Different surrogacy approaches for stream macroinvertebrates in discriminating human disturbances in Central China

Due to the difficulty of identifying many taxa of freshwater invertebrates to species, many researchers have assessed the utility of surrogates for species-level identifications (e.g. higher taxa) in bioassessment programs. Here, we examined the efficiency of two different approaches to species surrogacy, one using coarser taxonomic resolution and a second approach based on random aggregation (“Best practicable aggregation of species”, BestAgg), in portraying patterns of stream macroinvertebrates in Central China. The main objectives were: (1) to compare the discriminatory power of biodiversity indices and assemblage structure for different levels of human disturbances based on different taxonomic resolution and on BestAgg; (2) to identify the congruence of assemblage-environment and biodiversity-indices-environment relationships for datasets at the species level versus those at surrogate levels. We found that genus-level and BestAgg datasets accurately reproduced the pattern of species-level communities, whereas family- and order-level datasets did not. Specifically, both genus-level and BestAgg approaches performed almost as well as species-level data in distinguishing sites subjected to different disturbance levels. Most of the environmental variables that were important for species-level assemblages, also emerged as significant when analyzing genera and BestAgg surrogates, as shown by both analyses of indices and assemblage composition according to distance-based ordination models. Our results suggest that genus-level taxonomy, which resulted in the least loss of ecological information relative to species-level identification, is sufficient in studies of community ecology and bioassessment of stream macroinvertebrates in Central China. In addition, the BestAgg approach, which required identification of fewer taxa than genus-level analysis, has a similar ability to depict multivariate patterns of macroinvertebrate assemblages and differentiate different disturbance levels. Applying our results could enhance speed and cost-effectiveness of freshwater biomonitoring and bioassessment programs; however, independent determination of best taxonomic level and BestAgg will be required whenever a new geographic area or habitat type is assessed.     

Biodiversity shortcuts in biomonitoring of novel ecosystems

Hydropower reservoirs are novel ecosystems that present different challenges for the design of biomonitoring programs. To ensure long-term programs and wide spatial coverage, it is important to test the reliability of different cost-saving strategies that have been widely evaluated among researchers, such as taxonomic sufficiency, numerical sufficiency and surrogate groups. Using data on zooplankton composition, our objective was to test whether these strategies could be applied to increase the efficiency of biomonitoring programs in reservoirs. Zooplankton data were collected at the Santo Antônio do Jari Hydroelectric Plant, which is located between the states of Pará and Amapá (Amazon region, Brazil), over 23 months between 2012 and 2015. The data were organized in different taxonomic groups (cladocerans, copepods, rotifers and testate amoebae) and matrices by decreasing the taxonomic resolution (from species to genera and families) and the numerical resolution (from species abundance to species presence/absence) of the data. The ordination patterns obtained with Principal Coordinate Analysis for the different matrices were compared using Procrustes analyses. Our results suggest that ordination patterns using genus-level data were similar to those obtained with species-level data. However, analyses based on family-level data were often unable to reproduce results based on species-level data. Ordination patterns using presence/absence data were similar to those obtained from abundance data. We also found that the strengths of the relationships between ordinations derived from different taxonomic groups (e.g., rotifers and cladocerans) were low and often not significant. We conclude that the use of zooplankton genera and presence/absence data may be a reliable strategy to monitor reservoirs. However, our results highlight the need to monitor different zooplankton groups, as the ordination patterns depicted by a given group were poorly related to those generated by a second zooplankton group.     

Taxonomic and Numerical Resolutions of Nepomorpha (Insecta: Heteroptera) in Cerrado Streams

Transformations of natural landscapes and their biodiversity have become increasingly dramatic and intense, creating a demand for rapid and inexpensive methods to assess and monitor ecosystems, especially the most vulnerable ones, such as aquatic systems. The speed with which surveys can collect, identify, and describe ecological patterns is much slower than that of the loss of biodiversity. Thus, there is a tendency for higher-level taxonomic identification to be used, a practice that is justified by factors such as the cost-benefit ratio, and the lack of taxonomists and reliable information on species distributions and diversity. However, most of these studies do not evaluate the degree of representativeness obtained by different taxonomic resolutions. Given this demand, the present study aims to investigate the congruence between species-level and genus-level data for the infraorder Nepomorpha, based on taxonomic and numerical resolutions. We collected specimens of aquatic Nepomorpha from five streams of first to fourth order of magnitude in the Pindaíba River Basin in the Cerrado of the state of Mato Grosso, Brazil, totaling 20 sites. A principal coordinates analysis (PCoA) applied to the data indicated that species-level and genus-level abundances were relatively similar (>80% similarity), although this similarity was reduced when compared with the presence/absence of genera (R = 0.77). The presence/absence ordinations of species and genera were similar to those recorded for their abundances (R = 0.95 and R = 0.74, respectively). The results indicate that analyses at the genus level may be used instead of species, given a loss of information of 11 to 19%, although congruence is higher when using abundance data instead of presence/absence. This analysis confirms that the use of the genus level data is a safe shortcut for environmental monitoring studies, although this approach must be treated with caution when the objectives include conservation actions, and faunal complementarity and/or inventories.     

Different aggregation approaches in the chironomid community and the threshold of acceptable information loss

Due to the problem of identification, Chironomidae larvae, although very abundant, are often avoided or not properly used in bioassessment programs. The aim of this work was to test how different aggregation processes—taxonomic resolution and the random aggregation approach (best practicable aggregation of species—BestAgg) affect the analysis of chironomid communities regarding any information loss. The self-organizing map method, together with classification strength analysis and Spearman’s rank correlation, revealed that the genus-level and BestAgg-abundance matrix most accurately approximated the species-level community pattern. The subfamily-level dataset was ineffective at presenting the chironomid community structure, with a substantially lower concordance with the species-level dataset. The biologic environmental gradients analyses presented the same set of important environmental variables for the species-level, genus-level, and BestAgg-abundance matrix. The indicator values analysis showed that indicator genera provide information very close to that gained from species indicators. According to our results, the numeric relationship between species and higher taxa influences taxonomic scaling, limiting Chironomidae family aggregation, with acceptable information loss only up to genus level. In addition, the BestAgg approach, with the maximum level of aggregation, properly assesses the community structure and consequently describes environmental conditions.     

Is coarse taxonomy sufficient for detecting macroinvertebrate patterns in floodplain lakes?

Taxonomic sufficiency (TS) — defined as the minimum taxonomic detail required to discern some ecological pattern of interest — has been used extensively in bioassessment and biodiversity studies as a way of avoiding a portion of the time and monetary costs associated with species diagnoses. The taxonomic sufficiency for detecting species-level patterns among floodplain-lake benthic-invertebrate assemblages remains unexplored. We examined cross-taxonomic-level congruence in assemblage-environment relationships among 23 Chinese floodplain lakes. Our objectives were: (1) to compare the correlation between species richness and density and those at coarser taxonomic resolution; (2) to identify whether assemblage-environment relationships depend on taxonomic scale; and (3) to test whether the proportion of between-lake variability accounted for by environmental variables was independent of taxonomic scale. When taxonomic structure was described using sequentially coarser taxonomic aggregations, species-level patterns of richness and abundance were sequentially obscured (i.e., genus-level taxonomy best preserved patterns in species composition, order- and class-level taxonomy poorly represented species composition). Similar environmental variables were important for distinguishing lake species assemblages and genus assemblages; however, different environmental variables were important for describing family-, order-, and class-level assemblage patters. Moreover, environmental variables accounted for a similar amount of biological variability, regardless of taxonomic scale. Our results suggest genus taxonomy as sufficient for rapid assessments of lake diversity. Numerical dominance of the species- and genus-rich Chironomidae, Tubificidae, and Naididae, may account for the marked loss of information that occurs when lake invertebrates are assigned only to their families. In summary, we describe taxonomic sufficiency to detecting patterns of richness and abundance among subtropical lake macroinvertebrate faunas. This study will interest Chinese benthologists concerned with conservation and bioassessment.     

New frameworks for species surrogacy in monitoring highly variable coastal ecosystems: Applying the BestAgg approach to Mediterranean coastal lagoons

Benthic invertebrates are good indicators of aquatic ecosystem health. Yet, environmental monitoring and assessment of community changes in relation to both natural and human sources of disturbance involves considerable efforts for sample processing and time-consuming identifications of organisms, which make challenging large-scale and continuous monitoring programs required under the current regulatory frameworks at European scale. The use of higher taxa (e.g. families) as surrogates for species is a mainstream approach to reduce cost and time associated to fine taxonomic resolution in environmental studies, especially concerning macro-invertebrate communities. However, this approach of ‘taxonomic sufficiency’ simply relies on the static grouping of organisms in taxa belonging to a single higher taxonomic level irrespective of their ecological relevance or difficulties in their taxonomic identification, leading to unnecessary losses of taxonomic detail or ecological information. A new approach, namely the Best Practicable Aggregation of Species (BestAgg), has been recently developed as an alternative procedure for species surrogacy. BestAgg is based on aggregating species in the minimum number of surrogates sufficient to depict species-level community patterns consistently, while capitalizing on ecological information. Although the approach has been successfully applied to marine and freshwater invertebrate assemblages, its effectiveness in transitional water systems, where the complex and highly variable environmental conditions may affect the performance of surrogacy methods, still remain untested. Here, we applied the BestAgg approach to quantifying spatio-temporal patterns of variability of macro-invertebrate assemblages from Mediterranean coastal lagoons (Northern Adriatic Sea). Surrogates were defined using species-level data from a representative lagoon system, which served as pilot study. Then, they were used to analyze macro-invertebrate assemblages in two independent lagoons in the same geographic area. Results showed that BestAgg surrogates were effective in depicting multivariate patterns of macro-invertebrate assemblages as at species level over and beyond potential variations among the investigated lagoons. The use of families, following a more classic approach based on taxonomic sufficiency, also provided results comparable to those obtained using species. However, with respect to families, BestAgg surrogates allowed an estimated timesaving of 40% higher while still retaining an equivalent amount of information on species-level patterns. More importantly, BestAgg allowed exploiting different criteria of species aggregation, leading to a set of surrogates more aligned with ecological/functional characteristics of organisms, suggesting that BestAgg approach may provide a fresh perspective for optimizing trade-offs between pragmatism and the need for relevant ecological information in environmental assessment and monitoring.     

Environmental barcoding: a next-generation sequencing approach for biomonitoring applications using river benthos

Timely and accurate biodiversity analysis poses an ongoing challenge for the success of biomonitoring programs. Morphology-based identification of bioindicator taxa is time consuming, and rarely supports species-level resolution especially for immature life stages. Much work has been done in the past decade to develop alternative approaches for biodiversity analysis using DNA sequence-based approaches such as molecular phylogenetics and DNA barcoding. On-going assembly of DNA barcode reference libraries will provide the basis for a DNA-based identification system. The use of recently introduced next-generation sequencing (NGS) approaches in biodiversity science has the potential to further extend the application of DNA information for routine biomonitoring applications to an unprecedented scale. Here we demonstrate the feasibility of using 454 massively parallel pyrosequencing for species-level analysis of freshwater benthic macroinvertebrate taxa commonly used for biomonitoring. We designed our experiments in order to directly compare morphology-based, Sanger sequencing DNA barcoding, and next-generation environmental barcoding approaches. Our results show the ability of 454 pyrosequencing of mini-barcodes to accurately identify all species with more than 1% abundance in the pooled mixture. Although the approach failed to identify 6 rare species in the mixture, the presence of sequences from 9 species that were not represented by individuals in the mixture provides evidence that DNA based analysis may yet provide a valuable approach in finding rare species in bulk environmental samples. We further demonstrate the application of the environmental barcoding approach by comparing benthic macroinvertebrates from an urban region to those obtained from a conservation area. Although considerable effort will be required to robustly optimize NGS tools to identify species from bulk environmental samples, our results indicate the potential of an environmental barcoding approach for biomonitoring programs.     

Insights into discriminating water quality status using new biodiversity measures based on a trait hierarchy of body-size units

Biofilm-dwelling protozoa have successfully used as a feasible bioindicator for bioassessment of water quality status in marine ecosystems. Based on a dataset of biofilm-dwelling protozoa in coastal waters of the Yellow Sea, we demonstrated a spatial variation in body-size spectrum of protozoan communities along a gradient of increasing environmental pollution. Two biodiversity indices, as a new indicator of water quality, were proposed, first being body-size diversity (Δ′) logistically corresponded to taxonomic diversity index but with a trait hierarchy of body-size units based on Euclidean distance resemblance, and the second a modified body-size diversity index (Δ′_m) with a modified hierarchy based on the trait matrix. The values of both indices Δ′ and Δ′_m were found to be significantly correlated with the changes of environmental variables, especially the nutrients. Furthermore, the body-size diversity (Δ′_mrk) at body-size-rank-1 (“genus-level”) resolution might be used as a potential surrogate of those at “species-level” resolution. Thus, we suggest that the ecological parameters based on body-size spectrum may be used as potential bioindicator of water quality status, and that the body-size rank sufficiency might be an effective time-efficient protocol for monitoring programs by identifying taxa to “genus-level” body-size rank.     

The use of coarser taxonomic resolution in studies of predation on marine sedimentary fauna

Given the logistical difficulties, cost, and time involved in species-level identifications, several authors have proposed the use of coarser taxonomic resolution (e.g. family, order) in studies of pollution. The use of surrogates instead of species relies on their sufficiency to detect community responses to the pollution gradient without appreciable loss of information. No studies, however, have applied this approach to experimental studies such as community responses to predation disturbance and evaluated the performance of surrogates at the spatial scales typical of experiments. We addressed both problems by analyzing the results of three predation experiments carried out in Bonne Bay, Newfoundland. We pooled species data into coarser taxonomic categories (family to class) and determined whether effects of predation that were evident at the species level were also evident with the use of each coarser surrogate and increasing data transformation. Our results indicate that non-transformed data at the family level represent a reasonable surrogate of species; however, the ability to discriminate between ambient and (predator) manipulated sediments is gradually lost with data transformation and with the pooling of species into coarser taxonomic categories. Successive data transformation indicates that in this system predation plays a strong role on dominant but not necessarily rare species. Moreover, our results suggest that varying reliability of surrogates precludes the identification of a single general level of taxonomic sufficiency to be used in experimental studies. The use of surrogates, therefore, is suggested only after scrutiny and evaluation, and should be limited to preliminary studies where biodiversity has been well described.     

DNA barcode assessment of Mediterranean mayflies (Ephemeroptera), benchmark data for a regional reference library for rapid biomonitoring of freshwaters

Accurate identification of aquatic species is fundamental to freshwater research. In this paper, we targeted Ephemeroptera, a key taxonomic insect group for biomonitoring of water bodies and present an overview on the efficacy of the DNA barcoding approach to document species identity in the Mediterranean region. We sequenced the mitochondrial cytochrome c oxidase (COI) in 39 nominal species. Sample discrimination and species identification were investigated by evaluating haplotype identity and similarity, intra-/interspecific genetic distances, optimal identification of barcoding gap thresholds, estimates of species monophyly and comparative species matches on available reference libraries. The resolving power of the obtained data was discussed in the light of statistical tools such as Spider R-package and Poisson Tree Processes. High levels of species identification were achieved with all the used methodologies, and the occurrence of cryptic species was suggested. We conclude that DNA barcoding is a powerful tool for taxonomic research in Mediterranean mayflies, with great promise to ameliorate biodiversity inventories of freshwater ecosystems and to provide the necessary accuracy for water quality assessment programs. Our results further indicated we need to upgrade the current regional mayfly diversity knowledge. The development of a Mediterranean reference library could integrate this new information system.     

Non-biting midges in biodiversity conservation and environmental assessment: Findings from boreal freshwater ecosystems

Non-biting midges (Diptera: Chironomidae) are frequently overlooked in freshwater biodiversity surveys and environmental assessment, yet they are commonly the most abundant and the most diverse taxon in freshwater ecosystems. We reviewed the diversity patterns and assemblage–environment relationships of non-dipterans and chironomids mainly in boreal freshwater ecosystems building on previously reported findings. Although generally the same environmental gradients are correlated with assemblage structure, their relative importance varies between chironomids and non-dipterans. Chironomid assemblage response to and recovery from human impacts are also likely to differ from that of other common benthic taxa. Thus, environmental assessments may be biased if chironomids are not included. Different surrogacy approaches have thus far shown little success in accounting for chironomid species richness and assemblage structure, and there appears to be no easy short-cut for the examination of chironomids as part of freshwater surveys. However, we show that genus-level identification of pupal exuviae provides a reliable and rapid way of estimating chironomid species richness at least in boreal freshwater ecosystems. In addition, we demonstrate that the inclusion of chironomids may increase the signal-to-noise ratio in bioassessment data sets, and that this information can be obtained with modest increases in costs.     

Large-Scale Biomonitoring of Remote and Threatened Ecosystems via High-Throughput Sequencing

Biodiversity metrics are critical for assessment and monitoring of ecosystems threatened by anthropogenic stressors. Existing sorting and identification methods are too expensive and labour-intensive to be scaled up to meet management needs. Alternately, a high-throughput DNA sequencing approach could be used to determine biodiversity metrics from bulk environmental samples collected as part of a large-scale biomonitoring program. Here we show that both morphological and DNA sequence-based analyses are suitable for recovery of individual taxonomic richness, estimation of proportional abundance, and calculation of biodiversity metrics using a set of 24 benthic samples collected in the Peace-Athabasca Delta region of Canada. The high-throughput sequencing approach was able to recover all metrics with a higher degree of taxonomic resolution than morphological analysis. The reduced cost and increased capacity of DNA sequence-based approaches will finally allow environmental monitoring programs to operate at the geographical and temporal scale required by industrial and regulatory end-users.     

Multiple-stressor effects on stream invertebrates: DNA barcoding reveals contrasting responses of cryptic mayfly species

Most freshwater ecosystems are subject to multiple anthropogenic stressors, which commonly reduce biodiversity across all levels. Existing freshwater bioassessment programmes aim at identifying responses of aquatic biota to stressors. For practical reasons, higher-level taxonomic groups (e.g. genus or family) are often used in these programmes. This approach, however, may bias assessment results as different species can differ substantially in their biological traits, thus emphasising the need for species-level data. DNA barcoding can reliably generate species-level data for animals by sequencing a fragment of the mitochondrial cytochrome c oxidase subunit I gene (COI). This allows investigating species-specific responses to environmental stressors. In this study, we sampled 43 stream sites in southern New Zealand spanning wide gradients of agricultural stressors (fine sediment and nutrient levels). We first used conventional morphological assessment to determine stream invertebrate responses to the stressors, focusing on two important indicator taxa, the mayfly Deleatidium and the snail Potamopyrgus. We then tested for the presence of cryptic species in Deleatidium and Potamopyrgus using DNA barcoding of the COI gene for 520 and 305 specimens, respectively. While all Potamopyrgus specimens belonged to a single species, Deleatidium consisted of 12 distinct molecularly identified clades that likely represent distinct species. Finally, we compared stressor responses assessed at genus and species level. While overall Deleatidium abundance was unrelated to stressor levels, some of the individual clades differed clearly in the magnitude and direction of their responses to nutrient and sediment stress. While the most abundant cryptic Deleatidium clade (clade 1) showed no relationship to sediment or nutrient levels, clades 2 and 3 responded negatively to nutrient or sediment increases, respectively. These contrasting patterns indicate that individual freshwater invertebrate species, often merged to a higher taxonomic level for biomonitoring purposes, can differ substantially in their tolerance to stressors and respond in more complex ways than observed at genus level. Overall, our results highlight the considerable potential and importance of including DNA barcoding into freshwater ecosystem assessment and biomonitoring programmes.     

A Test of the Higher-Taxon Approach in the Identification of Candidate Sites for Marine Reserves

Alternatives to species-level identification have been advocated as one solution to the problem of selecting marine reserves with limited information on the distribution of marine biodiversity.This study evaluated the effects on selection of candidate sites for marine reserves from using the higher-taxon approach as a surrogate for species-level identification of intertidal molluscs and rocky reef fishes. These effects were evaluated by determining the percentage of species included in candidate reserves identified from genus-, family- and order-level data by a complementarity-based reserve selection algorithm, and by testing for correlations between the irreplaceability values of locations. Candidate reserves identified from genus- and family-level data of intertidal molluscs included a similar percentage of all species as the reserves identified from species-level data. Candidate reserves selected from genus- and family-level data of rocky reef fishes included, respectively, 3–7% and 14–23% fewer species than reserves selected from species-level data. When the reserve identification process was constrained by a practical planning limit (a maximum of 20% locations able to be reserved) the reserves selected from genus- and family-level data of intertidal molluscs, and genus-level data of rocky reef fishes, included a similar percentage of species as the reserves identified from species-level data. Irreplaceability values of locations for species, genera and families of intertidal molluscs were highly correlated, and irreplaceability values of locations for species and genera of rocky reef fishes were highly correlated. This study suggests that genus- and family-level data for intertidal molluscs, and genus-level data for rocky reef fishes, are suitable surrogates for species in the identification of candidate sites for marine reserves.     

An approach to identifying potential surrogates of periphytic ciliate communities for monitoring water quality of coastal waters

For identifying the potential surrogate of periphytic ciliate communities for monitoring marine water quality, the different taxonomic resolutions/taxa as surrogates and different data transformations were studied based on two datasets of ciliate communities in Korean coastal waters. Multivariate analyses showed that: (1) a dominant Zoothamnium duplicatum significantly masked the temporal patterns of periphytic ciliate community; (2) the order level resolution maintained sufficient information to evaluate the efficient patterns of ciliate communities in response to environmental impacts; (3) the vagile-ciliate assemblage at species-level resolution was as costly as whole periphytic ciliate communities without Z. duplicatum at the order level; and (4) the severity of data transformations played a crucial role for effectiveness of surrogates, e.g., heavy transformation for species level and mild for higher. These results suggest that the use of lower taxonomic resolutions is time-efficient and would allow improving sampling strategies of large spatial/temporal scale monitoring researches in the marine ecosystem.     

Odonata (Insecta) as a tool for the biomonitoring of environmental quality

Despite the fundamental dependence of human populations on water resources, a range of anthropogenic impacts, in particular the removal of riparian vegetation, threaten freshwater environments. One of the most effective means of evaluating the effects of anthropogenic disturbance in aquatic ecosystems is the use of bioindicators, and the insects of the order Odonata are among the most efficient indicators, due to their enormous sensitivity to environmental changes. In this context, the present study aimed to verify which parameters of the odonate community (species richness, abundance/biomass, composition, taxonomic diversity and taxonomic/phylogenetic distinctness) are most effective for the evaluation of the loss of environmental integrity. The study focused on 50 streams in the northeast of the Brazilian state of Pará. The streams were sampled during the dry season, between June and August 2011. The physical characteristics of each stream were evaluated using a Habitat Integrity Index (HII). The species composition provided the best parameter for the evaluation of ecological integrity, providing a relatively accurate assessment at a lower mean research cost than other parameters. Taxonomic diversity and distinctness also provided relatively reliable results, contributed additional information on the evolutionary relationships among the odonate taxa, and also provided a low-cost approach. Deconstructing communities is necessary to detect impacts, considering the considerable variation in the environmental requirements of the different species. Overall, the parameter that best responded to gradients of disturbance was species composition, followed by diversity and taxonomic distinctness. Given these findings, odonate-based biomonitoring should focus on these parameters to guarantee the optimal detection and evaluation of habitat alterations.     

A diagnostic biotic index for assessing acidity in sensitive streams in Britain

Despite the history of freshwater biomonitoring, there is still a dearth of proven indices that allow accurate status assessment while simultaneously diagnosing the cause of impairment, particularly when stressors are multiple. Here, we present an approach to developing diagnostic indices where the sensitivity of biota is quantified using multivariate ordination. We applied the approach to the development of an index to detect acidity in British streams.Using a 197-site calibration dataset, we quantified variation in macroinvertebrate assemblages and determined which environmental variables best described the pattern. We then ranked taxa along an acid–base gradient, having first considered the merits of factoring out confounding variation from natural environmental factors. The response of the new species-level Acid Water Indicator Community (AWICsp) index to variation in base-flow and storm-flow pH and acid neutralising capacity (ANC) was quantified using independent data. Performance was also compared with existing family-level and species-level indices.AWICsp was consistently the species-level diagnostic index most clearly related to base-flow pH, storm-flow pH and ANC, accounting for 38–56% of the variation in acid conditions among the 76 test sites.Given the need to develop bio-diagnostic indicators, these data illustrate how organisms can indicate causes of stream impairment using robust and objective procedures, and when applied to strong environmental gradients such as acid–base status. We suggest that given the necessary calibration data, this approach could be applied successfully to other widespread stressors with equally strong biological effects such as organic pollution and fine sediment deposition, particularly if used in combination with RIVPACS-type predictive bioassessment models.     

Assessment of ecological impairment of Arctic streams: Challenges and future directions

As increased growth and development put pressure on freshwater systems in Arctic environments, there is a need to maintain a meaningful and feasible framework for monitoring water quality. A useful tool for monitoring the ecological health of aquatic systems is by means of the analysis and inferences made from benthic invertebrates in a biomonitoring approach. Biomonitoring of rivers and streams within the Arctic has been under‐represented in research efforts. Here, we investigate an approach for monitoring biological impairment in Arctic streams from anthropogenic land use at two streams with different exposure to urban development in Iqaluit, Nunavut, Arctic Canada. Sites upstream of development, at midpoint locations, and at the mouth of each waterbody were sampled during 6 campaigns (2008, 2009, 2014, 2015, 2018, and 2019) to address spatial and temporal variability of the macroinvertebrate community. The influence of taxonomic resolution scaling was also examined in order to understand the sensitivity of macroinvertebrates as indicators in Arctic aquatic systems. We demonstrate that standard biological metrics were effective in indicating biological impairment downstream of sources of point‐source pollutants. A mixed‐design ANOVA for repeated measures also found strong interannual variability; however, we did not detect intra‐annual variation from seasonal factors. When examining metrics at the highest taxonomic resolution possible, the sensitivity of metrics increased. Likewise, when trait‐based metrics (α functional diversity) were applied to indicators identified at high taxonomic resolution, a significant difference was found between reference and impacted sites. Our results show that even though Arctic systems have lower diversity and constrained life‐history characteristics compared to temperate ecosystems, biomonitoring is not only possible, but also equally effective in detecting trends from anthropogenic activities. Thus, biomonitoring approaches in Arctic environments are likely a useful means for providing rapid and cost‐effective means of assessing future environmental impact.     

phylochipanalyser - a program for analysing hierarchical probe sets

The recent introduction of phylochips that contain molecular probes facilitates environmental microbial identification in a single experiment without previous cultivation. A set of probes recognizing species at different taxonomic levels is denoted as a hierarchical set. Application of hierarchical probe sets on a DNA microarray allows the assessment of biodiversity with different resolutions. It significantly increases the robustness of the results retrieved from phylochip experiments because of the possible consistency checks of hybridization across different taxonomic levels. Here, we present a computer program, phylo-chipanalyser, for the hierarchy editing and the evaluation of phylochip data generated from hierarchical probe sets.