freshwater salinization, a common stressor of streams worldwide. We applied both methods in headwater streams along a salinity gradient within the coal-mining region of central Appalachia USA. Metrics of taxonomic richness, community composition, and trophic function differed between the methods, yet most metrics exhibiting significant response to SC for full-enumeration samples also did for rapid bioassessment samples. However, full-enumeration yielded taxonomic-based metrics consistently more responsive to the salinization gradient. Full-enumeration assessments may potentially provide more complete characterization of macroinvertebrate communities and their response to increased salinization, whereas the more cost-effective and widely employed rapid bioassessment method can detect community alterations along the full salinity gradient. These findings can inform decisions regarding such tradeoffs for assessments of freshwater salinization in headwater streams and highlight the need for similar research of sampling and enumeration methodology in other aquatic systems and for other stressors.

Elevated dissolved major ions (salinization) from surface coal mining are a common impact to central Appalachian headwater streams. Salinization is associated with alterations of benthic macroinvertebrate communities, as many organisms are adapted to the naturally dilute streams of the region. These geochemical and biological alterations have been observed in streams decades after mining, but it remains unclear whether and at what rate water quality and aquatic biota recover after mining. To address this issue, we analyzed temporal trends in specific conductance (SC), ion matrix ratios, and benthic macroinvertebrate communities over an eight-year period in 23 headwater streams, including 18 salinized by surface coal mining. We found strong, negative correlations between SC and diversity of benthic macroinvertebrate communities. Temporal trend analysis demonstrated limited recovery of water chemistry to natural background conditions. Five of the 18 mining-influenced streams exhibited declining SC; however, annual rates of decline in these streams ranged from 1.9% to 3.7% of mean annual SC, suggesting long time periods will be required to reach established benchmark values (ca. 25 years) or values observed in our five reference study streams (ca. 40 years). Similarly, there was limited evidence for recovery of macroinvertebrate community metrics, even in the few mining-influenced streams with decreasing SC. These findings indicate that salinization and its biological effects persist, likely for decades, in central Appalachian headwater streams. Our work also highlights the value of long-term monitoring data for assessing recovery potential of salinized freshwaters, as well as the need for improved understanding of water quality and biological recovery processes and time frames.

Headwater streams impacted by surface coal mining in the central Appalachian region of the eastern USA have characteristics not shared by reference-quality streams. These include elevated salinity, often measured using specific conductance (SC) and cited as a primary stressor of benthic macroinvertebrate communities. The study objective was to assess influence by mining-origin stressors on benthic macroinvertebrate community structure in headwater streams. Stream habitat characteristics were measured and benthic macroinvertebrates were sampled from 12 central Appalachian streams, 9 of which were influenced by mining. Multiple benthic macroinvertebrate community metrics, including Ephemeroptera density, richness, and composition were correlated negatively with watershed mining extent and with SC. Predator density and scraper richness were correlated negatively with watershed mining, stream-water selenium, and SC. Clinger richness was correlated positively with stream substrate characteristics including large cobble-to-fines ratios and relative bed stability, and was correlated negatively with watershed mining and SC. Relationships of predator density and scraper richness with selenium concentrations, and relationships of clinger richness with stream substrate characteristics, are consistent with stress mechanisms revealed by prior studies. Improved understanding of how habitat features are altered by mining and influence community structure in headwater streams can inform water resource management in mining areas.

Toxic effects of selenium (Se) contamination in freshwaters have been well documented. However, study of Se contamination has focused on lentic and larger order lotic systems, whereas headwater streams have received little scrutiny. In central Appalachia, surface coal mining is a common Se source to headwater streams, thus providing a useful system to investigate Se bioaccumulation in headwater food chains and possible longitudinal patterns in Se concentrations. Toward that end, we assessed Se bioaccumulation in 2 reference and 4 mining‐influenced headwater streams. At each stream, we sampled ecosystem media, including streamwater, particulate matter (sediment, biofilm, leaf detritus), benthic macroinvertebrates, salamanders, and fish, every 400 m along 1.2‐ and 1.6‐km reaches. We compared media Se concentrations within and among streams and evaluated longitudinal trends in media Se concentrations. Selenium concentrations in sampled media were higher in mining‐influenced streams compared with reference streams. We found the highest Se concentrations in benthic macroinvertebrates; however, salamanders and fish bioaccumulated Se to potentially harmful levels in mining‐influenced streams. Only one stream demonstrated dilution of streamwater Se with distance downstream, and few longitudinal patterns in Se bioaccumulation occurred along our study reaches. Collectively, our results provide a field‐based assessment of Se bioaccumulation in headwater food chains, from streamwater to fish, and highlight the need for future assessments of Se effects in headwater streams and receiving downstream waters. Environ Toxicol Chem 2020;39:692–704. © 2020 SETAC