Arctic freshwater biodiversity is rapidly changing due to climate warming, resource extraction, infrastructure development, and landscape transformation. To improve understanding, predict future responses, and inform policy formulation, research needs must be clearly identified. Using a horizon scan survey, Arctic freshwater experts from government, international agencies, and Indigenous Peoples identified 77 biodiversity research questions with 17 highlighted as most important for near term assessment. These questions span nine thematic categories: biodiversity and taxonomic challenges, hydrological change, productivity and food webs, ecosystem connectivity, methods, monitoring and assessment, permafrost change, winter ecology, anthropogenic development, and Indigenous Knowledge. Climate change emerged as the major driver among all categories and research questions. A key priority identified was the urgent need for long-term, harmonized monitoring programs among Arctic countries. Multiple knowledge gaps detected suggest that circumpolar research collaborations are required to tackle these issues.

Shifts in hydroclimatic regimes associated with global climate change are affecting the timing and duration of winter ice-cover in temperate and high-latitude lakes. Less is known on how associated changes in ice quality potentially affect under-ice ecological processes and related biogeochemistry, particularly in shallow lake systems. This experimental study examined how differing surface ice-cover types (slushed white ice, unmanipulated ice formation [black], snow-on-ice) affected under-ice light and oxygen regimes and associated chlorophyll a concentrations, and water quality parameters using a combination of aboveground mesocosms and natural ponds over two consecutive winter seasons. In both systems, light transmission under white ice did not differ significantly from black but was significantly greater than snow-on-ice. Measures of light extinction coefficients taken at the ice-water interface in the experimental ponds increased for black, white, and snow-on-ice, respectively, with all values being above thresholds for autotrophic activity. Under-ice dissolved oxygen levels in all mesocosm ice treatments increased continually over time with increasing day length, peaking prior to ice off. Accumulated DO levels were aligned with observed chlorophyll a concentrations, with peaks early after ice onset, and decreases as winter progressed though patterns differed between years. No significant differences were observed in mean chlorophyll a levels in snow-removed treatment ponds, regardless of whether white or black ice was present while the snow-on-ice ponds displayed consistently lower levels. This study highlights the complexities and importance of using manipulative experimental approaches to advance our understanding of how alterations in surface ice-cover quality affect under-ice hydro-ecological processes.

Winter lake ice conditions are undergoing rapid changes because of alterations in global and regional hydroclimatic conditions. The traditional understanding of lake ice growth and evolution through a winter period is the downward progression of ice until air temperatures rise and melt, and breakup ensues. A unique meteorological condition of substantial mid-winter warming in the foothills of the Canadian Rockies allowed for the identification of a phenomenon where a liquid water layer was trapped between ice layers near the surface of a lake. Phytoplankton analysis identified that the interstitial water layer had a bloom of motile phytoplankton belonging to the order Chlamydomonadales. Stable isotopes suggest the upward movement of pelagic water in combination with landscape runoff contributed to the formation of the interstitial water layer. This study provides new insights and illustrates the complexities involved in understanding the physicochemical and biological mechanisms involved in shaping the winter ecology, as well as subsequent ice-free periods, of lakes under a changing climate.

Multistakeholder Science Committees (MSC's) are increasingly used to inform science assessments and syntheses supporting the development of environmental regulations and policies. By bringing together a diversity of pertinent rights holders and stakeholders they can create holistic and inclusive outcomes that would not otherwise be produced if participants are drawn from a narrow range of expertise and jurisdictional representation. However, MSC's also create notable challenges. As practitioners and leaders of a multitude of MSC's, we draw from our collective experiences to identify key steps we feel will ensure high performance of MSC's. We highlight the importance of recognizing the mandate letter and developing a jointly agreed‐upon Terms of Reference (TOR) and then identifying specific aspects related to: (i) roles and responsibilities of participants; (ii) founding principles required to enable the work of a MSC; (iii) acceptable behaviours for MSC members; and (iv) mechanisms to assess the consequences when undesired behaviours and actions are displayed. We also identify actions and behaviours that will most likely result in the failure of the MSC. Practical implication: The ability to diagnose the underlying causes of challenges to MSC's performance, provides opportunities to resolve them so that the performance can be improved and undesirable actions and behaviours are minimized or avoided.

Municipal wastewater effluent (MWWE) is a common source of nutrient enrichment and provides a route for emerging substances of concern (ESOCs) to enter aquatic systems. Community composition and abundance metrics of benthic macroinvertebrates are commonly utilized to assess ecological impacts associated with nutrient enrichment; however, the responses of these metrics in systems with diverse chemical mixtures from MWWE, are not well understood. This study specifically addresses the effects of cumulative loading of tertiary-treated MWWE through responses in benthic macroinvertebrate communities in experimental control and treatment streams. Treatment streams used source river water previously exposed to upstream wastewater treatment plants but with an additional 5% by volume tertiarily treated MWWE, while control streams used only source river water. Surbers and artificial substrate rock baskets were used to examine impacts on both established and colonizing benthic communities, respectively. No significant differences were observed between the control and treatment streams in any of the community metrics of well-established benthic communities. In contrast, significant decreases in colonizing taxon diversity and evenness were found between treatment and control streams. The dominant taxa (most abundant family, by percentage of sample) in the community, often filter feeders, significantly increased in percentage of the total community in treatment streams. This response was consistent with a nutrient enrichment effect, with no evidence of ESOC related toxicity. This study highlights the need for bioassessment programs to utilize approaches involving varied in-situ sampling methods and controlled exposure systems to gain a better understanding of how various stages of community-level development are impacted by urban pollutants such as MWWE.

Athabasca oil sands in Alberta, Canada, are large bitumen deposits and are one of the world's largest petroleum reserves. This research contributes to the growing body of knowledge on the influence of this naturally occurring bitumen on freshwaters. Using laboratory-based exposure studies, we examined the life cycle responses of the aquatic midge Chironomus riparius to both naturally formed solid bitumen incorporated in the sediment and its corresponding aqueous extracts, denominated as elutriates. The 28-day partial life cycle assay involved bitumen samples from two distinct geological origins in the Athabasca River Basin (Clearwater and McMurray formations), comprising both weathered and freshly collected bitumen from a total of 4 different rivers. Our results demonstrate a measurable impact of sediment-embedded bitumen on C. riparius life history traits, namely on their growth and emergence patterns. Furthermore, we observed that bitumen samples from the Ells River (McMurray formation), which were freshly collected from exposed river bank soil deposits, exerted the strongest effects on most studied eco-physiological endpoints. Bitumen extracts from the Steepbank River and Athabasca River in the McMurray Formation and Steepbank River in the Clearwater Formation followed, underscoring the geographical variance in bitumen-induced toxicity. Exposure to elutriates, simulating "weathered" bitumen generally did not induce adverse effects in C. riparius life-cycle endpoints compared to elutriates prepared from freshly eroded bank soils. This emphasizes the importance of considering bitumen sources, their age, and the aquatic receiving environment when assessing potential adverse exposure effects. Our study shows that exposure to freshly eroded soils/sediments can potentially affect benthic invertebrates. More research is needed to understand how hydrological changes affect bitumen sediment exposure and the associated risks to aquatic biota.

To fully understand the ecological and cumulative effects of mining activities on the surrounding aquatic systems of the Canadian oil sands region, it is essential to understand the consequences of exposure to bitumen-containing soils/sediment from natural geomorphological processes. Both physical and chemical stress on aquatic biota can potentially result from exposure to natural bitumen, resulting from hillslope erosional processes and slumping of bankside soils into the rivers, affecting both riverbed habitat and water quality. The magnitude and duration of bitumen-containing soil's fluvial soils/erosional input into receiving watersheds depends on the interannual variability in the regional hydroclimatology and related seasonal and extreme flow events. The primary objective of this study was to evaluate the potential ecotoxicological effects associated with erosional input of riverbank bitumen soils using controlled exposures. A series of integrated, laboratory-based ecotoxicological bioassays were conducted using organisms with different ecological and functional traits (Daphnia magna (Cladocera), Physa acuta (Gastropoda), and Aliivibrio fischeri (Bacteria)). All model organisms were exposed to elutriates produced from natural bitumen from four different regional rivers: fresh bitumen from shoreline outcrops at the Steepbank River upper and lower reaches (STB-CF and STB-MF, respectively) and the lower-Ells River (EL-MF) and aged, fluvially processed/weathered bitumen from the shoreline of the Athabasca River (ATB-MF). All tested organisms responded negatively to STB-MF and EL-MF elutriates. Low toxicity was also observed in the STB-CF and ATB-MF samples. These results follow the chemical analysis of the parental material and elutriates, where higher levels of metals, polycyclic aromatic compounds and naphthenic acids were detected in the EL-MF sample. In summary, this study shows that eroded and transported bitumen-containing soils and sediments could be a natural source of contaminant exposure to aquatic biota. This fluvial pathway should be considered when assessing background toxicity and the toxicological and ecological effects of oil sands mining activities.

Multiple stressors resulting from anthropogenic actions are increasingly recognized as a major threat to aquatic ecosystems. In general, ecosystems change as they respond to multiple threats that interact in complex ways, depending on the natural environment. This scenario poses complex tasks for researchers, managers, and policymakers, which require a well-defined framework to provide a clear roadmap that identify steps to apply in adaptive management decisions, monitoring designs and policy implementation. Building upon core elements of previous work, we present a Multiple Stressors Assessment Framework (MSAF) for aquatic ecosystems that provides a roadmap on the achievement of an improved integration between monitoring designs, data acquisition, evaluation processes, and management actions. The MSAF involves seven steps: 1) problem formulation and the definition of the ecosystem type and the spatial-temporal scale, 2) data compilation on the ecosystems' environmental characteristics and the definition of the type, identity and intensity of environmental stressors, 3) data compilation/collection on the biological/ecological receptors (endpoints) to stressors and selection of response variable to monitor (based on structure-based indicators and functional metrics), 4) characterization of the stressor-response relationships and their interactions, 5) construction of specific ecological conceptual models and choice of adequate statistical approaches to test the conceptual models' viability, 6) generation of hypotheses on interactive effects on biological/ecological endpoints, validation of models, hypotheses testing and, if possible, comparison of results with controlled experiments in realistic settings, and 7) recommendations to adaptive monitoring and if necessary, improvement of the study design, and eventual inclusion of other hypotheses and statistical approaches in the context of adaptive management actions. We review progress made in Europe, the USA and Canada in this field using case examples, highlight the approaches taken by the different jurisdictions that align with our framework and identify the linkages between multiple stressors assessments and decision-making for each region. We conclude that a disconnection remains between the investigation of the combined effects of multiple stressors and the implementation of management practices and policy translation. The way forward is through a collaborative effort to create standardized methodologies and appropriate programmes in this field. We hope the proposed framework can be used as a foundation to diagnose multiple stressor interactions and identify responses of ecological indicators to inform effective adaptive management of freshwater ecosystems globally.

Data analysis is one of the most relevant steps of aquatic benthic environmental monitoring and research studies, and should be a fundamental consideration in both the planning (i.e., defining appropriate sampling design strategies) and implementation phases (i.e. application of appropriate standardized sampling procedures). A common objective of these studies is to identify relationships between environmental stressors and benthic bioindicator metrics. However, assessing these relationships is a complex process. Multivariate regression model adjustment coupled with forward and backward model selection routines is an appropriate complementary statistical analysis tool to test for the existence of statistically significant associations between a nonautocorrelated biological response and each variable within a group of environmental covariates included in a model. With this in mind, we developed SDesti, a user-friendly R package to analyze benthos data (number of individuals, biomass, chlorophyll concentration, or biological indices, excluding beta diversity metrics). SDesti contains four user accessible functions. AnalysisDescriptives() and Estimation() give information on the quality, homogeneity and representativeness of the data for one sampling campaign for one site. TimeLineAnalysisDescriptives() performs the descriptive analysis that usually precedes the adjustment of a regression model. TimeLineAnalysis() automatically adjusts an adequate regression model (linear, Poisson, quasipoisson, or negative binomial) and also returns the necessary measures and graphics to evaluate the quality of the adjustment and verify the model assumptions. SDesti greatly simplifies the process of data analysis and can be easily used by non-statisticians. The analytical package includes a complete manual that provides detailed information: on the data structure requirements, on the variable nomenclature rules and program operating procedures, on the data analysis (complemented with examples) and on the interpretation of the results (type??SDesti on R console). SDesti eliminates redundancy, reduces human error and, coupled with a suitable sampling design, standard sampling and sample treatment procedures, it contributes to improve the consistency of the results in environmental studies. SDesti for windows operating systems and installation instructions can be accessed at: https://www.doi. org/10.17632/3h8347w6d9.1

The increasing risk of wildfire has focused attention on the timescale of the impact and recovery of river ecosystems and methods for their bioassessment. An 18-year pseudo time-series was exploited to document patterns in benthic macroinvertebrate impact and recovery and evaluate the efficacy of alternative metrics to assess fire damage. Macroinvertebrates were surveyed by kick-sampling and data were collected on river habitats. Details of river catchments and wildfire were collated as a GIS database. Macroinvertebrate richness and abundance recovered rapidly, marked by a phase of dynamic increase, followed by relative stability (0-2 years and 3-18 years, respectively). Across sites, richness and abundance were best explained by time since fire. A biotic index of general river quality was ineffective as an indicator of fire damage. While a metric of K-selected taxa (Odonata richness) was generally indicative of fire-affected assemblages, a contrasting metric of r-selected taxa (percentage of chironomids, baetids, and simuliids) was not. Ordination analysis revealed time as a significant determinant of community structure across sites; however, its overall statistical importance was eclipsed by habitat characteristics (water quality, shade, altitude, and latitude) that were associated with ecological variation across both recently affected sites and the putatively recovered communities. These results highlight the stochastic processes - environmental and ecological - that frame the macroinvertebrate response to wildfire. This probabilistic context emphasizes the difficulties of developing indicator taxa for wildfire bioassessment and reinforces the importance of standardized survey protocols and the use of contrasting metrics in the assessment of wildfire impact on the ecological quality of rivers.

In the Athabasca region, the oil sands are located at or near the surface making open-pit mining viable. In addition, the Athabasca River and its tributaries flow through these oil sands deposits, thereby receiving bitumen-associated contaminants through natural fluvial erosional and weathering processes. A key knowledge gap has been related to understanding both the magnitude and significance of the toxicological and ecological effects on aquatic organisms exposed to naturally occurring bitumen entering fluvial systems. Using the Daphnia magna model system, this study assessed the ecotoxicological effects of exposure to bitumen-elutriate treatments that simulated the early stages of fluvial/erosional exposure conditions. No significant among-site differences were observed in the survival of D. magna after 48 h exposure to elutriates produced from a 24 h extraction cycle, and chemical analysis indicated low concentration of a complex mixture of hydrocarbon and metal contaminants. In contrast, the same elutriates impaired reproduction and growth after a 21-day chronic exposure. F1 neonates from the chronic tests were tested for sensitivity to the reference substance potassium dichromate, revealing a decrease in their sensitivity. Inter-generational effects were also observed, with a significant decrease in subsequent neonate production, when daphnids were moved to a clean medium. Supplemental acute toxicity assays using 48 and 72 h bitumen extraction cycles progressively increased daphnid mortality after a 48-h exposure to the respective elutriates. This indicates that bitumen-associated contaminants are being liberated after initial input and fluvial washing (24 h), highlighting the need for future work to assess toxicity responses and associated elutriate water chemistry of a longer fluvial exposure time-series. This work contributes to our understanding of the possible effects of natural bitumen exposure on riverine aquatic ecosystems, providing new information to inform the delineation of baseline conditions to assess environmental change and the design of future regional effects-based monitoring programs.

Distinguishing municipal wastewater effluent (MWWE) from other industrial effluents or through an urbanized watershed can be challenging. In complex receiving environments, linking environmental responses to specific compounds or effluents is not always straight forward. In order to characterize the inherent complexity of tracing MWWE in aquatic systems influenced by multiple stressors, a proposed multi-tracer suite is intended to highlight areas of potential biological concern. Characterization and quantification of effluent exposure to aquatic biota in this manner is essential to shape policies intended to encourage wastewater infrastructure development (i.e. treatment plant upgrade) and broader environmental management. This paper describes the use of a comprehensive suite of tracers that includes isotopes in support of a core surveillance program, demonstrating its effectiveness both empirically and with respect to diagnostic value contributed to monitoring programs.

Catchment wildfire can decimate freshwater benthos when burnt material washes through river channels. We conducted detailed seasonal surveys over the course of one-year at N = 9 sites following summer-time wildfire in 2009 and N = 3 sites following summer-time wildfire in 2010 (constituting one-year time-series of 9 * 5 and 3 * 5 samples, respectively). Basic one-year-on surveys were conducted at an additional 12 sites following 2009 wildfires (Sum(postfire):Sum(+one.yr); N = 12 * 2). Burnt sites were compared with 6 reference sites surveyed seasonally between autumn and summer, 2009-2010 (N = 6 * 4), supplemented by 6 additional sites surveyed in summer 2004 (total reference samples: N = 6 * 5). While benthic macroinvertebrates were largely unaffected by the fire event, richness and abundance were decimated during the winter, yet recovered to initial survey levels by the following summer. The differential response of assemblages in the exceptionally wet winter of 2009-10 versus 2010-11 highlighted the catalytic role of rainfall as a driver of benthic disturbance. Ecological disturbance was proportionally greater for less abundant taxa with community evenness peaking at the time of maximum disturbance. Seasonal dynamics in fire-impacted and reference sites followed a similar pattern, implying that despite the major reduction in macroinvertebrate standing crop the general character of benthic processes was sustained. One year after the wildfire event community structure was similar to the immediate post-fire assemblages and generally indistinguishable from reference samples. The statistical importance of habitat parameters at the landscape and local scale (catchment size, landuse, slope, bank management and benthic substrate) were indicative of mechanistic processes underlying wildfire disturbance-recovery and define the scope for mitigation management. The remarkable resilience of community structure in these Mediterranean streams marks an emphatic contrast to the response of benthic macroinvertebrates to comparable disturbance processes in temperate regions. Given the increasing geographic scale and frequency of fires accompanying global warming wildfire-risk may become a leading issue for river management. (C) 2018 Elsevier B.V. All rights reserved.

ABSTRACTThe extraction of oil sands from mining operations in the Athabasca Oil Sands Region uses an alkaline hot water extraction process. The oil sands process water (OSPW) is recycled to facilitate material transport (e.g., ore and tailings), process cooling, and is also reused in the extraction process. The industry has expanded since commercial mining began in 1967 and companies have been accumulating increasing inventories of OSPW. Short‐ and long‐term sustainable water management practices require the ability to return treated water to the environment. The safe release of OSPW needs to be based on sound science and engineering practices to ensure downstream protection of ecological and human health. A significant body of research has contributed to the understanding of the chemistry and toxicity of OSPW. A multistakeholder science workshop was held in September 2017 to summarize the state of science on the toxicity and chemistry of OSPW. The goal of the workshop was to review completed research in the areas of toxicology, chemical analysis, and monitoring to support the release of treated oil sands water. A key outcome from the workshop was identifying research needs to inform future water management practices required to support OSPW return. Another key outcome of the workshop was the recognition that methods are sufficiently developed to characterize chemical and toxicological characteristics of OSPW to address and close knowledge gaps. Industry, government, and local indigenous stakeholders have proceeded to utilize these insights in reviewing policy and regulations. Integr Environ Assess Manag 2019;15:519–527. © 2019 SETAC

Environmental contextNanotechnology has great potential for managing agricultural plant disease. This study compares effects of various nano and conventional copper formulations on Collembola Folsomia candida, a model arthropod often used to test soil pollutants. Although toxicity varied between formulations, with a nanopesticide showing one of the highest toxicities, the differences were mainly due to the active copper compound rather than its nano formulation. AbstractNanotechnology has recently become a major asset in agricultural practices owing to the improvement and provision of solutions for plant disease management, especially in the form of nanopesticides. These products are considered as one of the main direct sources of nanomaterials in terrestrial ecosystems, and for that reason, it is essential to understand and evaluate their behaviour and toxicity in the environment. In addition, the panoply of similar compounds makes it difficult to accurately evaluate if different formulations may induce different effects on non-target organisms. We aim to compare the toxicity and bioavailability of different copper formulations (nano and non-nano) applied to the soil using the model organism Folsomia candida. Reproduction tests were performed in two different soils (Lufa 2.1 and 2.2) with two equilibrium times after spiking (0 and 48h). Depending on the copper form present in the formulation, the half maximal effective concentration (EC50) values of the non-nano pesticides varied from 274mgCukg−1 in Champion® to 3030mgCukg−1 in Cupravit® in Lufa 2.2 and 48h equilibrium. The nano formulation displayed one of the highest toxicities to collembolans, with an EC50 of 156mgCukg−1. Regarding the soil type, a higher toxicity in Lufa 2.1 was observed probably related to the soil characteristics, namely lower pH and lower organic content, which increase the metal solubility and consequently the bioavailability. The only exception was the nanopesticide Kocide 3000®, whose toxicity was higher in Lufa 2.2. This study emphasises the importance of understanding the links between metal bioavailability and toxicity to support the more robust environmental risk assessment of different Cu fungicide formulations.

Research investigating climate-driven changes in northern lake ecosystems is complicated by a legacy of initiatives that have used sporadic observations, often confined to open-water seasons, to define the lake state. These observations have conventionally been lake water samples analyzed for a suite of physical and chemical parameters and are indicative of only the days or hours immediately before sampling. Monitoring approaches that sample a broader scope of limnological parameters over a continuous period are needed to augment existing strategies. A study of the seasonal changes to limnological parameters in Noell Lake was performed by analyzing continuous, hourly data collected from a series of automated and non-automated moorings over the period July 2012 to July 2013. Noell Lake was found to be strongly stratified throughout the open-water and under-ice seasons, with two prominent mixing periods in spring and fall. Processes of cryoconcentration and respiration intensified density-driven stratification while the lake is ice-covered, with the deep holes of Noell Lake becoming particularly saline and oxygen-depleted all year. Hypoxia was prevalent during the under-ice season because these physical and biogeochemical processes eliminated mixing from the lower lake depths while oxygen demand remained high. Use of continuous hourly monitoring facilitated improved understanding of the dynamical response of Noell Lake to atmospheric forcing.

Over the last five decades, the Athabasca River Basin in Alberta, Canada, has been subjected to a wide range of environmental stressors from diverse human developments. This has resulted in an escalation of government, academic, industry and community-based monitoring and research efforts. However, despite all the attention received, a comprehensive synthesis of what has been studied is lacking, in particular, in relation to the efforts examining single versus multiple stressors. Based on a systematic literature review, we found 386 publications from 1969 to 2018 on the Athabasca River focusing on single stressors (68.4%) compared to multiple stressors (31.6%). There was a significant shift in the focus of studies between the 1990s and present from assessing threats of pulp and paper developments to those related to oil sands activities, with studies most predominantly addressing chemical stressors. Despite these efforts, there remain significant knowledge gaps regarding the cumulative effects of multiple stressors, particularly on biological and ecological endpoints. Correspondingly, a wide range of contradictory conclusions were reported regarding the ecological, regulatory and societal significance of the reported environmental impacts, highlighting both the complexity and often lack of standardization of approaches used. This emphasizes the need for improved integration of monitoring and research activities that are hypothesis driven, have clear objectives, and are better aligned with environmental management processes and decisions.

Veterinary pharmaceuticals are widely used as food additives in the poultry industry, and the unknown consequences of releasing these compounds into the environment are of concern. The purpose of the present study was to determine the direct impact of 2 veterinary pharmaceuticals (nicarbazin and monensin), commonly used in the poultry industry, on nontarget invertebrates and plant species. Ecotoxicological tests were used to evaluate the acute and chronic toxicity in earthworms (Eisenia andrei), collembolans (Folsomia candida), and 2 plant species (Brassica rapa and Triticum aestivum). Chemical analytical measurements were in good agreement with the nominal concentrations used, although some variability was seen. The results obtained showed no effects of nicarbazin at the highest nominal tested concentration of 1000 mg a.i./kg soil dry weight on any of the organisms, whereas exposure to monensin caused a concentration-specific response pattern. Species sensitivity to monensin decreased in the following rank order: B. rapa > T. aestivum > E. andrei > F. candida, with measured median effect concentrations (based on soil exposure) ranging between approximately 10 and 120 mg/kg. Our results emphasize the importance of using a test battery when assessing ecotoxicological effects by using different ecophysiological endpoints and species from different trophic levels. Environ Toxicol Chem 2018;37:3145-3153. (c) 2018 SETAC

The current scenario of worldwide exponential increase in river impoundment (dams) and the compounded effects of climate change are among the most important threats to freshwater ecosystems. The sharp decline in the biodiversity of impacted rivers demands the enhancement of available tools for biomonitoring and improved approaches for informing environmental decision-making. Here, we demonstrate examples of how fish trait analyses could be used to assess and predict the response of fish communities to damming and how this approach has potential advantages over traditionally used methods by linking suites of traits to stressor effects through plausible cause and effect mechanisms. Using a trait-based analysis is advantageous as it transcends taxonomy, can be applied across broad spatial scales and be easily integrated into current assessment programs. Therefore, it is a promising tool for biomonitoring in freshwater ecosystems. However, some challenges remain in the application of this approach namely the lack of universality of trait-habitat links; the availability, consistency, and applicability of existing trait data; low discriminatory power and poor mechanistic understanding. Nonetheless adaptive river management can benefit from this approach by sustainably operating dams in the light of knowledge on how the functional structure of fish communities are altered, thus enabling essential habitats for fish to be maintained.