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• Current bioassessment methods are not well suited to account for complex natural environmental gradients. • Proposed method uses correlated residual occurrence to estimate biological condition. • Method estimates condition without assumption of "minimally disturbed" conditions present in sample. • Method allows estimate of condition to be partitioned to potential contributing stressors. Bioassessment of complex and heterogeneous ecosystems is a challenge when there are multiple, strong, natural environmental gradients; unknown, or spatially varying, mixtures of stressors; and large numbers of taxa with unknown responses to both the environmental gradients and the stressors. Current methods of bioassessment are not designed for use under this set of constraints. To address this gap, we have developed an assessment method appropriate for well-sampled, heterogeneous systems with many taxa. In the bioassessment described below, we model taxa occurrence as a function of natural environmental gradients, then use residual covariance patterns between all pairs of taxa to estimate the impact of human disturbance across sites as a latent construct. The derivation of the method from an underlying causal model allows the metric value at each site and the associated taxa responses to be partitioned into contributions from a set of putative stressors. We apply this method as a case study to the subtidal benthic invertebrate community of Puget Sound, WA (USA) and demonstrate a partial decomposition of the metric values to a set of stressors including sediment organic carbon, nitrogen, metals, and organic pollutants. While this method provides new opportunities to estimate, communicate, and understand the ecological condition of complex, heterogeneous ecosystems, due to the requirement for broad, detailed data to inform its estimates, it will likely be most appropriate for monitoring programs. [ABSTRACT FROM AUTHOR]

• B-MMI and three indices are built to assess benthic macroinvertebrate integrity. • The shared effects of hydromorphology and physico-chemistry are analyzed. • The main environmental factors contributed to B-MMI, D/A, S/T and FFGs for substrate types are recognized. Hydrology, water quality and biological pressures can influence structure and function of stream and river ecosystems. However, in practice, identifying the shared effects of factors on communities instead of isolated effects is a challenging task. Benthic macroinvertebrate community can reflect bottom conditions of streams and is less disturbed by river flows and human activities. Therefore, it is suitable to analyze the shared effects of hydromorphological and physico-chemical parameters. Benthic macroinvertebrate based Multi-Metric Index (B-MMI) was built to evaluate overall status and the effects on three biological traits were calculated, including diversity and abundance (D/A), sensitivity and tolerance to pollutions (S/T) and functional feeding groups (FFGs). Redundancy Analysis (RDA) was performed to evaluate the percentage of explained variance of 18 hydromorphological and physico-chemical parameters on invertebrate community. Our analysis showed that the two facets of the environment have high shared explained variances (28.2%–44.5%). Relatively, physico-chemical parameters have higher contributions on B-MMI than hydromorphological parameters. Seasonal analysis showed the shared effects are higher in dry season than wet season. S/T characteristics are most sensitive to seasonal shared effects, which in wet season can best show the isolated effects of the two facets of the environment. At the catchment-scale, middle stretches had higher B-MMI values since stony substrate and less disturbed land use types. And reach studies showed channel morphology contributed more in stony reaches while bottom conditions contributed more in silty and sandy reaches. Our findings consequently give rise to concern to the integrity index of benthic invertebrate community, which allows to show large shared effects of hydromorphological and physico-chemical factors. Besides catchment scale, reach scale also help add the perspective of substrate diversity and heterogeneity in habitat restoration and conservation. [ABSTRACT FROM AUTHOR]

• The General Soil Quality Index (GISQ) is used for the first time to assess reclamation of a coal mine. • Maximum differences between the 1-y site and forests were evident, verifying the sensitivity of the indicator. • Rehabilitation operations of the Cerrejón mine allowed recovery of soil macrofauna. The evaluation and success of ecological reclamation can be assessed by measuring soil physical, chemical and biological variables, either in isolation or combined into composite indicators. In this study we tested the suitability of biological, chemical and physical quality indicators–and their combination in a General Indicator of Soil Quality (GISQ)—to monitor soil quality in restored areas of an open cast coal mine. These composite indicators were computed with principal component analyses (PCA) and co-inertia multivariate analyses (CoIA). Our biological indicator showed a significant recovery of soil invertebrate communities along the chronosequence. Taxonomic richness increased from 7 taxa the 1st year to 13–17 taxa in 6–20-y sites, far less than in forests (19–20). Soil pH, bulk density and proportion of physical and macro aggregates were highest in the 1-y site, while soil organic matter (SOM), total N and proportion of biogenic aggregates were highest in older sites. In general, the three sub-indicators and the GISQ yielded the lowest values in the 1-y site (from 0.1 to 0.3 on a scale of 0.1 to 1.0), intermediate in the 16- and 20-y sites, (0.4–0.7) and reached highest values in the two forests (0.4–1.0). The GISQ methodology proved efficient in assessing progress in the reclamation process which should not be achieved only by monitoring vegetation cover changes. [ABSTRACT FROM AUTHOR]

Highlights • An ecosystem model of a temperate estuary was developed in AQUATOX 3.1. • Macroinvertebrates respond differently to single stressor and multiple stressors effects. • Temperature and river flow interact antagonistically on macroinvertebrate communities. • The production of the Minho estuary is highly dependent on hydrodynamics. • Ecosystem models should be used for sustainable environmental management. Abstract An ecosystem model of the Minho estuary (NW coast of Iberian Peninsula) was implemented in AQUATOX 3.1 (US-EPA) to check whether the effects of temperature rise, dry years, rainy years and river flow decrease acting isolated (single stressor) or combined (multiple stressor) would induce the same type of response on macroinvertebrate biomass variation and to identify the type of stressor interactions. The model was parameterised with site-specific and species-specific data and accounts for a food web with primary producers, benthic invertebrates, fish and detritus, with 12 biotic groups, 4 groups of detritus and 12 forcing functions. Results showed that macroinvertebrate biomass responded differently to single stressor and multiple stressor scenarios and interactions among the tested stressors were antagonistic. During medium term simulations (∼6 years), the biomass of macroinvertebrate communities from the Minho estuary was maintained or slightly increased in single scenarios of temperature rise but the occurrence of antagonistic interactions between temperature rise, river flow decrease, dry years and rainy years counteracted the increasing tendency in multiple stressor scenarios. Overall, the present results highlight the strong dependence of the system's biomass and production on hydrodynamics and contribute to increase knowledge on the mechanistic processes behind this. Thus, we recommend an ecosystem-based management of the Minho River basin supported by models such as the present one. [ABSTRACT FROM AUTHOR]

Highlights • The effect of morphological alterations to lake littoral zones was investigated. • Macroinvertebrate communities differed among shore types and habitats. • Morphological alteration had a negative effect on macroinvertebrate biodiversity. • Regional indicator taxa were identified for different shore types and habitats. • We validated the use of macroinvertebrates to assess morphological alterations. Abstract Human lake shore alterations often result in a substantial decrease of littoral and riparian habitat diversity and physical complexity, but the intensity at which shore alterations affect biodiversity may differ among European geographical regions. We tested if the response of littoral macroinvertebrate communities to human shoreline alterations is consistent among geographical regions. We compared community composition and diversity of human altered with those of unmodified littoral zones from 51 lakes across seven European countries in four geographical regions based on pooled composite as well as habitat-specific macroinvertebrate samples. Taxon richness and community composition differed among shore types and different habitats in all geographic regions, with morphological alteration having an overall negative effect on macroinvertebrate taxon richness. In addition, habitat heterogeneity also had a strong effect on littoral communities, with highest taxon richness found in the structurally complex macrophyte habitats in all regions. Average proportional densities of Diptera and Oligochaeta taxa generally increased in morphologically altered shores in all geographical regions, while Bivalvia, Crustacea, Ephemeroptera, Gastropoda and Trichoptera showed comparatively lower numbers in many anthropogenically altered sites. Furthermore, taxon richness was positively correlated with habitat diversity. We were able to relate changes in littoral communities to anthropogenic shoreline alterations, and linked the effect to the loss of habitats and habitat complexity. The results of our study demonstrate that littoral macroinvertebrates respond consistently negative to the influence of morphological alterations across European geographical regions in terms of biodiversity. While macroinvertebrates have previously been identified to be useful descriptors of morphological change in single countries/regions, we can now validate that they can be used to assess the ecological status of lakes in terms of morphological alterations across European regions. Our results can be used to further improve ealready existing WFD-compliant multimetric indices, for example by including taxa groups, which show a strong reaction to shoreline alterations. This could be supported by the inclusion of a suit of indicator taxa reflecting the loss of complex habitats such as macrophytes in the lake littoral. [ABSTRACT FROM AUTHOR]

Highlights • Snail assemblages were concurrently influenced by saline and hydrologic conditions. • Salinity was a more important control on Gastropoda than hydroperiod. • Wetland conservation should recognize the interaction of salinity and hydrology. Abstract Invertebrate community structure in wetlands is determined by a complex suite of environmental factors and biotic interactions. Hydrology (i.e. hydroperiod and water permanence) is considered the paramount environmental control of freshwater wetlands, with temporary drying being a major constraint on biota. However, factors controlling invertebrate assemblages in saline-alkaline wetlands remain poorly investigated. Moreover, most previous studies analyzing environmental filtering on wetland invertebrates have focused on local scales, and cross-regional studies are rare. In this study, the snail fauna was used to evaluate environmental filtering across saline-alkaline intermittently inundated and perennially inundated marshes in Songnen Plain and freshwater intermittently inundated and perennially inundated marshes in Sanjiang Plain, of Northeastern China. Multivariate analyses showed snail assemblages were concurrently being influenced by saline conditions (Sanjiang, for freshwater versus Songnen, for saline), and hydrologic conditions (intermittently inundated wetlands versus perennially inundated wetlands in Songnen and Sanjiang). Snail abundance and richness were significantly higher in freshwater wetlands of the Sanjiang Plain than in saline-alkaline wetlands of the Songnen Plain. Snail abundance of perennially inundated wetlands was higher than intermittently inundated wetlands in Sanjiang Plain, as predicted, but the reverse was true in Songnen Plain wetlands, contrary to prediction. Across Northeastern China, salinity was a more important control on snail assemblages than hydroperiod, a pattern previously unreported, and salinity mediated the impacts of hydroperiod. In regions where saline wetlands occur, the unique relationships between saline conditions and hydroperiod need to be considered for the assessment and conservation of threatened wetland resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • We develop new multimetric index and diagnostic tool to assess small standing waters. • Ten environmental predictors allow to define metric reference values per site. • The BECOME index discriminates 94% of impaired sites whatever pressure types. • The index is sensitive to 13 land use-, hydromorphology- and biotic-based pressures. • The BECOME d diagnostic tool helps to identify major sources of SSW alteration. Small shallow lakes and ponds (SSWs) have high conservation value and support numerous ecosystem services. However, these small ecosystems face many threats, including eutrophication and internal biotic pressures like Cyprinidae or exotic bioturbators crayfish, which tend to shift biodiverse SSWs to a turbid state dominated by phytoplankton unfitted to numerous usages, and compromise the effectiveness of their restoration. The ecological quality of SSWs and the efficiency of their management still remain poorly evaluated because of the lack of adapted tools. To fill this gap, we propose a new multimetric index (BECOME) and a diagnostic tool (BECOMEd) both based on macrophyte and invertebrate communities. BECOME exhibits a high sensitivity to the impact of surrounding crops, urbanization and fertilized meadows, morphological alterations, and various internal biotic sources of alterations, in a wide variety of geological and climatic contexts. BECOME is especially innovative, because taking into account internal biotic sources of pressures neglected by most of the existing biological WFD-compliant indices for European lakes and ponds, despite their importance in SSW threats. BECOMEd allows to identify the major alteration sources and estimates their relative contribution to SSW degradation, helping managers to prioritize actions or to evaluate their effectiveness. The statistical design applied for the index construction has been fitted to develop biological index for ecosystems influenced by a wide amplitude of numerous environmental conditions. This design could be easily applied elsewhere in the world, for SSWs but also for other types of ecosystems. [ABSTRACT FROM AUTHOR]

The relations between benthic macroinvertebrate communities and eco-factors usually are nonlinear and highly complex, and are often difficult to evaluate. In this study, canonical correlation analysis (CCA) and a generalized additive model (GAM) were applied to identify the key eco-factors that influence the community characteristics of benthic macroinvertebrates in a shallow water lake--Baiyangdian Lake. The water depth (H), water transparency (secchi disc depth, SD), concentration of chlorophyll-a (Chl-a), water temperature (T), concentration of dissolved oxygen (DO), oxidation and reduction potential (ORP), ammonium nitrogen (NH 4 -N) and nitrate nitrogen (NO 3 -N) in water, median particle diameter (D 50 ), ammonium nitrogen in the substrate (NH 4 -N soil ), and biomass of macrophytes, are the main eco-factors affecting the spatial distribution and structure of the benthic macroinvertebrate community in the shallow freshwater lake. This study is the first to introduce GAM to habitat suitability evaluation for benthic macroinvertebrates in large shallow lakes, and to use the Margalef index (d M ) instead of individual indicator species to indicate diversity variation. Five factors, including H, T, NH 4 -N soil , organic matter (OM) in the substrates, and the biomass of macrophytes, were selected in the optimal model by stepwise regression. The response curves generated by the GAM indicated that the diversity of benthic macroinvertebrates was negatively correlated with H and (NH 3 -N soil ) and was positively correlated with T and OM. The response curve showing the relation between taxa diversity and the biomass of macrophytes was unimodal. The current study examined the combined influence of multiple eco-factors on benthic macroinvertebrates, and increased understanding of relations between the benthic macroinvertebrate community and eco-factors in a shallow lake system. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Excessive fine sediment accumulation (i.e., siltation) in streams and rivers originates from several human activities and globally results in heavy alterations of aquatic habitats and biological communities. In this study the correlation between fine sediment and several benthic invertebrate community metrics was tested through a manipulative approach in alpine streams, where siltation mainly results as a physical alteration (i.e., the clogging of substrate interstices) without the influence of co-occurring confounding factors. We selected 12 candidate metrics, belonging to three different categories: compositional, structural and functional. We first carried out a manipulative experiment where artificial substrates were used to provide standardized conditions of siltation. All candidate metrics were calculated for each artificial substrate and the selection of the best combination of metrics was statistically performed with an information-theoretic approach. All candidate metrics were calculated both at family level and also at a mixed level (family and genus) in order to account for the systematic resolution. Then, data from a field study on alpine streams affected by mining activities were used as independent dataset for testing the performance of the selected metrics. We found that the total taxa richness, the EPT (Ephemeroptera, Plecoptera and Trichoptera) richness and the abundance of benthic invertebrates associated to rheophilous conditions and coarse mineral substrates were the most sensitive metrics. When these metrics were aggregated into a multimetric index in the validation dataset, we observed high and significant correlations between index values and the quantity of fine sediment for both taxonomic levels, especially for the mixed level. The findings of this study provide useful tools for biomonitoring the effects of fine sediment in low order, mountainous streams and contribute to improve our diagnostic ability on stressor-specific alterations. [ABSTRACT FROM AUTHOR]

Species co-occurrence and site-specific characteristics have a great influence on biotic community composition at local scales and thus contribute to large variations at broad spatial scales. In this paper, we studied invertebrate communities in 63 river sites of the Lower Mekong Basin (LMB) sampled over 609 thousand km 2 . We identified important macroinvertebrate taxa of the component communities (i.e. annelids, crustaceans, mollusks and insects), and key geo-environmental factors that explained the total variance (BD Total ) of the communities at large spatial scale. We used the “ Species Contributions to Beta Diversity” (SCBD) and “ Local Contributions to Beta Diversity” (LCBD) approaches to partition total beta diversity (BD Total ), identified the important macroinvertebrate taxa (those with high SCBD indices), and estimated the uniqueness of sites in community composition (LCBD indices). SCBD indices showed which taxa were the most important in structuring the four component communities: there were 29 insect taxa, which mainly characterized the upstream sites, and 18 mollusk, 7 annelid and 6 crustacean taxa, which all represented the downstream sites. We used linear regression models to investigate the influence of geo-environmental factors and of component communities on LCBD indices. Our results showed great variation in composition within the LMB (BD Total = 0.80 on a 0-to-1 scale). Five sites of the main channel exhibited significant uniqueness (LCBD indices) in community composition. One of them was a hotspot location occupied by a community with exceptional taxonomic composition, which should be protected. Four other sites were degraded by human activity and in need of restoration. Multiple regressions indicated that the global LCBD indices are better explained by the environmental factors, i.e. water conductivity, river depth and Secchi depth (adjusted R 2 = 0.26), than by the geographical factors. Among the component communities, mollusks’ and insects’ LCBDs were the determinants responsible for the variation in the global LCBD indices (adjusted R 2 = 0.84). The uniqueness in community composition of the sites (i.e. LCBDs) that we estimated provides useful ecological information, which could be used to support restoration and conservation planning for the LMB. [ABSTRACT FROM AUTHOR]

• Plant resistance to hydropeaking was tested using functional trait-based indices. • Grasses resisted well hydropeaking flooding and water-level fluctuations. • Trees and shrubs may successfully cope with hydropeaking baseflow periods. • Forbs were rather vulnerable to all the hydropeaking disturbances. • Our indices may help detect suitable species to restore hydropower rivers. Hydropeaking, which refers to large and rapid flow fluctuations caused by the turning on or off of hydro-turbines to generate electricity, is a topic of growing interest due to its impact on fluvial ecosystems. To date, most hydropeaking studies have focused on the impact of this hydropower operation mode on invertebrate and fish communities, but little attention has been paid to its impact on riverine communities and how functional traits may make plants resistant to hydropeaking. We determined how a set of 32 plant functional traits are expressed in 14 riverine species, and how such expression affects their capacity to cope with common sources of hydropeaking disturbance (i.e., inundation, water stress, and rapid water fluctuations linked to up-ramping and down-ramping hydropeaking operations). We categorized species as "resistant", "partially-resistant" or "vulnerable" based on the capacity of each trait to confer resistance to hydropeaking disturbances. Two indexes (i.e., "hydropeaking plant species resistance index" (HPPR) and "hydropeaking plant community resistance" index (HPCR)) were developed to rank our species based on their tolerance to hydropeaking and to determine which were the commonest "hydropeaking-resistant" traits within the plant community. Our results evidenced that coincidences in trait expression are common between species with similar growth forms. Grasses were the most resistant to inundation and water fluctuations, whereas trees and shrubs were so to water stress. In general, forbs were rather vulnerable to all the hydropeaking disturbances. The differences observed between the resistance expected and the obtained for several plant species illustrate the importance of our approach to fine-tune the diagnostics on plant species vulnerability to hydropeaking.. We believe this initiative will help river managers to detect suitable species to restore rivers affected by hydropower production. [ABSTRACT FROM AUTHOR]

[Display omitted] • The invertebrate OTU abundance (%) in wetland showed that Cnidaria > Porifera > Rotifera > Mollusca > Annelida > others. • 'Simpson' diversity index was the most effective to distinguish the differences in invertebrate communities. • The class-level alpha diversity showed higher recognition than other taxonomic levels. • Insecta, Ascidiacea, and Monogononta were biomarkers for lake, river, and estuary habitats, respectively. • Explanation of environmental factors on OTU richness showed the taxon-level tendency phylum > class > order > family > genus. Invertebrates play vital roles in maintaining biodiversity and food web structure. However, it is difficult to identify invertebrate taxa across complex habitats due to the limitation of traditional morphology. In subtropical wetlands, environmental DNA (eDNA) metabarcoding was used to characterize the composition and diversity of aquatic invertebrates and analyze the environmental impacts on invertebrate community structure. According to the relative abundance (%) of invertebrate OTU richness, 30 sampling sites in wetlands were clustered into six zones, which exhibited significant spatial (i.e., wetland type-specific) differences in taxonomic composition. The relative OTU abundance (%) at the phylum level showed that Cnidaria (48.5%) > Porifera (19.4%) > Rotifera (11.0%) > Mollusca (9.2%) > Annelida (5.3 ± 2.8%) > others (less than 2.2%). Of the five alpha diversity indexes, 'Simpson' was the most effective index to distinguish the spatial differences in invertebrate diversity, and the class-level alpha diversity showed higher recognition than other taxonomic levels. The class-level biomarkers that could indicate the habitat-specific composition of local invertebrates were Insecta, Cnidaria, Hydrozoa, and Gastropoda in the inflow river; Ascidiacea and Demospongiae in the fluvial wetland; Clitellata, Gymnolaemata, and Monogononta in the lacustrine wetland; and Echinoidea in the estuarine wetland. The associations between environmental factors and invertebrate OTU richness based on redundancy analysis showed the taxon-level tendency of phylum (78.5%) > class (73.4%) > order (69.3%) > family (64.9%) > genus (61.2%). Our results demonstrated that aquatic invertebrate diversity profiling by environmental DNA metabarcoding can effectively reflect the composition, diversity and biomarkers of invertebrate communities. In the future, because of its great application potential, the eDNA technique may play an important role in biomonitoring complex water environments. [ABSTRACT FROM AUTHOR]

In rivers, the ecological effects of drought typically result in gradual adjustments of invertebrate community structure and functioning, punctuated by sudden changes as key habitats, such as wetted channel margins, become dewatered and dry. This paper outlines the development and application of a new index (Drought Effect of Habitat Loss on Invertebrates – DEHLI) to quantify the effects of drought on instream macroinvertebrate communities by assigning weights to taxa on the basis of their likely association with key stages of channel drying. Two case studies are presented, in which the DEHLI index illustrates the ecological development of drought conditions and subsequent recovery. These examples demonstrate persistent drought effects months or several years after river flows recovered. Results derived using DEHLI are compared with an established macroinvertebrate flow velocity-reactive index (Lotic-invertebrate Index for Flow Evaluation – LIFE score) and demonstrates its greater sensitivity to drought conditions. Data from a number of rivers in south east England were used to calibrate a statistical model, which was then used to examine the response of DEHLI and LIFE to a hypothetical multi-year drought. This demonstrated a difference in response between sampling seasons, with the spring model indicating a lagged response due to delayed recolonisation and the autumn model differentiating habitat loss and flow velocity-driven responses. The application of DEHLI and the principles which underlie it allow the effects of drought on instream habitats and invertebrates associated with short or long term weather patterns to be monitored, whilst also allowing the identification of specific locations where intervention via river restoration, or revision of existing abstraction licensing, may be required to increase resilience to the effect of anthropogenic activities exacerbated by climate change. [ABSTRACT FROM AUTHOR]

Invasive bivalves often act as ecosystem engineers, generally causing physical alterations in the ecosystems in which they establish themselves. However, the effects of these physical alterations over benthic macroinvertebrate communities’ structure are less clear. The objective of this study was to characterize the ecological effects of the invasive bivalves Corbicula fluminea and Limnoperna fortunei on the structure of benthic macroinvertebrate communities in neo-tropical reservoirs. Three hypotheses were tested: (1) invasive bivalves act as facilitator species to other benthic macroinvertebrates, resulting in communities with higher number of species, abundance and diversity; (2) invasive bivalves change the taxonomic composition of benthic macroinvertebrate communities; (3) invasive bivalves increase the complexity of benthic macroinvertebrate communities. For that it was used data from 160 sampling sites from four reservoirs. We sampled sites once in each area, during the dry season from 2009 to 2012. The first hypothesis was rejected, as the presence of invasive bivalves significantly decreased the host benthic communities’ number of species and abundance. The second hypothesis was corroborated, as the composition of other benthic macroinvertebrates was shown to be significantly different between sites with and without invasive bivalves. We observed a shift from communities dominated by common soft substrate taxa, such as Chironomidae and Oligochaeta, to communities dominated by the invasive Gastropoda Melanoides tuberculata . The biomass data corroborated that, showing significantly higher biomass of M. tuberculata in sites with invasive bivalves, but significantly lower biomass of native species. Benthic macroinvertebrate communities presenting invasive bivalves showed significantly higher eco-exergy and specific eco-exergy, which corroborate the third hypothesis. These results suggest that while the presence of invasive bivalves limits the abundance of soft bottom taxa such as Chironomidae and Oligochaeta, it enhances benthic communities’ complexity and provide new energetic pathways to benthic communities in reservoirs. This study also suggests a scenario of invasion meltdown, as M. tuberculata was facilitated by the invasive bivalves. [ABSTRACT FROM AUTHOR]

Urbanization and its physical and chemical effects on aquatic environments influence invertebrate communities negatively. Yet, it is not clear how urbanization affects inter-annual variation of invertebrate assemblages in streams. We 1) evaluated urbanization effects on the ecological conditions (biotic and abiotic) of streams in Manaus and 2) analyzed invertebrate community variation over time (between 2003 and 2010). Data on abiotic variables and invertebrates from 2003 were obtained from a previous study. In 2010 we sampled abiotic variables and invertebrate communities in the same low-order urban streams sampled in 2003 (n = 40). We recorded high values of total nitrogen, total phosphorous, deforestation, total impervious area (TIA), water temperature, pH, and electrical conductivity in the most urbanized streams, as compared to the least-impacted ones. In contrast, the least-impacted streams had high dissolved oxygen concentrations. Water quality was poorer in 2010 than in 2003: oxygen concentration was lower and total nitrogen, total phosphorous, deforestation, and TIA significantly higher in 2010. We recorded higher inter-annual variation of abiotic variables in the most-impacted streams as compared to the least-impacted streams. EPT (%, Ephemeroptera, Plecoptera, and Trichoptera) and richness metrics decreased with urbanization. On the other hand, % OP (percent of Oligochaeta and Psychodidae) increased with urbanization. Observed and EPT richness and% OP increased between 2003 and 2010. On the other hand, rarefied richness decreased between years. Increases of observed and EPT richness between 2003 and 2010 were related to low inter-annual variability in streams conditions; however, differences of% OP and rarefied richness were not related to inter-annual variability in environmental conditions. The degree of urbanization did not explain the magnitude of the within-stream difference of invertebrate communities between 2003 and 2010. The increased effects of urbanization represented by the abiotic variables sampled and the reduction of invertebrate richness and increased dominance of tolerant taxa indicate that public policy is not enough to protect or mitigate human impacts on the urban water systems under study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Makuleke Wetlands receive water from rivers influenced by anthropogenic inputs. • Multivariate macroinvertebrate analyses to assess ecosystem structure and function. • Aquatic biodiversity was some of the highest recorded in the Global South. • Wetland ecosystem structure is in a suitable condition to support high biodiversity. • Invasive species threaten native biodiversity in this premier conservation area. The Ramsar-accredited Makuleke Wetlands are located in the Makuleke Concession in the northern Pafuri region of the Kruger National Park in South Africa. The Pafuri area holds up to 75% of Kruger National Park's total biodiversity, emphasising the Makuleke Wetlands' international environmental importance. The Makuleke Wetlands are composed of the floodplains of the Luvuvhu and Limpopo rivers, with an estimated 31 wetlands present within the floodplains. Ten floodplain wetlands were assessed in the Makuleke region, eight of which are fed by the Limpopo River and the other two from the Luvuvhu River. Water and aquatic invertebrate communities were sampled at each site during surveys in April and September 2015 to provide baseline information on the aquatic biota of this Ramsar site. Multivariate data analytical techniques were used to assess the role of season and water quality in structuring the aquatic invertebrate communities of the wetlands. Macroinvertebrate functional feeding group ratios were also calculated as an indication of wetland ecosystem structure and function. Aquatic invertebrate diversity was some of the highest recorded for wetlands in South Africa, indicating the important role these habitats play in supporting high biodiversity in the Makuleke region. Worryingly, one of the most prolific invasive molluscan species, Tarebia granifera , was present in the wetlands and is a significant threat to native biodiversity of this conservation area. Community characteristics and ecosystem structure and function of the aquatic invertebrates further indicated that the Makuleke Wetland habitats were of good quality and provided a sufficient stable substrate for all aquatic invertebrates. Functionally, the system was characterised as reliant on heterotrophic inputs as autotrophic sources are limited. This is the first study of its kind for the region and lays the groundwork for future ecosystem studies on these important wetlands in the second-largest floodplain of South Africa. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sediment bypass tunnels (SBT) deliver sediment downstream of dams. • Benthic invertebrate communities after SBT installation were monitored for 16 years. • A dramatic recovery within a few years was suggested based on community similarity. • Filterer and large-sized taxa were replaced by scraper and small-sized taxa. • Additional actions are needed to maintain habitat heterogeneity in the long-term. A sediment bypass tunnel (SBT) is a dam facility used to mitigate reservoir sedimentation and is expected to contribute to river ecosystem restoration by delivering sediment to the degraded downstream channel. We analyzed past monitoring data of benthic invertebrates sampled downstream of the Asahi Dam in Nara Prefecture Japan to understand the long-term changes in the invertebrate community after the installation of the SBT. Before the SBT installation, the reaches upstream of the dam (one Up site) and downstream of the dam (two Down sites) showed different invertebrate communities, dominated by invertebrates that preferred clean cobble beds, sand and gravel layers, or run habitats in the former and invertebrates that preferred stable or porous beds or pool habitats in the latter. A significant increase in the Up–Down site community similarity within a few years after the SBT installation indicated a rapid recovery of the invertebrate community at the Down sites. During the 16 years of the after-SBT period, the total density and taxon richness at the Down sites increased in the early half, while they decreased in the latter half due to bed changes associated with the continuous accumulation of sediments. The change in dominant invertebrates from taxa of the large sizes to those of the small sizes and the increase in the interhabitat community similarity suggest that the bed of the Down sites became finer and flatter by sand and gravel that filled interstitial spaces of cobbles in the late stage. While the invertebrate community at the Down sites recovered dramatically by the sediment supply through the SBT, additional actions (e.g., cobble augmentation, installation of flow guiding structures) to maintain a balanced sediment size distribution and developed pool-riffle structures would be necessary to maintain the potential habitat heterogeneity and biodiversity in the long term. Our study also demonstrated that invertebrates responded to the sediment supply according to their habitat preferences, which suggests that the classifications of invertebrates by habitat-related traits (e.g., bed-residence types and pool-riffle types in this study) would help to properly understand the sediment and bed status of river reaches under channel degradation or aggradation. [ABSTRACT FROM AUTHOR]

Coal mining in central Appalachia USA causes increased specific conductance in receiving streams. Researchers have examined benthic macroinvertebrate community structure in such streams using temporally discrete measurements of SC and benthic macroinvertebrates; however, both SC and benthic macroinvertebrate communities exhibit intra-annual variation. Twelve central Appalachian headwater streams with reference quality physical habitat and physicochemical conditions (except for elevated SC in eight streams) were sampled ≤fourteen times each between June 2011 and November 2012 to evaluate benthic macroinvertebrate community structure. Specific conductance was recorded at each sampling event and by in situ data loggers. Streams were classified by mean SC Level (Reference, 17–142 μS/cm; Medium, 262–648 μS/cm; and High, 756–1535 μS/cm). Benthic macroinvertebrate community structure was quantified using fifteen metrics selected to characterize community composition and presence of taxa from orders Ephemeroptera, Plecoptera, and Trichoptera. Metrics were analyzed for differences among SC Levels and months of sampling. Reference streams differed significantly from Medium-SC and High-SC streams for 11 metrics. Medium-SC streams had the most metrics exhibiting significant differences among months. Relative abundances of Plecoptera and Trichoptera were not sensitive to SC, as the families Leuctridae and Hydropsychidae exhibited increased relative abundance (vs. reference) in streams with elevated SC. In contrast, Ephemeroptera richness and relative abundance were lower, relative to reference, in elevated-SC streams despite increased relative abundance of Baetidae. Temporal variability was evident in several metrics due to influence by taxa with seasonal life cycles. These results demonstrate that benthic macroinvertebrate communities in elevated-SC streams are altered from reference condition, and that metrics differ in SC sensitivity. The time of year when samples are taken influenced measured levels and differences from reference condition for most metrics. [ABSTRACT FROM AUTHOR]

Most ecosystems are subjected to multiple stressors derived from natural and anthropogenic sources and community responses to human disturbance in naturally stressful habitats may differ from those in more benign habitats. We examined the influence of a natural (geology-driven acidity) vs. human-induced stress (land drainage) and their interaction on the composition and concordance of stream diatom, bryophyte and invertebrate communities. To account for differing drainage impacts in circumneutral (sedimentation) and naturally acid (reduced pH and increased metal concentrations) streams we investigated concordance in three groups of streams: reference (circumneutral and naturally acidic reference), circumneutral (reference and drained) and naturally acidic (reference and drained) streams. We expected diatoms to respond more strongly to anthropogenic acidification and more weakly to sedimentation compared to bryophytes and invertebrates. We expected overall strong concordance among the three taxonomic groups, but especially so in reference streams. All three organism groups had distinct species composition in naturally acidic vs. circumneutral streams. Concordance between communities was overall strong, especially so in the reference streams. All groups responded to drainage disturbance in both types of streams. Invertebrates were slightly less responsive to increased acidification in the naturally acidic streams but were more affected by sedimentation in the circumneutral streams than were the other two groups. The natural stressor affected communities more than the anthropogenic stressors. Naturally stressed communities were affected by an anthropogenic stressor as much as those in more benign habitats, although the additional stressor was similar to the initial stress (further reduction of stream pH). Naturally acid streams may need special concern in bioassessment because models based on circumneutral reference sites will likely produce biased predictions for these streams. [ABSTRACT FROM AUTHOR]

Identifying ecological response variables sensitive to hydrological change is a key step in determining the impacts of river flow alterations on aquatic ecosystems and in setting environmental flows that sustain certain ecological values. Building on the successful use of flow regime sensitive aquatic invertebrate indices in other countries, particularly the UK based Lotic Index for Flow Evaluation (LIFE), we provide two variants of a similar index for use in New Zealand (LIFENZ and a weighted variant: LIFENZ_W). As in the original LIFE, the New Zealand indices were based on water velocity preference categories assigned to aquatic invertebrate taxa using professional judgement. To calculate the indices a lookup table is used to assign a score to each taxon based on their velocity category and abundance. For the LIFENZ_W variant an additional step down weighted the scores if the taxon has a general compared to a more specific velocity preference. The two index variants were correlated with each other and to similar environmental parameters. Across a total of 74 sites, both indices were correlated with depth-averaged water velocity. Changes in index values, both between sites and temporally within sites, were predominantly associated with changes in hydrological parameters, such as the magnitude and length of time since a recent high flow, and to a lesser degree with other physico-chemical parameters. Commonly used indices in New Zealand designed to respond to nutrient enrichment (MCI and variants) were not correlated with local water velocity, but were correlated with antecedent flow conditions and were likely influenced by effects of flow stability on algal growth. Further testing of LIFENZ and LIFENZ_W in combination with MCI is recommended, particularly in rivers subject to more extreme hydrological and water quality stresses and with regard to other physical parameters such as hydraulic habitat. However, the LIFENZ and its weighted variant (LIFENZ_W) appear to be useful tools for understanding and managing the effects of hydrological alteration on aquatic invertebrate communities in New Zealand. As LIFENZ and LIFENZ_W were strongly correlated and only showed a relatively small deviation from a slope of 1 we recommend the use of the more straightforward LIFENZ in almost all circumstances. [ABSTRACT FROM AUTHOR]

• Aquatic community diversity decreased with increasing body size. • Body size affected distance-decay relationship of benthonic communities. • Higher effects of body size on benthonic community assembly than planktonic one. • Biotic interactions between microbial species were mediated by their body sizes. Body size play a key role in driving bioecological patterns by affecting community assembly processes at the organism level. However, the extent to which the relative influences of ecological processes operating community assembly with different body sizes at different habitat types in freshwater ecosystem is still unclear. Here, we conducted a comprehensive biodiversity survey on bacterial, fungal and invertebrate communities in planktonic and benthonic habitats of Dongting Lake, China, and evaluated the biogeographic distribution pattern and community assembly processes of distinct organism groups with different body sizes. Significant negative relationships between body size and community diversity indexes were observed in two habitats, and significant relationship between body size and distance-decay relationship was only observed in benthonic habitat. Body size showed stronger correlations with the ecological processes and ecological interactions of distinct organisms in benthonic habitat. Specifically, body size showed significantly positive correlation with the relative influence of deterministic processes which controlled the microbial community assembly processes, whereas body size was significantly positively correlated with stochastic processes in zoobenthos community. Molecular ecological network analyses also found that the average clustering coefficients and among-module connectivity were significantly negatively and positively correlated with their corresponding body size, respectively. Slops of correlations between body size and these parameters (including the null deviation value, dispersal rate, niche breadth and among-module connectivity) were steeper in benthonic habitat than that in planktonic habitat. Our findings suggested that body size operated the aquatic organism community assembly to affect their biogeographic distribution pattern, and the effect was stronger in benthonic habitat than in planktonic habitat. This study provides a better understanding of the mechanisms supporting the aquatic biodiversity on the sight of organism life-history trait. [ABSTRACT FROM AUTHOR]

[Display omitted] • Disturbance from land use change and tsunamis impact Chilean invertebrates. • Aquatic and terrestrial communities respond differently to wetland disturbance. • Coastal wetland invertebrate communities vary with latitudinal gradients. • Disturbance impacts on size vary according to salinity. • Taxonomic diversity and size-based metrics detect different disturbance impacts. The frequency and intensity of extreme events in coastal wetlands is increasing due to climate change. These, in combination with other threats such as habitat loss, can have strong effects on the biodiversity and ecosystem services of coastal wetland ecosystems. Here we examined how traditional (community composition and taxonomic diversity) and alternative indices based on body size (size diversity and the slope of size spectra) respond to single and combined effects of anthropogenic disturbances, extreme event disturbances, and key environmental drivers, for both aquatic and terrestrial invertebrates in Mediterranean coastal wetlands in Chile. We studied 18 coastal wetlands over more than 500 km along the Chilean coast. We applied both univariate (GLMMs and GAMMs) and multivariate statistics (RDA and variation partitioning) to identify additive and non-additive effects on invertebrates. We also examined latitudinal trends, and tested the potential of alternative metrics to detect interactions between disturbances. We found latitude-specific vulnerability to disturbances in Chilean coastal wetlands. Non-additive effects were more important for aquatic invertebrates, while additive effects were more important for terrestrial invertebrates. In many cases, disturbance effects depended on the environmental conditions of study sites, especially salinity. This study suggests that size-based metrics may be better than taxonomic metrics at detecting interactions among different disturbances, especially for aquatic invertebrates. [ABSTRACT FROM AUTHOR]

Macroinvertebrate communities have been widely used as a tool for assessing the environmental quality of freshwater ecosystems, whereas zooplankton communities have been to some extent neglected. However, the importance of using different indicators to achieve a more comprehensive framework of assessment regarding water quality has been recognized. This study compared estimates of species richness (number of species) and the Shannon–Wiener index for data on macroinvertebrate and zooplankton communities in tropical reservoirs and related them to their trophic state. The trop+hic classification was obtained by applying the Carlson index (1977) modified by Toledo et al. (1983), and the index of the Brazilian Society of the Environmental Technology Agency. The comparative response of the different indicators was analyzed using a series of bivariate correlations (Draftsman’s plot). The results illustrate that diversity measures, namely species richness, responded differently when related to the trophic classification of reservoirs, depending on the community considered. The species richness of zooplankton was positively related to hypereutrophic conditions, due to the higher number of rotifer species, including tolerant generalist species and at the same time, as a result of the exclusion of species from other groups, whereas for macroinvertebrates, species richness was negatively related to hypereutrophic conditions. Melanoides tuberculatus , which exhibits a high tolerance and competitive ability under such conditions, was the dominant species in macroinvertebrate communities, which excluded endemic species and reduced local richness and diversity. The same indicators applied to the zooplankton and macroinvertebrate communities might therefore provide contradictory responses regarding ecological quality assessment in tropical reservoirs, which suggest that zooplankton should be taken into account among the biological quality elements considered in the ecological quality assessment, management, and restoration of water bodies. [ABSTRACT FROM AUTHOR]

Abstract: Multimetric indices of biotic integrity provide a quantitative measure of biological quality and have been developed for several taxonomic groups. Community integrity for fish is typically represented by the multimetric Index of Biotic Integrity (IBI), while for macroinverterates the Invertebrate Community Index (ICI) can be applied. Given the considerable sampling efforts required for biomonitoring, it is important to know the extent to which indices based on particular taxonomic groups respond differently to (anthropogenic) stressors in the environment. The three goals of our study were (1) to assess the concordance of freshwater fish and macroinvertebrate communities, (2) to derive stressor–response relationships for IBI and ICI pertaining to multiple environmental factors and (3) to compare the responses of IBI and ICI to these environmental factors in the state of Ohio (USA). We used a database containing abiotic as well as biotic information for 545 local catchments located across Ohio (USA). Our 22 environmental factors covered physiography, water chemistry, physical habitat quality and toxic pressure. Concordance between the fish and invertebrate communities was assessed using a Mantel test. Response patterns of IBI and ICI to each of the environmental factors were analyzed by constructing stressor–response curves with Boosted Regression Trees (BRT). Fish community integrity was primarily related to physical characteristics of the stream (channel- and riffle quality) and latitude, whereas invertebrate community integrity mainly responded to the phosphorus concentration. Response curves showed that the two indices responded similarly to most of the water chemistry variables, while responses differed for physiographical and physical habitat quality variables. [Copyright &y& Elsevier]

[Display omitted] • Hiking impacts are still understudied, particularly on invertebrate communities. • Biases in publications prevents generalization of findings and management actions. • Mortality and behavioral effects need to be separated. • Literature-derived classification of species responses is unadvisable. • The joint use of plant and invertebrate species, when possible, is endorsed. Hiking is a natural exercise that has become one the most popular outdoor activities, promoting physical fitness and de-stress without large investments or special equipment. However, hiking has downsides, particularly in the areas in which it takes place. From soil compaction and erosion to disturbance and ecological impacts, mounting evidence shows that it is far from innocuous to ecosystems. Despite spanning several decades, research on the impacts of hiking on ecosystems and particularly on the pertinence of using ecological indicators is still scarce. This work reviews the published information conducted with invertebrates and, by doing so, offers insights to guide not only management actions but also further investigation in this scope. We address some of the current knowledge gaps and provide recommendations by focusing on ground beetles (Coleoptera: Carabidae) for their sensitivity to disturbance, representativeness but also due to their taxonomic and functional diversity. Due to the limited number of studies published so far, the classification of species based on their habitat preference, within the context of trail impacts, is non-consensual. Alternatively, such classification should derive from its respective study and avoid being generalized, or done with great caution. Additionally, sampling methods that distinguish mortality from behavioural changes were considered crucial to determine possible effects. Ultimately, the joint use of both vegetation and invertebrates, particularly ground beetles, was considered relevant to assess hiking trail ecological impacts. [ABSTRACT FROM AUTHOR]

Abstract: Aquatic ecosystems are amongst the most heavily altered ecosystems and exhibit a disproportional loss of biodiversity. Numerous stressors, such as nutrient enrichment, contaminant pollution, sedimentation and alterations in stream hydrology and habitat structure, account for these losses. Understanding these forces is of utmost importance to prevent riverine ecosystems from further deterioration and to provide helpful insights for restoration practices. In the present study, we analyse the response of biological indicators to a large number of environmental factors. For this, benthic invertebrate assemblages from 83 sites in Germany were described based on 25 metrics from four different metric types. The condition of the sites was described using 27 environmental factors: 13 for water quality, 4 for land use in the catchment and 10 for local scale habitat structure. The relative importance of single environmental predictors or predictor combinations for benthic invertebrate assemblages was analysed with single and multiple linear regression models. The results for the latter models were statistically supported via a bootstrap approach. The models revealed the importance of water quality and catchment-scale land use in explaining benthic invertebrate assemblages; in particular, chloride, oxygen, total organic carbon and the amounts of artificial surfaces and arable land were the most important predictors. Models including solely structural variables such as plan form, bank structures and substrate diversity had lower goodness of fit values than those for other variables. Regarding the four different assemblage metric types, functional metrics had on average lower goodness of fit values than composition/abundance, richness/diversity and sensitivity/tolerance metrics. Among the richness/diversity metrics, however, the model results for the Shannon–Wiener and Simpson diversity indices and evenness were poor. Our results show that catchment-related factors and water quality were of overriding importance in shaping biodiversity patterns and causing species loss. In contrast, structural degradation at a local scale was not the most significant stressor. This finding might explain why structural restoration at a reach scale often yields a low benefit–cost ratio and may be considered to represent inappropriate investment prioritisation. [Copyright &y& Elsevier]

Abstract: Within transitional/estuarine environments ‘ecosystem functioning’ has been mostly investigated with “traditional” taxonomic analysis, based on the taxonomic composition of benthic invertebrate communities. However, ‘ecosystem functioning’ depends also greatly on the functional characteristics (biological traits) of organisms. It was a priori suggested that the biological traits of the subtidal benthic invertebrate communities within an estuarine environment would respond to the high variability of environmental pressures (natural and human induced) within this type of ecosystem. For this study, traditional taxonomic analysis (species richness, species density and Shannon–Wiener diversity) as well as biological trait analysis were used together for the first time to investigate the response of the subtidal benthic invertebrate communities to the environmental pressures within the Mondego estuary (Portugal). Biological trait analysis, in addition to traditional taxonomic analysis provided a more comprehensive understanding of the functioning within this type of ecosystem. Some of the most important outcomes are: (i) the trait “salinity preference” was the most important trait that distributed the species along the estuary, (ii) the central part of the estuary appeared to be under higher environmental stress levels than the other areas, as suggested by a dominance of some “opportunistic” traits (e.g. small short-lived species), (iii) the ratio between functional diversity (FD) and Shannon–Wiener diversity (H′) indicated lower functional redundancy at the upper reaches of the estuary. Our results, suggest that the ratio (FD/H′) might be a helpful tool to visualize this functional attribute and could potentially be applied to different communities from distinct environments. Using the traditional taxonomic analysis alone, this last functional aspect would not be detectable. Therefore, the inclusion of biological traits analysis is recommendable for estuarine ecological studies. [Copyright &y& Elsevier]

Abstract: Drainage ditches are a prominent feature of many intensively managed agricultural areas. These small, shallow, line-shaped waterbodies could harbor a rich macroinvertebrate community, resembling that of natural small lentic ecosystems. Despite their high biodiversity potential, many ditch ecosystems are degraded due to nutrient enrichment, resulting in a shift from a mesotrophic system characterized by a diverse vegetation of emergent-, submerged-, and floating macrophytes to a hypertrophic state dominated by Lemnaceae or phytoplankton. Tools to assess the ecological quality of drainage ditches are currently lacking. Therefore, a multimetric index based on macroinvertebrates was developed to assess the ecological quality of drainage ditch systems in The Netherlands. Based on a large dataset from regional water district managers, who conduct routine sampling of macroinvertebrates in drainage ditches, a degradation gradient composed of 223 samples was derived, which represented the combined stressors eutrophication, organic pollution and salinity. We used a stepwise process to evaluate the discriminatory efficiency of a variety of diversity, abundance/composition, tolerance/sensitivity, and functional metrics for assessing ecological degradation in drainage ditches. After evaluating metric range, strength of correlation to the stressor gradient, degree of redundancy, and sample- and seasonal repeatability, five metrics were selected for the drainage ditch multimetric index: number of Trichoptera families, percentage of Gastropoda families, percentage of taxa preferring fresh water (Cl− <300mgL−1), Dutch Saprobic index, and the percentage of predator taxa. The relationship of these single metrics with the stressor gradient is discussed. [Copyright &y& Elsevier]

Abstract: Seasonal changes in macroinvertebrate taxon abundances that are related to life history introduce temporal variation into macroinvertebrate community structure that can potentially confound bioassessments. In this study, macroinvertebrates from three rural and three urban streams were sampled monthly to assess temporal variability in community structure, determine how taxon life-cycle seasonality affects this variability, and determine if this temporal variability confounds biotic index interpretations. Temporal variation in taxon abundances was higher in the rural streams than in the urban streams, and 17 of 23 indicator taxa from rural streams exhibited, or are known to exhibit, either fast- or slow-seasonal life cycles. Conversely, five taxa were identified as indicators for urban streams, but only two of these taxa exhibited seasonal life cycles. Further, the life-cycle seasonality of many rural stream indicator taxa appeared to be linked to the seasonality of environmental conditions such as hydrologic permanence and benthic leaf detritus availability. Macroinvertebrate bioassessment index (MBI) scores were higher in the rural streams than in the urban streams during all months except June, July, and October when no difference was detected. We attribute the reduced discriminatory power of the MBI in the summer and early autumn to the life-cycle of a single taxon (Stenelmis sp.), and its effects on % Clingers – a component metric of the MBI. Stenelmis sp. exhibited a non-seasonal life cycle with a larval development time of approximately 12 months with considerable overlapping of cohorts present during the summer and early autumn when an extended first instar recruitment period was evident. During this overlap period, urban stream MBI values increased resulting in no statistical difference in the MBI between urban and rural streams in June, July, and October. Analyses of temporal variability in taxon abundances and life-history characteristics, as completed in this study, can greatly contribute to the creation and/or validation of bioassessment protocols. [Copyright &y& Elsevier]

Abstract: To assess biotic responses to anthropogenic pressures, a seasonal monitoring of benthic macroinvertebrates, physicochemical and hydromorphological parameters has been applied in 11 sites along two highly impacted river basins in southwestern Greece, mainly during the year 2006. In the first river basin, the upper reaches were covered by thick riparian forest, replaced by intensive agriculture and livestock in the mid-reaches, while the lower parts were characterized mainly by agroindustrial activities. The second river basin was impacted by the discharge of raw cheese whey effluents in the mid-reaches, while the lower parts were protected by thick riparian vegetation. The mid- and lower parts of the first river basin (Peiros–Parapeiros rivers) were impaired by dam constructions, agricultural intensity and urbanization. In the second river basin (Vouraikos river), the 3/5 of the river length, located in the mid-reaches, was degraded due to the discharge of untreated cheese whey effluents. Water quality of the lower reaches was highly recovered due to the presence of thick riparian vegetation. Macroinvertebrate diversity was strongly correlated to pollution, as sites with major physicochemical and hydromorphological degradation presented low taxonomic richness and diversity values, while non-impacted sites were characterized by a considerable presence of E.P.T. taxa and higher diversity. The current study indicates the significant impact of land use changes to the water quality, which consequently influence the distribution of biota, pointing out the critical role of the riparian vegetation to the detoxification of surface waters. [Copyright &y& Elsevier]

Abstract: Wetlands are extensively used in heavy metal bioremediation, and it is important to know how biota are impacted by such toxins. I examined invertebrate communities in six experimental wetland ponds in Ithaca, NY, USA to assess the effects of residual cadmium. Three ponds had been treated with cadmium in 1983, and still had average levels of 3.6mg/kg in the sediment in 2001. Also, two of the cadmium ponds and one non-cadmium pond had predatory fish populations. I quantified the variable effects on invertebrate communities using non-parametric statistics, CCA (canonical correspondence analysis), and three published multi-metric tests (). Cadmium effects could not be seen in ponds with fish because invertebrate abundance in these ponds was low. In ponds without fish, cadmium appeared to have significant influence on invertebrate abundance, but not on diversity. None of the multi-metric tests detected a cadmium impact. This study suggests that trophic interactions between fish and invertebrates should be considered in wetland index development and implementation. [Copyright &y& Elsevier]

Abstract: The space-for-time approach is widely used in fundamental and applied ecology but assemblages from some habitats are highly variable. For example, streams may show marked spatio-temporal changes in the taxonomic composition of the macroinvertebrate assemblages. We exemplify the effect of the temporal component ‘season’ on some assemblage-derived stream quality assessment metrics under the assumptions of the space-for-time and the replicated samples approaches. Benthic macroinvertebrates were sampled in spring, summer, and fall from two stream types, namely streams in the Pleistocene sediments of the alpine foothills and small fine substrate dominated siliceous highland rivers in southern and central Germany. As exemplified for ASPT and the German multimetric index (MMI), the data showed no effect of season when samples were regarded as independent, whereas stream quality decreased between spring and fall in the replicated samples approach. The transformation of MMI to rank-ordered stream quality classes depicted a decrease in perceived stream quality in 29% and 54% of the sites by summer and early fall, respectively, when compared to spring samples. We thus suggest (1) to test seemingly robust metrics in a repetitive measures approach for other stream types and regions, and (2) to standardize the sampling season for ecological quality assessment. Based on this example, we assume that many subtle, but significant, environmental trends are still to be detected in highly heterogeneous habitats from various ecosystems. [Copyright &y& Elsevier]

Abstract: The successful use of macroinvertebrates as indicators of stream condition in bioassessments has led to heightened interest throughout the scientific community in the prediction of stream condition. For example, predictive models are increasingly being developed that use measures of watershed disturbance, including urban and agricultural land-use, as explanatory variables to predict various metrics of biological condition such as richness, tolerance, percent predators, index of biotic integrity, functional species traits, or even ordination axes scores. Our primary intent was to determine if effective models could be developed using watershed characteristics of disturbance to predict macroinvertebrate metrics among disparate and widely separated ecoregions. We aggregated macroinvertebrate data from universities and state and federal agencies in order to assemble stream data sets of high enough density appropriate for modeling in three distinct ecoregions in Oregon and California. Extensive review and quality assurance of macroinvertebrate sampling protocols, laboratory subsample counts and taxonomic resolution was completed to assure data comparability. We used widely available digital coverages of land-use and land-cover data summarized at the watershed and riparian scale as explanatory variables to predict macroinvertebrate metrics commonly used by state resource managers to assess stream condition. The “best” multiple linear regression models from each region required only two or three explanatory variables to model macroinvertebrate metrics and explained 41–74% of the variation. In each region the best model contained some measure of urban and/or agricultural land-use, yet often the model was improved by including a natural explanatory variable such as mean annual precipitation or mean watershed slope. Two macroinvertebrate metrics were common among all three regions, the metric that summarizes the richness of tolerant macroinvertebrates (RICHTOL) and some form of EPT (Ephemeroptera, Plecoptera, and Trichoptera) richness. Best models were developed for the same two invertebrate metrics even though the geographic regions reflect distinct differences in precipitation, geology, elevation, slope, population density, and land-use. With further development, models like these can be used to elicit better causal linkages to stream biological attributes or condition and can be used by researchers or managers to predict biological indicators of stream condition at unsampled sites. [Copyright &y& Elsevier]

Abstract: In contrast to most large rivers in Europe, the biggest European river Volga including its tributaries has still remained uncontaminated in its headwaters. Therefore the upper Volga River system represents an appropriate system for investigation of relations of bioassessment indices with natural environmental factors. Moreover, it allows the definition of reference conditions for medium-size and large lowland rivers in Europe. The aim of this study was to analyse relations between Saprobic Index (SI), SPEAR indices, and other macroinvertebrate community indices and basic environmental factors in the upper Volga River system. Besides, preliminary ecological status classification (according to the EU Water Framework Directive) was proposed for SI and SPEARpesticides indices for the system investigated. The analysed data set contained information on macroinvertebrates, basic habitat characteristics and water physico-chemical parameters from 53 sample sites. The results showed that SI and SPEAR indices were independent of channel width and related river longitudinal factors. Furthermore, the results indicated the index SPEARpesticides to be potentially applicable across different types of watercourses as well as across different biogeographical regions in Europe showing similar boundaries of ecological status classes (at least between High, Good, and Moderate). A Multi-Habitat-Sampling method was recommended for SPEARpesticides. Saprobic reference conditions of the lowland rivers were found to be beta-mesosaprobic. The relatively high boundary between High and Good classes resulted from naturally high organic matter concentrations. Due to indicating common pollution sources (i.e. organic, agricultural and industrial), the herein suggested methodologies have a potential to be applied in other large river systems in Europe. The reference condition characteristics described for the headwaters of the Volga River system can be used as a reference for medium-sized and large rivers in the regions where establishment of reference sites of these types is impossible (e.g., many regions in Europe). [Copyright &y& Elsevier]

Abstract: While compositional diversity is a common metric for assessing human impacts on aquatic communities, functional diversity is scarcely employed, though highly desirable from the perspective of the European Water Framework Directive. Using abundance data from 99 minimally disturbed sites (i.e., no or very weak anthropogenic impact) from a national survey, we studied the spatial variability of compositional and functional biodiversity metrics across a predefined ecoregional classification. Metrics of compositional diversity comprised taxonomic and EPT richness and Simpson diversity. Functional diversity metrics were based on Rao''s Quadratic Entropy (RQE), which described the differences among benthic invertebrate genera in eleven biological traits (e.g., size, life cycle, reproduction types, feeding habits). Using generalized linear models we show that taxonomic richness may vary greatly across ecoregions, contrasting with Simpson diversity and functional metrics that varied weakly in response to natural environmental variability. Functional diversity metrics, because of their stability in response to natural environmental variability, may be useful tools for assessing human impairment to ecosystem function. We further tested the response of functional diversity metrics to a specific human impact (sewage) and demonstrated significant modifications of functional diversity downstream of sewage pollution. Further investigations are required to test the ability of functional diversity metrics to precisely and accurately indicate different types of human impacts. [Copyright &y& Elsevier]

Abstract: Acid mine drainage (AMD) causes different responses in riverine benthic macroinvertebrate communities than that caused by organic pollution. The response is similar to that for metal toxicity and acidity where the impact is severe, or for inert solids where the impact is moderate to mild. Biotic indices are based on saprobity and so do not accurately reflect community disturbance for either toxicity or inert solids and thus cannot be considered as reliable indicators for AMD. The expected community response to both toxicity and inert solids is best described simply in terms of suppression of both taxon richness (S) and abundance (n) regardless of saprobity. A simple model (AMD′) is proposed that provides a precise and reliable metric of the effects of AMD in rivers. [Copyright &y& Elsevier]

Abstract: Over the last two centuries wet heathlands and associated habitats, such as poor fens and bogs, have suffered extensive fragmentation. Recently, large-scale projects aim to restore these rare habitats throughout Europe. To evaluate post-restoration trajectories of wet heathlands, suitable monitoring tools are urgently needed. Here, we investigated whether spider communities are useful tools for evaluating the restoration success of wet heathlands. Ordination revealed that dissimilarity in spider communities between patches of different age classes resulted mainly from vegetation cover and soil moisture. By using a functional trait-approach, we tested if the time since restoration affects trait distribution of spiders in wet heathlands. Typical wet heathland spider species were less common with increasing vegetation encroachment and lower water content. New patches were inhabited by summer active, eurytopic (non-heathland) spiders, while more typical heathland species were found in middle-aged and old patches. Our results suggest that time-related changes in vegetation structure and moistness of restored wet heathlands are clearly reflected by spider communities. Although mobile spiders quickly recolonize the restored heathlands, it takes time for typical heathland spiders to settle. Restoration measures should prevent the negative effects of a vegetation encroachment and a high density of forested edges and should rehabilitate the hydrological cycle in order to preserve rare heathland spiders. We discuss that accounting for responses of spiders provides additional information to guide wet heathlands restoration. [Copyright &y& Elsevier]

Abstract: Biotic indices for algae, macroinvertebrates, and fish assemblages can be effective for monitoring stream enrichment, but little is known regarding the value of the three assemblages for detecting perturbance as a consequence of low-level nutrient enrichment. In the summer of 2006, we collected nutrient and biotic samples from 30 wadeable Ozark streams that spanned a nutrient-concentration gradient from reference to moderately enriched conditions. Seventy-three algal metrics, 62 macroinvertebrate metrics, and 60 fish metrics were evaluated for each of the three biotic indices. After a group of candidate metrics had been identified with multivariate analysis, correlation procedures and scatter plots were used to identify the four metrics having strongest relations to a nutrient index calculated from log transformed and normalized total nitrogen and total phosphorus concentrations. The four metrics selected for each of the three biotic indices were: algae—the relative abundance of most tolerant diatoms, the combined relative abundance of three species of Cymbella, mesosaprobic algae percent taxa richness, and the relative abundance of diatoms that are obligate nitrogen heterotrophs; macroinvertebrate—the relative abundance of intolerant organisms, Baetidae relative abundance, moderately tolerant taxa richness, and insect biomass; fish—herbivore and detritivore taxa richness, pool species relative abundance, fish catch per unit effort, and black bass (Micropterus spp.) relative abundance. All three biotic indices were negatively correlated to nutrient concentrations but the algal index had a higher correlation (rho=−0.89) than did the macroinvertebrate and fish indices (rho=−0.63 and −0.58, respectively). Biotic index scores were lowest and nutrient concentrations were highest for streams with basins having the highest poultry and cattle production. Because of the availability of litter for fertilizer and associated increases in grass and hay production, cattle feeding capacity increases with poultry production. Studies are needed that address the synergistic effect of poultry and cattle production on Ozark streams in high production areas before ecological risks can be adequately addressed. [Copyright &y& Elsevier]

[Display omitted] • Habitat conditions and spatial position controlled phytobenthos community. • Benthic invertebrate community was shaped by habitat conditions. • Phytoplankton community remained unchanged in spite of dams. • Riverine organism best tracked double damming. We studied three commonly used bioindicator groups: phytoplankton, phytobenthos and benthic invertebrate communities' structure patterns in transitions between lotic and lentic habitats as consequences of two consecutive large dams constructed in the early twentieth century on the intermediate reach of a lowland river in Normandy (NW, France), the Selune. According to sampling station position along the river, including two in the two reservoir lakes, we defined three sorts of transitions, from upstream to downstream: lentic to lotic transition (hereafter len-lot), lentic to lentic transition (hereafter len-len), within the two reservoir lakes, and lentic to lotic transition (hereafter len-lot). Lot-len transition, imposed by damming, and the recovery of lotic character of the river afterward dams, promoted different diversity patterns for the studied organisms' groups. Phytobenthos' α diversity significantly incresed in the len-lot transition, and the highest β diversity score was observed in the lot-len. Both, habitat conditions and spatial controls drove phytobenthos community structure. Benthic invertebrate community was mainly shaped by habitat conditions. Invertebrate's α diversity significantly changed in the lot-len and len-lot transitions, with the β diversity score being the highest in the lot-len transition. Community's traits composition of invertebrates best fitted predictions on lotic- and lentic- type communities. Phytoplankton's α diversity remained unchanged in the transitions and subsequently β diversity scores were low. According to the results, we proposed three classes of organisms based on their response to river damming: i) organisms indifferent or tolerant to dams effect, like phytoplankton communities in this study, that were neither hampered by changes in water flow velocity, and did not display dispersal limitation neither; ii) organisms sensitive to habitat conditions shift but not limited in their dispersal capacity by the dam, like benthic invertebrates and phytobenthos in this study. Benthic invertebrate community and phytobenthos communities differed in their response likely due to their differential dispersal capabilities and niche breadth; iii) organisms limited in their dispersal by the dam, not represented in this study. Riverine organisms best tracked transitions, while β diversity assessment revealed as the most useful metric to disentangle the relative contribution of dispersal limitation or habitat modification provoked by multiple dams. [ABSTRACT FROM AUTHOR]

• Invertebrate richness and equitability were congruent across taxonomic resolutions. • Ordination diagrams based on family- and finest-level resolution were congruent. • Ordination diagrams based on different numerical resolutions were less congruent. • Family-level is a good surrogate of wetland invertebrate community-level patterns. The efficiency of biodiversity assessments and biomonitoring studies is commonly challenged by limitations in taxonomic identification and quantification approaches. In this study, we assessed the effects of different taxonomic and numerical resolutions on a range of community structure metrics in invertebrate compositional data sets from six regions distributed across North and South America. We specifically assessed the degree of similarity in the metrics (richness, equitability, beta diversity, heterogeneity in community composition and congruence) for data sets identified to a coarse resolution (usually family level) and the finest taxonomic resolution practical (usually genus level, sometimes species or morphospecies) and by presence-absence and relative abundance numerical resolutions. Spearman correlations showed highly significant and positive associations between univariate metrics (richness and equitability) calculated for coarse- and finest-resolution datasets. Procrustes analysis detected significant congruence between composition datasets. Higher correlation coefficients were found for datasets with the same numerical resolutions regardless of the taxonomic level (about 90%), while the correlations for comparisons across numerical resolutions were consistently lower. Our findings indicate that family-level resolution can be used as a surrogate of finer taxonomic resolutions to calculate a range of biodiversity metrics commonly used to describe invertebrate community structure patterns in New World freshwater wetlands without significant loss of information. However, conclusions on biodiversity patterns derived from datasets with different numerical resolutions should be critically considered in studies on wetland invertebrates. [ABSTRACT FROM AUTHOR]

• Analysis on the response Mechanism of Benthic Community and Environmental factors. • Analysis of community structure and characteristics of community structure. • Identification of benthic community structure driving factors. The characteristics of the benthic community structure can effectively reflect the health status of the river ecosystem and the quality of the river ecological environment. It is of great significance to identify the limiting factors of benthic community structure for the maintenance of river ecosystem health. As a typical semi-arid ecological fragile area, the eco-environmental problems in the Wei River basin have become increasingly prominent. The benthic community structure is affected by multiple stresses such as habitat degradation and water quality deterioration. In this study, 18 national monitoring stations were selected to investigate the ecological environment and benthic invertebrate community characteristics in the Wei River basin in October 2019. W-statistics, Shannon-Winer index, Pielou index, Margalef index, and B-IBI index were selected to evaluate the community characteristics of benthic macroinvertebrates from three aspects of the community stability, community diversity, and community integrity. Principal component analysis, Pearson correlation analysis, and canonical correspondence analysis were used to analyze the correlation and variability between zoobenthos community index and environmental factors. The results showed that the spatial difference of benthic community structure in the Wei River basin was not significant, and the Sal, NH 3 -N, Tub, DO in water environment and heavy metals in sediment were the main environmental factors affecting the community structure of benthos. Improving water quality and controlling pollution were the main strategies to improve benthic biodiversity and promote sustainable development in the Wei River basin. [ABSTRACT FROM AUTHOR]

• Median lethal time (LT50) is a measure of sensitivity to desiccation stress. • LT50 of tropical freshwater invertebrates ranged from 4.18 to 19.06 days. • LT50 is predicted by desiccation-resistance traits, cuticle content and dry body mass. • LT50 predicts community response to various drought intensities in nature. The intensification of dry seasons is a major threat to freshwater biodiversity in Neotropical regions. Little is known about resistance to drying stress and the underpinning traits in Neotropical freshwater species, so we don't know whether desiccation resistance allows to anticipate shifts in biological diversity under future climate scenarios. Here, we used the aquatic invertebrates that live in the rainwater-filled leaves of tank bromeliads, to examine the extent to which desiccation resistance of species measured in the laboratory predicts community response to drought intensification in nature. We measured desiccation resistance in 17 invertebrate species (>90% of the biomass usually found in bromeliads of French Guiana) by recording the median lethal time (LT50) of experimental populations exposed to controlled conditions of residual moisture. In the field, we placed rainshelters above tank bromeliads to emulate drought scenarios ranging from the ambient norm to IPCC scenarios and extreme events, and we recorded the response of functional community structure. LT50 ranged from 4.18 to 19.06 days, and was related to cuticle content and dry body mass. Among other functional indicators that represent strategies to optimize resource use under stressful conditions (e.g., habitat use, trophic specialization), LT50 was the best predictor of community structure responses along a gradient of emulated drought intensities. Therefore, species' LT50s measured under laboratory conditions can be used to forecast aquatic community response to drying stress in nature. Anticipating how species will cope with drought has never been more important for environmental managers to support climate change adaptation. We show that desiccation resistance in freshwater invertebrates is a key indicator of potential population size and local–global range shifts, and this could be especially true in the Neotropics where species have narrow physiological tolerances for climatic variation. [ABSTRACT FROM AUTHOR]

• We tested the effects of in situ water warming on river biofilm communities. • The biomass of algae and invertebrates was similar between thermal conditions. • Cyanobacteria and nematodes were relatively favoured at heated site. • Nematode taxonomic and functional diversity was greater at heated site. • Biofilm community changes may be potential bio-indicator of warming. Water warming, either resulting from global or local drivers, is of growing concern for aquatic environments. Changes in thermal regimes may alter the functioning and the trophic dynamics of river ecosystems as most aquatic biota like micro-algae, invertebrates, or fish are poikilotherms. Because biofilms integrate basal and intermediate components of aquatic food webs, examination of their responses to warming should contribute to a better understanding of the effects of ongoing climate change on river ecosystems. In this study, we considered sites that were or were not exposed directly to thermal effluents from a nuclear power plant as " in situ laboratories" of the effect of climate change and water warming. To compare the structure of algal and invertebrate communities dwelling in epilithic biofilms subjected to different thermal regimes in the Garonne River, sets of concrete tiles were placed in the river and the biofilm growing on these standard substrates was sampled after two months of colonisation. The site located within the thermal plume directly downstream of the thermal effluents showed warmer average water temperature (mean ΔT of about 1.5 °C over the study period) and greater daily temperature fluctuations in comparison to the control site. Algal and invertebrate biomass did not differ significantly, but the structure of communities differed markedly between sites. At the heated site, the proportion of cyanobacteria was higher, while there were fewer micro-crustaceans and larvae of insects and bivalves. However, the population of chironomids showed a greater proportion of relatively large individuals. Interestingly, nematodes were more abundant, and their communities comprised more species at the heated site. Their feeding-types were also more diverse showing a greater proportion of algivores, large-sized omnivorous and predatory species. Changes in the abundance and age structure further showed that some bacterivore species, such as Eumonhystera vulgaris , thrived especially well at the heated site, whereas another bacterivore, Monhystrella paramacrura , thrived well at the control site. In the context of climate change, our results highlight that warmer and more fluctuating water temperatures have the potential to alter the body-size spectrum, species composition, distribution of feeding specialisations and age structure within biofilm-dwelling communities. [ABSTRACT FROM AUTHOR]

• We evaluated the potential of passive acoustic monitoring in water quality assessment. • Specific frequency bands related to the sound-producing invertebrate community. • Sound-producing invertebrates were relatively insensitive to anthropogenic stressors. • Acoustic patterns associated with the fluctuation in dissolved oxygen saturation. • Passive acoustic monitoring could be used to estimate metabolism in water bodies. A major challenge in water quality assessment is to identify suitable indicators to monitor and assess the effects of anthropogenic stressors on the ecological status of freshwater ecosystems. Passive acoustic monitoring is a novel approach that could potentially be used to detect invertebrate species and ecological processes such as dissolved oxygen dynamics in freshwater environments. The aim of the present study was to evaluate to what extent sounds can be used for water quality assessment. We performed a field study to relate acoustic indices to the intensity of several stressors, the invertebrate community composition and the dissolved oxygen dynamics in 20 temperate lowland streams and drainage ditches impacted to a varying degree by agricultural activities and discharges from waste water treatment plants. Our results showed that the recorded acoustic patterns were primarily associated with the fluctuation in dissolved oxygen saturation, while specific frequency bands could be related to the sound-producing invertebrate community. We observed that acoustic indices do not allow to detect the adverse effects of anthropogenic stressors on the invertebrate community composition, presumably due to the prevalence of Heteroptera which are relatively insensitive to stressors, but make a lot of sounds. A strong relation between acoustic indices and oxygen fluctuation indicate that passive acoustic monitoring may be used to estimate metabolism in water bodies. We suggest that the next step in freshwater ecoacoustics will be to precisely characterise each source of sound emitted during the processes of primary production, respiration and re-aeration, in order to distinguish these parameters. This may overcome some of the challenges encountered in the estimation of metabolism from diel dissolved oxygen curves. [ABSTRACT FROM AUTHOR]

• Metabarcoding successfully captured invertebrate fingerprints in 52 Danish streams. • Invertebrate profiles were clearly separated based on ecological quality. • Molecular assessment captured greater taxonomic diversity than conventional method. • Metabarcoding approach showed potential for extraction of new indicator BQE. • Metabarcoding is a viable alternative for freshwater ecosystem assessment. Stream water quality assessments are conducted by analysing invertebrate communities as a biological quality element (BQE). In Denmark, water quality assessments of streams are often estimated according to the Danish Stream Fauna Index (DSFI). The conventional DSFI method is time consuming and requires highly specialized expertise for species identification of the relevant indicator invertebrates. Furthermore, conventional species identification of relevant indicators may be hampered by differences in, or lack of, developmental stages or due to damages during the sampling process. Metabarcoding has the potential to overcome the challenges associated with conventional morphology-based species identification. Using high-throughput DNA sequencing, metabarcoding of invertebrates collected from stream water provides an alternative to the expertise of taxonomic experts. The present study applies metabarcoding using universal invertebrate primers targeting the mitochondrial cytochrome oxidase I (COI) gene to determine stream water qualities. The obtained community profiles were compared to conventional water quality assessments according to the Danish Stream Fauna Index (DSFI). Multivariate data analysis of obtained sequences resulted in distinct clusters of taxonomic units, which reflected the stream water quality as defined by the DSFI. In conclusion, the present study supports the knowledge that invertebrates are efficient as BQE for stream water quality assessment. DNA sequencing by metabarcoding provided a unique fingerprint of the studied communities of invertebrates and was successful in describing the stream water quality. [ABSTRACT FROM AUTHOR]

• Non-indigenous species are widespread and abundant in the Tagus and Sado estuaries. • Three and ten NIS were detected in the Sado and Tagus estuaries, respectively. • Ruditapes philippinarum is the dominant non-indigenous species. • The Tagus estuary is more invaded than the Sado estuary. Non-indigenous species (NIS) are increasingly widespread and abundant in coastal areas, hence being considered indicators to assess the environmental status of marine waters under the Marine Strategy Framework Directive. However, information on the effects of biological invasions on species composition and abundance is still scarce, particularly for soft-sediment benthic communities, which remain poorly understood. Therefore, the present study aimed at monitoring the benthic communities of two Portuguese estuarine systems, with a particular focus on NIS. Sampling surveys were conducted at the Tagus and Sado estuaries, in three different years. Invertebrate communities were collected at sampling stations located along the estuarine gradient, using a clam dredge, and several water and sediment parameters were measured at the same locations. NIS represented nearly one fourth (23%) of the total observed individuals across all years and estuaries, with Ruditapes philippinarum accounting for 22% of the total abundance across estuaries and years. Although both estuaries presented a similar total number of species (91 at the Tagus and 81 at the Sado), three-fold more NIS were identified at the Tagus estuary. The frequency of occurrence of the NIS Crassostrea (Magallana) gigas , Mya arenaria and Panopeus occidentalis increased significantly over the three years at the Tagus estuary and decreased significantly for Dyspanopeus sayi from 2015 to 2018. The Tagus and Sado estuaries presented distinct and diverse communities, with the abundance of R. philippinarum being eleven-fold greater at the Tagus estuary than at the Sado estuary. This study provides a baseline list of the NIS occurring in two of the main Portuguese estuarine systems, as well as an approach to estimate NIS abundance, richness, frequency of occurrence and community diversity. Although most studies on NIS impacts have focused on single species, the assessment of the environmental status of marine waters requires that overall impacts of NIS on marine ecosystems are determined. This study indicated metrics that are appropriate to evaluate changes in soft-sediment benthic communities associated to the introduction of NIS. [ABSTRACT FROM AUTHOR]

• Stream communities were evaluated across extensive spatial and temporal scales. • Considerable temporal variation in communities was observed. • Local contribution to beta diversity negatively correlated with dispersal capacity. • Large-scale spatial structure was important in structuring communities. • Both spatial and temporal variation in diversity should be considered simultaneously. It is increasingly well understood that stream communities are regulated by both local niche and regional dispersal processes, but comprehensive tests of these factors with datasets that cover extensive spatial and temporal scales are rare. Based on 1180 benthic invertebrate community samples from 2005 to 2012 in central low mountain streams of Germany, we tested the hypotheses that: 1) local contribution to beta diversity (LCBD: a measure of the uniqueness of communities) would decline with increasing average community dispersal capacity; and 2) owing to the relatively large spatial extent of the study region, regional dispersal processes would override local niche controls in structuring community composition. We found considerable temporal variation in LCBD and a negative correlation between LCBD and community dispersal capacity. However, no statistically significant correlation between species contribution to beta diversity (SCBD) and species dispersal capacity was observed. The large-scale spatial structure among locations (representative of dispersal limitation) was important in structuring benthic communities. Although much of the variation was explained by the shared effects of local processes and large-scale spatial variables, environmental controls were stronger than regional processes in few cases in the variance partitioning analysis, with the annual mean temperature and mean diurnal range of temperature being the important drivers. Given the highly varied correlates of beta diversity over time, we urge researchers to focus on not only spatial variation in diversity, but also the context of temporal variation. [ABSTRACT FROM AUTHOR]

• We used two biological indices to assess aquatic invertebrate responses to drying. • We examined responses in 34 temporary river sites with contrasting flow permanence. • Responses to no-flow were best predicted at near-perennial sites during drought. • Index responses to drying were more erratic at the most intermittent sites. • We identify DEHLI as an index to characterize community responses to river drying. Many river networks include temporary reaches that stop flowing and may dry during unpredictable droughts (near-perennial) or more frequently (intermittent). A few biological indices have been developed to assess invertebrate community responses to hydrological variability, including the instream conditions associated with drought, but their performance in temporary streams remains poorly known. We evaluated the ability of two such indices, the Lotic-invertebrate Index for Flow Evaluation (LIFE) and the Drought Effect of Habitat Loss on Invertebrates (DEHLI), to predict responses to flow cessation and drying in temporary streams with contrasting flow permanence regimes. We used a 26-year dataset comprising spring-season invertebrate community samples and daily discharge measurements from 46 sites in a cool, wet temperate region, to examine relationships between hydrological variables and changes in index scores. We also identified taxon-specific thresholds at which occurrence changed with increasing drying and flowing durations. Both indices effectively characterized responses to increasing no-flow durations. DEHLI also reflected community changes following flow resumptions, identified differences in responses among flow permanence groups, and was particularly able to predict community responses at near-perennial sites. DEHLI scores at near-perennial sites took on average three years after a drying event to return to values typical of perennial sites, whereas responses to increasing flow duration were more erratic at intermittent sites. Lotic specialists declined whereas lentic and semi-aquatic taxa increased in occurrence with no-flow duration after summers with <50 days without flow, due to changes in the availability of preferred habitat types. Community responses to drying events were less predictable among intermittent than near-perennial sites, likely because differences in habitat conditions and connectivity may lead intermittent communities to harbour contrasting pools of species with strategies that promote persistence during and/or recolonization after drying. We identify DEHLI as an index that can characterize community responses to drying in temporary streams with contrasting flow permanence regimes. We also recommend the development of new indices that include lentic, semi-aquatic and terrestrial as well as lotic taxa, to more comprehensively describe and predict community responses to changing instream conditions. [ABSTRACT FROM AUTHOR]

• Macroinvertebrate community structure was used to indicate phosphorus pressure. • TRPI was more closely associated with phosphorus concentrations than other metrics. • TRPI can be applied to historic monitoring data to track trajectories of change. Nutrient enrichment represents one of the most important causes of detriment to river ecosystem health globally. Monitoring nutrient inputs can be particularly challenging given the spatial and temporal heterogeneity of nitrogen and phosphorus concentrations and the indirect and often lagged effects on instream communities. The objective of this paper was to explore the association between family level macroinvertebrate community data and Total Reactive Phosphorus (TRP). To achieve this, a biological index for phosphorus sensitivity (Total Reactive Phosphorus Index – TRPI) was developed and tested utilising invertebrate community and chemical data from two datasets, one consisting 88 sites across England and the other 76 sites, both sampled in spring and autumn using the same methodology between 2013 and 2015. There was a significant association between TRPI and TRP concentrations that was stronger than other biological indices of elevated phosphorus, including the TDI (diatoms) and MTR (macrophytes), currently available in the UK. Additional testing and validation are presented via local case studies, where results indicate that macroinvertebrate family sensitivity is dependent upon a range of abiotic factors including season (time of year), benthic substrate composition, altitude, and water alkalinity. [ABSTRACT FROM AUTHOR]