Macroinvertebrate-based Index Research Articles

Community Structure and Water Quality Assessment of Benthic Macroinvertebrates in Hongze Lake.

This study investigated the species, density, biomass and physicochemical factors of benthic macroinvertebrates in Hongze Lake from 2016 to 2020. Redundancy analysis (RDA) was used to analyze the relationship between physicochemical parameters and the community structure of macroinvertebrates. Macroinvertebrate-based indices were used to evaluate the water quality conditions in Hongze Lake. The results showed that a total of 50 benthic species (10 annelids, 21 arthropods and 19 mollusks) were collected. The community structure of benthic macroinvertebrates varied in time and space. The dominant species were Limnodrilus hoffmeisteri (L.hoffmeisteri), Corbicula fluminea (C.fluminea), Nephtys oligobranchia (N.oligobranchia). In 2016, arthropods such as Grandidierella sp. were the dominant species of benthos in Hongze Lake while annelids and mollusks dominated from 2017 to 2020, such as L.hoffmeisteri, N.oligobranchia, C.fluminea. The benthic fauna of Chengzi Lake and Lihewa District were relatively abundant and showed slight variation, while the benthic macroinvertebrates of the Crossing the water area were few and varied greatly. RDA showed that changes in benthic macroinvertebrate structure were significantly correlated with dissolved oxygen (DO), Pondus Hydrogenii (pH) and transparency (SD). The Shannon Wiener, Pielou, and Margalef indices indicate that Hongze Lake is currently in a moderately polluted state. Future studies should focus on the combined effects of various physicochemical indicators and other environmental factors on benthic communities.

Bioassessment of multiple stressors in Afrotropical rivers: Evaluating the performance of a macroinvertebrate-based index of biotic integrity, diversity, and regional biotic indices

Many streams and rivers outside conservation areas across the Afrotropics face multiple stressors from land use change, urbanization, and excessive water withdrawals. Thus, there is a need to develop cost-effective tools for assessing and monitoring ecological changes to inform management decisions. Studies utilizing macroinvertebrate communities as indicators of the ecological condition of streams and rivers in the Afrotropics use diverse methods, including diversity, richness, biotic and multimetric indices. However, some of these indices are region- or country-specific, which limits their general use across multiple regions or countries. In this study, we address this challenge by testing and comparing the performance of diversity and richness indices (e.g., Shannon-Wiener and Simpson), regional biotic indices (the African Scoring System Version 5 [SASS5], Tanzanian River Scoring System [TARISS] and a biotic index developed for the Ethiopian highlands [ETHbios]), and a macroinvertebrate-based index of biotic integrity (M-IBI) in assessing the ecological condition of Afrotropical rivers with the transboundary Mara River, Kenya and Tanzania, as a case study. In this study, we analyzed water and habitat quality degradation caused by multiple stressors such as land use change, organic pollution and flow alteration and the corresponding responses in macroinvertebrate communities. We utilized macroinvertebrates data collected from 143 sites covering the entire gradient of the river and its major tributaries in Kenya and Tanzania. To develop the M-IBI, we used 12 metrics that describe macroinvertebrate community richness, composition, tolerance to disturbances (indicator taxa), and the composition of functional feeding groups. Although all the biotic indices were sensitive to poor water quality and human disturbance of the river, the M-IBI performed better than biotic indices (SASS5, Tanzanian River Scoring System, and Ethiopian highlands), diversity and richness indices by having a higher discriminatory ability of site categories according to different levels and types of disturbance. Diversity and richness indices performed poorly and failed to discriminate between stressor gradients in the river. This study demonstrates a need for testing and evaluating indices or protocols before adoption and use in biomonitoring streams and rivers in other countries and regions. There is an even greater need to assess the tolerance of macroinvertebrate taxa before inclusion in biotic indices for improved performance as discriminators of multiple stressors.

Macroinvertebrate-based index of biotic integrity for assessing the ecological condition of Lake Wanchi, Ethiopia

Background: Lake Wanchi is one of the Ethiopian lakes that have huge ecological, socio-economic and aesthetic value. This study was conducted to assess the ecological condition of Lake Wanchi using the macroinvertebrate-based index of biotic integrity between September 2016 and should 2017.Methods: Four sampling sites (LWS 1, LWS 2, LWS 3, and LWS 4) were purposively selected. A rapid bioassessment protocol criterion was accustomed to categorize the sites. About 1249 macroinvertebrate individuals were collected using the D-frame net with a mesh size of 500µm. Physico-chemical analysis was also done to assess the link between the benthic macroinvertebrate structure and environmental factors within the system.Results: The benthic index of biotic integrity ranged from 12.54 to 100 and also the sites were categorized into three quality ranks: LWS 1 and 3 as fair, LWS 2 as good, and LWS 4 as very good. Conclusions: The study confirmed that Lake Wanchi was largely influenced by agricultural and other anthropogenic factors. This study concluded that the benthic index of biotic integrity is an appropriate tool for water quality and ecological assessment in the lakes.

A Bayesian Belief Network learning tool integrates multi-scale effects of riparian buffers on stream invertebrates

Riparian forest buffers have multiple benefits for biodiversity and ecosystem services in both freshwater and terrestrial habitats but are rarely implemented in water ecosystem management, partly reflecting the lack of information on the effectiveness of this measure. In this context, social learning is valuable to inform stakeholders of the efficacy of riparian vegetation in mitigating stream degradation. We aim to develop a Bayesian belief network (BBN) model for application as a learning tool to simulate and assess the reach- and segment-scale effects of riparian vegetation properties and land use on instream invertebrates. We surveyed reach-scale riparian conditions, extracted segment-scale riparian and subcatchment land use information from geographic information system data, and collected macroinvertebrate samples from four catchments in Europe (Belgium, Norway, Romania, and Sweden). We modelled the ecological condition based on the Average Score Per Taxon (ASPT) index, a macroinvertebrate-based index widely used in European bioassessment, as a function of different riparian variables using the BBN modelling approach. The results of the model simulations provided insights into the usefulness of riparian vegetation attributes in enhancing the ecological condition, with reach-scale riparian vegetation quality associated with the strongest improvements in ecological status. Specifically, reach-scale buffer vegetation of score 3 (i.e. moderate quality) generally results in the highest probability of a good ASPT score (99–100%). In contrast, a site with a narrow width of riparian trees and a small area of trees with reach-scale buffer vegetation of score 1 (i.e. low quality) predicts a high probability of a bad ASPT score (74%). The strengths of the BBN model are the ease of interpretation, fast simulation, ability to explicitly indicate uncertainty in model outcomes, and interactivity. These merits point to the potential use of the BBN model in workshop activities to stimulate key learning processes that help inform the management of riparian zones.

Biotic indices of hydrological variability as tools to inform dynamic ecological status assessments in river ecosystems

River biomonitoring uses biotic indices that assess human-induced degradation, including pollution, by comparison with type-specific static biological reference conditions. However, index scores that indicate pollution may reflect biological responses to natural hydrological variability associated with low flows and drying, leading biomonitoring schemes to misclassify sites as degraded. To address this, dynamic, site-specific adjustments of static biological reference conditions have been proposed, but current biomonitoring tools cannot facilitate implementation of these adjustments. We analyzed 329 samples from mediterranean-climate rivers in Greece, to evaluate the use of six stressor-specific macroinvertebrate-based indices of hydrological variability (CEFI, DEHLI, ELF, LIFE, LIFENZ, MIS-index) as tools to facilitate dynamic adjustments of static biological reference conditions. We examined macroinvertebrate assemblage responses to physicochemical and land use drivers in relation to each sample's hydrological conditions, as assessed by the six indices. We evaluated index performance beyond the region of development by exploring correlations among indices, including correlations with the region-specific Greek ELF index, for which 100% of taxa were represented. We also examined the influence of inorganic nutrient pollution on index performance by comparing index scores from samples with and without nutrient pollution. Season, water temperature, agricultural land use and nutrient pollution were major drivers of macroinvertebrate assemblage composition. Indices were positively correlated but correlation strength varied considerably, driven primarily by taxonomic representation (the proportion of sampled taxa included in each index's calculation), and potentially also by differences in river types, taxonomic resolution and sampling strategies. All indices identified site-specific hydrological conditions both in the presence and absence of nutrient pollution. We recommend the development of region-specific biotic indices of hydrological variability, or regional adaptation of existing indices, to represent 100% of the regional taxa pool and thus to enable acceptable performance beyond their region of development. Such indices could inform dynamic adaptation of static biological reference conditions by assessing site-specific hydrological conditions based on a macroinvertebrate assemblage, without the collection of additional, abiotic field data. Application of our proposed approach could prevent misclassification of ecological status, thus avoiding time-demanding and costly mismanagement of rivers and streams.

Assessing water quality in the Kelebek Stream branch (Gediz River Basin, West Anatolia of Turkey) using physicochemical and macroinvertebrate-based indices

This study was carried out in Kelebek, which is the most important stream in Gediz River Basin, Turkey, to determine water quality by using macroinvertebrate-based metrics and physicochemial variables. In addition, we also aimed to investigate the effects of anthropogenic pressure and dam construction on stream macroinvertebrates during the study period. In this study, following biotic indices are used: Saprobi Index (SI), Biological Monitoring Working Party (BMWP), Average Score per Taxon (ASPT), Family Biotic Index (FBI), Belgian Biotic Index (BBI), as well as diversity indices: Shannon-Weaver index (SWDI), Simpsons index (SDI) and Margalef index (MDI). Collection of macroinvertebrate samples and the physicochemical measurements were carried out monthly for a year. As a result of the identification, the most dominant macroinverterate group was Insecta. Our results show the presence of 9 taxonomic group in the stream which belong to nine groups: Oligochaeta, Mollusca, Crustacea, Ephemeroptera, Plecoptera, Trichoptera, Odonata, Coleoptera, Diptera. Canonical correlation analysis (CCA) indicates importance of physicochemial variables in the distribution of different macroinvertebrates groups (total variance 88%), species (total variance 86.2%) and biotic indices (total variance 88.2%). The water quality along the Kelebek Stream show variation from good class in station #1, #2 and #5, to moderate in station #3 and #4. We conclude that BMWP (Original), BMWP (Spanish), BMWP (Greek) and ASPT indices are suitable for assessing stream health by macroinvertebrates.

A comparison of metric scoring and health status classification methods to evaluate benthic macroinvertebrate-based index of biotic integrity performance in Poyang Lake wetland

Methods for metric scoring and health status classification in development of index of biotic integrity (IBI) vary considerably across published studies. The difference between ecosystem health assessment results from these alternative methods for scoring and classification has rarely been studied systematically. Poyang Lake in China has experienced severe degradation over recent decades. Here, we aimed to develop a benthic macroinvertebrate-based index of biotic integrity (B-IBI) to assess the wetland health of Poyang Lake, and to evaluate the difference in assessment results using different methods of scoring and classification. Data on benthic macroinvertebrate assemblages, water quality and human-induced disturbances were collected at 30 sampling sites. Forty-nine attributes of macroinvertebrate assemblages were tested, and only the attributes that were significantly correlated with disturbance gradients or showed strong discriminatory power between reference and impaired sites were selected as the B-IBI metrics. Two scoring, two thresholding and three classification methods were applied for metric scoring and health status classification. Five assemblage attributes, i.e. the number of taxa, Shannon-Wiener diversity index, % Diptera, ASPT index and the number of predator taxa, were selected as the B-IBI metrics. Health status assessments varied considerably among the various metric scoring and classification methods, suggesting the importance of standardizing the methods for scoring and classification to be able to compare assessment results across different areas and time periods. The wetland health of Poyang Lake was rated as fair, which indicates that the wetland has experienced anthropogenic pressure and substantial changes in macroinvertebrate assemblage structure. Further, sample sites adjacent to tributary river mouths were in poor or very poor condition, suggesting that pollutant input by rivers has strong negative impacts on wetland health. Effective management of the entire lake basin and its watershed is therefore important for the wetland conservation.

Bioassessment in the aquatic ecosystems of highly urbanized agglomeration in India: An application of physicochemical and macroinvertebrate-based indices

Abstract Benthic macroinvertebrates (B-macros) from fourteen sampling sites from lentic (lake), intermediate (canal) and lotic (river) ecosystems of Jamshedpur Steel City (JSC) were analyzed, to monitor the changes in their distribution in relation to water quality. JSC is one of the largest Urban Agglomeration in India, which houses more than 1200 industries. The effect of pollution on B-macros communities was analyzed by comparing the physicochemical characteristics (pH, electrical conductivity (EC), total dissolved solids (TDS), alkalinity (ALK), dissolved oxygen (DO), biochemical oxygen demand ( BOD 5 20 ), total Kjeldahl nitrogen (TKN), and chloride (Cl-)) with that of diversity (Shannon Index and Simpson’s diversity index) and biotic indices (Biological Monitoring Working Party (BMWP), Average Score Per Taxon (ASPT), and Family Biotic Index (FBI)). Correlation analysis between the abundance of B-macros and that of physicochemical parameters indicated that EC and ALK are the driving factors for the abundance of B-macros. Scatter plots between physicochemical parameters and indices exhibited that ASPT was the most reliable method for bioassessment. This study would be useful for developing countries like India, where water management practices are almost negligible. Also, the use of B-macros in bioassessment will not only enable the policymakers and regulating agencies to understand the pollution level of any aquatic ecosystem, but also help them to add knowledge regarding the variety of aquatic fauna found in the ecosystems affected with several industrial and domestic pollutants. Moreover, this study will provide a reference to researchers for further identification of B-macros up to genus or species level.

Prioritizing management goals for stream biological integrity within the developed landscape context

Stream management goals for biological integrity may be difficult to achieve in developed landscapes where channel modification and other factors constrain in-stream conditions. To evaluate potential constraints on biological integrity, we developed a statewide landscape model for California that estimates ranges of likely scores for a macroinvertebrate-based index that are typical at a site with the observed level of landscape alteration. This context can support prioritization decisions for stream management, like identifying reaches for restoration or enhanced protection based on how observed scores relate to model predictions. Median scores were accurately predicted by the model for all sites in California with bioassessment data (Pearson correlation r = 0.75 between observed and predicted for calibration data, r = 0.72 for validation). The model also predicted that 15% of streams statewide are constrained for biological integrity within their present developed landscape, particularly for urban and agricultural areas in the South Coast, Central Valley, and Bay Area regions. We worked with a local stakeholder group from the San Gabriel River watershed (Los Angeles County, California) to evaluate how the statewide model could support local management decisions. To achieve this purpose, we created an interactive application, the Stream Classification and Priority Explorer, that compares observed scores with predictions from the landscape model to assign priorities. We observed model predictions consistent with the land-use gradient from the upper to lower watershed, where potential limits to achieving biological integrity were more common in the heavily-urbanized lower watershed. However, most of the sites in the lower watershed scored within their predicted ranges, and were therefore given a low priority for restoration. In contrast, 2 low-scoring sites in the undeveloped upper watershed were prioritized for causal assessment and possible future restoration, whereas 3 high-scoring sites were prioritized for protection. The availability of geospatial and bioassessment data at the national level suggests that these tools can easily be applied to inform management decisions at other locations where altered landscapes may limit biological integrity.

A comparison of macroinvertebrate-based indices for biological assessment of river health: A case example from the sub-tropical Richmond River Catchment in northeast New South Wales, Australia

Abstract Globally, river health is deteriorating due to increased anthropogenic pressures. Accurately assessing river health is crucial for the management of river resources with macroinvertebrates commonly used as biological indicators of ecological integrity. Complex biological data is made more straightforward using indices as they offer the ability to rapidly communicate complex science in a simple form. Management decisions are often based on the results of biological river health assessments, making the identification of the most appropriate, robust and sensitive macroinvertebrate-based index vital when undertaking catchment specific assessments. Selection of a macroinvertebrate-based index should rely on a scientific method rather than arbitrary selection criteria. This study aimed to compare the performance of several macroinvertebrate-based indices to identify the index or indices most appropriate to the Richmond River Catchment (RRC) in northern New South Wales, Australia. River health within the RRC is poor with a clear pollution gradient from upper to lower catchment sites. Six commonly used indices were calculated using family-level identification. The biological assessment supported the physicochemical results with a gradient in river health from upper to lower catchment. Family Richness and Family Richness Percent were assessed as the most usable indices. In studies that have restricted time, budget and expertise they will provide accurate but limited information on river health. SIGNAL2 was identified as the most valid index for assessing river health due to its overall sensitivity to changes in river health, and level of detail on anthropogenic impacts. The poor performance of the AUSRIVAS, EPT and BCI limits or precludes their use for river health assessment in the RRC. While this model for identification and selection of an appropriate macroinvertebrate-based index for catchment scale river health assessments was useful in this context, it needs to be improved with a larger dataset and a greater environmental gradient of river health to make a less subjective evaluation.

Development of macroinvertebrate-based multimetric index and establishment of biocriteria for river health assessment in Malaysia

Abstract Economic and industrial growth in Malaysia has led to various environmental problems, which in turn affected the quality of human life and nature. At present, the management plans, particularly for river rehabilitation, are less effective in addressing issues related to Malaysian rivers. To date, most of the efforts undertaken have focused on evaluating the physicochemical properties of water, whereas biological evaluation determining the health of a river ecosystem is less attended to. Therefore, this study has aimed to develop a multimetric index and biocriteria applicable to the biological assessment of Malaysian streams. Four rivers in the state of Johor have been selected as the sources, each representing different gradients of land use. The reference and impaired sites both have been determined based on various physicochemical, instream features and riparian habitat quality criteria. The resulting candidate metrics have then been evaluated in terms of redundancy, sensitivity and responsiveness to environmental changes, using the stepwise procedures. Integration of six potential metrics across three categories (i.e. taxonomic richness, taxonomic composition, and tolerance and intolerance index) has consequently produced a four-level discriminatory biocriteria for river health assessment: 93% (non-impaired). The re-scored result has revealed that the water quality of Sg Ayer Hitam Besar to be non-impaired, with excellent water quality. Meanwhile, Sg Berasau and Sg Mengkibol have slightly impaired water quality, whereas Sg Melana is moderately impaired with fair to poor water quality. Thus, this multimetric index has strongly differentiated the reference and impaired conditions accordingly, which substantiated the suitability of the discriminatory criteria for Johor stream assessment. Hence, the establishment of macroinvertebrate-based index of biotic integrity (MIBI) and biological criteria may provide indispensable information in managing river ecosystem more effectively.

Taxonomic changes and non-native species: An overview of constraints and new challenges for macroinvertebrate-based indices calculation in river ecosystems

Freshwater ecosystems face many threats in the form of reduced water quantity, poor water quality and the loss of biodiversity. As a result, aquatic biomonitoring tools are required to enable the evaluation of these critical changes. Currently, macroinvertebrate-based indices are globally the most widely used biomonitoring tools in fluvial ecosystems. However, very little is known about the potential effects of changes in taxonomic understanding (updating of classification and nomenclature) or the presence of new non-native species for biotic indices calculation. This is especially relevant given that errors, incorrect classification or exclusion of new/updated nomenclature may affect ecological status evaluations and have direct consequences for the management and conservation of freshwater systems. In this discussion paper the main constraints, challenges and implications of these issues are outlined and case studies from a range of European countries are discussed. However, similar challenges affect rivers and managers globally and will potentially be amplified further in the future. Bioassessment science needs to be open to improvements, and current tools and protocols need to be flexible so that they can be updated and revised rapidly to allow new scientific developments to be integrated. This discussion highlights specific examples and new ideas that may contribute to the future development of aquatic biomonitoring using macroinvertebrates and other faunal and floral groups in riverine ecosystems.

基于大型底栖无脊椎动物完整性指数的鄱阳湖湿地生态健康评价

基于大型底栖无脊椎动物完整性指数的鄱阳湖湿地生态健康评价

Zambian Invertebrate Scoring System (ZISS): A macroinvertebrate-based biotic index for rapid bioassessment of southern tropical African river systems

An extensive survey of tropical rivers, conducted during 2009–2012 throughout Zambia, collected 151 samples of benthic macroinvertebrates, located on 95 rivers in six of the nine freshwater ecoregions. Associated data for physico-chemistry, human activities and ecosystem stressors were collected. Data were used to develop and test a new Rapid Bioassessment Protocol (the Zambian Invertebrate Scoring System: ZISS) for assessment of water quality and river condition in both wadeable and non-wadeable rivers. ZISS, which is based on the South African Scoring System (SASS), includes a total of 85 taxa, of which 79 are shared with SASS. Assignment of sensitivity weightings to new ZISS taxa was based on sensitivity weightings of closely related SASS families; known life-history modes and anatomical adaptations; and correlation of occurrence to impact ratings. The ability of the ZISS to measure impacts was assessed by determining the relationships between ZISS metrics and impacts. ZISS data for the Kafue River demonstrated the efficacy of the ZISS for detecting moderate to high impacts on water quality and river condition. ZISS represents a major step in developing a user-friendly, widely applicable, macroinvertebrate-based biotic index, which can provide easily interpretable assessments of river condition for southern tropical African rivers.

Macroinvertebrates and its impact in assessing water quality of riverine system: A case study of Mahanadi river, Cuttack, India

The aim of this study was to identify the diverse macroinvertebrates present in river Mahanadi, Cuttack in India and to evaluate the role of macroinvertebrates in assessing river water quality and pollution level. We conducted field study of the river at Cuttack (85°46’21.29” E 20°28’15.81” N & 85°49’45.23” E 20°30’50.00” N) during 2013-2014 and collected aquatic invertebrate samples from 12 stations on river basin. The samples were analysed to explore the various families of Macroinvertebrates communities present in river Mahanadi, to examine the status of water quality of the river using biological indicators, to determine whether there are relationships between water chemistry and presence of typical macroinvertebrates and to develop a Macroinvertebrates based index to bio-assessment of Mahanadi River. A total of 484 taxa were identified and about 244 taxa of bivalves and 184 taxa of gastropods were collected. Presence of high number of pollution tolerant taxa and pollution sensitive taxa (Ephemeroptera, Plecoptera, Tricoptera and Chironomidae) indicated increased risk of water pollution and calculated biotic score (8), biological monitoring working party (BMWP) score (52), average score per taxa (ASPT) score (4) and macroinvertebrate-based index (MBI) value indicated moderate pollution level in the river. We recorded pH, total hardness, dissolved oxygen (DO), biological oxygen demand (BOD), total nitrite, chloride and total phosphate of water and physico-chemical parameters supported the values of biological assessment of water quality. Studying macaroinvertebrates helped to gain knowledge about aquatic faunal biodiversity in river Mahanadi and to develop a method for diagnosis of the health of river ecosystem and for measuring water pollution level.

Testing the response of macroinvertebrate communities and biomonitoring indices under multiple stressors in a lowland regulated river

River systems and their communities are exposed to diverse and multiple threats. Understanding how these threats affect the behaviour of biomonitoring indices is essential in order to provide reliable tools for the management and conservation of watercourses. To this purpose we tested the relationship of the STAR_ICMi index and its metrics, LIFE index and macroinvertebrate community with hydrology, water chemistry and land use in 8 sites located along the Oglio River course (Northern Italy), a watercourse originating from a large and deep lake. Macroinvertebrates and water samples were collected seasonally from summer 2013 to summer 2015 and daily discharge data were used to calculate several indices of hydrological alteration. A subset of these variables was selected by principal component analysis for using in the data analysis. The influence of hydrology, water chemistry and land use on macroinvertebrate community structure was explored with the variance partitioning method, while their influence on biomonitoring indices was analysed in a linear mixed effect model framework. Temporal and spatial constraints were explicitly considered in both analyses. Macroinvertebrate community structure was mainly related to these last two factors and to their joint effects with water chemistry and hydrology. STAR_ICMi, its metrics (with the exception of the Shannon index) and LIFE were related to the distance from the lake outlet, a proxy of mean annual discharge, groundwater input and artificial land use. STAR_ICMi, ASPT and EPT richness were also inversely related to the flow variability in the 3 months preceding sample collection. Surprisingly LIFE index was not related to any of the hydrological variables. The results of this study highlight weakness in the current biomonitoring tools and support the need for further investigations on macroinvertebrate interrelations with environmental drivers and their spatial and temporal structure. This is essential to overcome the limitations that may affect the reliability of macroinvertebrate-based indices in aquatic biomonitoring.

Validation of a Macroinvertebrate-Based Index of Nutrient Status in Streams Using Macroinvertebrate, Water-Chemistry, and Diatom Data

Abstract Determination of the causes of water-impairment is a critical part of bioassessment, and it is useful to be able to infer causes from the same sampling data used to assess the impairment. Determination of excess nutrient inputs to a waterbody as a cause of impairment is especially important because of the severity and ubiquity of nutrient-related water-quality problems nationwide. To that end, we tested and validated in New Jersey waters a macroinvertebrate-based nutrient biotic index (NBI) for phosphorus and nitrogen developed by the New York State Department of Environmental Conservation (NYSDEC). We used macroinvertebrate, water-chemistry, and diatom data from New Jersey streams collected in the state biomonitoring program and a study of diatom—nutrient relationships. We calculated tolerance values for widespread taxa based on frequency of occurrence in samples from sites with a range of nutrient concentrations. The NBI of a sample was calculated as a sum of the tolerance values of taxa in a s...

Pollution evaluation in the Shahrood River: Do physico-chemical and macroinvertebrate-based indices indicate same responses to anthropogenic activities?

This study evaluates the impact of anthropogenic activities on the Shahrood River using water physico-chemical variables and macroinvertebrates data sets obtained over a period of 12 months between February 2012 and February 2013 at 8 sampling sites. Biotic indices i.e. FBI and BMWP based on macroinvertebrates and physico-chemical indices (MPI, HPI and NSF-WQI) were employed to evaluate the water quality status in connection with natural- and human-induced pressures. Based on physico-chemical indices, water quality was categorized as low polluted level and it is suitable for drinking purposes. The water quality based on biotic indices was related to the anthropic activities; a clear deterioration of the water quality was observed from upstream to downstream sites. The water quality along the river changed from very good (class I; reference sites) to good (class II; midstream sites) and turned into moderate (class III) and poor (class IV) quality (downstream sites). These findings indicate that biotic indices are more powerful indicators in assessing water quality than physico-chemical indices. Allocapnia, Glossosoma and Hesperoperla were exclusively related to least disturbed sites, and Naididae, Orthocladiinae and Ecdyonurus were found in sites showing notable degradation. Our results recommended that the use of macroinvertebrates could be employed as a cost-effective tool for biomonitoring and controlling of polluted riverine ecosystems in the Middle East. Finally, the results from this study may be useful not only for developing countries, but also for any organization struggling to use macroinvertebrate based indices with restricted financial resources and knowledge.

How do low-abundance taxa affect river biomonitoring? Exploring the response of different macroinvertebrate-based indices

The contribution of rare taxa to aquatic bioassessments remains a subject of debate, and generates contrasting positions among researchers. Very little is known about the effect of low-abundance taxa (LAT) for calculating both single and multimetric macroinvertebrate-based indices, as well as the ecological status classification. In this study, we aimed to: i) identify the aquatic macroinvertebrates that need special attention during index applications given their low abundance; ii) analyse the effect of excluding LAT on single (IBMWP and IASPT) and multimetric (STAR_ICMi) biological indices; and iii) investigate the influence of LAT on river ecological status assessments. To this end, two different river basins in SE Spain and N Italy with contrasting climatic conditions and river types were selected. Our results showed that almost all the taxa at the family level can act as low-abundance taxa. In particular, the LAT belonged mainly to orders Diptera, Trichoptera, Coleoptera, Gastropoda and Hemiptera. The IndVal analysis stressed Tabanidae, Cordulegasteridae and Hydroptilidae as the most characteristic low-abundance families in the Spanish data set, while Dryopidae and Athericidae were identified mostly in N Italy. Excluding LAT affected the studied index values and the resulting bioassessment classification, except for the IASPT index. Loss of the entire LAT pool reduced the ecological status for 78% of the samples for the IBMWP index. Changing took place in 41% of the samples when considering the STAR_ICM index. Relevant changes were detected even when considering loss of 50% of the LAT, especially with the IBMWP index. Similar values and patterns were obtained in each considered quality class and river type. Our results provide useful information about controversial taxa and stress the significance of LAT in river biomonitoring. Excluding LAT is discouraged, although different responses according to the considered index were detected. The IBMWP index always obtained lower values (coupled mainly with an underestimation of ecological classes), while STAR_ICMi and, especially the IASPT index, were less affected by excluding LAT. Paying special attention to all the protocol application stages is recommended, with emphasis placed when using the IBMWP index.

Ecological assessment of morphological shore degradation at whole lake level aided by aerial photo analysis

Hydromorphological alterations of lake shores constitute an important pressure on Central European lakes. The local ecological effects of such alterations can be assessed by multimetric assessment methods based on eulittoral macroinvertebrate communities. However, such tools so far only enable a local assessment even if the European Union Water Framework (EU WFD) requires an assessment at whole-lake level. Since due to time and financial constraints it is not feasible to perform small-scale macroinvertebrate assessments over the whole length of the lake shore, the site-specific ecological assessment result needs to be extrapolated. In this study, we analyse the use of a physical habitat survey method including both ground surveys and aerial photo analysis (HML = HydroMorphology of Lakes survey protocol) to enable an extrapolation from local to whole lake ecological assessment. For that purpose, we correlated individual macroinvertebrate metrics as well as results of a multimetric macroinvertebrate-based index (I) with the areal cover of surrounding natural shore elements, (II) with the hydromorphological impact within an encircling rectangle around the macroinvertebrate sampling site, and (III) with the hydromorphological impact in the adjacent epi-, euand sublittoral subsegments. Building up on this, an ecological whole lake assessment was achieved by averaging multimetric index scores calculated for each subsegement based on a regression equation between the multimetric index and the hydromorphological impacts in the three subsegments. This whole lake assessment approach can most likely be applied to geographical regions outside Central Europe and lake types not analysed here (fluvial lowland lakes, prealpine/alpine lakes), but more studies are necessary to verify this. Eventually, the extrapolation presented here may complement existing lake assessments under the EU WFD solely focusing on water quality so far.