Stream Condition Index Research Articles

Establishment and application of the health evaluation system for rain-sourced rivers and lakes in coastal cities

Abstract Conducting a health assessment of rivers and lakes is a technical approach that enables the accurate diagnosis of water health status and scientific analysis of aquatic ecological environments. This paper focuses on studying the typical rain-sourced water bodies of Huangrigang River and Dishui Lake (DSL) in Lin-gang, Shanghai. The Australian Stream Condition Index and the Analytic Hierarchy Process were used to establish a typical river and lake health evaluation index system. Expert scoring and least-squares methods were used to determine the weights of each index, and a quartile method was used to establish the evaluation criteria. The evaluation results indicate that the health status of the Huangrigang River is sub-healthy with a score of 72.1, whereas DSL is healthy with a score of 75.7. The low flow velocity of the regional river and the weak mobility of the water body are the main issues affecting the health status of the HRGR. Additionally, the density of phytoplankton in the river is significantly high. Dripping Lake is faced with two major problems: a high risk of eutrophication and a high density of phytoplankton in the lake. This article provides theoretical support for the sustainable use of regional water resource.

An Evaluation of Indices of Biotic Integrity for Algal and BMI Assemblages in Streams of the Los Angeles Region

ABSTRACTThe Los Angeles region contains a number of heavily altered watersheds, resulting in the degradation of both water and habitat quality along numerous streams. Assessing the impacts of these anthropogenic stressors on biological communities has primarily focused on the California Stream Condition Index (CSCI), a measure of the biotic integrity of benthic macroinvertebrate assemblages. To complement the CSCI an Algal Stream Condition Index (ASCI) was developed to assess the biotic integrity of both soft‐bodied and diatomaceous algal assemblages. Using random forest modeling, we evaluated the performances of the CSCI, the ASCI for diatom assemblages (D_ASCI), and the ASCI for hybrid assemblages containing both diatoms and soft‐bodied algae (H_ASCI). We found that our models of the D_ASCI and H_ASCI could account for approximately 77% and 78% of their observation variation across the watersheds of the Los Angeles region, nearly as high as the 82% accounted for by the CSCI. This indicates the future potential of using indices of biotic integrity based on, or in part, diatom assemblages for streams in this region as additional forms of bioassessment.

Identifying Functional Flow Linkages Between Stream Alteration and Biological Stream Condition Indices Across California

Large state or regional environmental flow programs, such as the one based on the California Environmental Flows Framework, rely on broadly applicable relationships between flow and ecology to inform management decisions. California, despite having high flow and bioassessment data density, has not established relationships between specific elements of the annual hydrograph and biological stream condition. To address this, we spatially and temporally linked USGS gage stations and biological assessment sites in California to identify suitable paired sites for comparisons of streamflow alteration with biological condition at a statewide scale. Flows were assessed using a set of functional flow metrics that provide a comprehensive way to compare alteration and seasonal variation in streamflow across different locations. Biological response was evaluated using the California Stream Condition Index (CSCI) and Algal Stream Condition Index (ASCI), which quantify biological conditions by translating benthic invertebrate or algal resources and watershed-scale environmental data into an overall measure of stream health. These indices provide a consistent statewide standard for interpreting bioassessment data, and thus, a means of quantitatively comparing stream conditions throughout the state. The results indicate that indices of biological stream condition were most closely associated with flow alteration in seasonality and timing metrics, such as fall pulse timing, dry-season timing, and wet season timing. Magnitude metrics such as dry-season baseflow, wet season baseflow, and the fall pulse magnitude were also important in influencing biological stream conditions. Development of ecological flow needs in large-scale environmental programs should consider that alteration to any of the seasonal flow components (e.g., dry-season baseflow, fall pulse flow, wet-season baseflow, spring recession flow) may be important in restructuring biological communities.

Exploring relationships among stream health, human well-being, and demographics in Virginia, USA

Quantification of empirical relationships between ecosystem health and human well-being is uncommon at broad spatial scales. We used public data for Virginia (USA) counties to examine pairwise correlations among two indicators of stream health, thirteen indicators of human well-being, and four demographic metrics. Our indicators of stream health included the Virginia Stream Condition Index (VSCI) and the percentage of stream kilometers with a fish consumption advisory (%FCA); these measures are inversely related. VSCI and %FCA were correlated with some indicators of human health, safety and security, and living standards, as well as with some demographic metrics. VSCI was most strongly correlated (positively) with the percentage of a county’s population self-identifying as White; %FCA was most strongly correlated (positively) with overall mortality rate (number of deaths per 100,000 people). This exploratory study highlights the need for future multidisciplinary, multiscale studies to characterize toxicological, epidemiological, socioeconomic, and political linkages – including causal mechanisms – between ecosystem health and human well-being.

Characterizing benthic macroinvertebrate and algal biological condition gradient models for California wadeable Streams, USA

Abstract The Biological Condition Gradient (BCG) is a conceptual model that describes changes in aquatic communities under increasing levels of anthropogenic stress. The BCG helps decision-makers connect narrative water quality goals (e.g., maintenance of natural structure and function) to quantitative measures of ecological condition by linking index thresholds based on statistical distributions (e.g., percentiles of reference distributions) to expert descriptions of changes in biological condition along disturbance gradients. As a result, the BCG may be more meaningful to managers and the public than indices alone. To develop a BCG model, biological response to stress is divided into 6 levels of condition, represented as changes in biological structure (abundance and diversity of pollution sensitive versus tolerant taxa) and function. We developed benthic macroinvertebrate (BMI) and algal BCG models for California perennial wadeable streams to support interpretation of percentiles of reference-based thresholds for bioassessment indices (i.e., the California Stream Condition Index [CSCI] for BMI and the Algal Stream Condition Index [ASCI] for diatoms and soft-bodied algae). Two panels (one of BMI ecologists and the other of algal ecologists) each calibrated a general BCG model to California wadeable streams by first assigning taxa to specific tolerance and sensitivity attributes, and then independently assigning test samples (264 BMI and 248 algae samples) to BCG Levels 1–6. Consensus on the assignments was developed within each assemblage panel using a modified Delphi method. Panels then developed detailed narratives of changes in BMI and algal taxa that correspond to the 6 BCG levels. Consensus among experts was high, with 81% and 82% expert agreement within 0.5 units of assigned BCG level for BMIs and algae, respectively. According to both BCG models, the 10th percentiles index scores at reference sites corresponded to a BCG Level 3, suggesting that this type of threshold would protect against moderate changes in structure and function while allowing loss of some sensitive taxa. The BCG provides a framework to interpret changes in aquatic biological condition along a gradient of stress. The resulting relationship between index scores and BCG levels and narratives can help decision-makers select thresholds and communicate how these values protect aquatic life use goals.

Using co-occurrence network topology in assessing ecological stress in benthic macroinvertebrate communities.

Ecological monitoring of streams has often focused on assessing the biotic integrity of individual benthic macroinvertebrate (BMI) communities through local measures of diversity, such as taxonomic or functional richness. However, as individual BMI communities are frequently linked by a variety of ecological processes at a regional scale, there is a need to assess biotic integrity of groups of communities at the scale of watersheds. Using 4,619 sampled communities of streambed BMIs, we investigate this question using co‐occurrence networks generated from groups of communities selected within California watersheds under different levels of stress due to upstream land use. Building on a number of arguments in theoretical ecology and network theory, we propose a framework for the assessment of the biotic integrity of watershed‐scale groupings of BMI communities using measures of their co‐occurrence network topology. We found significant correlations between stress, as described by a mean measure of upstream land use within a watershed, and topological measures of co‐occurrence networks such as network size (r = −.81, p < 10–4), connectance (r = .31, p < 10–4), mean co‐occurrence strength (r = .25, p < 10–4), degree heterogeneity (r = −.10, p < 10–4), and modularity (r = .11, p < 10–4). Using these five topological measures, we constructed a linear model of biotic integrity, here a composite of taxonomic and functional diversity known as the California Stream Condition Index, of groups of BMI communities within a watershed. This model can account for 66% of among‐watershed variation in the mean biotic integrity of communities. These observations imply a role for co‐occurrence networks in assessing the current status of biotic integrity for BMI communities, as well as their potential use in assessing other ecological communities.

Evaluation of EPT macroinvertebrate metrics in small streams located within the non-connected stormwater management region of Kansas City, Missouri, USA

AbstractDuring 2012-2014, we evaluated macroinvertebrate communities in streams draining the non-connected stormwater management region (Municipal Separate Storm Sewer System, or MS4) within the Kansas City metropolitan area utilizing the Missouri bioassessment protocols. Trends in aquatic life impairment status based on Missouri's Macroinvertebrate Stream Condition Index (MSCI), as well as richness and abundance of EPT indicator metrics (Ephemeroptera, Plecoptera, Trichoptera), were compared between rural control sites and both transitional and urban stream sites representing varying stages of land use conversion. As compared to non-urban control sites, EPT taxa richness was significantly lower at MS4 urban sites during all three years (p = 0.007 – 0.013) and MS4 transitional sites during one of three years (p=0.48). EPT abundance (%) was significantly lower at MS4 urban sites during all years (p = 0.008 – 0.013) and MS4 transitional sites during one of three years (p=0.34). Mean EPT abundances ranged between 0.6% - 10.3% at urban MS4 sites, and always exceeded 18% at control sites. Both EPT richness and abundance were lower at the MS4 control site but means for EPT and other core metrics at this site were most often similar to non-urban control sites based on analysis of variance (ANOVA). MS4 transitional sites with active development in their watersheds were partially-supporting in their impairment status, and EPT metrics had lower means and generally more variability than control sites. Temporal trends indicate non-urban control and MS4 control sites consistently meet fully-supporting impairment status based on overall MSCI scores, but no study sites currently meet regional expectations (as defined by state reference streams) for either of the EPT metrics. Results indicate that Missouri and Kansas biocriteria for both EPT metrics are not consistently being met at any stream sites in the Kansas City metro area, including fully-supporting control sites and MS4 streams that receive stormwater runoff in watersheds with urban development that is well-established or currently transitioning to urban or suburban land uses.

Macroinvertebrate sensitivity thresholds for sediment in Virginia streams.

Sediment is the most commonly identified pollutant associated with macroinvertebrate community impairments in freshwater streams nationwide. Management of this physical stressor is complicated by the multiple measures of sediment available (e.g., suspended, dissolved, bedded) and the variability in natural "healthy" sediment loadings across ecoregions. Here we examine the relative importance of 9 sediment parameters on macroinvertebrate community health as measured by the Virginia Stream Condition Index (VSCI) across 5 ecoregions. In combination, sediment parameters explained 27.4% of variance in the VSCI in a multiregion data set and from 20.2% to 76.4% of variance for individual ecoregions. Bedded sediment parameters had a stronger influence on VSCI than did dissolved or suspended parameters in the multiregion assessment. However, assessments of individual ecoregions revealed conductivity had a key influence on VSCI in the Central Appalachian, Northern Piedmont and Piedmont ecoregions. In no case was a single sediment parameter sufficient to predict VSCI scores or individual biological metrics. Given the identification of embeddedness and conductivity as key parameters for predicting biological condition, we developed family-level sensitivity thresholds for these parameters, based on extirpation. Resulting thresholds for embeddedness were 68% for combined ecoregions, 65% for the Mountain bioregion (composed of Central Appalachian, Ridge and Valley, and Blue Ridge ecoregions), and 88% for the Piedmont bioregion (composed of Northern Piedmont and Piedmont ecoregions). Thresholds for conductivity were 366 μS/cm for combined ecoregions, 391 μS/cm for the Mountain bioregion, and 136 μS/cm for the Piedmont bioregion. These thresholds may help water quality professionals identify impaired and at-risk waters designated to support aquatic life and develop regional strategies to manage sediment-impaired streams. Inclusion of embeddedness as a restoration endpoint may be warranted; this could be facilitated by application of more quantitative, less time-intensive measurement approaches. We encourage refinement of thresholds as additional data and genus-based metrics become available. Integr Environ Assess Manag 2019;15:77-92. Published 2018. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Tools for managing hydrologic alteration on a regional scale: Setting targets to protect stream health

Abstract Widespread hydrologic alteration creates a need for tools to assess ecological impacts to streams that can be applied across large geographic scales. A regional framework for biologically based flow management can help catchment managers prioritise streams for protection, evaluate impacts of disturbance or interventions and provide a starting point for causal assessment in degraded streams. However, lack of flow data limit the ability to assess hydrologic conditions across a region. Hydrologic models can address this problem. Regionally calibrated hydrologic models were used to estimate current and reference flows at 572 bioassessment sites in southern and central coastal California. Flow alteration was characterised as the difference in 39 flow metrics calculated from simulations of present‐day and reference flow time‐series, calculated under up to four precipitation conditions. Biological condition was assessed with the California Stream Condition Index (CSCI) and its components. Logistic regressions were used to predict the likelihood of high scores (i.e. ≥10th percentile of the CSCI reference calibration data). Statistically significant relationships between increasing severity of hydrologic alteration and decreasing biological condition were used to set thresholds that reflected tolerance for risk of a stakeholder advisory group. An index of hydrologic alteration was created by selecting flow metrics based on their importance for predicting biological response variables in boosted regression tree models. Metrics were selected in the order of decreasing importance, and no more than two metrics per metric class were selected (i.e. duration, frequency, magnitude, timing and variability). Seven metrics were selected: HighDur (duration of high‐flow events), HighNum (# of high‐flow events), NoDisturb (duration between high‐ or low‐flow events), MaxMonthQ (maximum monthly discharge), Q99 (99th percentile of daily streamflow), QmaxIDR (interdecile range of annual maxima) and RBI (Richards–Baker Index). Applying the index to data from a probabilistic survey, 34% of stream‐miles in southern California were estimated to be hydrologically altered. One of four management priorities were assigned to each site based on biological condition and hydrologic status: protection (healthy and unaltered, 52% of stream‐miles), monitoring (healthy but altered 4%), evaluation of flow management (unhealthy and altered, 30%) and evaluation of other management (unhealthy but unaltered, 14%). Regionally derived biologically based targets for flow alteration allow catchment managers to prioritise activities and conduct screenings for causal assessments across large spatial scales. Furthermore, regional tools pave the way for incorporation of hydrologic management in policies and catchment planning designed to support biological integrity in streams. Development of regional tools should be a priority where hydrologic alteration is pervasive or expected to increase in response to climate change or urbanisation.

Potential Impacts of Stream Crossing Traffic On Macroinvertebrate Communities in the Missouri Ozark River

AbstractDepending on intensity, physical disturbance can either decrease or increase diversity of stream macroinvertebrate communities. Recreational activities in parks are one component of physical disturbance. Our objective was to evaluate the effects of stream crossings and recreational traffic on macroinvertebrate assemblages. Five stream‐crossing sites were sampled during winter and summer in the Current River, Ozarks National Scenic Riverways, Missouri, USA. Stream‐crossing traffic was assessed using trail cameras. At each site, macroinvertebrates were collected from four locations: riffle upstream of crossing, riffle immediately downstream of crossing and second and third riffles downstream of crossing. We compared sites and locations within sites using standard metrics (taxa richness, Ephemeroptera, Plecoptera and Trichoptera richness, biotic index and diversity) and their composite stream condition index (SCI) plus multivariate analyses (Nonmetric multidimensional scaling and correlations). Stream crossings had no detectable impacts on macroinvertebrate communities in winter, but in summer location, effects were present. Patterns in SCI scores across locations varied among sites, with no consistent declines in macroinvertebrate diversity downstream of crossings. Longitudinal stream effects dominated over potential stream‐crossing effects on macroinvertebrate communities. Overall, high SCI scores indicated that current levels of stream crossings and traffic in this scenic riverway do not pose a threat to macroinvertebrate communities at the spatial and temporal scale of this study. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Calibration and validation of a regionally and seasonally stratified macroinvertebrate index for West Virginia wadeable streams

Multimetric indices (MMIs) are routinely used by federal, state, and tribal entities to assess the quality of aquatic resources. Because of their diversity, abundance, ubiquity, and sensitivity to environmental stress, benthic macroinvertebrates are well suited for MMIs. West Virginia has used a statewide family-level stream condition index (WVSCI) since 2002. We describe the development, validation, and application of a geographically- and seasonally partitioned genus-level index of most probable stream status (GLIMPSS) for West Virginia wadeable streams. Natural classification strata were evaluated with reference site communities using mean similarity analysis and non-metric multidimensional scaling ordination. Forty-one metrics spanning six ecological categories (richness, composition, tolerance, dominance, trophic groups, and habits) were evaluated for sensitivity, responsiveness, redundancy, range and variability across seasonal (spring and summer) and regional (mountains and plateau) strata. Through a step-wise metric selection process, 8-10 metrics were aggregated to comprise four stratum-specific GLIMPSS models (mountain/plateau and spring/summer). A comparison of GLIMPSS with WVSCI exhibited marked improvements where GLIMPSS detecting greater stream impacts. A variation of the GLIMPSS, which differs only in the family-level taxonomic identification of Chironomidae (GLIMPSS (CF)), was comparable to the full GLIMPSS. These MMIs are robust yet practical tools for evaluating impacts to water quality, instream and riparian habitat, and aquatic wildlife in wadeable riffle-run streams based on sensitivity, responsiveness, precision, and independent validation. These models may be used effectively to detect degradation of the naturally occurring benthic community, assess causes of biological degradation, and plan and evaluate remediation of damaged stream ecosystems.

Ecological Integrity of Streams Related to Human Cancer Mortality Rates

Assessments of ecological integrity have become commonplace for biological conservation, but their role for public health analysis remains largely unexplored. We tested the prediction that the ecological integrity of streams would provide an indicator of human cancer mortality rates in West Virginia, USA. We characterized ecological integrity using an index of benthic macroinvertebrate community structure (West Virginia Stream Condition Index, SCI) and quantified human cancer mortality rates using county-level data from the Centers for Disease Control and Prevention. Regression and spatial analyses revealed significant associations between ecological integrity and public health. SCI was negatively related to age-adjusted total cancer mortality per 100,000 people. Respiratory, digestive, urinary, and breast cancer rates increased with ecological disintegrity, but genital and oral cancer rates did not. Smoking, poverty, and urbanization were significantly related to total cancer mortality, but did not explain the observed relationships between ecological integrity and cancer. Coal mining was significantly associated with ecological disintegrity and higher cancer mortality. Spatial analyses also revealed cancer clusters that corresponded to areas of high coal mining intensity. Our results demonstrated significant relationships between ecological integrity and human cancer mortality in West Virginia, and suggested important effects of coal mining on ecological communities and public health. Assessments of ecological integrity therefore may contribute not only to monitoring goals for aquatic life, but also may provide valuable insights for human health and safety.

Seasonal variability of landuse impacts on macroinvertebrate assemblages in streams of western Georgia, USA

We examined the influence of land use/land cover (LULC) on macroinvertebrate assemblages and environmental conditions in streams draining 18 small watersheds in the Southern Outer Piedmont ecoregion in Georgia, USA, over a 24-mo period of record. Specifically, we analyzed relationships among LULC categories (i.e., % impervious surface (IS), pasture, silviculture, and deciduous/evergreen forest) and hydrological, physicochemical, and benthic habitat variables, and macroinvertebrate metrics. Macroinvertebrate metrics were related primarily to % IS and % deciduous forest cover, with lowest biotic integrity (species diversity, taxon richness, biological stream condition index) found in high % IS watersheds. Biotic integrity declined with decreasing % forest cover throughout the seasons, and multiple regression models and partial correlation analysis revealed that physicochemical and benthic habitat variables explained more variation in macroinvertebrate metrics throughout the seasons than did hydrological variables at most sites. Based on nonmetric multidimensional scaling, heavily urbanized sites were strongly separated from all other sites in terms of assemblage structure. Total ordination distance among seasonal samples from the same sites increased as % forest cover increased. This pattern might have arisen because urbanized streams had high abundances of a few tolerant, persistent taxa and lacked many ephemeral taxa found in less disturbed systems. The influence of anthropogenic LULC on macroinvertebrate assemblages appears to be consistent throughout the year and reduces seasonal changes in assemblages. LULC-associated differences among assemblages are strongly associated with changes in physicochemistry and benthic habitat conditions that probably are mediated by hydrological alterations associated with altered LULC in the watersheds of this region.

Effects of Highway Construction on Stream Water Quality and Macroinvertebrate Condition in a Mid‐Atlantic Highlands Watershed, USA

Refining best management practices (BMPs) for future highway construction depends on a comprehensive understanding of environmental impacts from current construction methods. Based on a before-after-control impact (BACI) experimental design, long-term stream monitoring (1997-2006) was conducted at upstream (as control, n = 3) and downstream (as impact, n = 6) sites in the Lost River watershed of the Mid-Atlantic Highlands region, West Virginia. Monitoring data were analyzed to assess impacts of during and after highway construction on 15 water quality parameters and macroinvertebrate condition using the West Virginia stream condition index (WVSCI). Principal components analysis (PCA) identified regional primary water quality variances, and paired t tests and time series analysis detected seven highway construction-impacted water quality parameters which were mainly associated with the second principal component. In particular, impacts on turbidity, total suspended solids, and total iron during construction, impacts on chloride and sulfate during and after construction, and impacts on acidity and nitrate after construction were observed at the downstream sites. The construction had statistically significant impacts on macroinvertebrate index scores (i.e., WVSCI) after construction, but did not change the overall good biological condition. Implementing BMPs that address those construction-impacted water quality parameters can be an effective mitigation strategy for future highway construction in this highlands region.

Role of Stream Restoration on Improving Benthic Macroinvertebrates and In-Stream Water Quality in an Urban Watershed: Case Study

Many stream restoration projects do not include a requirement for long-term monitoring after the project has been completed, resulting in a lack of information about the success or failure of certain restoration techniques. The National Risk Management Research Laboratory, part of the U.S. EPA Office of Research and Development, evaluated the effectiveness of stream bank and channel restoration as a means of improving in-stream water quality and biological habitat in Accotink Creek, Fairfax City, Va., using discrete sampling and continuous monitoring techniques before and after restoration. This project monitored the effects of a 549 m (1,800 linear-ft) restoration of degraded stream channel in the North Fork of Accotink Creek. Restoration, which was intended to restore the stream channel to a stable condition, thereby reducing stream bank erosion and sediment loads in the stream, included installation of native plant materials along the stream and bioengineering structures to stabilize the stream channel and bank. Results of sampling and monitoring for 2 years after restoration indicated a slight improvement in biological quality for macroinvertebrate indices such as Virginia Stream Condition Index, Hilsenhoff Biotic Index, and Ephemeroptera, Plecoptera, Trichoptera taxa; the differences were statistically significant at 90% level of confidence with the power of greater than 0.8. However, indices were all below the impairment level, indicating poor water quality conditions. No statistically significant differences in chemical constituents and bacteriological indicator organisms were found before and after restoration as well as upstream and downstream of the restoration. The results indicated that stream restoration alone had little effect in improving the conditions of in-stream water quality and biological habitat, though it has lessened further degradation of stream banks in critical areas where the properties were at risk. Control of storm-water flows by placing best management practices in the watershed might reduce and delay discharge to the stream and may ultimately improve habitat and water quality conditions.

Influence of Conductivity Dissipation on Benthic Macroinvertebrates in the North Fork Holston River, Virginia Downstream of a Point Source Brine Discharge during Severe Low-Flow Conditions

ABSTRACT The North Fork Holston River (NFHR) was examined in fall 2005 to determine the potential impact of a brine discharge on benthic macroinvertebrates. Conductivity of the discharge ranged from 5900 to 10,930 μ S/cm with a highest measurement of 18,000 μ S/cm. During normal flow, conductivity dissipates rapidly downstream of the discharge; however, low-flow conditions in 2005 hindered dissipation. Benthic macroinvertebrate surveys determined statistically significant differences (p = .05) in all metrices between sites excluding taxa richness. Hydropsychid caddisflies were the predominant taxa at the first two sites below the brine discharge, accounting for 74.3 and 68.8% of the organisms collected. Therefore, Ephemeroptera-Plecoptera-Trichoptera (EPT) abundance minus Hydropsychidae [EPT-H] was the most predictive parameter measured. When hydropsychids were removed from statistical analyses, mean EPT abundance was highest at upstream reference sites 1 and 2 (256 and 297, respectively) and reduced at all downstream sites, ranging from 24 to 52 EPT organisms. Virginia Stream Condition Index (SCI) scores indicated impairment downstream of the discharge with scores of 46.9, 41.8, and 55.8, well below the impairment threshold of 61. These results suggest subchronic, intermittent toxicity occurs under low-flow and may contribute to altered benthic macroinvertebrate assemblages downstream of the brine discharge for approximately 26 miles.

Land Use, Geology, Enrichment, and Stream Biota in the Eastern Ridge and Valley Ecoregion: Implications for Nutrient Criteria Development1

Abstract: The eastern panhandle region of West Virginia is entirely within the Appalachian Ridge and Valley ecoregion. It is underlain by limestone in the eastern part and by shale and sandstone in the western part. Agricultural and urban development has affected the condition of the streams of this region. We examined samples from 165 stations in the Ridge and Valley, collected from 1998 to 2004. Land use, geological characteristics, physical and chemical parameters, and algal and macroinvertebrate assemblages were used to identify potential stressors that affect streams in the region. Our analyses indicated that both human land uses and ecoregional differences led to elevated nutrient concentrations in streams of the study areas. Multiple regression analyses indicated that both agricultural and urban land use in the watershed were associated with high nutrient concentrations (NO2+3, total nitrogen, and total phosphorus) in streams. These elevated nutrient concentrations have led to increased algal biomass, increased trophic state, and degradation of macroinvertebrate community in the streams. Values of the West Virginia Stream Condition Index, as well as several other benthic macroinvertebrate metrics, decreased with increased nutrient concentrations and conductivity, especially in the limestone region. When regional differences were partitioned out in the analysis, nutrient concentrations became the strongest stressor in the limestone region while conductivity exhibited less of an effect on macroinvertebrate metrics. Meanwhile, periphyton diagnostic metrics also responded to increased nutrient concentrations, suggesting nutrients could be a cause of biological degradation in the Eastern Ridge and Valley region. Multiple approaches and multiple lines of evidence (reference approach and stressor‐response approach) were applied to develop nutrient benchmarks for different geological regions in the study watershed.

A Comparison of Single and Multiple Habitat Protocols for Collecting Macroinvertebrates in Wadeable Streams1

Abstract: In 2003, we compared two benthic macroinvertebrate sampling methods that are used for rapid biological assessment of wadeable streams. A single habitat method using kick sampling in riffles and runs was compared to a multiple habitat method that sampled all available habitats in proportion of occurrence. Both methods were performed side‐by‐side at 41 sites in lower gradient streams of the Piedmont and Northern Piedmont ecoregions of the United States, where riffle habitat is less abundant. Differences in sampling methods were examined using similarity indices, two multimetric indices [the family‐level Virginia Stream Condition Index (VSCI) and the species‐level Macroinvertebrate Biotic Integrity Index (MBII)], their component metrics, and bioassessment endpoints based on each index. Index scores were highly correlated between single and multiple habitat field methods, and sampling method comparability, based on comparison of similarities between and within sampling methods, was particularly high for species level data. The VSCI scores and values of most of its component metrics were not significantly higher for one particular method, but relationships between single and multiple habitat values were highly variable for percent Ephemeroptera, percent chironomids, and percent Plecoptera and Trichoptera (Hydropsychidae excluded). A similar level of variability in the relationship was observed for the MBII and most of its metrics, but Ephemeroptera richness, percent individuals in the dominant five taxa, and Hilsenhoff Biotic Index scores all exhibited differences in values between single and multiple habitat field methods. When applied to multiple habitat samples, the MBII exhibited greater precision, higher index scores, and higher assessment categories than when applied to single habitat samples at the same sites. In streams with limited or no riffle habitats, the multiple habitat method should provide an adequate sample for biological assessment, and at sites with abundant riffle habitat, little difference would be expected between the single and multiple habitat field methods. Thus, in geographic areas with a wide variety of stream types, the multiple habitat method may be more desirable. Even so, the variability in the relationship between single and multiple habitat methods indicates that the data are not interchangeable, and we suggest that any change in sampling method should be accompanied by a recalibration of any existing assessment tool (e.g., multimetric index) with data collected using the new method, regardless of taxonomic level.

Response of Fish and Macroinvertebrate Bioassessment Indices to Water Chemistry in a Mined Appalachian Watershed

Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based index (West Virginia Stream Condition Index, WV-SCI) to acid mine drainage (AMD)-related stressors in 46 stream sites within the Cheat River watershed, West Virginia. We also identified specific stressor concentrations at which biological impairment was always or never observed. Water chemistry was extremely variable among tributaries of the Cheat River, and the WV-SCI was highly responsive across a range of AMD stressor levels. Furthermore, impairment to macroinvertebrate communities was observed at relatively low stressor concentrations, especially when compared to state water quality standards. In contrast to the WV-SCI, we found that the MAH-IBI was significantly less responsive to local water quality conditions. Low fish diversity was observed in several streams that possessed relatively good water quality. This pattern was especially pronounced in highly degraded subwatersheds, suggesting that regional conditions may have a strong influence on fish assemblages in this system. Our results indicate that biomonitoring programs in mined watersheds should include both benthic invertebrates, which are consistent indicators of local conditions, and fishes, which may be indicators of regional conditions. In addition, remediation programs must address the full suite of chemical constituents in AMD and focus on improving linkages among streams within drainage networks to ensure recovery of invertebrate and fish assemblages. Future research should identify the precise chemical conditions necessary to maintain biological integrity in mined Appalachian watersheds.

Interactive effects of multiple stressors and restoration priorities in a mined Appalachian watershed

We surveyed benthic macroinverte- brate communities, water chemistry, and thermal regime in the Cheat River, WV, USA in an attempt to quantify the interactive effects of multiple stressors on ecological condition and identify priorities for restoration in this mined Appalachian watershed. We used a novel ap- proach, which combined use of the West Virginia Stream Condition Index (WVSCI) to quantify ecological losses and community similarity anal- ysis to assign specific levels of ecological loss to AMD, thermal effluent, and their interaction. Finally, we developed an ecological currency to quantify the relative benefits of a restoration program that focused either on AMD remedia- tion or heat reduction and to identify spatially explicit restoration priorities. Variation in eco- logical condition was strongly correlated to vari- ation in water quality when AMD and heat stress occurred in isolation. Acute inputs of AMD or heat caused predictable reductions in condition followed by rapid recovery downstream. How- ever, benthic communities failed to recover from combined inputs of heat and AMD even when these stressors occurred at relatively low levels. Over the course of an entire year, AMD alone was over two times more responsible than heat alone for ecological loss. Consequently, AMD is the dominant factor limiting ecological condition and should be the primary target for restoration. Nevertheless, an AMD · heat interaction also was responsible for extensive ecological loss in lower reaches of the river. Consequently, full restoration of the lower Cheat River mainstem will require an approach that integrates AMD remediation with effective management of ther- mal effluent. Our results provide some of the first field evidence of the interactive effects of multiple stressors on biological communities in a mined watershed. This approach may be valuable for quantifying impacts from multiple interacting stressors and for prioritizing restoration efforts in other mined watersheds.