Multimetric Macroinvertebrate Index Research Articles

Development of Macroinvertebrate Multimetric Index for Assessment of Large Rivers in Thailand.

Human activities are a significant threat to the health of river ecosystems, especially in developing countries. In Thailand, benthic macroinvertebrates have been widely used for bioassessment for aquatic ecosystem evaluation. However, most of them focuses on streams, which may not be applicable to large rivers. This study aimed to fill this gap by developing a macroinvertebrate multimetric index for Thailand's large rivers. Sampling was conducted in 15 rivers, and 41 sites across Thailand. Physico-chemical parameters, habitat characteristics, and macroinvertebrates were analyzed. Macroinvertebrate data were analyzed and metrics calculated. The seven selected core metrics, including Plecoptera taxa, EPT taxa, insect individuals %, Crustaceans and Mollusca individuals %, collector-gatherers taxa, intolerant taxa in BMWPThai, and Hilsenhoff Biotic Index, showed a strong response to anthropogenic disturbance. The final Thailand Large River Multimetric Index (TLMI) classified river health from "Excellent" to "Very Poor" condition. The validation of TLMI confirmed its ability to distinguish river health conditions. Overall, the TLMI can used as an assessing and monitoring ecological health tool for Thailand's large rivers, that can be applied for river management and conservation.

Aquatic macroinvertebrate community responses to pollution of perfluoroalkyl substances (PFAS): Can we define threshold body burdens?

The pollution of per- and polyfluorinated alkyl substances (PFAS) in aquatic environments is a worldwide concern of which the ecological impact is still not well understood. Especially field-based effect studies in aquatic ecosystems are generally lacking, creating a knowledge gap that goes along with monitoring and regulatory challenges. Therefore, this study examined if bioaccumulated PFAS concentrations could be related to ecological responses assessed by changes in the macroinvertebrate community structure. In addition, threshold body burdens that are protective of ecological damage were estimated. Aquatic macroinvertebrates were sampled in 30 streams across Flanders (Belgium) and 28 PFAS target analytes were measured in three resident taxa (Gammarus sp., Asellus sp. and Chironomus sp.) and translocated zebra mussels (Dreissena polymorpha). The macroinvertebrate community structure was assessed by calculating the Multimetric Macroinvertebrate Index Flanders (MMIF). Primarily long-chain perfluorinated carboxylic acids (PFCAs) were detected in both resident taxa (passive biomonitoring) and zebra mussels (active biomonitoring). Based on a 90th quantile regression model, safe threshold body burdens could be calculated for PFTeDA (7.1 ng/g ww) and ΣPFAS (2264 ng/g ww) in Gammarus sp. and for PFOA (5.5 ng/g ww), PFDoDA (1.7 ng/g ww), PFTrDA (0.51 ng/g ww), PFTeDA (2.4 ng/g ww), PFOS (644 ng/g ww) and ΣPFAS (133 ng/g ww) in zebra mussel. An additional threshold value was calculated for most compounds and species using the 95th percentile method. However, although these estimated thresholds are pertinent and indicative, regulatory applicability requires further lines of evidence and validation. Nevertheless, this study offers first-time evidence of associations between accumulated PFAS concentrations in invertebrates and a reduced ecological water quality in terms of macroinvertebrate community structure and highlights the potential of Gammarus sp. and zebra mussels to serve as reliable PFAS biomonitoring species.

Assessing biodiversity and regulatory ecosystem services in urban water bodies which serve as aqua-Nature-based Solutions

In sight of a growing urban population and intensified extreme weather events, cities must integrate in their urban planning elements to both reduce their impact (i.e., air and water pollution, degradation of habitats, loss of biodiversity) and increase their resilience to climate change. In contrast to engineering solutions, which normally not only fail to adequately address these issues but often also exacerbate them, Nature-based Solutions are an efficient strategy which can help cities become more sustainable. Aqua-Nature-based Solutions (aNBS) tackle water-related hazards by enhancing water regulation and mitigating flood and drought impacts. However, under a warming climate, aNBS are expected to often dry-out, changing biodiversity and the ecosystem services they support. The aim of this study is to compare the biodiversity of temporarily and permanently wet urban waterbodies which function as aNBS. We selected two pond complexes with different hydroperiod (i.e., different duration, amplitude and frequency of inundation) and studied the riparian vegetation and aquatic macroinvertebrate biodiversity. The Multimetric Macroinvertebrate Index of Flanders was used to determine the macroinvertebrate biodiversity and to assess water quality of the ponds. Using water stable isotopes and piezometers, the hydrological dynamics were studied in order to identify the water regulating ecosystem services these ponds deliver. The results showed that the selected pond complexes have a high plant biodiversity, particularly in temporary ponds. Water quality ranged from moderate to poor and macroinvertebrate biodiversity tended to be greater in permanent ponds. Plant and macroinvertebrate alien species were also found in the aNBS. Regarding water regulating ecosystem services, the pond complexes enhanced infiltration and groundwater recharge, providing resilience to both flooding and drought. Our findings corroborate previous studies on the need of diversifying urban ponds’ hydroperiod to support biodiversity. Thus, integrating well-designed aNBS into urban planning might be a way to make cities more resilient to water climate-related hazards while enhancing biodiversity.

ASSESSMENT BY MACROINVERTEBRATES OF THE ECOLOGICAL QUALITY OF SHALLOW LAKE WITH RICH SAPROPEL SEDIMENTS

In this research, the ecological quality of the Lake Vēveru (Latvia, Rēzekne district) according to macroinvertebrates was investigated. The Lake Vēveru has a large sapropel deposit. The Lake Vēveru is relatively little affected by human economic activity, the only moderate impact is sapropel mining in the lake in 2009-2012, it is planned to resume industrial sapropel mining in the lake. During the period of sapropel removal, a decrease in the transparency of water is noted due to the nutrient flow into the water mass, pH increases, the habitat of planktonic and benthic organisms is disturbed. Macroinvertebrates samples were collected and analyzed using standard methods in the open pelagic and littoral zones of the lake in different seasons. The ecological quality of the lake was assessed in accordance with the requirements of the European Water Framework Directive in Latvia. To characterize the ecological status of the lake the Latvian Lake Macroinvertebrate Multimetric Index was used. According to the Ecological Quality Ratio (EQR) the lake indicates a good ecological status of the water. However, a moderately low species diversity index indicates the dominance of certain taxa. In general, macroinvertebrates species that are often and widely found in Latvia and are environmentally tolerant have been found in the lake. Water temperature, pH, conductivity, dissolved oxygen, oxidation reduction potential, chlorophyll-α were measured with a HACH OTT DS5 Probe. Water transparency was measured using a Secchi disc.

Development of macroinvertebrate based multimetric index for ecological health monitoring in Lake Hawassa, Ethiopia

Little information is available on the use and applicability of biotic indices in aquatic resource conservation and management in Eastern Africa, especially in lentic ecosystems. The aim of this study was to develop a macroinvertebrate multimetric index (MMIH) to assess the ecological condition of Lake Hawassa. Sampling sites were clustered based on percentage disturbance score (PDS) and categorized into minimally (three sites), moderately (three sites) and highly disturbed (three sites). Physicochemical and invertebrate sampling was done at these clustered sites along the lakeshore area from February to November 2015 and 2016. Out of a total of 35 macroinvertebrate candidate metrics, ten core metrics were selected based on redundancy analysis, metrics response to environmental parameters, percent discriminatory efficiency (%DE) and box and whisker plots, and incorporated in the development of MMIH. The developed MMIH index performed well and showed a clear demarcation between the reference and non-reference sites and between the three-disturbance levels. The validation of the MMIH index performed well in discriminating the independent data sets taken from Lake Hawassa and L. Ziway. Besides, it also showed a strong but inverse relation with PDS (R2 = 0.91, P = 0.0003). Hence, in a lentic ecosystem, this index should be considered as a starting point in terms of lake bio-assessment in Ethiopia, but additional data in all ecoregions of the country are necessary to determine the long-term reliability and usefulness of the MMIH. In the short-term, this index will provide resource managers and aquatic environmentalists with a tool to assess the ecological condition of freshwater lakes.

Assessment of the biological water quality and response of freshwater macroinvertebrates to thermal stress in an Afrotropical warm spring.

Freshwater macroinvertebrates have been widely used as environmental stress indicators. However, information on their response to natural thermal stress is relatively scarce, particularly in the tropics. Using the multimetric macroinvertebrate approach, the biological water quality of the warm and cold springs of the Ikogosi Warm Spring in Nigeria was evaluated, with a view to ascertaining the response of freshwater macroinvertebrates to natural thermal stress. Macroinvertebrates and water samples were collected from the warm (stressed) and cold (less-stressed) springs, as well as the confluence stream, within the renowned Ikogosi Warm Spring of Southwest Nigeria. The less-stressed cold spring had much more dissolved oxygen than the warm spring and other thermally stressed stations but less than the warm spring and other thermally stressed stations for water temperature, electrical conductivity, total dissolved solids, Ca2+, Mg2+, and water hardness. Generally, the macroinvertebrate taxonomic richness (30 species) and EPT richness (3 species) of the Ikogosi Warm Spring indicated an impaired freshwater system. Using the multimetric macroinvertebrate index (MMI), the warm spring was of poor biological water quality while the cold spring was of good biological water quality. At the confluence of both springs, the MMI declined to poor and moderate water quality. Although the thermal stress of the Ikogosi Warm Spring is natural, the government should take the necessary steps to regulate tourist activities so that the site's naturalness is preserved and the water quality is not further degraded on account of human-induced stressors such as deforestation, waste dumping, and washing activities.

Benthic Macroinvertebrate Multimetric Index for River (BMIR): Development of a multimetric index based on benthic macroinvertebrates for rivers in Türkiye

Stream types determined according to altitude, slope and alkalinity in six different hydrobiogeographic regions of Türkiye were taken as the basis of the study. In line with the European Water Framework Directive, a macroinvertebrate based multimetric method was tested for Turkish rivers as a potential assessment. In this study, benthic macroinvertebrate data (3502 samples obtained from 1925 stations with reference points) were used to create a multimetric index for all river types in the hydrobiogeographic regions of Türkiye. Nine (9) biological metrics were evaluated and index development criteria were chosen to capture meaningful results at the ecosystem, community and individual levels. The metric combinations were chosen to show the best distinction between areas with no or only very minor anthropogenic disturbances and stressed areas (with discrimination efficiency values). The multimetric index, which includes three different metrics from three different metric categories, distinguishes reference or slightly distorted areas from stressed areas with an efficiency close to 100%. Index values were divided at a five-scale system between one (High) and zero (Bad) for biological evaluation. Further testing and research can be done so that the index will provide a more useful result as a bioassessment tool for decision makers in hydrobiogeographic regions. Also, the index can provide a basis for methods by which river status is assessed based on stress factors.

A multimetric macroinvertebrate index for the assessment of the ecological status of Lithuanian rivers

We present the design of the Lithuanian River Macroinvertebrate Index (LRMI) – a Water Framework Directive compliant method for assessing the ecological status of Lithuanian rivers that primarily addresses the eutrophication pressure. It is a multimetric index that averages the ecological quality ratios of two conventional metrics – the Danish Stream Fauna Index (DSFI) and the Average Score Per Taxon (ASPT) – as well as the two newly assembled metrics – the taxonomic richness of Diptera, Ephemeroptera, and Plecoptera (#DEP) and the difference between the pooled relative abundances of Ephemeroptera, Heteroptera, and Plecoptera versus Crustacea and Hirudinea (%EHP–%CrHi). The LRMI showed significant correlations with hydrochemical indicators of nutrient enrichment in the national river dataset. Moreover, our analysis showed its potential sensitivity toward hydromorphological alterations of the riverine habitats. Finally, the results indicated that further developments concerning minor type-specific adjustments of the currently set ecological class boundaries may be beneficial to the new method.

Genus-level, trait-based multimetric diatom indices for assessing the ecological condition of rivers and streams across the conterminous United States

Taxonomic inconsistency in species-level identifications has constrained use of diatoms as biological indicators in aquatic assessments. We addressed this problem by developing diatom multimetric indices (MMIs) of ecological condition using genus-level taxonomy and trait-based autecological information. The MMIs were designed to assess river and stream chemical, physical and biological condition across the conterminous United States. Trait-based approaches have the advantage of using both species-level and genus-level data, which require less effort and expense to acquire than traditional species-based approaches and eliminate the persistent taxonomic biases introduced over vast geographic extents. For large-extent assessment programs that require multiple taxonomic laboratories to process samples, such as the United States Environmental Protection Agency’s (U.S. EPA’s) National Rivers and Streams Assessment (NRSA), the trait approach can eliminate discrepancies in species-level identification or nomenclature that hinder diatom data interpretation. We developed trait-based MMIs using NRSA data for each of the three large ecoregions across the U.S. - the East, Plains, and West. All three MMIs performed well in discriminating least-disturbed from most-disturbed sites. The MMI for the East had the greatest discrimination ability, followed by MMIs for the Plains and West, respectively. The performance of the MMIs was comparable to that observed in existing NRSA fish and macroinvertebrate MMIs. Our research shows that trait-based diatom indices constructed on genus-level taxonomy can be effective for large-scale assessments, and may also allow programs such as NRSA to assess trends in freshwater condition retrospectively, by revisiting older diatom datasets. Moreover, our genus-based approach facilitates including of diatoms into other assessment programs that have limited monitoring resources.

Natural and anthropogenic factors and their interactions drive stream community integrity in a North American river basin at a large spatial scale

Urbanization, agriculture, and other human activities can exert considerable influence on the health and integrity of stream ecosystems. These influences vary greatly over space, time, and scale. We investigated trends in stream biotic integrity over 19 years (1997–2016) in relation to natural and anthropogenic factors in their spatial context using data from a stream biomonitoring program in a region dominated by agricultural land use. Macroinvertebrate and fish diversity and abundance data were used to calculate four multimetric indices (MMIs) that described biotic integrity of streams from 1997 to 2016. Boosted regression trees (BRT), a machine learning technique, were used to model how stream integrity responded to catchment-level natural and anthropogenic drivers including land use, human population density, road density, runoff potential, and natural factors such as latitude and elevation. Neither natural nor anthropogenic factors were consistently more influential on the MMIs. Macroinvertebrate indices were most responsive to time, latitude, elevation, and road density. Fish indices were driven mostly by latitude and longitude, with agricultural land cover among the most influential anthropogenic factors. We concluded that 1) stream biotic integrity was mostly stable in the study region from 1997 to 2016, although macroinvertebrate MMIs had decreased approximately 10% since 2010; 2) stream biotic integrity was driven by a mix of factors including geography, human activity, and variability over yearly time intervals; 3) MMI responses to environmental drivers were nonlinear and often nonmonotonic; 4) MMI composition could influence causal inferences; and 5) although our findings were mostly consistent with the literature on drivers of stream integrity, some commonly seen patterns were not evident. Our findings highlight the utility of large-scale, publicly available spatial data for understanding drivers of stream biodiversity and illustrate some potential pitfalls of large scale, integrative analyses.

The coastal plain headwater stream restoration (CP-HStR) index: a macroinvertebrate index for assessing the biological effectiveness of stream restoration in the Georgia coastal plain, USA.

Stream restoration projects undertaken as compensatory mitigation pursuant to Sect.404 of the U.S. Clean Water Act must be evaluated using ecological performance standards that are objective and verifiable and based on the best available science that can be measured or assessed in a practicable manner. While performance standards for physical stream conditions are common, evaluating biological conditions following stream restoration activities has proven more problematic. We developed a macroinvertebrate multimetric index for headwater streams in three Southeastern Plains subecoregions (65g, 65h, and 65l) of Georgia using 76 sites sampled in 2019. An abiotic disturbance gradient based on principal components analysis of instream habitat, physicochemical, and land use variables was employed to assign condition classes (good, fair, poor) among sites within each subecoregion. We identified genus-level macroinvertebrate richness and proportional richness of traits-based metrics (habit and functional feeding groups) that demonstrated high discriminatory power between good and poor abiotic conditions and response to individual stressors. Subecoregion-specific metrics were then standardized and aggregated to develop the final index and biological reference curves. These biological reference curves represent a continuum of relevant regional conditions against which a stream enhancement or restoration project may be assessed relative to other streams throughout the region and allow for the award of mitigation credit, if applicable, to be based directly on the relative improvement of biological conditions. These biological performance standards will supplement other performance standards (hydrologic and geomorphic measures) necessary to evaluate the effectiveness of stream restoration projects in the study area.

The relevance of European Biota Quality Standards on the ecological water quality as determined by the multimetric macro-invertebrate index: A Flemish case study

European Biota Quality Standards (EQSbiota), for compounds with low water solubility and high biomagnification, were created to sustain water quality and protect top predators and humans from secondary poisoning. In reality, for multiple compounds, an exceedance of these standards is often reported in literature without a decrease in ecological water quality determined by biotic indices. In the present study, threshold concentrations were defined in biota (from 44 sampling locations throughout Flanders (Belgium)), above which a good ecological water quality, assessed by the Multimetric Macroinvertebrate Index Flanders (MMIF), was never reached. Threshold values were compared to current EQSbiota. Accumulated perfluoroctane sulfonate (PFOS), mercury (Hg), hexabromocyclododecane (HBCD), polybrominated diphenyl ethers (PBDEs), dioxins and polychlorinated biphenyls (PCBs) concentrations were measured in muscle tissue of European yellow eel (Anguilla anguilla) and perch (Perca fluviatilis). Fluoranthene and benzo(a)pyrene were also analyzed in translocated mussels (Dreissena bugensis, D. polymorpha and Corbicula fluminea). Threshold values could only be calculated using a 90th quantile regression model for PFOS (in perch; 12 µg/kg ww), PCBs (in eel; 328 µg/kg ww) and benzo(a)pyrene (in mussels: 4.35 µg/kg ww). The lack of a significant regression model for the other compounds indicated an effective threshold value higher than the concentrations measured in the present study. Alternatively, the 95th percentile of concentrations measured in locations with a good ecological quality (MMIF≥0.7), was calculated for all compounds as an additional threshold value. Finally, fish concentrations were standardized for 5% lipid content (or 26% dry weight content for PFOS and Hg). Threshold values for PFOS and benzo(a)pyrene and the 95th percentiles for dioxins and fluoranthene were comparable to the existing standards. For all other compounds, the 95th percentile was higher than the current EQSbiota, while for HBCD, it was lower. These results strongly advise revising and fine-tuning the current EQSbiota, especially for ∑PBDE and HBCD.

Evaluating macroinvertebrate metrics for ecological assessment of large saline rivers (Argentina).

Benthic macroinvertebrates have been used around the world as indicators of the biological quality of freshwater habitats. Because of the intensive deterioration of waterbodies as a result of different land uses, indicators are used for environmental monitoring, control and remediation. The aim of this study was to assess (1) the sensitivity of taxonomical metrics and (2) functional traits to select the most appropriate for evaluating environmental impacts on rivers with high salinity and (3) to propose a multimetric index based on the selected metrics. Information from a preexisting database on twenty-eight sites in the Salado River basin (Argentina) was used. One hundred and twenty-three metrics were calculated to assess sensitivity to different land uses along the gradient of habitat condition, from low-disturbed (reference), to medium-disturbed (agricultural and industrial) and high-disturbed (agricultural, industrial and urban). This gradient was defined by available information in original articles and by quantifying the percentage of the different land uses. Filtering collectors (%), Gathering collectors (%), Ostracoda density, Limnodrilus hoffmeisteri/Total density, Naididae (%), Tubifex/Total density and Pristina/Total density were the metrics that distinguished the different land uses along the gradient of habitat condition. These metrics were used to propose a macroinvertebrate multimetric index in saline rivers: Index of Benthic Invertebrates in Saline Rivers (IBIS). Thus, this study provides a useful tool for management and monitoring of saline rivers and diagnoses of salinized environments.

Temporal Variability of Macroinvertebrate Assemblages in a Mediterranean Coastal Stream: Implications for Bioassessment.

Macroinvertebrates from a small forest stream in central-south Chile were sampled monthly from September 2017 to August 2018 to assess temporal variability in the assemblage and the effects of that variability on ecological indicators. Higher precipitation and flows occurred in winter months, and water quality varied among months. We collected 59 macroinvertebrate taxa, finding higher taxa richness and abundances in summer months than in winter months. Four taxa demonstrated marked seasonality, being abundant in some months and then decreasing in following months (Limnoperla jaffueli (Navás), Nousia maculata (Demoulin), Smicridea sp. (McLachlan), Chironomidae spp.). The scores of the family Hilsenhoff Biotic Index (HBI), Hilsenhoff Species-level Biotic Index (HSBI), Multimetric Macroinvertebrate Index (MMI), and Chilean Biological Monitoring Working Party (ChBMWP) index varied throughout the year reflecting natural variability. However, only HBI and HSBI scores were significantly different among seasons, ranging across three water quality classes (excellent, very good, and good), showing the lowest water classes in spring, coinciding with higher abundances of tolerant species. The MMI and ChBMWP indicated good and very good site conditions throughout the year, respectively. Shannon-Weaver diversity ranged between 2.59 (April) and 1.78 (February); however, Pielou evenness had high values throughout the year (> 0.62), except in February. Changes in macroinvertebrates composition throughout the year were explained primarily by discharge, water temperature, and conductivity. Our findings indicate that natural monthly variability in macroinvertebrate assemblages influences the scores of biological indices throughout the year. Therefore, we recommend that natural stream variability be accounted for in biomonitoring programs. We also emphasize the need to use caution when interpreting biological index scores to avoid misinterpretations in stream quality classification.

Setting Priorities in River Management Using Habitat Suitability Models

Worldwide river systems are under pressure from human development. River managers need to identify the most important stressors in a stream basin, to propose effective management interventions for river restoration. In the European Union, the Water Framework Directive proposes the ecological status as the management endpoint for these interventions. Many decision support tools exist that use predictive water quality models to evaluate different river management scenarios, but only a few consider a river’s ecological status in this analysis explicitly. This paper presents a novel method, which combines abiotic monitoring data and biological monitoring data, to provide information and insight on why the ecological status does not reach the good status. We use habitat suitability models as a decision support tool, which can identify the most important stressors in river systems to define management scenarios. To this end, we disassemble the ecological status into its individual building blocks, i.e., the community composition, and we use habitat suitability models to perform an ecological gap analysis. In this paper, we present our method and its underlying ecological concepts, and we illustrate its benefits by applying the method on a regional level for Flanders using a biotic index, the Multimetric Macroinvertebrate Index Flanders (MMIF). To evaluate our method, we calculated the number of correctly classified instances (CCI = 47.7%) and the root-mean-square error (RMSE = 0.18) on the MMIF class and the MMIF value. Furthermore, there is a monotonic decreasing relationship between the results of the priority classification and the ecological status expressed by the MMIF, which is strengthened by the inclusion of ecological concepts in our method (Pearson’s R2 −0.92 vs. −0.87). In addition, the results of our method are complementary to information derived from the legal targets set for abiotic variables. Thus, our proposed method can further optimize the inclusion of monitoring data for the sake of sustainable decisions in river management.

The Relation of Lotic Fish and Benthic Macroinvertebrate Condition Indices to Environmental Factors Across the Conterminous USA.

National and regional ecological assessments are essential for making rational decisions concerning water body conservation and management at those spatial extents. We analyzed data from 4597 samples collected from 3420 different sites across the conterminous USA during the U.S. Environmental Protection Agency's 2008-2009 and 2013-2014 National Rivers and Streams Assessment. We evaluated the relationship between both fish and macroinvertebrate multimetric index (MMI) condition scores and 38 environmental factors to assess the relative importance of natural versus anthropogenic predictors, contrast site-scale versus watershed-scale predictors, and examine ecoregional and assemblage differences. We found that most of the environmental factors we examined were related to either fish and/or macroinvertebrate MMI scores in some fashion and that the factors involved, and strength of the relationship, varied by ecoregion and between assemblages. Factors more associated with natural conditions were usually less important in explaining MMI scores than factors more directly associated with anthropogenic disturbances. Local site-scale factors explained more variation than watershed-scale factors. Random forest and multiple regression models performed similarly, and the fish MMI-environment relationships were stronger than macroinvertebrate MMI-environment relationships. Among ecoregions, the strongest environmental relationships were observed in the Northern Appalachians and the weakest in the Southern Plains. The fish and macroinvertebrate MMIs were only weakly correlated with each other, and they generally responded more strongly to different groups of variables. These results support the use of multiple assemblages and the sampling of multiple environmental indicators in ecological assessments across large spatial extents.

Disentangling the potential effects of land-use and climate change on stream conditions.

Land‐use and climate change are significantly affecting stream ecosystems, yet understanding of their long‐term impacts is hindered by the few studies that have simultaneously investigated their interaction and high variability among future projections. We modeled possible effects of a suite of 2030, 2060, and 2090 land‐use and climate scenarios on the condition of 70,772 small streams in the Chesapeake Bay watershed, United States. The Chesapeake Basin‐wide Index of Biotic Integrity, a benthic macroinvertebrate multimetric index, was used to represent stream condition. Land‐use scenarios included four Special Report on Emissions Scenarios (A1B, A2, B1, and B2) representing a range of potential landscape futures. Future climate scenarios included quartiles of future climate changes from downscaled Coupled Model Intercomparison Project ‐ Phase 5 (CMIP5) and a watershed‐wide uniform scenario (Lynch2016). We employed random forests analysis to model individual and combined effects of land‐use and climate change on stream conditions. Individual scenarios suggest that by 2090, watershed‐wide conditions may exhibit anywhere from large degradations (e.g., scenarios A1B, A2, and the CMIP5 25th percentile) to small degradations (e.g., scenarios B1, B2, and Lynch2016). Combined land‐use and climate change scenarios highlighted their interaction and predicted, by 2090, watershed‐wide degradation in 16.2% (A2 CMIP5 25th percentile) to 1.0% (B2 Lynch2016) of stream kilometers. A goal for the Chesapeake Bay watershed is to restore 10% of stream kilometers over a 2008 baseline; our results suggest meeting and sustaining this goal until 2090 may require improvement in 11.0%–26.2% of stream kilometers, dependent on land‐use and climate scenario. These results highlight inherent variability among scenarios and the resultant uncertainty of predicted conditions, which reinforces the need to incorporate multiple scenarios of both land‐use (e.g., development, agriculture, etc.) and climate change in future studies to encapsulate the range of potential future conditions.

Development of a multimetric index based on benthic macroinvertebrates for downstream Jajrud River in Tehran province, Iran

Jajrud River is the main source of drinking water in the East of Tehran. The river originates from heights of the Alborz Mountain in Northern Tehran. In this study, five stations were sampled for water quality assessment in downstream. Brgjhan and Afjeh stations were considered as reference stations. Benthic macroinvertebrate sampling was repeated 3 times at each station with a Surber sampler device and an area of 900 square cm and a mesh size of 250 microns, in four seasons. For the development of MMIDJ (Multimetric Macro-invertebrate Index Downstream Jajrud-MMIDJ) multimetric index based on benthic macro-invertebrate, 25 bio-indicators were compared in the reference stations with the data of two years, 2013 and 2014. The features of the bio-indicators included measurement of components tolerance, composition, richness, and trophic. MMIDJ multimetric index was developed from 6 indices including HFBI (Hilsenhoff Family Biotic Index), BMWP/ASPT (Biological Monitoring Working Party/Average Score per Taxon), NJIS (New Jersey Impairment Score), MMIF (Multimetric Macro-invertebrate Index Flanders), % Ephemeroptera, and BBI (Belgian Biotic Index). Indices selected were significantly correlated with at least one physicochemical parameter and low degree of changes like % Chironomidae, % non-insects, the ratio of EPT (Ephemeroptera, Plecoptera, and Trichoptera) individuals to Chironomidae, and high density. Water quality in MMIDJ multimetric index was classified into four. Index values were from 6 to 30. The water quality improved from 6 to 30. With regard to water quality assessment of Jajrud River using MMIDJ multimetric index, Jajrud River did not have a good quality. Appropriate management actions should be considered in Jajrud River for improvement of the water quality.

Aproximación preliminar a un índice multimétrico de macroinvertebrados (IMARBO) para evaluar el estado ecológico de ríos de las cuencas alta y media del río Chicamocha en Boyacá, Colombia

Se desarrolló una propuesta preliminar de un Índice Multimétrio de Macroinvertebrados para Ríos del Departamento de Boyacá (IMARBO) con el fin de valorar el estado ecológico de cinco ríos y quebradas de las cuencas alta y media del río Chicamocha. Se caracterizaron parámetros fisicoquímicos y biológicos de la comunidad de macroinvertebrados acuáticos en tres tramos de referencia y nueve estaciones con diferente grado de alteración por deforestación, modificación de hábitats y vertimientos domésticos e industriales. El gradiente de estrés ambiental se estableció mediante un análisis de componentes principales (ACP) y correlaciones bivariadas. Se calcularon 21 métricas de la comunidad de macroinvertebrados, de las cuales se seleccionaron seis para la conformación del IMARBO mediante correlaciones con el gradiente ambiental. Para las métricas seleccionadas se calculó su Eficiencia Discriminativa (ED) entre estaciones de referencia y perturbadas. El índice incluyó la riqueza de familias de Ephemeroptera, Plecoptera y Trichoptera (EPT), el % de riqueza de Ephemeroptera, el % de riqueza de Plecoptera, la abundancia total de individuos, el % de abundancia de Filtradores y el índice BMWP/Col. Con los valores de los percentiles de las métricas en los tramos de referencia se elaboraron las escalas de integridad biótica y de calidad ecológica de los ríos estudiados, las cuales se validaron preliminarmente con una base de datos independiente en una cuenca cercana a la estudiada. El índice propuesto constituye una aproximación preliminar que requerirá futuras comprobaciones a través de un mayor número de datos. Sin embargo, los resultados permitieron diferenciar con claridad los ríos menos contaminados y con una integridad biótica alta (Gámeza y Monguí) de aquellos fuertemente deteriorados y cuyas comunidades de macroinvertebrados presentan muy baja integridad biótica (Chicamocha, Malsitio, Nobsas). De esta manera, el IMARBO podría convertirse en una herramienta útil para la gestión ambiental de los ríos de la región.

A Macroinvertebrate Multimetric Index for the Bioassessment of Wetlands Adjacent to Agriculture Fields in the Sanjiang Plain, China

Adjacent intensive agriculture disturbs the natural condition of wetlands. However, to assess the effect of this agriculture on wetlands, few studies have used indices based on aquatic invertebrates. Multi-metric indices (MMIs) have been successfully used to assess freshwater ecosystems worldwide and are an important management tool, but little is known about their applicability in the Sanjiang Plain, Northeast China. In this study, we developed a MMIs for aquatic invertebrates to assess freshwater wetlands in this region. The aquatic invertebrate assemblages were sampled in 27 wetlands in the Sanjiang Plain that included those in natural reserves and those affected by adjacent, intensive agriculture. Twenty-four candidate metrics were initially reviewed and screened before four core metrics were selected: total number of taxa, number of Hemiptera taxa, proportion of Gastropoda, and proportion of predators. Mann-Whitney U tests, Box and Whisker plots, correlation analyses, and redundant metric tests were used to assess the ability of metrics to distinguish among reference and impaired wetlands. Four ordinal rating categories for wetland were defined: poor, fair, good, and excellent. Of the impaired freshwater wetlands, 76.2% were in poor or fair categories. The MMIs was robust in discriminating reference wetlands from impaired wetlands and therefore have potential as a biomonitoring tool to assess the condition and to guide the restoration efforts of freshwater wetlands in Northeast China.