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Protection of freshwater fish diversity is a global conservation priority in face of its alarming decline in the last decades. A crucial step to protect freshwater fish diversity is the production of prompt and precise evaluation of community composition and spatial distribution. Metabarcoding of environmental DNA (eDNA metabarcoding) generally surpasses traditional methods for documenting diversity and community composition in aquatic environments. Nevertheless, empirical evidence evaluating how eDNA transportation in water affect community composition and structure via eDNA metabarcoding data remains scarce. Using a brown trout (Salmo trutta) cage transplant experiment in the St. Lawrence River (Canada), a large fluvial system, we tested the detection and relative abundance of species’ eDNA along 15 sampling locations. We detected brown trout eDNA in five localities up to 5,000 m from the cage, but only one sampling location situated 10 m downstream and in the direct line of the cage was affected at the community composition level. This locality showed a relative abundance of brown trout eDNA of 13.1%, while the four others showed a relative abundance under 1.0%. K-means cluster analysis confirmed the impact of brown trout eDNA on community composition by separating this locality from all others. Based on species loading of a redundancy analysis, we showed that this different k-means group was associated with the high relative abundance of brown trout. No evidence of transport effect of brown trout eDNA on fish community composition was observed in any other sampling locations. Together, our results support the view that eDNA metabarcoding can be both a conveyor belt of biodiversity information and a precise tool to study the composition and structure of fish communities in river.

• A theoretical framework for the relationship among resources, economy, and ecology is built. • The coupling coordination level exhibits geographical heterogeneity, with superior performance in upstream provinces. • Spatial variation and key issues are discussed in detail with geographical detector model. • Factors affecting coupling coordination are becoming balanced and diversified. • Three development suggestions are proposed to promote coupling coordination level. The development of the Yellow River Basin (YRB) has been constrained by resource utilization, ecological conservation, and economic growth. The aim of this study was to establish a theoretical framework for characterizing the relationships among resources, economy, and ecology in the YRB using panel data and remote sensing data from nine provinces in the basin from 2002 to 2022. Furthermore, a coupling coordination degree model and geographical detector model were used to evaluate the spatiotemporal coupling and relevant factors. Our findings were manifold. (1) The coupling coordination degree in the YRB and its provinces has improved to varying degrees, with upstream provinces showing stronger coordination than midstream and downstream provinces. (2) The most significant growth rates were observed during 2002–2006 and 2014–2018. However, a noticeable decline in the coupling coordination degree occurred during 2006–2010, indicating that ecological constraints and negative effects were pronounced when resource constraints were not apparent. (3) The average coupling coordination degree of resources, economy, and ecology in the YRB in 2022 was 0.684. Excellent coordination was observed in Shandong Province and Henan Province, and good coordination was observed in Shaanxi Province and Shanxi Province. (4) In the initial part of the study period, the water resource supply, demand, and allocation had strong effects on the coordination degree. Over time, the focus shifted from a single system to multiple systems, which increased the similarity in the explanatory power of different factors. Additionally, an in-depth analysis using the coupling coordination degree and relevant factors was conducted to characterize the policy orientations of different periods in the YRB. Policy recommendations were provided on the basis of the natural conditions and socio-economic conditions of the YRB. The findings of this study have implications for coupling coordination relationships and high-quality development in the YRB. Generally, our results provide key insights that will aid coordinated and sustainable regional development. [ABSTRACT FROM AUTHOR]

Highlights • Developed indicators based on concepts of general resilience and river ecology. • Indicators addressed diversity/redundancy, connectivity, and controlling variables. • Indicators were assessed across four reaches of a floodplain-river ecosystem. • Results suggest contrasts in general resilience among reaches. • Indicators are generally transferable to other large, floodplain-river ecosystems. Abstract Large floodplain-river ecosystems are often highly modified to provide services that society desires, yet these modifications can limit an ecosystem's ability to adapt to changing conditions. The adaptive capacity of an ecosystem, its general resilience, is a conceptual framework for considering how a system will respond to such changes. We sought to apply aspects of three general resilience principles (diversity and redundancy, connectivity, and controlling variables) to our understanding of floodplain-river ecosystem structure and function. We demonstrate the applicability of this approach in a case study of the Upper Mississippi River System (UMRS). In doing so, we developed ten indicators that highlight important structural and functional aspects of this floodplain-river ecosystem, and likely underlie the capacity of large rivers to cope with environmental change and disturbance. We developed diversity and redundancy indicators for aquatic habitats, patterns of floodplain inundation, and fish communities. Connectivity indicators included metrics of longitudinal and lateral connections. Controlling variable indicators included deviations from historic water surface elevation fluctuations, water clarity, nutrient concentrations, and aquatic invasive species. This set of indicators provides a simple description of the adaptive capacity of four distinct reaches of the UMRS: Upper Impounded, Lower Impounded, Unimpounded Reaches of the Upper Mississippi River and the entire Illinois River. High aquatic habitat diversity and redundancy, fish functional diversity and redundancy, and water clarity, and the scarcity of invasive fish species are all factors that likely contribute to the high general resilience of the Upper Impounded Reach. However, the limited longitudinal connectivity and establishment of a minimum water level for navigation are factors that may inhibit the general resilience of this reach. In the Lower Impounded Reach, there is high within-reach variability for individual indicators such as aquatic habitat diversity, fish functional diversity and redundancy, and longitudinal and lateral connectivity. In the Unimpounded Reach, a high degree of longitudinal connectivity likely enhances its general resilience, but low aquatic habitat diversity, low lateral connectivity, and relatively high number of invasive fish species inhibit general resilience. For the Illinois River Reach, the relatively high fish functional diversity and redundancy likely contributes to its general resilience, whereas high number of invasive fish species, low water clarity, low lateral connectivity, and high range of water levels may inhibit general resilience. Indicators derived from application of concepts of general resilience provide insight into the current coping capacity of the UMRS and identify opportunities for enhancing resilience. [ABSTRACT FROM AUTHOR]

Highlights • Increasing agriculture and urbanization lead to changes in the biodiversity of streams. • Land use categories proved to be poor predictors of fish community structure and diversity. • Environmental gradients influenced fish communities rather independently of land use type. • Maintenance of natural conditions in conservation areas is important for fish diversity. • Agricultural and urban streams can contribute to the maintenance of fish diversity. Abstract Increasing agriculture and urbanization inevitably lead to changes in the biodiversity of stream ecosystems. However, few studies examined comprehensively how biodiversity is distributed within and among protected, agricultural and urban land use types in streams. We studied environmental characteristics of streams and patterns of species richness and other community attributes of stream fish communities in these three characteristic land use types in the catchment of the Danube River, Hungary. Land use separated streams to some degree based on their environmental characteristics. However, both between stream environmental and fish community variability were high in most types, and comparable to land use type level differences in case of many streams. A variety of environmental gradients influenced fish community structure rather independently of land use type, which was also influenced by spatial drivers. Non-native fishes modified the structure of native fish communities, especially in agricultural streams, although their modification effect varied more among individual streams than among land use types. In conclusion, land use type proved to be a poor predictor of fish communities in this human modified landscape. We found that even intensively managed areas (i.e. agricultural and urban) can contribute to the maintenance of fish diversity in this biogeographic region, or at least their potential can be comparable to those streams which flow in protected areas. Thus, conservation management should focus on maintaining streams in more natural condition in protected areas and/or use the potential of non-protected agricultural and urban streams in maintaining fish diversity in human modified landscapes. [ABSTRACT FROM AUTHOR]

Highlights • Leaf decomposition rates are affected by forest biomass removal. • Conventional logging is more detrimental than the logging residue removal practise. • Fungi:Bacterial ratio, a generally overlooked predictor, is crucial for leaf decomposition. Abstract The complexity and multidimensionality of freshwater processes require multiple metrics to assess their responses to disturbances. However, studies have historically relied on structural attributes, while functional attributes have received much less attention. The relative ease of implementing functional attributes, like leaf decomposition assays, make them an attractive choice to complement structural attributes (e.g. species diversity and community composition). However, the congruence of these disparate attributes is still debatable, as studies have reported results to be strongly context-dependent. The concept of using forest biomass as a source of alternative energy instead of fossil fuel has led to rapid changes in forestry practices. One of these practices involves removal of logging residues that would have otherwise been left on site (logging residue removal, LRR), potentially leaving the landscape prone to high erosion, run-off and sedimentation. This study investigated the decomposition rates of alder leaves in sites affected by LRR compared with conventionally logged (CL) and near-natural, non-harvested sites. Our results revealed CL as having the strongest effects, while LRR had an intermediate response, both in terms of decomposition rates (k total , k microbial and k shredders) and microbial biomass. These results match those for structural attributes reported previously at the same sites, thus providing multiple lines of evidence for the ecosystem-level impacts of forestry activities. Bacterial biomass on decomposing leaves was consistently several orders of magnitude greater than that of fungi in all study streams and treatments. Most previous research on the relative contributions of shredders, fungi and bacteria to leaf decomposition has focused on fast-flowing riffles and more research is needed to clarify their relative roles in other types of running waters, such as the slow-flowing, strongly allochthonous and humic forest streams studied by here. In conclusion, this study points to further need to revise the current practice of forestry activities in light of its negative impact on biodiversity. [ABSTRACT FROM AUTHOR]

Highlights • Inter-operator variability was estimated for the monitoring of French rivers using IBD 2007 and IBMR. • Inter-operator variability was significant in terms of taxa lists and abundance for a single site. • The index scores were consistent despite differences in community composition assessments. • Inter-operator variability had a significant influence on ecological status. Abstract The Water Framework Directive (WFD1) requires a level of "confidence" and "precision" in the established freshwater monitoring system, as several sources of variability can contribute significantly to the misclassification of water body ecological status. Diatoms and macrophytes are required by the Directive as biological quality element (BQE2) and are routinely used in France to monitor the health of rivers. The present study evaluated uncertainties related to the application of the data acquisition protocol for the two vegetation-based assessment methods in France (Biological Diatoms index, IBD 2007 3 and Biological River Macrophyte index, IBMR4). We aimed to estimate the overall impact of inter-operator variability on IBD 2007 and IBMR results, and on river ecological status classification, at the French national scale. A systemic approach was designed and sampling surveys were conducted at the same sites by three different operators belonging to different French bodies involved in monitoring. Results showed significant inter-operator variability regarding the species lists obtained, but also in terms of richness and abundance metrics. However, statistical analyses did not reveal any significant difference in the distribution of IBD 2007 and IBMR scores between the three operators, among all sites considered together. The mean deviation at a site was ±0.85 for the diatom index (differences ranged between 0 and 6.6 IBD 2007 points) and ±0.57 for the macrophyte index (the effective range was 0 and 3 IBMR points). In general, inter-operator variability was higher for moderate and poor ecological status classes. The distribution of such variability observed along the entire quality gradient of our data set, for both diatoms and macrophytes, was used to fit a model able to define the probability for a site to belong to a given status class according to its index score. Identifying and quantifying the key factors that contribute to the potential misclassification of the ecological status finally allowed us to propose future recommendations in order to minimise the main sources of error. [ABSTRACT FROM AUTHOR]

Highlights • Changes in biodiversity in response to disturbances are variable across scales. • Impacts of selective harvesting were assessed in stream benthic communities. • Responses varied between streams based on hydrology and across spatial scales. • Biodiversity patterns at fine scales may indicate future broader impacts. • Our study provides a framework for analysing and managing impacts to biodiversity. Abstract In forestry, selective timber harvesting best management practices (BMPs) are widely adopted to mitigate the effects of clearfell harvesting on stream ecosystems. However, there have been surprisingly few studies experimentally assessing the effects of selective harvesting on freshwater benthic macroinvertebrate assemblages and how anthropogenic disturbances impact biodiversity across multiple spatial scales. We assessed how selective timber-harvesting BMPs affected alpha and beta diversity of stream macroinvertebrates when measured across three spatial scales – between harvested impact and unharvested control streams, among pools within streams, and among samples within pools. Using a multiple paired, Before-After Control-Impact design of two pairs of streams draining unharvested control and harvested impact catchments, we sampled stream macroinvertebrates bimonthly over two years before and after selective timber harvesting. Effects of selective harvesting varied between 'impact' streams and among different spatial scales. At the whole-stream scale, harvesting did not impact either alpha or beta diversity in both pairs of control-impact streams. Within streams, harvesting temporarily reduced beta diversity in streams with increasingly intermittent flow, yet caused brief increases in beta diversity in increasingly permanently flowing streams. At the finest spatial scale, harvesting had transient variable effects on within-pool beta diversity in one pair of experimental streams but not the other. The absence of impacts of selective harvesting on alpha diversity at all three spatial scales, and the only transient impacts on beta diversity suggest that these BMPs are sufficient to allow timber harvesting while simultaneously preserving headwater stream biodiversity. Our study provides a basis for developing monitoring programs to assess the relative impacts and consequences of anthropogenic disturbances on multi-species assemblages across different spatial scales. Our findings suggest fine scale (within-stream) beta diversity may be a more sensitive indicator of catchment disturbances than comparisons of alpha and beta diversity at broader scales among streams. [ABSTRACT FROM AUTHOR]

Highlights • We review approaches to the assessment of ecological condition and conservation management of large floodplain rivers. • The review highlights research gaps and emphasizes the importance of developing more holistic indicators of ecosystem condition. • Indicators that better reflect landscape level changes in structure and functioning of floodplain rivers are needed. • Studies that distinguish the role of different river floodplain habitat types in ecosystem services provision are needed. • More effective spatial conservation prioritization tools are needed at the river floodplain scale. Abstract Large floodplain rivers (LFRs) are currently threatened by high levels of human alteration, and utilization is expected to grow. Assessments to determine ecological condition should address the specific environmental features of these unique ecosystems, while conservation management requires balancing maintenance of good ecological condition with the ecosystem services provided by LFRs. However, a systematic evaluation of the scientific literature on assessment of ecological condition of LFRs and trade-offs to guide conservation management is currently lacking. Here, we reviewed 153 peer reviewed scientific articles to characterize methodological patterns and trends and identify knowledge gaps in the assessment of LFRs. Our review revealed that most approaches used classical biotic indices for assessing ecological condition of LFRs. However, the number of articles specifically addressing the peculiarities of LFRs was low. Many studies used watershed level surveys and assessed samples from small streams to large rivers using the same methodological protocol. Most studies evaluated the status of main stem river habitats only, indicating large knowledge gaps with respect to the diversity of river-floodplain habitat types or lateral connectivity. Studies related to management were oriented toward specific rehabilitation actions rather than broader conservation of LFRs. Papers relating to ecosystem services of LFRs were especially few. Most importantly, these studies did not distinguish the different functional units of river-floodplain habitat types (e.g. eupotamon, parapotamon) and their role in ecosystem services provision. Overall, the number of articles was too low for meaningful analyses of the relationships and tradeoffs between biodiversity conservation, maintaining ecological condition, and use of ecosystem services in LFRs. Our review highlights research gaps and emphasizes the importance of developing more holistic indicators of ecosystem condition, which better reflect landscape level changes in structure and functioning of LFRs. As human use of water and land increases, the need to develop more effective spatial conservation prioritization tools becomes more important. Empirical research in this field can aid in solving conflicts between socio-economic demands for ecosystem services and nature conservation of LFRs. [ABSTRACT FROM AUTHOR]

Geodiversity, i.e. the variety of the abiotic environment, is considered to be positively correlated to biodiversity. In streams, the importance of physical heterogeneity for biodiversity variation is well known, but the usefulness of explicitly measured geodiversity indices to account for biodiversity has not been tested. We developed a technique to measure in-stream geodiversity, based on different types of stream flow, geomorphological processes and landforms observed from photographs taken during the field work, and substrates based on traditional field observations. We further tested the utility of these geodiversity measures in explaining variation in the biodiversity of macroinvertebrates in near-pristine streams. Our specific objective was to examine the explanatory power of geodiversity compared to traditional environmental variables, such as water chemistry, depth and current velocity. While most biodiversity indices correlated more strongly with traditional environmental variables, the influence of geodiversity on biodiversity was also evident. Unique effect of flow richness on species richness and that of total geodiversity on functional richness were higher than those of the traditional environmental variables. Our findings suggested that in-stream geodiversity offers a valuable concept for characterizing stream habitats. If further developed and tested, in-stream geodiversity can be used as a cost-efficient proxy to explain variation in biodiversity in stream environments. [ABSTRACT FROM AUTHOR]

Rivers provide numerous ecological and cultural services for humans and wildlife that are vulnerable to increasing demands for freshwater and renewable energy production. Run-of-river (RoR) dams are becoming a common energy production alternative on coastal mountain streams throughout the world, but their ecological impacts remain poorly understood. A well-described indicator of water quality sharing steep mountain stream habitat with RoR developments, the American dipper ( Cinclus mexicanus ) river bird is an ideal species for studying potential eco-hydrological impacts of RoR dams. We monitored American dipper populations over two years at stream sites with and without RoR dams across three watersheds in coastal British Columbia, Canada. We found that dippers selected regulated streams across seasons, with the headpond and diversion reach frequently used for foraging. Regulated streams also had higher dipper densities in the slow-flowing habitats, a higher occupancy rate of banded dippers, a higher rate of confirmed year-round residents, and a greater proportion of adults; however, fewer hatch-year dippers were recorded on regulated streams, which may indicate lower reproductive potential or juvenile survival. RoR reaches modified by flow abstraction may offer an opportunity for altitudinal migrant dippers to exploit a consistent food resource closer to their high elevation breeding territory, enabling them to take on a “resident strategy” that is more typical of low elevation river habitats. However, the long-term consequences of year-round occupancy and foraging in headponds requires further investigation, as it could have positive or negative impacts on dippers and their associated foodweb. Collectively, our data suggest that high elevation, RoR-regulated streams provide stable year-round habitat for the American dipper and that presence and density of this species can be used to accurately track changes in stream flow and condition following dam installation. [ABSTRACT FROM AUTHOR]

There are increasing calls for “conservation stocking” to counter declines in Atlantic salmon ( Salmo salar ) populations, the assumption being that stocking can bypass population bottlenecks and increase recruitment over natural processes. However, there are too few quantitative studies with sufficient data to assess the efficacy of conservation stocking. The Girnock Burn is a unique long-term monitoring site where adult and juvenile salmon numbers have been monitored for over 50 years, including 11 years with conservation stocking. Adults were monitored at a fixed trap and juveniles were monitored by electrofishing. In stocked years, ova were incubated in surface water to reduce density-independent over-winter mortality. In eight years, eyed ova were stocked at uniform densities to reduce local density-dependence. In three years, stocking replicated natural spatial variability in ova deposition removing any potential benefits of reduced local density-dependence. Juvenile production was estimated by summing the product of reach-scale density estimates and river area obtained from a novel spatial statistical river network model that incorporated the effects of capture probability, habitat and stock level. Capture probability varied with life-stage (age 0+ fry or ≥1+ parr), electrofishing pass and day of the year, but importantly also exhibited a positive temporal trend across years. Survival from ova to fry was density-independent and higher under uniform stocking than natural spawning or simulated natural spawning. Under uniform stocking, fry densities varied smoothly with altitude, while under natural spawning and simulated natural spawning, fry exhibited a more patchy distribution. Increased fry production did not translate to increased parr production, which was strongly density-dependent. This likely reflected the inability of fry to move between stocked locations and suitable overwintering habitat, decreasing survival between fry and parr life-stages. Consequently, there was no overall benefit of stocking. The modelling framework used in this study provides a valuable approach for interpreting long-term datasets where site locations, equipment and staffing vary over time. The long-term Girnock dataset was valuable in separating management action from natural population regulation and permitting understanding of ecological processes. The study indicates that conservation stocking can be ineffective, even where implemented to best scientific standards. It is therefore recommended that a detailed understanding of local population dynamics is obtained, and a realistic appraisal of the expected benefits of stocking is undertaken, before management actions are considered. [ABSTRACT FROM AUTHOR]

Tracking river ecosystem responses to river flow restoration is a necessary and important step for adaptive management of environmental flow. In this study, we used a unique experimental scheme to investigate the responses of water quality, periphyton, and river metabolism to a new environmental flow in a flow-reduced river in Japan. After implementing the new environmental flow, water quality improved. Periphyton biomass increased substantially in terms of both chlorophyll a and ash-free dry mass. However, the new flow also promoted the growth of filamentous species that could deteriorate the river environment. River metabolism was determined by continual measurement of the diel oxygen concentration. Gross primary production and ecosystem respiration both increased after the increase in environmental flow. These results indicate that the periphyton and metabolism can potentially be used as indicators for monitoring river ecosystem response to increased minimum environmental flow. [ABSTRACT FROM AUTHOR]

In South America, the presence of the non-native mollusc Limnoperna fortunei ( Dunker, 1857 ) (Mollusca, Bivalvia, Mytilidae) in rivers and reservoirs may result in several impacts on the environment and economic activities. In a continental scale, the factors that most influence the dispersion of the species are anthropogenic vectors such as the movement of boats and people. Due to this, distribution models based solely on climatic variables often fail to predict the areas most subject to invasion, both spatially and temporally. An alternative to overcome this problem is the evaluation assuming the phenomenon as a complex system. In this paper, we have used a cellular automata model to predict the spread of the golden mussel in the Brazilian territory, on a temporal and spatial scale. We assume three parameters of interest: a) altitude b) characteristics of the river, and c) human population density. Transition rules were defined based on various considerations discussed in the article. The algorithm estimated satisfactorily the risk of invasion by L. fortunei to date (year of 2016), and the simulations for the years 2030 and 2050 predicted a high risk of invasion in north and northeastern Brazil. The increased risk of invasion predicted by the model for the next decades indicates that prevention and control measures should be applied immediately and this is of the utmost importance for the country to be able to comply with the #9 Aichi target. [ABSTRACT FROM AUTHOR]

Hydropower dam development in the Mekong River Basin is threatening both biodiversity and the output of the world’s largest inland fishery. Fragmentation of the river system by dams blocking the free movement of riverine species can have a direct impact on migratory fish species, which constitute a significant portion of the basins wild fishery. Fish passes, which allow fish to bypass dams, are often proposed as potential solutions to these problems. However, there is uncertainty around the effectiveness of fish passes in the species-rich environment of the Lower Mekong, and this has real consequences for the region and its development strategies. As a first step to evaluate the effects of dams in the region, we used the Dendritic Connectivity Index (DCI) to examine the impact on connectivity by providing fish passage on as many as 105 current, under construction and planned dams on the Sesan, Srepok and Sekong tributaries of the Mekong River. Our results indicate that, at the current stage of development, overall connectivity of the river system is sensitive to the efficiency of fish passes – and with highly efficient fish passes, connectivity comparable to a natural network is possible. However, as the number of dams on each tributary increase, even highly efficient fish passes are unable to improve connectivity significantly. While this paper does not explicitly focus on the functioning and limitation of fish passes, this broader analysis clearly establishes that, if constructed, robust monitoring for the newly-designed fish pass on the Lower Sesan II dam would be critical for evaluating and informing future development strategies. [ABSTRACT FROM AUTHOR]

In this study we developed a predictive diatom-based model to assess the ecological status of streams and rivers of Northern Spain. Diatom samples were collected with standard protocols over stones from 676 sites distributed along existing environmental conditions across Northern Spain, during seven years between 2002 and 2008 (n = 1056 samples). This dataset included a network of 91 reference sites selected by using criteria that confirmed the absence of relevant human pressures according WFD. A multinomial logistic regression using GAAC cluster-derived reference sites group as response variable was performed. The independent variables included obligatory typology factors (WFD System A typology descriptors), and other optional typology B descriptors were included in the model performed on a forward stepwise procedure. The Ecological Quality Ratios (EQRs) were obtained by dividing the observed similarity between the diatoms composition in each sample by the expected median similarity of each type reference diatom community. The model predictions (EQRs) responded significantly to eutrophication and intensive agriculture pressures, but were not related with sewages, hydromorphological alterations and extensive agriculture pressures. These results demonstrated the accuracy of the diatom model in predicting nutrient enrichment in Northern Spanish rivers and streams. [ABSTRACT FROM AUTHOR]

The implementation of the European Water Framework Directive, especially regarding the establishment of fish indexes for riverine habitats, has taken different paths in different countries. For example, in Italy previous efforts have been directed towards a taxonomy-based index, contrarily to most other European countries where an ecofunctional approach took place. Taxonomical indexes are particularly hard to apply to Mediterranean countries, where fish taxonomy is often revised causing problems in practical implementation. Alternatively, ecofunctional characteristics of fish communities could be exploited to inform on river habitat quality and to detect anthropogenic impacts, thus reducing the index sensitivity to the taxonomical variability of the fish fauna. We therefore proposed a new, multimetric index based on ecofunctional traits of fish species (EFFI, EcoFunctional Fish Index) and tested it on 208 river sampling stations of the Emilia-Romagna region, northern Italy. Using theoretical reference communities, ecological quality ratios were estimated for the whole area expressing the ecological distance of each site from reference conditions. Perhaps unsurprisingly, this work underlined how fish communities were more degraded at lower altitudes than at higher ones. EFFI scores were remarkably close to two already-established indexes for chemical (LIM) and macrozoobenthos communities (IBE) alteration. Further work should explore the validity of this approach over a wider geographical range as well as investigate the definition of environmental class boundaries and its potential intercalibration with other indexes. [ABSTRACT FROM AUTHOR]

Tamarisk ( Tamarix spp.) is an invasive plant species that is rapidly expanding along arid and semi-arid rivers in the western United States. A biocontrol agent, tamarisk beetle ( Diorhabda carinulata ), was released in 2001 in California, Colorado, Utah, and Texas. In 2009, the tamarisk beetle was found further south than anticipated in the Colorado River ecosystem within the Grand Canyon National Park and Glen Canyon National Recreation Area. Our objectives were to classify tamarisk stands along 412 km of the Colorado River from the Glen Canyon Dam through the Grand Canyon National Park using 2009 aerial, high spatial resolution multispectral imagery, and then quantify tamarisk beetle impacts by comparing the pre-beetle images from 2009 with 2013 post-beetle images. We classified tamarisk presence in 2009 using the Mahalanobis Distance method with a total of 2500 training samples, and assessed the classification accuracy with an independent set of 7858 samples across 49 image quads. A total of 214 ha of tamarisk were detected in 2009 along the Colorado River, where each image quad, on average, included an 8.4 km segment of the river. Tamarisk detection accuracies varied across the 49 image quads, but the combined overall accuracy across the entire study region was 74%. Using the Normalized Difference Vegetation Index (NDVI) from 2009 and 2013 with a region-specific ratio of >1.5 decline between the two image dates (2009NDVI/2013NDVI), we detected tamarisk defoliation due to beetle herbivory. The total beetle-impacted tamarisk area was 32 ha across the study region, where tamarisk defoliation ranged 1–86% at the local levels. Our tamarisk classification can aid long-term efforts to monitor the spread and impact of the beetle along the river and the eventual mortality of tamarisk due to beetle impacts. Identifying areas of tamarisk defoliation is a useful ecological indicator for managers to plan restoration and tamarisk removal efforts. [ABSTRACT FROM AUTHOR]

In South Korea, Eurasian otter ( Lutra lutra ) habitat has increased since the 1990 s because of legal protection, forest development, and increased public awareness. Although otters have been detected throughout the country, a precise investigation of habitat conditions has not previously been undertaken. We hypothesized that higher values of stream health assessment programme (SHAP) indices would indicate better habitat for otters. Otter distribution based on spraint density was investigated along 600 m riverside transects at 250 sites in the Nakdong River basin. We defined four otter population categories (absent, rare, normal, and abundant) and compared the results with presence and absence data. Use of the four population categories provided more details about habitat conditions than presence and absence analysis. The highest spraint densities were found at higher altitudes, and densities declined in areas with high human density and urbanization. The benthic macro-invertebrate community index was highly positively related to the otter population indices. In terms of fish as prey items, the proportion of species tolerant to environmental change were negatively related to otter indices, otherwise number of species sensitive to environmental change positively related. Overall, stream health assessment indices provided the highest correlations with otter population numbers and distribution. [ABSTRACT FROM AUTHOR]

Water resource managers face increasing challenges in identifying what physical and chemical stressors are responsible for the alteration of biological conditions in streams. The objective of this study was to assess the comparative influence of multiple stressors on benthic diatoms at 98 sites that spanned a range of stressors in an agriculturally dominated region in the upper Midwest, USA. The primary stressors of interest included: nutrients, herbicides and fungicides, sediment, and streamflow; although the influence of physical habitat was incorporated in the assessment. Boosted Regression Tree was used to examine both the sensitivity of various diatom metrics and the relative importance of the primary stressors. Percent Sensitive Taxa, percent Highly Motile Taxa, and percent High Phosphorus Taxa had the strongest response to stressors. Habitat and total phosphorous were the most common discriminators of diatom metrics, with herbicides as secondary factors. A Classification and Regression Tree (CART) model was used to examine conditional relations among stressors and indicated that fine-grain streams had a lower percentage of Sensitive Taxa than coarse-grain streams, with Sensitive Taxa decreasing further with increased water temperature (>30 °C) and triazine concentrations (>1500 ng/L). In contrast, streams dominated by coarse-grain substrate contained a higher percentage of Sensitive Taxa, with relative abundance increasing with lower water temperatures (<29 °C) and shallower water depth (<0.3 m). Quantile regression indicated that maximum water temperature appears to be a major limiting factor in Midwest streams; whereas both total phosphorus and percent fines showed a slight subsidy-stress response. While using benthic algae for assessing stream quality can be challenging, field-based studies can elucidate stressor effects and interactions when the response variables are appropriate, sufficient stressor resolution is achieved, and the number and type of sites represent a gradient of stressor conditions and at least a quasi-factorial design. [ABSTRACT FROM AUTHOR]

The development of microbial community-based biological indicators for assessing aquatic ecological status is urgently needed in heavily impaired regions, due to the local extinction of traditional indicator macroorganisms. The aim of this study was to develop and validate a microbial community-based index of biotic integrity (MC-IBI) for the assessment of rivers in the Taihu Basin, China. MC-IBI was developed based on sediment samples collected from 55 sites of 42 rivers, with least disturbed sites as reference sites. High-throughput sequencing and real-time PCR methods were employed to measure the microbial diversity and abundance of the samples. A total of 341 candidate metrics related to microbial diversity, composition, pollution tolerance and function categories were established based on microbial data. Five core metrics, including% FCA (percentage of Firmicutes, Chloroflexi and Acidobacteria), log 16S rRNA /ARG (log the ratio of 16S rRNA gene to antibiotic resistance gene), log AOB/AOA (log the ratio of ammonium oxidizing bacteria to ammonium oxidizing archaea), nirK / nirS (ratio of nirK gene to nirS gene) and BFG/A (ratio of Bacteroidetes, Firmicutes and Gammaproteobacteria to Alphaproteobacteria), were identified to develop a MC-IBI. The developed MC-IBI was demonstrated to be robust using a validation dataset. Further, the MC-IBI showed a significantly negative association with the index of water quality. The river ecological conditions of the 55 sampled sites in the Taihu Basin were defined as excellent (9.1%), good (14.5%), moderate (25.5%), poor (23.6%) and bad (27.3%) separately based on the MC-IBI scores. Overall, the MC-IBI provides a novel assessment tool for the ecological health status of freshwater rivers. [ABSTRACT FROM AUTHOR]

Temporary rivers comprise a significant proportion of river networks globally and their prevalence is expected to increase as a result of future climate change and anthropogenic water resource pressures. Despite this, the influence of drying events on freshwater biomonitoring tools within temporary rivers has received limited research attention within temperate environments. This study examines the effects of flow permanence and longitudinal drying patterns on selected biomonitoring indices used within the United Kingdom to assess the ecological status of waterbodies within the context of the Water Framework Directive. These indices are based on faunal tolerances and preferences to nutrient enrichment (BMWP, ASPT and Ntaxa) and flow velocity (Family LIFE). Long-term biomonitoring data from four rivers within southern England were examined, two of which dry longitudinally from the headwaters and two that dry within the mid-reaches. The results demonstrate that all of the biomonitoring indices examined differed significantly between each ‘hydrological class’ (i.e. temporary versus perennial reaches), with those based on absolute scores (BMWP and Ntaxa) displaying greater differences compared to those derived using scores standardized by the number of taxa recorded (ASPT and Family LIFE). The individual influence of drying pattern did not have a significant effect on any biomonitoring index. However, the interaction between the hydrological class and drying pattern significantly influenced all biomonitoring indices, indicating that the effect of flow intermittency on the metrics examined differed between drying patterns. Flow permanence explained a greater amount of statistical variation compared to the hydrological class and highlights the importance of the duration of flowing conditions on biomonitoring indices. The results indicate that flow intermittency has a significant effect on freshwater biomonitoring tools and highlights the need to incorporate this knowledge into existing management and environmental policy frameworks to prevent the misclassification of the ecological status of temporary streams. [ABSTRACT FROM AUTHOR]

A number of physical, chemical and biological water quality parameters are measured to understand quality conditions of a riverine environment. Various aggregation techniques have been used to reflect the combined effect of the existing or proposed quality levels. Water Quality Index (WQI) has been developed primarily for fresh water environments. Organic pollutants are not considered in many WQIs because analyses of organics are rather expensive. In general, fecal coliform and total coliform counts are measured to reflect biological contamination of water. With growing consensus on considering rivers as ecological entity, rather than merely a source of water for human consumptions, the emphasis is changing from water quality index (WQI) to River Health Index (RHI). As benthic macroinvertebrate species are differentially sensitive to many biotic and abiotic factors in river environment, macroinvertebrate community structure has commonly been used as indicator of stream water condition. A number of river health assessment methodologies have been proposed in past and several indices such as Ecological Health Index (EHI), Ecological Quality Index (EQI), Overall Index of Pollution (OIP) and River Pollution Index (RPI) have been developed using water quality variables and aquatic species for evaluating the ecological health of river systems. This paper attempts to review and summarize some of these indices with particular emphasis on measurable parameters included in such formulations. The analyses suggest that with sufficient scientific experience and understanding in this area, it is possible to define a River Health Index (RHI) by including algae, macroinvertebrates and fish species as measurable parameters along with routine physico-chemical characteristics of river water. One such formulation on RHI has been proposed by the authors in this paper. The novelty of the proposed formulation include simple calculations and presentation of RHI value on 0–100 scale. The biological indices used in ACEDP (2011) requires biological expertise which is not normally available with water resource managers. Hence species identification and counting based simple biotic indices have been proposed so that it can be easily done by non experts also. River Health Level (RHL) can be categorized as ‘critical’ or ‘excellent’ based on RHI value <=20 or >80. Thus RHI values can be used to identify the healthy or unhealthy stretches of the river. RHI can serve as scientific tool to assess the current status, need and effectiveness of any intervention required to improve the condition of the river. Application of this RHI formulation on main stream of river Ganga (India) is under study. [ABSTRACT FROM AUTHOR]

Rivers and streams that dry up are found on every continent, and can form a large proportion of river networks. When rivers are dry, traditional indicators of river health – such as aquatic macroinvertebrates, fish or water quality – cannot be measured. Aquatic health indicators are widely used to assess wetted habitats, but currently no universally applicable indicators have been developed or applied to assess dry riverbed health. Dry riverbeds are often the ‘typical’ state of many intermittent rivers and streams; however, the ecological health of these habitats is rarely, if ever, assessed in monitoring programs. Resource managers have called for indicators of intermittent river health during the dry phase. The use of terrestrial invertebrate biota (e.g. ants, beetles, and spiders) as indicators in this study provides a novel solution to assessing rivers when they are dry. We developed a conceptual model of human-induced stressors (i.e. disturbance by livestock and feral mammals) on dry riverbed biota, which guided the selection of potential health indicators. Livestock and feral mammals are one of the most significant stressors on riverine ecosystems in Queensland, and impact riverbeds by altering the substrate through compaction, rooting and pugging. We trialled the use of metrics of terrestrial invertebrate assemblages as indicators of dry riverbed health in four Australian dryland catchments: Bulloo, Paroo, Warrego and Nebine. We used quantile regression and found that terrestrial invertebrate communities responded negatively (and significantly, p < 0.05) to a gradient of disturbance, defined by on-the-ground field measurements of livestock and feral mammal impacts. This response to stressors was predicted by the initial conceptual model. We conclude that terrestrial invertebrates in this study are suitable indicators of dry riverbed health, as they are impacted by disturbance from livestock and feral mammals. They can be used in the same way that indicators, such as aquatic macroinvertebrates, are traditionally used to assess river health. We also successfully combined indicators of wet and dry habitats to provide a holistic assessment of the health of intermittent river ecosystems incorporating all sections of the river network. We suggest that this approach should be adopted by other river health monitoring programs in rivers around the world. [ABSTRACT FROM AUTHOR]

River management and planning of restoration actions require a detailed analysis of stream conditions. However, most biotic and hydromorphological indices that have been developed for implementing the European Water Framework Directive (WFD) are characterized by limited spatial and temporal scales of application. In addition, the indices based on the biological quality elements defined by the WFD are sensitive to water quality but not to hydromorphological alterations. To overcome these limitations, alternative hydromorphological and biotic indices have recently been developed. In this study we compared the results obtained with the Morphological Quality Index (MQI) to those of three biotic indices, the Odonate River Index (ORI) and two BQE-based indices, in seven rivers of northern Italy. MQI and ORI resulted highly and significantly correlated, and alterations of river functionality and continuity were the most relevant impacts affecting dragonfly assemblages. Conversely, no significant relationships were found between the MQI and both BQE-based indices and assemblages. The significant correlation between MQI and ORI can be explained by the correspondence of the spatial scale of application (i.e. the whole river corridor). In contrast, the lack of correlation between the BQE-based indices and MQI can probably be attributed to the different spatial scales at which the indices work. The results of this study underline the importance of evaluating the lateral dimension of the river corridor and the need to apply reach-scale indices to achieve a comprehensive evaluation of river corridor conditions and to define appropriate management actions. [ABSTRACT FROM AUTHOR]

Understanding, predicting, and managing the spatiotemporal complexity of stream thermal regimes requires monitoring strategies designed specifically to make inference about spatiotemporal variability on the whole stream network. Moreover, monitoring can be tailored to capture particular facets of this complex thermal landscape that may be important indicators for species and life stages of management concern. We applied spatial stream network models (SSNMs) to an empirical dataset of water temperature from the Snoqualmie River watershed, WA, and use results to provide guidance with respect to necessary sample size, location of new sites, and selection of a modeling approach. As expected, increasing the number of monitoring stations improved both predictive precision and the ability to estimate covariates of stream temperature; however, even relatively small numbers of monitoring stations, n = 20, did an adequate job when well-distributed and when used to build models with only a few covariates. In general, winter data were easier to model and, across seasons, mean temperatures were easier to model than summer maximums, winter minimums, or variance. Adding new sites was advantageous but we did not observe major differences in model performance for particular new site locations. Adding sites from parts of the river network with thermal regimes which differed from the rest of the network, and which were therefore highly influential, improved nearby predictions but reduced model-estimated precision of predictions in the rest of the network. Lastly, using models which accounted for the network-based spatial correlation between observations made it much more likely that estimated prediction confidence intervals covered the true parameter; the exact form of the spatial correlation made little difference. By incorporating spatial structure between observations, SSNMs are particularly valuable for accurate estimation of prediction uncertainty at unmeasured locations. Based on our results, we make the following suggestions for designing water temperature monitoring arrays: (1) make use of pilot data when possible; (2) maintain a distribution of monitors across the stream network (i.e., over space and across the full range of covariates); (3) maintain multiple spatial clusters for more accurately estimating correlation of nearby sites; (4) if sites are to be added, prioritize capturing a range of covariates over adding new tributaries; (5) maintain a sensor array in winter; and (6) expect reduced accuracy and precision when predicting metrics other than means. [ABSTRACT FROM AUTHOR]

River classification is one of the recommendations of the European Water Framework Directive 2000/60/EC, which establishes that classifications should be carried out according to different variables hierarchically organized from a smaller to a larger scale. We suggest incorporating into the Directive’s hierarchical system a geoecological unit (lithotopo unit) that discriminates rivers with similar geomorphological features and ecological funtionality. The lithotopo units are not an alternative to the Directive typology, they are a complement intended to improve it. Our method is divided into two stages, the first focused on the development of LTUs and the second on their validation. We applied the concept of lithotopo units to a 30,000 km 2 region in the NW of the Iberian Peninsula (Spain) using a Geographic Information System and field work. Seven kinds of lithotopo units were identified for the study area, each with its own geomorphological processes and dynamics, and, as a consequence, particular associated habitats. Cartographic validation was done through the analysis of 122 sample sites distributed in eight basins. Of the five validation variables originally employed, specific stream power and median grain size are the two that yielded the best results. Each kind of lithotopo unit displays a range of values of specific stream power and median grain size that is internally homogeneous but different from that of the other units. The methodology thus produced, which can be applied to other regions, is transparent, objective and quantitative. [ABSTRACT FROM AUTHOR]

Fragmentation is a major threat to the integrity of stream ecosystems and maintaining connectivity is a primary goal for conservation to promote natural system functioning. In human dominated systems with extensive anthropogenic fragmentation, resource managers are faced with prioritizing restoration actions to provide the most cost-effective conservation strategies. Road crossings, particularly poorly designed culverts, limit fish passage and thus population connectivity and access to seasonally important resources. Culvert assessment protocols, such as the one developed by the North Atlantic Aquatic Connectivity Collaborative (NAACC), are useful tools for managers to evaluate culvert passability and prioritize restoration actions across broad spatial extents, however the justification of such protocols requires empirical field based investigations. In this study we collected Brook Trout genetic samples from 28 headwater streams, of which 17 were separated by a culverted road crossing and 11 were included as a comparison to natural genetic structuring. The objectives of this research were to 1) determine what effect culverts had on the genetics of Brook Trout populations, 2) evaluate the ability of the NAACC culvert assessment protocol to predict genetic patterns and 3) identify the culvert characteristics that best explained genetic variability. We found significant increases in genetic differentiation at sites with culverts compared to those without, but no differences in genetic diversity metrics. Although the NAACC classifications did not predict the extent of genetic differentiation, the openness ratio of culverts (cross sectional area/length) was significantly correlated, suggesting it may need to receive a higher weighting in assessment protocols. Our results highlight the necessity to match appropriate prioritization strategies with desired management objectives in order to design the most effective conservation actions. [ABSTRACT FROM AUTHOR]

Rivers provide many services to humans, however, globally, they have been historically impacted from over-exploitation for human needs. Such impacts are likely to increase into the future leading to poorer river health and the service functions provided by rivers are being lost. This study focused on the river health evaluation for river protection and sustainable water management. Eight indices were selected to structure an evaluation index system, consisting of physical, chemical, and biological elements, for river health evaluation. Among them, a new index, Ratio of Environmental flow to Streamflow (RES), was proposed to evaluate the satisfaction degree of environmental flow and to establish a common standard for the comparison of habitat quality among different rivers. A combined model consisted of fuzzy matter-element and projection pursuit models was established for the evaluation of river health, which was adopted to convert several indices in the evaluation index system to a comprehensive indicator. The Huai River Basin was selected as the case study area. The results showed that the river health of the whole Huai River was at the medium level. Four river reaches such as Reach I, II, IV and V were in the middle level, while only Reach III was at the sub-healthy level. This study is expected to provide scientific knowledge for the improvement of river health and water allocation. [ABSTRACT FROM AUTHOR]

In the present study, the ecological status of four major South Korean rivers flowing near industrial complexes is assessed using physico-chemical analyses and various descriptors based on benthic diatom assemblages. Principal component analysis conducted with physical and chemical variables singled-out four sites as more severely impacted (higher concentration of metals and total nitrogen, higher conductivity and biological oxygen demand), while the remaining 12 sites indicated less impacted conditions, although showing nutrient enrichment. Less-contaminated sites based on physico-chemical properties showed higher cell densities, higher richness and diversity, a larger proportion of live and healthy-looking diatoms, lower production of lipid bodies (in terms of number and size) and fewer teratologies than more-contaminated sites. Non-taxonomical metrics (cell heath status, cell size, lipid bodies and valve deformities) were in good agreement with traditional taxonomical metrics (assemblage structure, richness, diversity). Overall, water quality assessment based on diatom assemblages and diatom-based metrics had a good fit with the available physico-chemical data and agreed on the most impacted sites. However, additional sites showed signs of degradation based on the diatom metrics used. This suggests that the use of biotic indicators provides useful complementary information on the health status at the selected sites. [ABSTRACT FROM AUTHOR]

Hydrological indicators such as duration, frequency, magnitude, rate and timing of flow events are used to evaluate and, in models, predict the response of aquatic species to hydrological conditions. Hydrological models are generally optimized without considering specific species preferences by minimizing overall differences between observed and simulated flows using common hydrological objective functions. We hypothesize that hydrological models optimized to implicitly consider species’ flow preferences will yield more reliable predictors. To test this hypothesis, we developed a flexible evaluation method in which the hydrological model was optimized for different objective functions. We tested this concept for benthic invertebrates and selected seven species-relevant hydrological indicators as well as four objective functions based on commonly used hydrological performance criteria. Model parameterizations for these cases were assessed on their ability to reproduce an indicator-based performance criterion developed by applying feature scaling to the indicators. The results show that three indicator-based objective functions performed up to 14% better than the standard hydrological performance criterion KGE. When optimizing for individual or multiple indicators, we found that it is important to consider that other indicators are compromised. An evaluation of this trade-off showed a considerable range in indicator values and implausible indicator depictions. We conclude that optimizing hydrological models to depict species preferences most effectively requires consideration of different objective functions that are based on hydrological indicators. Doing so, instead of simply optimizing to standard hydrological objective functions, can yield a rewarding result in terms of a more species-tailored model parameterization and, ultimately, a better prediction of aquatic species. [ABSTRACT FROM AUTHOR]

Increasing demand for water and a desire for greater human water security has facilitated the global expansion of dams, with river regulation acknowledged as the leading cause of biodiversity decline in rivers. Native biota within these stressed systems are also impacted by reductions in habitat availability, decreased hydraulic diversity, increased sedimentation, movement barriers, invasive species and altered flows that may profoundly change the character and functioning of rivers. Construction or enlargement of reservoirs is continuing, and whilst downstream impacts are often considered, upstream impacts receive far less attention. We develop a population model to examine the impacts of reservoir expansion on a threatened riverine species in South Eastern Australia: the two-spined blackfish. We examined two processes, loss of breeding habitat and increased predation, directly linked to reservoir expansion as well as a broader threat of recruitment failure due to sedimentation. These threatening processes were assessed using the expected minimum population size as an indicator of risk. As is often the case for threatened species, limited data were used to parameterise the model and sensitivity analysis performed to assess the appropriateness of the model parameterisation. The outcomes indicate that the two-spined blackfish population is vulnerable to the loss of breeding habitat particularly if two-spined blackfish are unable to spawn in the larger dam, although this vulnerability is ameliorated if the whole river is accounted for. Including possible impacts from the resident trout population for the whole river, indicates the two-spined blackfish to be vulnerable to low level predation particularly if the trout population have a high growth rate. Population modelling has rarely been used to predict the consequences of dam construction on aquatic species/communities. The example here shows it to be a powerful tool to visualise and quantify potential biodiversity outcomes. [ABSTRACT FROM AUTHOR]

Global rivers connect three large carbon reservoirs in the world: soil, atmosphere, and ocean. The amount and spatial pattern of riverine carbon flux are essential for the global carbon budget but are still not well understood. Therefore, three linear regression models for riverine DOC (dissolved organic carbon), POC (particulate organic carbon), and DIC (dissolved inorganic carbon) fluxes were established with related generating and transfer factors based on an updated global database. The three models then were applied to simulate the spatial distribution of riverine DOC, POC, and DIC fluxes and to estimate the total global riverine carbon flux. The major conclusions of this study are as follows: the correlation analysis showed that riverine DOC flux is significantly related to discharge ( r 2 = 0.93, n = 109) and soil organic carbon amount ( r 2 = 0.60), POC flux increases with discharge ( r 2 = 0.55, n = 98) and amount of soil erosion ( r 2 = 0.48), and DIC flux is strongly linked to CO 2 consumption by rock weathering ( r 2 = 0.66, n = 111) and discharge ( r 2 = 0.63). In addition, Asia exports more DOC and POC than other continents and North America exports more DIC. The Atlantic Ocean accepts the major portion of riverine DOC, POC, and DIC fluxes of all the oceans. The highest riverine DOC flux occurs in the 0–30°S zone, and the highest riverine POC and DIC fluxes appear in the 30–60°N zone. Furthermore, re-estimation revealed that global rivers export approximately 1.06 Pg C to oceans every year, including 0.24 Pg DOC, 0.24 Pg POC, 0.41 Pg DIC, and 0.17 Pg PIC. [ABSTRACT FROM AUTHOR]

Aquatic macroinvertebrates have been the basis for one of the primary indicators and a cornerstone of lotic biomonitoring for over 40 years. Despite the widespread use of lotic invertebrates in statutory biomonitoring networks, scientific research and citizen science projects, the sampling methodologies employed frequently vary between studies. Routine statutory biomonitoring has historically relied on semi-quantitative sampling methods (timed kick sampling), while much academic research has favoured fully quantitative methods (e.g. Surber sampling). There is an untested assumption that data derived using quantitative and semi-quantitative samples are not comparable for biomonitoring purposes. As a result, data derived from the same site, but using different sampling techniques, have typically not been analysed together or directly compared. Here, we test this assumption by comparing a range of biomonitoring metrics derived from data collected using timed semi-quantitative kick samples and quantitative Surber samples from the same sites simultaneously. In total, 39 pairs of samples from 7 rivers in the UK were compared for two seasons (spring and autumn). We found a strong positive correlation ( r s = +0.84) between estimates of taxa richness based on ten Surber sub-samples and a single kick sample. The majority of biomonitoring metrics were comparable between techniques, although only fully quantitative sampling allows the density of the community (individual m −2 ) to be determined. However, this advantage needs to be balanced alongside the greater total sampling time and effort associated with the fully quantitative methodology used here. Kick samples did not provide a good estimate of relative abundance of a number of species/taxa and, therefore, the quantitative method has the potential to provide important additional information which may support the interpretation of the biological metrics. [ABSTRACT FROM AUTHOR]

Freshwater macroinvertebrates have been extensively used as environmental indicators and are the most prevalent biological group used in aquatic bioassessment in the European Water Framework Directive (WFD 2000/60/EEC), usually through several popular indices, as the Biological Monitoring Working Party (BMWP). Many of these indices are based on taxa richness, i.e. the number of taxa present in a given area, as the simplest and most common measure of biodiversity. Given the importance to the WFD of the ecological status assessment by macroinvertebrates and the consequences thereof, sampling requires careful consideration and evaluation of the associated uncertainty. In this work, carried out in a Mediterranean river, we show that after 20 sample “kicks” it was possible to estimate the true taxa richness using Clench nonlinear asymptotic models (CM). However, cumulative curves of taxa extracted with kick sampling underestimated the true number of theoretical taxa (A). In order to achieve an acceptable error a very large sample size was required, always >20 kicks. According to these criteria, sampling was clearly inefficient in most localities. The minimum effort required to achieve a significant and acceptable level of taxa richness, for 90% of A, should be between 25 and 71 kicks and for 95% of A, 52–150 kicks. Both satisfactory percentages represent a mean difference of 2 (range 0–6) and 3 (range 1–8) taxa actually not being captured from the total predicted for each locality, for 90 and 95% of the CM asymptote, respectively. This study shows that by using the 20 kicks methodology it is possible to achieve reliable true macroinvertebrate richness estimates, but the establishment of the community composition, i.e. the full taxa making up any index score, will be inaccurate to an unknown degree. [ABSTRACT FROM AUTHOR]

There is a need for sensitive bio-monitoring and indicator tools in toxicant impact assessment to show the effect on fish health. Histopathological assessment of fish tissue is a bio-monitoring tool allowing for early warning signs of disease and detection of long term injury in cells, tissues or organs. The aims of this study were firstly to determine and compare the health status of the tigerfish ( Hydrocynus vittatus ) from two lowland rivers in Kruger National Park (KNP), secondly to attempt to explain the histological changes observed, through the application of a suite of multivariate statistics to relate changes to biotic levels of selected metals and organochlorine pesticides (OCPs) and thirdly to determine the suitability of H. vittatus as a bio-indicator of riverine health. Tigerfish were caught using rod and reel from the Olifants (n = 37) and Luvuvhu Rivers (n = 34) between 2009 and 2011. The histology-based fish health assessment (liver, kidney, gills and gonads) indicated that fish were in relatively good health. Even though fish were considered to be healthy, the general fish health in both rivers improved over time, corresponding to an overall decrease in river pollution, most notably in terms of metals. The incorporation of multiple lines of evidence in tigerfish, including histopathological changes and organ and whole organism indices, proved to be a valuable tool in using a bio-indicator approach toward river monitoring. These histopathological changes serve as an early warning system to more serious health concerns arising if the pollution in the rivers of the KNP is not dealt with. The use of a suite of uni- and multivariate statistics proved helpful in determining the links between fish health and river contamination and further proved to be a valuable tool in assessing spatial and temporal differences in river pollution and the effects thereof on the selected bioindicator. [ABSTRACT FROM AUTHOR]

• A new hybrid model DC-LSTM for daily streamflow forecasting is developed. • The model is examined for streamflow forecasting in different climate regions. • Integrating LSTM and dynamic classification can improve the performance of streamflow forecasting. • Box -Cox data transformation can further improve model performance in arid regions. Daily streamflow forecasting is a major determinant of ecological processes in running waters, healthy stream ecology and surrounding environment, and accurate streamflow forecasting provides a powerful foundation for ecological assessment, management, and decision-making. Recently, data-driven models for different flow regimes have shown excellent potential in streamflow forecasting. However, the boundaries between different flow regimes were selected arbitrarily without considering the changes in boundaries that often occur over time in the real world. Therefore, in this paper, an integrated modelling approach that couples a dynamic classification method with a long short-term memory networks (LSTM) model without data transformation (the DC-LSTM model) and an LSTM with Box-Cox data transformation (the DC-B-LSTM model) is developed to improve the performance of streamflow forecasting considering different flow regimes. The boundaries of dynamic classification are dynamic changing interval values of related hydrological variables improved from traditional classification method just using static single-variable threshold, so dynamic classification can more fully explore the relationship and information of hydrological data. The performance of both the DC-LSTM and DC-B-LSTM models is compared to that of the LSTM model without data classification (the traditional LSTM model) and with data classification using a traditional static method (the C-LSTM model) based on data from 8 stations within 4 river basins in different climate regions in the United States. The results show that both the DC-LSTM and DC-B-LSTM models out-perform the traditional LSTM models (with or without static data classification) for all river basins considered. Furthermore, the DC-B-LSTM model displays better performance than the DC-LSTM model in arid areas. [ABSTRACT FROM AUTHOR]

• Identification of indicator genera for flow provides important ecological information for large river benthic macroinvertebrate assemblages. • Taxa Indicator Threshold Analysis was applied on benthic macroinvertebrate monitoring data in a large river in Eastern Canada • Flow velocity was strongly associated with the distribution and relative abundance of benthic macroinvertebrates. • Hydraulic-habitat thresholds and taxa associations were linked to alternative flow scenarios. Holistic environmental flows frameworks are built on our understanding of key flow-ecology relationships that support sensitive taxa and critical ecosystem functions under different flow and water level scenarios. Most research on flow-ecology relationships has typically focused on small systems, with less known about flow associations, indicator taxa, and environmental thresholds of assemblage change along hydraulic gradients of large non-wadeable rivers. We assessed benthic macroinvertebrate assemblage structure and applied Taxa Indicator Threshold ANalysis (TITAN) on biomonitoring data collected during a six-year period in the Wolastoq | Saint John River in Atlantic Canada. Flow velocity was strongly associated with the distribution and relative abundance of benthic macroinvertebrates in the river, and taxon associations reflected functional adaptations to flow. We identified 33 genus-level indicator taxa that were either positively or negatively associated with flow velocity. Weaker taxa responses were shown for the gradient in median substrate particle size where 22 negatively and positively responding taxa were identified. We predicted changes in indicator taxon abundance under different flow scenarios using a hydrodynamic model, and characterised the distribution and availability of suitable hydraulic habitat patches within a 20 km reach downstream of a large hydropower generating station. These observations set the stage for the development of ecologically-based flow targets to support holistic environmental flow management in large rivers. [ABSTRACT FROM AUTHOR]

Anthropogenic modifications of sediment load can cause ecological degradation in stream and river ecosystems. However, in practice, identifying when and where sediment is the primary cause of ecological degradation is a challenging task. Biological communities undergo natural cycles and variation over time, and respond to a range of physical, chemical and biological pressures. Furthermore, fine sediments are commonly associated with numerous other pressures that are likely to influence aquatic biota. The use of conventional, non-biological monitoring to attribute cause and effect would necessitate measurement of multiple parameters, at sufficient temporal resolution, and for a significant period of time. Biomonitoring tools, which use low-frequency measurements of biota to gauge and track changes in the environment, can provide a valuable alternative means to detecting the effects of a given pressure. In this study, we develop and test an improved macroinvertebrate, family-level and mixed-level biomonitoring tool for fine sediment. Biologically-based classifications of sediment sensitivity were supplemented by using empirical data of macroinvertebrate abundance and percentage fine sediment, collected across a wide range of temperate river and stream ecosystems (model training dataset n = 2252) to assign detailed individual sensitivity weights to taxa. An optimum set of weights were identified by non-linear optimisation, as those that resulted in the highest Spearman’s rank correlation coefficient between the index (called the Empirically-weighted Proportion of Sediment-sensitive Invertebrates index; E-PSI) scores and deposited fine sediment in the model training dataset. The family and mixed-level tools performed similarly, with correlations with percentage fine sediment in the test dataset ( n = 84) of r s = −0.72 and r s = −0.70 p < 0.01. Testing of the best performing family level version, over agriculturally impacted sites ( n = 754) showed similar correlations to fine sediment ( r s = −0.68 p < 0.01). The tools developed in this study have retained their biological basis, are easily integrated into contemporary monitoring agency protocols and can be applied retrospectively to historic datasets. Given the challenges of non-biological conventional monitoring of fine sediments and determining the biological relevance of the resulting data, a sediment-specific biomonitoring approach is highly desirable and will be a useful addition to the suite of pressure-specific biomonitoring tools currently used to infer the causes of ecological degradation. [ABSTRACT FROM AUTHOR]

Abstract Xiong et al. (Ecological Indicators, 85, 2018, 861–868) recently published a paper testing the application of taxonomic and numerical surrogacy of rotifers in a Chinese heavy polluted river ecosystem. Despite interesting and useful results being presented in the study, some errors and flaws can still be identified. A number of mistakes in taxonomic information have affected the accuracy of the results involving taxonomic surrogates. The second concern is the inappropriate statistical treatment applied in the redundancy analysis models in this study. Here we report that the accuracy of family-level surrogate was underestimated due to the undervalued family number of rotifer assemblages. The performance of the family-level dataset in reproducing patterns of species-level assemblage, although it remains poorer compare to the genus-level surrogate, might be better accepted, especially in the two more severely disturbed regions (zone II and zone III). [ABSTRACT FROM AUTHOR]

This study aims to discuss the seasonal and spatial dynamics of fish assemblage of River Soan in relation with environmental changes. Survey was conducted during pre monsoon and post monsoon seasons in 2008. Physico chemical and biological samplings were carried out at 26 sites which were selected along the whole stretch of the river. High concentration of total phosphorous and conductivity, low pH and dissolved oxygen were measured at urban part of midstream zone whereas high concentration of total nitrogen was measured at downstream zone. A total of 22 species were collected during the survey among which Barilius pakistanicus , Puntius ticto , Crossocheilus diplochilus and Labeo dero were distributed throughout the river stretch. Maximum fish diversity was recorded at suburban part of midstream while its urban part was appeared to be the most species poor part of the Soan River. Herbivore individuals constituted the dominant trophic group of fish assemblage. Significant seasonal and spatial changes in fish assemblage were determined at river downstream. Upstream- downstream differences in fish assemblage were more pronounced during pre monsoon and seem to be related to thermal gradient and hydrological changes. Seasonal variations in fish assemblage were significant only at downstream zone and were influenced by velocity, floodplains and migration patterns in fish assemblage. Understanding of spatial and seasonal trends in fish assemblage in relation with their environment is of great importance for the management and conservation of fish assemblage. Findings of this study will be helpful in future attempts to restore and conserve the aquatic assemblages of Himalayan streams. [ABSTRACT FROM AUTHOR]

The method used to calculate ecological compensation remains an important but difficult issue in current studies of ecological compensation. In this study, we used the ecological compensation method to examine the natural, social, and economic interactions between ecological and economic systems at the administrative level and between upstream and downstream areas in a river basin, with the aim of capacity control in the total amount of pollutants discharged. We used the information entropy method to build the total pollutant allocation model, in which we included a range of indexes that reflected regional heterogeneity in factors such as population, economic structure, production level, pollution control, and the water environment. The relationship between the capital invested and the quantity of pollutants discharged was used to calculate the unit value of the pollutants, from which we constructed a quantitative model of ecological compensation standard for river basin water environment based on total pollutants control. We used the Xiao Honghe River Basin, China, as a case study, and calculated the ecological compensation values of the water environment from 2008 to 2012 with chemical oxygen demand (COD) as the main pollution evaluation index. From the upper to lower reaches, the compensation value gradually decreased while it gradually increased in terms of time scale. This study provides a valid approach that can be applied to develop a long-term effective mechanism for protecting river basin ecology and improving the system of ecological compensation in river basins. [ABSTRACT FROM AUTHOR]

Achieving sustainable freshwater resource management and conserving biodiversity require accurate and reliable pollution impact assessment. Biomonitoring is an integrative and holistic approach to assessing impact of pollution using biological indicators. In this study, we use the assemblage structure of the freshwater macroinvertebrate family Chironomidae to assess the impact of pollution in a South African river: the Swartkops River. Based on morphological deformities in the mentum of selected genera, we developed a new index, the extended toxic score index (ETSI), to assess the extent of deviation of ecological conditions at the impacted sites from that at the control site. Four sites i.e. Sites 1–4 characterised by different degrees of pollution were selected for chironomids and physico-chemical sampling over a period of three years (August 2009–September 2012). The ETSI was developed by taking into account the severity of deformities, and genera tolerances to pollution. The index was based on the deformities in the mentum of the five most dominant genera: Chironomus , Polypedilum , Tanytarsus , Dicrotendipes and Cricotopus . The values of nutrients, electrical conductivity and turbidity were elevated, and dissolved oxygen depleted at Sites 2, 3 and 4 compared with Site 1. Metal concentrations in the water column were relatively low (<0.3 mg/l). Site 1, i.e. the control site, supported more chironomid species (30 species). Site 2, situated upstream of the Kelvin Jones wastewater effluent discharge point, but influenced by diffuse pollution sources, had more species (22 species) than Sites 3 (10 species) and 4 (18 species). The species assemblage structure clustered largely by sites than by seasons, with the assemblage at Site 1 distinct to those at Sites 2, 3 and 4. The newly developed ETSI was sensitive to pollution, distinguishing between the ecological conditions at the sampling sites. The index placed Site 2 in Category D, indicative of poor ecological condition and Sites 3 and 4 in Category E, indicative of very poor conditions. We found the ETSI to be an appropriate and useful deformity-based tool for biomonitoring, and it can easily be modified and used in other river systems, both locally and internationally. [ABSTRACT FROM AUTHOR]

Rivers export nutrients to coastal waters. Excess nutrient export may result in harmful algal blooms and hypoxia, affecting biodiversity, fisheries, and recreation. The purpose of this study is to quantify for European rivers (1) the extent to which N and P loads exceed levels that minimize the risk of harmful algal blooms and (2) the relative shares of sources of N and P in rivers. This may help to identify effective management strategies to reduce coastal eutrophication. We focus on 48 rivers in 27 countries of the European Union (EU27). We used the Global Nutrient Export from Watersheds ( NEWS ) model to analyze nutrient export by rivers and the associated potentials for coastal eutrophication as reflected by Indicator for Coastal Eutrophication Potential (ICEP). In 2000, 38 of the 48 EU rivers indicated in our study had an ICEP > 0, indicating a relatively high potential for harmful algal blooms. These 38 rivers cover 60% of EU27 land area. Between 2000 and 2050 nutrient export by European rivers is projected to decrease. However, by 2050 still 34 EU rivers, covering 48% of the land area, have an ICEP > 0. This indicates that in these scenarios little progress is made in terms of environmental improvement. About one-third of the rivers with ICEP > 0 are N limited, and about two-thirds P limited. In N-limited rivers reducing N loads is a more effective way to reduce the risk for coastal eutrophication than reducing P, and vice versa. For N-limited rivers agriculture or sewage are the dominant sources of nutrients in river water. In P-limited rivers, sewage is found to be the dominant source of P, except for rivers draining into the Atlantic Ocean, where agriculture can also be dominant. A basin-specific approach is needed to effectively reduce N and P loads. [ABSTRACT FROM AUTHOR]

Fine sediments in excess of natural background conditions are one of most globally common causes of stream degradation, with well documented impacts on aquatic communities. The lack of agreement on methods for monitoring fine sediments makes it difficult to share data, limiting assessments of stream conditions across jurisdictions. We present a model that circumvents these limitations by inferring fine sediments in Oregon streams through sampling of macroinvertebrates. Tolerances to fine sediments (<0.06 mm diameter) were calculated for 240 macroinvertebrate taxa, from a calibration dataset of 446 sites across Oregon, as well as an independent validation dataset of 50 samples. Weighted averaging methods were used to infer fine sediment levels in streams by weighting the tolerances of modeled taxa observed in a sample by their abundances. The final model, the Biological Sediment Tolerance Index (BSTI), showed a strong relationship to measured fine sediments (calibration r 2 = 0.49, validation r 2 = 0.58). Root-mean-squared-error was small in the calibration dataset (2% fines), but larger in the validation dataset (14% fines). Repeatability was assessed by examining variability in BSTI at 14 sites across Oregon. Because field methods for sampling macroinvertebrates are standardized across resource agencies in Oregon and the responses of macroinvertebrates represent the actual effects of fine sediments on stream ecosystems, the BSTI may offer water resource managers’ a cost-effective method for assessing fine sediment conditions in their ongoing efforts to improve water quality across the state. [ABSTRACT FROM AUTHOR]

Since the mechanisms of eutrophication are complicated and many other factors affect these mechanisms, methods such as quantitative statistics and numerical simulation, have their limitations in analyzing the spatiotemporal relations of eutrophication. The rough set theory (RST) was used to describe the spatiotemporal relations of eutrophication in Da’ning River without any of other prior knowledge. Rules of relations in time and space affecting eutrophication in the Da’ning River backwater area were extracted by taking representation of relations in time and space among eutrophication at a long river section of Da’ning River backwater area, by taking nine sets of encrypted monitoring data in 2003 as example, and by making season, area and eutrophication level as the decision attributes, respectively, to represent specific features of the eutrophication phenomenon in the Da’ning River backwater area from the points of view of time, space, and level by analysis of spatiotemporal relationship rules. This study result shows that the temporal and spatial differences between eutrophication phenomena in the long river section of the Da’ning River backwater area are significant. Eutrophication for each section is less serious in autumn, more in spring and most in summer. Eutrophication degree gradually decreases from estuary to upstream, which is in conformity with reality. The RST of eutrophication in Da’ning River may inform environmental decision-makers and assist them in making more cost-effective decisions. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems are declining faster than their terrestrial and marine counterparts because of physical pressures on habitats. European legislation requires member states to achieve ecological targets through the effective management of freshwater habitats. Maps of habitats across river networks would help diagnose environmental problems and plan for the delivery of improvement work. Existing habitat mapping methods are generally time consuming, require experts and are expensive to implement. Surveys based on sampling are cheaper but provide patchy representations of habitat distribution. In this study, we present a method for mapping habitat indices across networks using semi-quantitative data and a geostatistical technique called regression kriging. The method consists of the derivation of habitat indices using multivariate statistical techniques that are regressed on map-based covariates such as altitude, slope and geology. Regression kriging combines the Generalised Least Squares (GLS) regression technique with a spatial analysis of model residuals. Predictions from the GLS model are ‘corrected’ using weighted averages of model residuals following an analysis of spatial correlation. The method was applied to channel substrate data from the River Habitat Survey in Great Britain. A Channel Substrate Index (CSI) was derived using Correspondence Analysis and predicted using regression kriging. The model explained 74% of the main sample variability and 64% in a test sample. The model was applied to the English and Welsh river network and a map of CSI was produced. The proposed approach demonstrates how existing national monitoring data and geostatistical techniques can be used to produce continuous maps of habitat indices at the national scale. [ABSTRACT FROM AUTHOR]

Assessing the ecological impacts of anthropogenic pressures is a key task in environmental management. Multimetric indices (MMIs), based on aquatic assemblage responses to anthropogenic pressures, have been used increasingly throughout the world. The MMI approach is a low-cost, rapid field method that produces an aquatic condition index that responds precisely to anthropogenic pressures, making it useful for conservation and environmental management. We developed four candidate MMIs based on benthic macroinvertebrate assemblages sampled at 40 randomly selected sites to assess the environmental condition of streams upstream of a hydroelectric power plant in the Brazilian Neotropical Savanna biome. Those MMIs were built from landscape-adjusted and unadjusted biological metrics as well as two alternative ways of choosing metrics. The alternative MMIs performances were tested by comparing their precision to distinguish least-disturbed areas, responsiveness to discriminate least- and most-disturbed areas, and sensitivity to anthropogenic pressures at catchment and local scales. The best performing MMI had landscape-adjusted metrics and was produced through use of principal component analysis for metric selection. It included 4 metrics: Ephemeroptera richness, average tolerance score per taxon, percentage of predator individuals, and percentage of Odonata individuals adjusted by elevation. This index discriminated well the anthropogenic pressures at local- and catchment-scales, and at both scales simultaneously, as indicated by an integrated disturbance index. Our methodological development included statistical criteria for identifying least- and most-disturbed sites, calibrating for natural landscape variability, and use of non-redundant metrics. Therefore, we expect it will provide a model for environmental assessment of water resources elsewhere in Brazil and in other nations. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the responses of diatoms, macroinvertebrates and fish to agriculture, urbanization and mining in the Manyame River Basin. Water quality sampling and benthic diatom, macroinvertebrate and fish community data were collected in April (end of the rain season) and September (dry season) 2013 at 44 sampling stations spread out across three land-use categories: commercial agricultural, communal agricultural and urban-mining areas. Commercial agricultural areas were relatively pristine as they were characterized by mature deciduous riparian forest strips which acted as riparian buffers thus protecting water resources from nonpoint source pollution. In communal agricultural areas a combination of poor agricultural practices (stream bank cultivation, overgrazing, soil erosions) and high human population densities had negative effects on water quality of streams draining these areas. Streams in urban-mining areas were highly stressed, being impacted primarily by physical habitat degradation and both point and nonpoint sources of pollution. A suite of environmental variables that varied with land-use pattern was assessed to find the combination of variables that best explained patterns of biota community composition. Community metrics i.e. the Trophic Diatom Index (TDI) based on diatoms, the South African Scoring system version 5 (SASS 5) based on macroinvertebrates and the Fish Assemblage Integrity Index (FAII) were used to determine the ecological status of study streams in relation to human-induced stressors. Data were also subjected to multivariate statistical techniques; canonical correspondence analysis (CCA), mantel test and cluster analysis to determine environmental gradients along which the diatom, macroinvertebrate and fish assemblages were distributed as well as to elucidate hypothesized differences in response to stressors among communities per land-use type. Using CCA, we assessed the individual importance of a set of environmental variables on each biotic community structure. ANOVA, showed a significant difference ( p < 0.05) in physical and chemical variables among commercial agricultural, communal agricultural and urban-mining sampling stations with no significant differences ( p > 0.05) between the 2 sampling periods. Based on CCAs carried out using individual variables, the strengths of relationships between diatoms and macroinvertebrates was generally high for nutrient levels, organic and metal pollution and other variables. However, fish assemblages showed a relatively low association with all water quality variables in the study; this might be explained by the high abundance of omnivores and air breathers which are able to tolerate a variety of environmental conditions. These patterns were also confirmed by the mantel test as well as the other CCAs carried out to investigate the simultaneous effects of environmental variables. These findings indicate that diatoms are more powerful indicators in accessing ecological stream/river quality and have potential for application in routine monitoring programs in tropical streams. [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]

There are several methodologies for the characterization and evaluation of river habitats. The scientific community has made a great effort in designing the best indexes for this purpose, and they have also been tested in different countries and rivers. Nevertheless, there has not been a transfer of that knowledge to land managers of these spaces or, at least, to those who design improvement and restoration measures. The aim of our research was the assessment of the Riparian Forest Quality Index (QBR), the “Riparian Quality Index” (RQI) and the “Fluvial Habitat Index” (IHF) as indicators of the ecological status of fluvial habitats and their application in restoration projects. The main results of this study were that the IHF index could be used as a support resource and as a monitoring tool to assess the habitat heterogeneity before and after any action is taken. However, when we evaluated the QBR and RQI indexes, the best results were with the first one. The total QBR suggests the urgency level of restoration in the section that is evaluated, and each of its sub-indexes identifies which element of the river is affected. Therefore, it will be a useful tool in decision making for the conservation of these characteristic spaces, especially for engineers who, as a result of their experience in biological and ecological processes, are involved in the design and building of ecosystems, particularly in rivers and on their banks. [ABSTRACT FROM AUTHOR]