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ABSTRACT Aim Location Taxon Methods Results Main Conclusions We address the relative importance of biogeographic regions (areas of endemism), regional climate and spatial factors on taxonomic, functional and phylogenetic beta diversity of bird assemblages in upland terra‐firme forests in the Amazon.Amazon biome.Birds.We gathered 27,498 occurrence records of 873 bird species for 115 bird assemblages distributed in all nine biogeographic regions delimited by the major Amazonian rivers. Only data from studies surveying whole communities with standard sampling methods and exhaustive sampling effort were included. We partitioned the fractions of taxonomic, functional and phylogenetic beta diversity explained by climate, biogeographic regions, spatial factors and the variation shared between them.Across the entire Amazon, we found higher total taxonomic (0.68 ± 0.10) than phylogenetic (0.46 ± 0.08) β‐diversity, and low functional β‐diversity (0.34 ± 0.08). Biogeographic regions showed the highest unique contributions explaining taxonomic and phylogenetic β‐total (7% and 5%, respectively) and turnover components (7% of β‐jtu taxonomic, 7% of β‐jtu phylogenetic), but accounted for only 2% of total functional β‐diversity and trait turnover. Climatic variables explained slightly more trait nestedness (5%) compared with species and lineage turnover (3% each). Species composition was clearly distinct between biogeographical regions limited by the Amazon River, but support for the effect of other rivers was mixed.Our study highlights the significant influence of biogeographic regions and climate on species composition in the Amazon. However, our findings also suggest that the Amazon River exerts a more pronounced impact on species distribution compared with other major Amazonian rivers. Species turnover across biogeographical regions is particularly evident at the species level, with minor effects observed in functional traits, suggesting that taxonomic turnover is driven mainly by functionally redundant species. In addition, recent diversification events, occurring predominantly at the tips of the phylogeny without substantial turnover at deeper nodes, are likely responsible for the patchy distribution of species across Amazonia. [ABSTRACT FROM AUTHOR]

Biodiversity is confronted globally by multiple stressors. Environmental policies must regulate these stressors to achieve targets, but how should that be done when the outcomes of limits on one stressor are contingent on other stressors, about which there is imperfect knowledge? Deriving regulatory frameworks that incorporate these contingencies is an emerging challenge at the science–policy interface. To be fit for implementation, these frameworks need to facilitate the inherently sociopolitical process of policy implementation and account transparently for uncertainty, such that practitioners and other stakeholders can more realistically anticipate the range of potential outcomes to policy. We developed an approach to quantify stressor limits that explicitly accounts for multistressor contingencies. Using an invertebrate data set collected over 30 years throughout New Zealand, we combined ecological and ecotoxicological models to predict biodiversity loss as a function of one stressor, treating multistressor contingencies as a form of uncertainty about the outcomes of limits on that stressor. We transparently accounted for that uncertainty by presenting regulatory limits as bands bounded between optimistic and pessimistic views that practitioners may have about the local context within which limits are applied. In addition to transparently accounting for uncertainties, our framework also leaves room for practitioners to build stakeholder consensus when refining limits to suit different local contexts. A criticism of this open, transparent approach is that it creates too much scope for choosing limits that are lenient on polluters, paralyzing on‐the‐ground management of multiple stressors, but we demonstrate that this is not necessarily the case. [ABSTRACT FROM AUTHOR]

The onset of glaciation in the late Cenozoic caused rapid bedrock erosion above the snowline; however, whether the influx of eroded sediment is recorded in continental weathering and basin accumulation rates is an ongoing debate. We propose that the transport of glacially eroded bedrock through the fluvial system damps the signal of rapid headwater erosion and results in steady basin‐integrated sediment flux. Using a numerical model with integrated glacial and fluvial erosion, we find that headwater bedrock erosion rates increase rapidly at the onset of glaciation and continue to fluctuate with climatic oscillation. However, bedrock erosion rates decrease in the downstream fluvial system because larger grain sizes from glaciers result in an increase in sediment cover effect. When erosion and sediment flux rates are averaged, long‐term sediment flux is similar to nonglacial flux values, while localized bedrock erosion rates in the glaciated landscape are elevated 2–4 times compared to nonglacial values. Our simulated values are consistent with field measurements of headwater bedrock erosion, and the pattern of sediment flux and fluvial erosion matches paraglacial theory and terrace aggradation records. Thus, we emphasize that the bedload produced from glacial erosion provides a missing link to reconcile late Cenozoic erosion records. Plain Language Summary: Glaciers are effective erosion agents and the start of mountain glaciation is thought to correspond to higher alpine erosion rates. However, at the landscape‐scale, there is little to no change in erosion rates across the start of glaciation. In order to connect across these scales, we use a computer model to calculate erosion rates and sediment transfer rates. We find that the increase in sediment size from glaciation will lower erosion rates in rivers. Larger sediment sits on the riverbed and protects the underlying rock from erosion. Despite rapid erosion by glaciers upstream of the river, the slower erosion rates in the river result in a constant rate of sediment transferred out. Therefore, sediment transfer from glacier to river systems is an important process for understanding erosion across landscape scales. Key Points: Bedrock erosion downstream of glaciers is damped through an increase in sediment cover effect caused by glacier‐produced sedimentBasin‐wide sediment flux is similar to unglaciated sediment flux at timescales of >100 kyGlacially derived bedload provides a missing link between rapid bedrock erosion rates and steady basin accumulation and weathering rates [ABSTRACT FROM AUTHOR]

The concept of 'legal personhood and rights of rivers' has developed as an alternative to anthropocentric legal frameworks that focus only on the instrumental values of rivers. Obtaining legal personhood marks a key milestone in legal recognition that could provide for the protection of rivers for more than the instrumental values that they hold. However, who could be considered legal persons is the subject of widespread debate in Western jurisprudence. Legalists hold that anything and anyone can be a legal person while Realists believe that a legal person is defined by certain attributes held only by certain categories of persons. One of the main arguments against the personhood of rivers raised by Realists is that rivers are not sentient beings and, consequently, they are incapable of holding the status of a legal person. The idea that nature is not a sentient being is mainly a Western construct. This research analyses the theory of legal personhood to determine whether rivers can and should be legal persons. It challenges the Realist claim that rivers cannot be legal persons because they lack sentience, drawing on Indigenous Vedda ontologies in Sri Lanka and Aboriginal worldviews from the continent now called Australia. The authors argue that a pluralistic approach to legal personhood is crucial in recognising and valuing our hyperconnected world, preventing categorisation, homogenisation and colonisation of ontologies and addressing sustainability challenges surrounding rivers. The research contributes to the existing scholarly work by defending the concept of legal personhood for rivers within a more pluralistic legal philosophy and addressing one of its major criticisms. [ABSTRACT FROM AUTHOR]

Remote sensing can be an effective tool for mapping river bathymetry, but the need for direct measurements to calibrate image‐derived depth estimates impedes broader application of this approach. One way to circumvent the need for field campaigns dedicated to calibration is to capitalize upon existing data. In this study, we introduce a framework for Bathymetric Mapping using Gage Records and Image Databases (BaMGRID). This workflow involves retrieving depth measurements made during gaging station site visits, downloading archived multispectral images, and then combining these two data sets to establish a relationship between depth and reflectance. We developed a processing chain that involves using application programming interfaces to obtain both depth measurements made during site visits and images centered on the gage and then linking depth to reflectance via an optimal band ratio analysis (OBRA) algorithm modified for small sample sizes. Applying this workflow to selected gages within two river basins indicated that depth retrieval from multispectral satellite images could be highly accurate, but with variable results from one image to the next at a given site. High resolution aerial photography was less conducive to bathymetric mapping in one of the basin considered. Of the four predictors of depth retrieval performance we evaluated (mean and standard deviation of depth, width, and an index of water clarity), only width was consistently significantly correlated with OBRA R2 (p < 0.026). Currently, BaMGRID is best‐suited for site‐by‐site analysis to support practical applications at the reach scale; continuous, basin‐wide mapping of river bathymetry will require additional research. Key Points: Combine depth measurements made during site visits to gaging stations with archived images to enable remote sensing of river bathymetryMultispectral satellite images acquired daily can yield highly accurate depth estimates, but high resolution air photos were less accurateBathymetric Mapping using Gage Records and Image Databases (BaMGRID) is well suited to site‐by‐site analysis for reach‐scale applications [ABSTRACT FROM AUTHOR]

Source‐to‐sink transfer of sediment and organic carbon (OC) is regulated by river mobility. Quantifying trends in river mobility is, however, challenging due to diverse planform morphologies (e.g., meandering, braided) and measurement methods. Here, we utilize a remote‐sensing method applicable to all planform morphologies to quantify the mobility timescales of 80 rivers worldwide. Results show that, across the continuum from meandering to braided rivers, there is a systematic reduction in the timescales of channel mobility and—to a lesser extent—floodplain reworking. This leads to a decrease in the efficiency with which braided rivers rework old floodplain material compared to their meandering counterparts. Reduced floodplain reworking efficiency of braided rivers leads to smaller channel‐belt areas relative to their size. Results suggest that river‐mobility timescales derived from remote sensing can aid in the characterization of sediment and OC storage and transit times at a global scale. Plain Language Summary: Rivers transport sediment and organic carbon (OC) from the mountains to the sea, and river movement affects sediment and OC transit times in landscapes. Understanding the controls on timescales of river movement is critical for assessing how fluvial processes influence the terrestrial carbon cycle. While previous work has quantified different river planform shapes on the Earth's surface (e.g., meandering, wandering, and braided), little is known about how the pace and nature of river movement is different between river planform shapes. This is because we lack methods to measure and compare river movement across different river planform shapes. Here, we leverage a tool to quantify river movement from time series of satellite imagery that is equally applicable to all river planform shapes. We apply this method to calculate the timescales of river movement of 80 rivers worldwide for the last 37 years. We show that (a) braided rivers migrate faster than meandering rivers, and (b) braided rivers move over a smaller area relative to their size. Comparing results with geochemical observations from the Río Bermejo—a well‐studied river for sediment‐OC cycling—we show that our mobility framework may provide a new way to assess sediment and OC storage timescales in floodplains. Key Points: We quantify timescales of floodplain reworking and channel‐overlap decay from satellite imagery of 80 rivers worldwideFrom meandering to braided planform morphology, there is a reduction in the overlap timescale and the reworking timescaleMobility timescales provide a means for remotely quantifying terrestrial‐sediment and organic‐carbon storage and transit [ABSTRACT FROM AUTHOR]

In the article the author shares the important role of the Schuylkill River located in Pennsylvania in writing her book "Utopia Found and Lost in Penn's Woods." Topics include brief description of the ecological location of the river, emphasis by scholars on the humanistic objects of inquiry and the concept of Black ecologies by authors J. T. Roane and Justin Hosbey.

The present work concerns the interaction between hydraulic processes and biological communities in rivers. In particular, the aim of this study is to investigate the interactions between flow dynamics and the freshwater mussels (FMs) to verify if the mussels' behavioural response to the hydrodynamic stress could be used to monitor natural extreme events in rivers. Although the influence of mussels on the kinematic characteristics of flow at the water–sediment interface was investigated by a certain number of studies, their behavioural response to flow, both in static and dynamic conditions, remains understudied. Laboratory experiments were performed in an artificial flume exposing Unio elongatulus to different values of flow discharge, both in steady and in unsteady conditions either with or without sediment transport. Mussels' behavioural responses were detected by using Hall sensor technology to measure gaping frequency, amplitude and duration, both in static conditions and under the effect of hydrodynamic stresses. Five categories of behavioural response were identified: Normal Activity (NA), Resting (Re), Transition (Tr), Adaptation (Ad) and Avoidance (Av). During NA (standard feeding and moving), FMs presented valve gaping, while during Re valves were kept constantly opened for water filtration. After a variation of flow discharge (ΔQ), FMs promptly reacted showing a transition from their normal behaviour, with constant gaping frequency (below 0.01 Hz), to higher valve gaping frequencies. The mean valves' gaping frequency increased as a function of ΔQ, and the highest values were reached in the presence of sediment transport. The mean valve opening amplitude was less sensitive to ΔQ. Its range of variation was very narrow with the highest values corresponding to the protrusion/retraction of the animals' foot to move or anchor to the substrate. The percentage of mussels responding to the discharge variation (Transition behaviour) increases with ΔQ confirming that mussels' behavioural response represents a promising tool for monitoring the occurrence of hydrodynamic stressors in fluvial systems. [ABSTRACT FROM AUTHOR]

Habitat fragmentation is emerging as a leading cause of biodiversity decline in riverine ecosystems. Several natural and human factors contribute to the fragmentation of rivers. River fragmentation is a growing problem that is widely spread and poses a significant challenge to the conservation of freshwater biodiversity, but its impact is not fully documented and acknowledged. Fragmentation impedes the movement of aquatic organisms and alters natural flow regimes, disrupting habitats and trophic supplies for aquatic biodiversity. It can also affect the adaptive ability of organisms to natural environmental changes, leading to a change in the structure and function of biotic communities. To understand the effects of fragmentation on river ecology, it is crucial to link its spatial and structural implications. This article examines the occurrence and frequency of fragmentation and its effects on the ecological community of benthic biota. This review aims to elucidate the overall effects of fragmentation on river ecology and recommends the possible measures to mitigate its impact. Urgent action is required to establish a comprehensive global network of free‐flowing river systems and revive previously exploited rivers in different regions to enhance the protection and sustainable utilization of river ecosystems. [ABSTRACT FROM AUTHOR]

When the Ebola virus crossed undetected into Sierra Leone and exacerbated the 2014-15 crisis, the World Health Organization blamed the breach on a traditional healer treating patients from Guinea. Meanwhile, local residents initially maintained that her death was not Ebola-related but a serpent's curse, an assumption grounded in lived experience of snake charmer spectacles. Both narratives drowned out evidence that the virus spread not via the healer's covert herbalism, but via her professional connections at the local government clinic and, more broadly, an overtaxed and undertrained public health system. This article takes local rumours around Ebola as vernacular epidemiologies that resonated with sensory experience. They show that both community and humanitarian actors had information; complications arose from the diverse experiences and expectations that shaped responses to that information. Such expectations emerge from the borderland geography, where colonial infrastructures continue to channel perception according to "upriver", "downriver", and "crossriver" phenomenologies. [ABSTRACT FROM AUTHOR]

Microbial pollution of recreational waters leads to millions of skin, respiratory, and gastrointestinal illnesses globally. Fecal indicator bacteria (FIB) are monitored to assess recreational waters but may not reflect the presence of Staphylococcus aureus, a global leader in bacterial fatalities. Since many community‐acquired S. aureus skin infections are associated with high recreational water usage, this study measured and modeled S. aureus, methicillin‐resistant S. aureus (MRSA), and FIB (Enterococcus spp., Clostridium perfringens) concentrations in seawater and sand at six beaches in Hilo, Hawai'i, USA, over 37 sample dates from July 2016 to February 2019 using culturing techniques. Generalized linear models predicted bacterial concentrations with physicochemical and environmental data. Beach visitors were also surveyed on their preferred activities. S. aureus and FIB concentrations were roughly 6–78 times higher at beaches with freshwater discharge than at those without. Seawater concentrations of Enterococcus spp. were positively associated with MRSA but not S. aureus. Elevated S. aureus was associated with lower tidal heights, higher freshwater discharge, onsite sewage disposal system density, and turbidity. Regular monitoring of beaches with freshwater input, utilizing real‐time water quality measurements with robust modeling techniques, and raising awareness among recreational water users may mitigate exposure to S. aureus, MRSA, and FIB. Practitioner Points: Staphylococcus aureus and fecal bacteria concentrations were higher in seawater and sand at beaches with freshwater discharge.In seawater, Enterococcus spp. positively correlated with MRSA, but not S. aureus.Freshwater discharge, OSDS density, water turbidity, and tides significantly predicted bacterial concentrations in seawater and sand.Predictive bacterial models based upon physicochemical and environmental data developed in this study are readily available for user‐friendly application. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the feasibility of measuring bathymetry using airborne green LiDAR in long and variable river reaches (4 km or more), across three rivers with varying gradients, water depths and light penetration (3.5–10 m), using four alternative LiDAR sensors. The accuracy of green LiDAR data was compared to in situ measurements collected by stratified transect point sampling and Multibeam bathymetry. Factors potentially limiting the feasibility of green LIDAR in rivers were explored. If remote sensing signals were reflected by the riverbed, the sensors generally provided elevation data consistent with in situ elevation measurements, indicating high accuracy (±10 cm) across different hydraulic conditions. The loss of green LiDAR data was mainly a consequence of limited signal water penetration capability, that is, water clarity. Secchi depth was a proxy variable strongly associated with green LiDAR penetration capability across rivers. Data loss was low up to the Secchi depth but increased rapidly thereafter. Surface water turbulence ('white water') and dark riverbed vegetation also increased green LiDAR signal loss. Sensors with lower point density and therefore less spatial resolution had more signal strength and therefore penetrated deeper water. However, with increasing coverage of surface turbulence ('white water'), the importance of high point density also increased. Signal power should be balanced with signal density (spatial resolution), depending on river characteristics and project objectives. We conclude that remote sensing green LiDAR bathymetry is a robust method that efficiently provides accurate elevation data across rivers with different hydraulic conditions and water depths. [ABSTRACT FROM AUTHOR]

India boasts of a vast freshwater resource network (rivers, wetlands, and groundwater), which has unique ecological, social and economic values associated with it. Despite their importance for both people and biodiversity, its freshwater ecosystems (FWEs) are heavily impacted through multiple factors such as pollution, overexploitation, habitat loss/modification and climate change. India is also among the hotspots of water resource overuse that has caused a serious decline in freshwater availability.Given that healthy FWEs lie at the centre for supporting the country's ecology, health, economy, livelihoods and ultimately achieving multiple policy goals, it is crucial that holistic and focused efforts are made to protect, conserve, and restore all types of FWEs.We call for an urgent and a greater focus on implementing conservation actions for FWEs in India and suggest the following strategy to enhance focus on their conservation: (1) establishing a shared freshwater conservation vision at a national scale, (2) developing and including national freshwater conservation goals within global efforts, (3) conducting simultaneous conservation action planning at regional scales and (4) bridge planning to implementation gap by strengthening key enabling conditions: i) mainstream FWE conservation within key existing governance instruments, ii) secure sustainable conservation funding, iii) improve data access and knowledge translation; iv) create national awareness around importance of FWEs; v) facilitate collaboration among key actors. [ABSTRACT FROM AUTHOR]

The loose‐equilibrium concept (LEC) predicts that ecological assemblages change transiently but return towards an earlier or average structure. The LEC framework can help determine whether assemblages vary within expected ranges or are permanently altered following environmental change.Long‐lived, slow‐growing animals typically respond slowly to environmental change, and their assemblage dynamics may respond over decades, which transcends most ecological studies. Unionid mussels are valuable for studying dynamics of long‐lived animals because they can live >50 years and occur in dense, species‐rich assemblages (mussel beds). Mussel beds can persist for decades, but disturbance can affect species differently, resulting in variable trajectories according to differences in species composition within and among rivers.We used long‐term data sets (10–40 years) from seven rivers in the eastern United States to evaluate the magnitude, pace and directionality of mussel assemblage change within the context of the LEC.Site trajectories varied within and among streams and showed patterns consistent with either the LEC or directional change. In streams that conformed to the LEC, rank abundance of dominant species remained stable over time, but directional change in other streams was driven by changes in the rank abundance and composition of dominant species.Characteristics of mussel assemblage change varied widely, ranging from those conforming to the LEC to those showing strong directional change. Conservation approaches that attempt to maintain or create a desired assemblage condition should acknowledge this wide range of possible assemblage trajectories and that the environmental factors that influence those changes remain poorly understood. [ABSTRACT FROM AUTHOR]

Salinization is a global threat to freshwater habitats that has been intensified by climate change. Monitoring, assessment and management of salinity is therefore essential. The first step is to set criteria that are sufficiently stringent to protect ecosystem health. However, many countries have not yet defined criteria, and there are substantial differences between criteria. This has been noted in the EU, where salinity is a required “supporting element” for ecological status in inland waters but also for implementation of UN Sustainable Development Goal (SDG) indicator 6.3.2. for “good ambient water quality” where different approaches and widely different threshold values were reported for salinity criteria. Much of this information has not been published and is difficult to access, hindering further efforts to address the problem. We first discuss the implications of salinization for freshwater ecological health. We go on to discuss the principles and guidelines on how salinity criteria to protect ecology should be established. Next, we review salinity criteria submitted as part of implementation of SDG indicator 6.3.2 and the EU Water Framework Directive. Finally, we discuss setting salinity thresholds in an already-warming world and the challenges facing anyone trying to develop salinity criteria to protect freshwater ecosystems. This article is categorized under: Water and Life > Stresses and Pressures on Ecosystems Water and Life > Conservation, Management, and Awareness Science of Water > Water Quality [ABSTRACT FROM AUTHOR]

The elevations of water surfaces hold important information on the earth's oceans and land surface waters. Ocean sea surface height is related to the internal change of the ocean's density and mass associated with ocean circulation and its response to climate change. The flow rates of rivers and volume changes of lakes are crucial to freshwater supplies and the hazards of floods and drought resulting from extreme weather and climate events. The Surface Water and Ocean Topography (SWOT) Mission is a new satellite using advanced radar technology to make headway in observing the variability of the elevation of water surfaces globally, providing fundamentally new information previously not available to the study of earth's waters. Here, we provide the first results of SWOT over oceans, rivers, and lakes. We demonstrate the potential of the mission to address science questions in oceanography and hydrology. Plain Language Summary: Earth is a water planet. The vast amount of ocean water has stored most of the heat released to the atmosphere since the Industrial Revolution through burning fossil fuels. Climate change is thus moderated by the ocean. Over land the freshwater in lakes, rivers, and reservoirs, a critical natural resource, is affected by the warming climate and direct human modifications. Processes of oceanic uptake of heat and carbon from the atmosphere and cycling of freshwater on land take place at spatial scales too small to have been adequately quantified from space. A new satellite, the Surface Water and Ocean Topography (SWOT) mission, was launched in December 2022. Using advanced radar technology, SWOT provides unprecedented global observations for understanding the ocean's role in climate change and how freshwater resources respond to human influence. SWOT observations near coasts will also advance understanding of how rising sea levels impact those coasts. Key Points: The first space observations of submesoscale ocean surface topography for understanding ocean's role in heat uptake from the atmosphereThe first space observations of the change of water storage of lakes and flow rates of rivers for understanding the freshwater cycleThe first space observations of the details of the change of coastal water levels to assess the impact of local sea level rise [ABSTRACT FROM AUTHOR]

American Eel (Anguilla rostrata) population characteristics and distribution remain drastically understudied in the Caribbean region. We conducted the first island‐wide study to evaluate the distribution of density, length, and sex in relation to distance from the mouth of 23 stream reaches in five rivers in Puerto Rico. We found 287 American Eel at a mean density of 156.7 fish/ha. Sex ratios favored females (52:3) but most of the eel sampled were undifferentiated or undetermined. Generalized linear modeling indicated that upstream habitats with low eel density were optimal environments for production of large and female eel. Our findings indicate that Puerto Rico could significantly contribute to the spawning population and strengthen knowledge of American Eel in the Caribbean. Our findings could be used to guide local and range‐wide conservation efforts to ensure stream connectivity and access to optimal upstream habitat for survival of the population. [ABSTRACT FROM AUTHOR]

The development of low‐oxygen zones threatening marine life (hypoxia) occurs annually in multiple coastal regions of the world. The largest estuary of the continental United States, the Chesapeake Bay, typically has ≈10 km3 of water with dioxygen concentrations <3 mg L−1 in July. As numerical methods for refining model resolutions in targeted areas are becoming common, there is interest in assessing the feasibility of simulating coastal hazards such as hypoxia in Earth System Models (ESMs). These coupled models are typically not constrained by observations and thus likely to feature systematic biases in their land, atmosphere, or ocean components. This study relies on four numerical experiments to evaluate the sensitivity of Chesapeake Bay hypoxia to changes or biases in its external physical forcings. Hypoxia exhibits only a minor decrease (−1.6%) after reducing the Bay's terrestrial freshwater discharge by 9.5% (but keeping terrestrial nutrient loadings the same). Changes in freshwater discharges have their largest impact on hypoxia during one extreme event (−37% during 2011 tropical storm Lee). Similarly, changing oceanic conditions on the shelf or their temporal frequency impact hypoxia by only 5%–6%, indicating that the latter is predominantly dictated by local conditions. Although these results are promising from the perspective of ESMs, additional components of ESMs will need to be evaluated before general conclusions can be reached. We notably speculate that the Bay's hypoxia would exhibit higher sensitivity to other forcings not examined here, notably air temperatures and nutrient loadings. Plain Language Summary: Many coastal embayments of the world experience the development of "dead zones" during the summer, defined by very low concentrations of oxygen in water. The dead zones negatively affect the ecosystem including commercially‐important fisheries. Such a dead zone can be found every summer in the Chesapeake Bay, the largest and most productive estuary in the continental United States. Although these phenomena are typically the focus of local or regional managers, recent improvements in computer capabilities raise the possibility that dead zones could be successfully represented in the same type of computer simulators used for century‐long projections of the Earth's climate. Such simulators would provide a long term projection for the severity of dead zones throughout the world. The present study examines whether a realistic representation of the Chesapeake Bay dead zone can be obtained using information from these global computer simulations. The results show that the representation of the dead zone is not substantially different when using the global data sets selected for this study. This positive outcome opens the door for additional tests that should focus on other components of the global simulators, notably air temperatures and nutrients inputs from the land to the coastal embayments. Key Points: Chesapeake Bay hypoxia shows only a weak sensitivity to continental shelf conditions and variabilityChanges in shelf hydrography propagate throughout the Bay but surface temperatures are set by the meteorological forcingShort term hydrological events are not always captured well by global land models which can impact hypoxia substantially [ABSTRACT FROM AUTHOR]

Water treatment plant operators need to understand federal and state laws as well as the standards that apply to water treatment systems. They should also understand how drinking water regulations are administered and why compliance is essential to providing safe drinking water to the public. [ABSTRACT FROM AUTHOR]

Australian freshwater turtles are declining, reflecting global turtle trends. Understanding variation in turtle diets and habitat requirements can guide protection and restoration of ecosystems. Diet and niche overlap were investigated in three co‐existing species of turtle—the broad‐shelled turtle Chelodina expansa, the eastern long‐necked turtle C. longicollis and the Macquarie turtle Emydura macquarii, in three rivers in the Murray–Darling Basin, Australia, in relation to environmental variables.Dietary variation in relation to water quality (salinity) and macrophyte cover was investigated using stable isotope analyses (δ15N and δ13C) of turtle tissues (plasma, red blood cell, whole blood and nail) representing food assimilation over different antecedent periods. These stable isotope results were consistent with current dietary understanding based on stomach flushing, indicating that isotope analyses are a non‐invasive method for obtaining dietary information.There were temporal dietary differences, with strong shifts between spring and summer sampling periods, particularly in the blood plasma. Intraspecific variation in diets reflected in δ15N and δ13C related to body size. There was evidence of high dietary overlap among the three species, potentially creating competition, particularly when they co‐occur or resources might be limited.Continued degradation of turtle habitats and water quality affects turtle diet and reduces habitat availability, forcing the three species of turtle to co‐exist in diminishing refugia, increasing interspecific competition for food. Protecting and restoring freshwater ecosystems, including maintaining freshwater refugia, is essential to conserve already declining populations of the three Australian freshwater turtle species. [ABSTRACT FROM AUTHOR]

This paper explores the everyday experiences of crossing rivers that form local borders. It proposes and utilises the term ‘riverborderscape’ to bring together the particularities, complexities, and creativities associated with these border crossings. The term draws on three areas of scholarship. First, the riverborderscape draws on recent scholarly attention to the materiality, and effects on understanding space and place, of watery environments. Second, the term draws on scholarship from within border studies and cognate disciplines that highlights the border as a liminal space. Third, landscape geographies are used to examine the imagination and performance of crossing riverborderscapes. The paper reports on research carried out with passengers, crew, and communities on three rivers in South West England where the ferry routes cross local administrative boundaries. Over the course of the research, participants shared their experiences of crossing these river borders through writing and drawings created while on board the ferry, as well as through surveys and interviews. The research highlights the effects of the materiality of the river on the routes and experiences of crossing, the role of humour in the construction and subversion of everyday boundaries, and the river in‐between as a liminal space, a landscape where the imagination may be unmoored and creative licence temporarily set free. [ABSTRACT FROM AUTHOR]

Floods in ideal landscapes follow a coherent pattern where single water‐covered areas expand and afterward recede following the inverse sequence, but deviate in real landscapes due to natural or human factors resulting in water coverage shifts. Using remote sensing, we introduced two indices to describe the discrepancies between spatially integrated versus pixel‐level frequency distributions under maximum inundated conditions (dext) and throughout all flooding conditions (dtot), expressed as the relative weight of shifts on each landscape's maximum registered coverage, theoretically ranging between no displacement (<20%) to maximum displacement (≪inf). Globally, over 36 years inundations exhibited redistributions representing, on average, 25% and 45% of their peak extents revealing previously unnoticed extra engaged areas and rotational movements within events, rising up to 500% in meandering rivers (South America) and irrigated croplands (Central Asia). We also assessed the influence of natural and human variables and discussed the indices' potential for advancing flood research. Plain Language Summary: While in ideal landscapes surface water should display the same spatial distribution across the expansion and recession stages of any flooding event, real dynamics may drift away from this expected pattern. We developed two indices based on remote sensing data to locate where these shifts are important and understand how they are influenced by nature and humans. By analyzing data from around the world, we discovered that thanks to the displacement from the ideal distributions, surface water covered globally an extra quarter of the area. Natural factors like low terrain ruggedness and high aridity foster much larger inundation displacement. In regions hosting rivers that carry large quantities of sediment and often change their course (e.g., India and Perú), displacement engages five times more area in floods than expected. We also found that water infrastructure like reservoirs and irrigation also influenced inundation displacement. For instance, displacement was very relevant in intensely irrigated regions like Central Asia and Australia, reflecting surface water deviation as needed for crop production. Because these variations scope water's spatiotemporal dynamics with important implications for the provision of many ecosystem services, their quantification and assessment allow us to monitor and understand our ongoing imprint on regional inundation dynamics. Key Points: We developed two complementary indices to describe water cover shifts between and within flooding eventsOver the last 36 years, shifts expanded the global flooded‐affected area by 25% with another 20% redistributing at intermediate stagesFlat topographies, arid climates, and irrigation favor this phenomenon while river dams and channels inhibit it over time [ABSTRACT FROM AUTHOR]

Heatwaves are a global issue that threaten microbial populations and deteriorate ecosystems. However, how river microbial communities respond to heatwaves and whether and how high temperatures exceed microbial adaptation remain unclear. In this study, we proposed four types of pulse temperature‐induced microbial responses and predicted the possibility of microbial adaptation to high temperature in global rivers using ensemble machine learning models. Our findings suggest that microbial communities in parts of South American (e.g., Brazil and Chile) and Southeast Asian (e.g., Vietnam) countries are likely to change due to heatwave disturbance from 25 to 37°C for consecutive days. Furthermore, the microbial communities in approximately 48.4% of the global river gauge stations are prone to fast stress inadaptation, with approximately 76.9% of these stations expected to exceed microbial adaptation after heatwave disturbances. If emissions of particulate matter with sizes not more than 2.5 μm (PM2.5, an indicator of human activities) increase by twofold, the number of global rivers associated with the fast stress adaptation type will decrease by ~13.7% after heatwave disturbances. Understanding microbial responses is crucially important for effective ecosystem management, especially for fragile and sensitive rivers facing heatwave events. [ABSTRACT FROM AUTHOR]

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An ongoing hydrogen peroxide pilot project at a Connecticut water treatment facility showed promising benefits beyond disinfection precursor oxidation, such as reduced total organic carbon, lower chemical costs, and improved aesthetics. [ABSTRACT FROM AUTHOR]

Eighteenth century river hydraulics used both theory and measurement to address problems of flood safety, navigation and defense related to the rivers. In the late eighteenth century the Dutch overseer of the rivers, Christiaan Brunings, integrated hydraulic theory and meteorological practices, which enabled him to design a unique instrument for measuring river flow. The question is whether the unprecedented detail of measurements fits the putative empirical stance in the eighteenth century. The interactions between theory, instrument, measurement, and other knowledge practices are here assessed using experiences in similar measurement practices. I argue that Brunings had theoretical and embodied understanding of hydrodynamics, as he knew how to design an instrument for flow measurement of sufficient accuracy for his purpose in the sociopolitical context of river management. [ABSTRACT FROM AUTHOR]

We show how the dire state of the Earth's rivers entangles intimately with 'thingifying' processes at the heart of colonial modernity. Known in many precolonial and Indigenous contexts as person‐like kin, we describe how rivers the world over have been re‐done primarily as thing—amoral, controllable, a potential commodity like anything else.We develop and work with a provisory concept of kin as those constituents of environments that reciprocally nurture, and contribute to the substance of, one another's life and wellbeing.We show how kinship with rivers figures centrally in primarily Indigenous‐led struggles in various regions of the globe for the recognition and enforcement of river personhood and rights. This is partly because people are motivated to fight passionately for their kin.With some careful caveats, we argue that associating river kinship exclusively with Indigenous worlds undermines its potential for global impact. Thus, as an apposite case study, the latter part of the paper focuses on some of the social–ecological trends which we suggest are opening up the possibility for the re‐establishment of 'riverkinship' in the United Kingdom.We reflect on the potential for riverkinship to help cultivate political constellations fitting to the challenges of the Anthropocene. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Inland waters are significant, yet highly uncertain, natural sources of nitrous oxide (N2O). Many emission models assume that N2O is only emitted from freshwaters, and that N2O sink behavior is negligible. However, observational studies have reported N2O undersaturation, suggesting that inland waters can act as N2O sinks due to net N2O consumption. This study leverages data from the National Ecological Observatory Network (NEON) and an existing global emission model to examine the prevalence of and controls on N2O undersaturation in streams, rivers, and lakes across scales and biomes. We find that N2O undersaturation is prevalent in the NEON data set (14%–30% of samples) and process‐based model outputs (38%), occurring across biomes and spatial scales. Failing to account for undersaturation in the NEON data set could result in an 100% overestimation of N2O emissions. These results show that consideration of N2O sink behavior is needed for accurate emission estimates. Plain Language Summary: Nitrous oxide (N2O) is a climate‐relevant greenhouse gas that is increasing in the atmosphere due to human activities. It also contributes to stratospheric ozone depletion. Inland waters (e.g., streams, rivers, and lakes) are significant, yet uncertain, sources of N2O to the atmosphere. In general, emission models assume that N2O is produced in and emitted from inland waters. However, field observations have shown that inland waters can also act as sinks of atmospheric N2O, potentially offsetting emissions. Understanding when and where inland waters act as N2O sinks is needed for accurate emission estimates. This study uses a large observational data set and an existing global emission model to explore when, where, and to what extent inland waters act as N2O sinks. The results show that N2O sink behavior is common and may significantly offset emissions. Key Points: Nitrous oxide (N2O) undersaturation in inland waters is prevalent, indicating that inland waters periodically act as sinks of atmospheric N2OPeriodic N2O sink behavior occurs at most monitored sites and the frequency of N2O sink behavior is invariant to ecosystem size or biomeN2O sink behavior has the strong potential to partially offset N2O emissions from inland waters [ABSTRACT FROM AUTHOR]

I explore by way of a thought experiment the temporality of waterways in the context of restorative art interventions. As a substance that moves and gives form, and as a medium that retains and discharges, connects and divides, water that flows can make tangible the experiential flow of return and anticipation. Arguably, this bi‐directional structuring of time is pivotal to transformative and reparative action. If restoration means 'going back' to memories of ecologies and places, it does so with a generative thrust forward. This is the life‐enabling orientation of recuperation that I discern connects diverse phenomenological concepts: Deborah Bird Rose's 'multispecies knots of ethical time', the idea of 'afterness' as developed by Gerhard Richter, Gaston Bachelard's 'rhythmic time', and Gerald Vizenor's 'survivance'. I bring these concepts to: (a) artistic water restoration projects that make imaginable, palpable, and real sustainable human‐water relationships, with a focus on the public works in Sydney by Turpin + Crawford Studio; (b) perspectives on water and time that Australian Indigenous thinkers have shared during my ethnographic research; and (c) the re‐naturalization of a river in Germany's postindustrial Ruhr region. I propose that thinking with water ethically and recognizing its temporal diversity opens up perspectives on the deindustrialisation of rivers and other bodies of water. [ABSTRACT FROM AUTHOR]

Stable isotope analyses, specifically δ13C and δ15N, are useful tools increasingly used to understand ecosystem function, food web structures, and consumer diets. Although the iconic tigerfish Hydrocynus vittatus is regarded as an apex predator in southern African freshwater systems, little information is available regarding their feeding behavior and how this may change with growth or differ between ecosystems, with most information stemming from stomach content analyses (SCA). The aim of the present study was to address this lack of information through a baseline study of the diet of large and small tigerfish in various lentic and lotic ecosystems in South Africa using stable isotope methods. Fish and various food web components and food sources were collected from two river and two lake ecosystems in South Africa. The δ13C and δ15N values for all samples were determined and multivariate analyses and Bayesian analytical techniques applied to determine the feeding ecology of H. vittatus and how this may differ with size and habitat type. Analyses revealed a substantial difference in the type and abundance of food sources contributing to the diet of H. vittatus between ecosystems, most prominently between the lotic systems, where less dietary specialization was observed, and lentic systems where more specialization was observed. Furthermore, there was a distinct difference in diet between small and large tigerfish, especially in the lotic system, indicating an ontogenetic diet shift as tigerfish grow and further supporting previous SCA studies. This is the first study of its kind on the African continent for H. vittatus and the findings illustrate the value of stable isotope analysis in providing in‐depth information into the feeding ecology of consumers and how this may differ between size classes and habitat types. [ABSTRACT FROM AUTHOR]

Animals are a critical component of biogeochemical cycles. While animal mediated fluxes of nutrients and energy have received considerable attention, the impacts of these fluxes on microbial community structure and function are comparatively understudied. Here, we investigated if freshwater mussel influences on biogeochemical cycling in stream sediment are accompanied by changes in sediment microbial community composition and ecoenzymatic activity, and if these relationships change under different nutrient regimes.We predicted that mussel effects on ecosystem function are reflected by modified sediment microbial communities. We hypothesized that if changes in either sediment ecoenzymatic function or microbial community composition are driven by mussel‐derived nutrient amendments, we should see muted changes in microbial community assemblages or function when a given nutrient is abundant. However, if microbial communities and function are influenced by other mussel functions, then we should see uniform changes regardless of nutrient availability.We transplanted freshwater mussels and natural river sediment to flow‐through mesocosms and monitored changes in microbial community composition over 1 week. Our results indicate that mussels always changed sediment microbial community composition, but the way communities changed was dependent on ambient nutrient concentrations.On the final day we measured the activity of ecoenzymes known to correlate to microbial function and nutrient availability. Mussels homogenized the stoichiometric ratios of ecoenzyme activities, indicating a consistent function of sediment microbes associated with freshwater mussels. Our results suggest that mussels may promote functional redundancy in sediment microbial communities and highlight the importance of animals in controlling biogeochemical transformations under changing nutrient conditions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Eutrophication is one of the largest threats to aquatic ecosystems and chlorophyll a measurements are relevant indicators of trophic state and algal abundance. Many studies have modeled chlorophyll a in rivers but model development and testing has largely occurred at individual sites which hampers creating generalized models capable of making broad‐scale predictions. To address this gap, we compiled a large data set of chlorophyll a concentrations matched to other water quality, meteorological, and reach characteristic data for a diverse set of 82 streams and rivers across the United States. We used this data set and extreme gradient boosting, a tree‐based machine learning algorithm, to predict daily chlorophyll a concentrations. Furthermore, we tested several practical considerations of broad‐scale models, such as making predictions at sites not included in model training or the utility of in situ water quality data versus universally available remotely estimated model inputs. Predictions were very strongly correlated to observations when compared against a randomly withheld subset of days; however, the model had lower accuracy when applied to completely novel sites withheld from model training. Turbidity and total nitrogen were the two most important variables for predicting chlorophyll a. Although in situ variables improved modeled estimates and were identified as more important during model interpretation, using only remote inputs still resulted in highly correlated predictions with small bias. Testing a model across many sites allowed for identification of common variables relevant to chlorophyll a and highlighted several challenges for applying data‐driven models to new sites or at larger spatial scales. Plain Language Summary: One of the largest threats to freshwater and marine ecosystems is excess primary productivity stimulated by increased nutrient availability. An overabundance of algae can cause degradation of ecosystems and risks for public health. Chlorophyll a routinely collected as a proxy measure for algal abundance and provides a common currency to compare across aquatic ecosystems. We compiled a data set of chlorophyll a, additional in situ water quality variables, reach characteristics, and broadscale meteorology to model daily chlorophyll concentrations at 82 rivers across the United States. Machine learning was used to predict daily chlorophyll concentrations and several challenges of broad‐scale modeling were investigated, such as extrapolating predictions to new sites or tradeoffs between data quality and quantity. While the model performed well against a withheld set of days for testing, it performed noticeably worse when entire sites were withheld for model testing. Turbidity and total nitrogen were the two most important predictors, and although in situ data resulted in better predictions, estimates solely made from remote data sets have potential for use in widespread predictions. Testing a model across many sites allowed us to identify variables that are commonly relevant to chlorophyll a and highlighted needs for future improvement of broad‐scale models. Key Points: Predicted daily chlorophyll a concentrations across a diverse set of streams and rivers using a decision tree machine learning algorithmModel estimates performed well at sites that contributed some data to model training but not at sites totally withheld from model trainingUsing in situ data for model inputs increased accuracy but ubiquitous remote data sets can provide reasonable estimates at many more places [ABSTRACT FROM AUTHOR]

The detection of river boundaries is a crucial branch of the intelligent perception of unmanned surface vehicles (USVs), it can be used to determine the driving areas of USVs, and also to ensure driving safety by limiting the effective drivable areas of USVs in the river areas. Aiming to detect the boundaries of incompletely structured river channels, this study proposes a real‐time detection method for river boundaries based on a Light Detection and Ranging (LiDAR) sensor. The point clouds that are disturbed by the water surface noise are filtered firstly, and then the spatial and geometric features are extracted separately from the point cloud detected above the water surface. To prevent the error detection and missing detection, the boundary point information is predicted and calibrated in real time by Extended Kalman Filter (EKF). A planning track generation algorithm for coastal autonomous cruise without relying on high‐precision maps, and a heading and distance adaptive control method by Proportional‐Integral‐Derivative (PID), and different driving line generation methods for driving along the narrow river and wide river are proposed respectively. The experimental data verification of river boundary detection shows that the algorithm is accurate, real‐time, and robust. [ABSTRACT FROM AUTHOR]

Drift or downstream dispersal is a fundamental process in the life cycle of many riverine organisms. In the face of rapidly declining freshwater biodiversity, there is a need to enhance our capacity to study the drift of riverine organisms, by overcoming the limitations of traditional labour‐intensive sampling methods that result in data of low temporal and spatial resolution.To address this need, we developed a new technology, the Riverine Organism Drift Imager (RODI), which combines in situ imaging with machine‐learning classification. This technique expands on the traditional methodology by replacing the collection cup of a drift net with a camera system that continuously images riverine organisms as they drift through the device. After being imaged, organisms are released into the environment unharmed. A machine‐learning classifier is used after field sampling to identify drifting organisms. Therefore, RODI provides a non‐invasive sampling method that can quantify organism drift at unprecedented temporal resolution.Multiple deployments have served to validate the performance of the technology in the field. In its current implementation, images are captured continuously for 1.5 h at 50 frames per second. We demonstrate that the quality of the resulting images enables a convolutional neural network classifier to identify organisms to the family level. The weighted F1 score, a metric for the performance of the classifier, was 94%, based on training and testing on a field‐collected dataset consisting of 4598 images of 285 organisms belonging to seven classes (one species, five families and one order).In conclusion, this work provides a proof of concept, demonstrating the viability of the deployment of RODI as an automated, in situ organism drift sampler. This novel approach offers the possibility to advance our fundamental understanding of the drift of riverine organisms and how this is affected by human impacts in natural streams while, at the same time, can serve as a cost‐effective tool for biodiversity monitoring. [ABSTRACT FROM AUTHOR]

Stream geodiversity is a novel concept that is used to describe the variety of geological, geomorphological and hydrological features at a reach‐scale level. In this study, we investigated the relationship between geodiversity and ecological indicators based on fishes, benthic macroinvertebrates and diatoms used for the ecological classification of rivers in line with the Water Framework Directive (WFD) 2000/60/EC. We examined whether geodiversity can be used as a proxy indicator of ecological quality, and we further tested if geodiversity can explain a significant amount of taxa richness variation. We hypothesized that undisturbed or minimally disturbed rivers will be more hydrologically and geomorphologically diverse, and as such, the ecological quality of streams will improve with geodiversity. We also attempted to quantify the probability of achieving 'good' ecological quality in relation to geodiversity levels through ordinal regression analysis. Although we did not find a significant relationship between geodiversity and taxonomic richness for any of the three freshwater groups, our results showed positive effects of geodiversity on all three ecological indicators. We also found that the likelihood of achieving the WFD target increases significantly with higher geodiversity. Our findings indicate that geodiversity can potentially serve as a proxy of ecological quality and highlight the need to consider the inclusion of geodiversity measures in ecological quality assessment systems. [ABSTRACT FROM AUTHOR]

Originating in Glacier Park, Montana, the transboundary St. Mary River has provided a focus for international water sharing for a century. It was dammed and diverted in the USA, and more extensively in Alberta, where it supports Canada's centre for agricultural irrigation. Following water withdrawals, the riparian cottonwoods (Populus angustifolia) collapsed, and we assessed the woodland decline downstream from the St. Mary Dam, through eight sets of aerial photographs over seven decades. These revealed 88% woodland loss from 1951 to 1999 (R2 = 0.984), including a steeper decline with the 1980s drought. Following the implementation of an environmental flow regime that increased minimum flows after 1993, the remnant woodlands were stabilized, with a slight recovery by 2022. Analyses of the historical hydrology revealed compound contributions to the woodland mortality. (1) Annual river flows declined with increasing water diversion, and (2) late summer flows were particularly depleted. (3) Dam operations resulted in abrupt stage recessions and irregular spikes. (4) Accompanying climate warming, the spring snowmelt advanced and late summer flows declined. (5) The greatest climatic influence involved multiple‐year clusters with high versus low flows, corresponding with the Pacific decadal oscillation (PDO) from 1920 to 1990 (R2 = 0.365), but less coupled thereafter. This long‐term study demonstrates the coordination between hydroclimatic variation, water management and the fate of riparian woodlands, which reveal ecosystem health. An environmental flow regime provided benefit, and for other regulated rivers in dry ecoregions, we recommend functional flow regimes that provide sufficient minimum flows and avoid abrupt flow recession or irregular spikes. [ABSTRACT FROM AUTHOR]

The present era of climate change and expanding population requires major improvements in sustained observation of global river discharge. Floods and droughts are affecting food supplies, and suspected long‐term trends require appropriate data for evaluation. Orbital remote sensing can address this observational need. Here we use satellite Ka‐ (36.5 GHz) and L‐band (1–2 GHz) passive microwave radiometry (PMR) to monitor river discharge changes and determine what size rivers can be measured and the frequencies and polarization configurations that yield the most robust results. Selected satellite gauging reaches (SGRs) can be measured at near‐daily intervals from 1998 to present (Ka‐band) and 2010 to present (L‐band). The SGRs are 10–36 km in length; the dynamic proportion of water surface area within each varies with river discharge. Due to contrasting dielectric properties, water and land emit different intensities of microwave radiation; thus emission from a mixed water/land pixel decreases as the proportion of water within the pixel increases. Depending on the river and floodplain morphology, water flow area can be a robust indicator of discharge and the microwave sensors can retrieve daily discharge to ±20%. Instead of spatial resolution, it is the sensor measurement precision, geolocation accuracy, and channel and floodplain morphology that most strongly affect accuracy. Calibration of flow area signals to discharge can be performed using nearby ground stations (even if now discontinued) or by comparison to hydrologic modeling. Plain Language Summary: River discharge (flow rate) measurements are critical to hydrology research and water resource management worldwide. Such data have long been collected on the ground at gauging stations, but environmental monitoring in an era of climate change and expanding population now requires major improvements in its quantity and quality. River flow area can be used to monitor streamflow variation, and such area observations are available from a variety of orbital satellite sensors. Passive microwave information offers the advantage of frequent (near daily) sampling with little interference from cloud cover. Flow area is monitored for defined satellite gauging reaches (SGRs) measuring 10–36 km in length depending on the sensor and band used. As demonstrated by comparison to ground gauging stations, Ka‐band and L‐band microwave information can both be used successfully. Ka‐band data offer higher spatial resolution and a time series extending back to 1998. L‐band SGR data from the SMAP polarimetric radiometer are less sensitive to small geolocation errors, and may provide better results especially for the larger rivers or those with forested floodplains. Key Points: Climate change and an expanding global population require major improvements in sustained observation of global river dischargePassive microwave radiometry from several satellite sensors can retrieve river discharge and watershed runoff at globally‐distributed satellite gauging reaches (SGRs)Ka‐band and L‐band information provides accurate and useful discharge time series to ±20% at well‐located SGRs [ABSTRACT FROM AUTHOR]

We use the five landscape ecology metrics of aggregation index, percentage of like adjacencies, interspersion and juxtaposition index, patch density, and Shannon's evenness index to assess spatial heterogeneity at 15 floodplains in the continental United States. Assessments are based on floodplain classes and patches delineated remotely using topography and vegetation. Floodplain reaches examined here represent diverse drainage areas, flow regimes, valley geometries, channel planforms, and biomes. We selected sites with minimal direct human alteration. Our objectives are to quantify floodplain spatial heterogeneity; evaluate whether statistically significant patterns are present; and interpret the statistical analyses with respect to the influence of lateral channel mobility and valley‐floor space available. We develop a conceptual model of the influences on lateral mobility and space available, and then test specific hypotheses derived from this conceptual model. These natural floodplains have a median aggregation index of 58.8%, median percentage of like adjacencies of 58.5%, median interspersion and juxtaposition index of 74.9%, median density of 1,241 patches/ha, and median Shannon's evenness index of 0.934 (n = 15). In other words, natural floodplains have moderate aggregation of classes, high evenness and intermixing of classes, and a wide range of patch densities. Drainage area, the ratio of floodplain/channel width, elevation, precipitation, total sinuosity, large wood volume, planform, and flow regime emerge as important variables to floodplain heterogeneity. These results highlight the influence of biotic‐abiotic interactions in shaping floodplain heterogeneity across diverse river corridors. Plain Language Summary: As river channels move across their valley floors, they create diverse topography including natural levees, cutoff meanders, secondary channels, and floodplain wetlands. These features increase the spatial variability of the floodplain. Many studies indicate that this variability strongly influences habitat abundance and diversity, storage of flood waters and excess nitrate or phosphate, and other floodplain functions. However, no one has systematically measured floodplain variability across multiple rivers and different geographic regions. We measured the variability of natural floodplains at 15 sites in the continental United States using metrics developed by landscape ecologists. We find that natural floodplains have distinctive variability signatures that relate to drainage area, the size of the floodplain, and other characteristics. Key Points: Natural floodplains have moderate aggregation of classes, high evenness and intermixing of classes, and a wide range of patch densitiesFloodplain heterogeneity reflects space available on the valley floor and lateral channel mobility [ABSTRACT FROM AUTHOR]

The microplastic loads in elvers of the critically endangered European eel Anguilla anguilla, sampled in the lower reaches of three English rivers, were very low (incidence: 3.3%, mean ± s.d.: 0.03 ± 0.18 particles) and did not vary with body length or between rivers. Particles were mostly black, polyolefins, fibres and fragments of size 101–200 μm. Current levels indicate a low contamination pressure locally and, consequently, management efforts might prioritise mitigating the effects of other stressors affecting the species. [ABSTRACT FROM AUTHOR]

Over the past several decades, we have increased our understanding of the influences of plant genetics on associated communities and ecosystem functions. These influences have been shown at both broad spatial scales and across many plant families, creating an active subdiscipline of ecology research focused on genes‐to‐ecosystems connections. One complex aspect of plant genetics is the distinction between males and females in dioecious plants. The genetic determinants of plant sex are poorly understood for most plants, but the influences of plant sex on morphological, physiological, and chemical plant traits are well‐studied. We argue that these plant traits, controlled by plant sex, may have wide‐reaching influences on both terrestrial and aquatic communities and ecosystem processes, particularly for riparian plants. Here we systematically review the influences of plant sex on plant traits, influences of plant traits on terrestrial community members, and how interactions between plant traits and terrestrial community members can influence terrestrial ecosystem functions in riparian forests. We then extend these influences into adjacent aquatic ecosystem functions and aquatic communities to explore how plant sex might influence linked terrestrial‐aquatic systems as well as the physical structure of riparian systems. This review highlights data gaps in empirical studies exploring the direct influences of plant sex on communities and ecosystems but draws inference from community and ecosystem genetics. Overall, this review highlights how variation by plant sex has implications for climate change adaptations in riparian habitats, the evolution and range shifts of riparian species and the methods used for conserving and restoring riparian systems. [ABSTRACT FROM AUTHOR]

Industrial‐scale metal mining has long been a feature of developing economies. Processing ores to recover minerals has generated large quantities of waste rock, tailings and contaminants. Mining‐related deposits, along with associated soil and water geochemistry, river modifications and other environmental changes, are a product of the nature, scale and intensity of past operations. These artefacts of historical mining create anthropogenic landscapes that extend far beyond individual sites due to the dispersal of mine waste by rivers and pose enduring threats to human and ecosystem health. Their presence and significance, however, are often overlooked by heritage and environmental managers. To be acknowledged as artefacts of the historical mining industry, landscape features must be identified and characterised with reference to the human activities that triggered their formation. This requires an interdisciplinary approach that incorporates anthropogenic landscape change at a regional scale. In this paper, we integrate archaeological, geomorphological and geochemical evidence to identify and analyse mining‐related changes to the Loddon River valley in Victoria, Australia. Nineteenth‐century gold mining caused extensive erosion of creeks and gullies and mobilised sediments that filled channels and spread over floodplains. In addition, tailing deposits concentrated arsenic at levels significantly above environmental background conditions. Recognising these legacies of historical mining is vital to understanding mining heritage and to managing healthy rivers, environments and communities. [ABSTRACT FROM AUTHOR]

In recent years scholars have advanced our understanding of the biophysical, socioeconomic, and geopolitical impacts of dams and hydropower infrastructure around the globe. Databases and maps have emerged that allow global comparisons between countries and river basins. However, reliable and freely available data do not exist for many regions. As a result, data limitations and quality issues persist, which limit the quality of analyses based on these datasets. This is particularly true in regions where hydropower infrastructure development is proceeding most rapidly, including South Asia's Third Pole region. We identify and describe serious quantitative and qualitative data dilemmas of existing databases. We divide these into location, size, type, and status. At the most basic level, these dilemmas mean that incorrect location and, more importantly, massive underrepresentation of existing and future projects generates incorrect conclusions. That underrepresentation results largely from uncritically equating absence of data with absence of infrastructure. We also argue that project function should be more reliably recorded (for both dams and hydropower projects), that project status should be clear (many existing projects are still passed off as future), and that smaller projects should be systematically recorded (their cumulative importance is often underestimated). These four dilemmas all have important implications for analyses based on existing datasets. The World Index of Hydropower, Dams, and Reservoirs (WIHDR) described here represents a major advance on all four points. For the first time, 652 existing hydropower plants (277 large and 375 small), 162 under construction, and 720 planned hydropower plants have been georeferenced and systematically recorded for the Indus‐Ganga‐Brahmaputra region. This article is categorized under:Science of Water > Water and Environmental ChangeWater and Life > Stresses and Pressures on EcosystemsScience of Water > Methods [ABSTRACT FROM AUTHOR]

Many of the world‐rivers are often ungauged or poorly gauged due to inadequate streamflow monitoring networks. Even with the limited available monitoring stations, only a few of them monitor both stage and discharge data. But when there is a need for estimation of discharges at a gauging station, where only stage data is monitored, one may employ a reverse routing technique using the stage data monitored at a nearby downstream gauging station. This study develops a novel single‐parameter reverse‐stage routing (RSR) model based on the second‐order approximate water surface gradient governing equation to estimate stage and discharge at any scantily‐gauged upstream river section using the known stage information available at the downstream section. A novel criterion is also developed for checking the applicability of the RSR model. Reverse routing experiments, carried out by the RSR model using different hypothetical downstream stage hydrographs in a number of hypothetical trapezoidal and rectangular channel reaches to reproduce the benchmark upstream stage and discharge hydrographs, demonstrate the good performance of the RSR model with the Nash–Sutcliffe Efficiency >98%, absolute volume conservation error <1.5%, and an absolute error in peak ≤1%. Subsequently, the RSR model was tested for three real‐river case studies in India and Italy with good reproduction performances, and along with the development of the corresponding normal rating curves at the upstream river sections. The study results reveal that the parsimonious RSR model has good potential for solving reverse routing problems with stable numerical solutions for rivers under ungauged and scantily‐gauged scenarios. Plain Language Summary: The discharge and flow depth variables at an upstream section of a river reach are often required for flood management and operating the downstream hydraulic control structures. However, many world‐rivers have poor streamflow monitoring infrastructure, and sometimes, only stage data at the downstream section of a reach are available. As the existing methods mostly use discharge as the operating variable, this study is aimed at developing an approach involving stage as an operating variable. Hence, the current study proposes a novel physically based parsimonious Reverse stage‐routing model for obtaining the upstream flow depth and the corresponding discharge, thus establishing the normal rating curve at the ungauged section, meant for field use. A novel applicability criterion is also advocated to check the failure of the routed solutions. Conclusively, the developed model has an excellent potential to establish normal rating curves at an ungauged or scantily‐gauged upstream river section for field applications by field engineers and water resources managers. Key Points: Based on the second‐order approximate water surface gradient equation, developed a novel reverse‐stage routing model with lateral flowDeveloped a novel applicability criterion ensuring stable stage‐discharge solutions at ungauged/scantily‐gauged upstream river sectionsIn hypothetical and real‐river cases, it efficiently solves reverse routing problems and can establish normal rating curves [ABSTRACT FROM AUTHOR]

Aim: Central Africa shelters diverse and iconic megafauna, which is threatened by climate and land‐use changes and increased hunting‐induced defaunation. Though crucial for coordinating regional conservation actions, how species assemblages are spatially structured remains poorly understood. This study aims to fill this knowledge gap for mammals across central African forests. Location: Tropical moist forests from Nigeria to the Albertine Rift. Methods: An extensive compilation of forest‐dwelling mammal species lists was made from wildlife and bushmeat‐related surveys across central Africa. A beta‐diversity approach enabling the clustering of surveys composed of similar species was implemented to identify and delimit zoogeographic districts, separately for three well‐documented mammal orders: carnivores, primates and artiodactyls. Random forest classification models were then used to identify the environmental determinants of the district's distribution and to produce a continuous zoogeographic map (and associated uncertainties) critical to assess the conservation status of each district and their ongoing threats. Results: While carnivores do not present a clear spatial structure within central African forests, our findings highlight the structuring role of rivers on both primate and artiodactyl assemblages' distributions. We retained eight and six spatially congruent districts for primates and artiodactyls, respectively. These districts were shaped by the Ubangi‐Congo River system, and the Cross and Sanaga Rivers, with a secondary role of insularity and precipitation identified for primates. Highly threatened districts were highlighted, especially in Nigeria and in the Democratic Republic of Congo, the latter including vast areas that are understudied and poorly represented in the protected area network. Main Conclusions: Beyond refining our understanding of the diversity and uniqueness of mammalian assemblages across central African forests, our map of zoogeographic districts has far‐reaching implications for the conservation of highly threatened taxa, allowing to target species and areas of interest for further sampling, conservation and rewilding efforts. [ABSTRACT FROM AUTHOR]

Climate change is altering hydrological cycles globally, and in Mediterranean (med‐) climate regions it is causing the drying of river flow regimes, including the loss of perennial flows. Water regime exerts a strong influence over stream assemblages, which have developed over geological timeframes with the extant flow regime. Consequently, sudden drying in formerly perennial streams is expected to have large, negative impacts on stream fauna. We compared contemporary (2016/17) macroinvertebrate assemblages of formerly perennial streams that became intermittently flowing (since the early 2000s) to assemblages recorded in the same streams by a study conducted pre‐drying (1981/82) in the med‐climate region of southwestern Australia (the Wungong Brook catchment, SWA), using a multiple before‐after, control‐impact design. Assemblage composition in the stream reaches that remained perennial changed very little between the studies. In contrast, recent intermittency had a profound effect on species composition in streams impacted by drying, including the extirpation of nearly all Gondwanan relictual insect species. New species arriving at intermittent streams tended to be widespread, resilient species including desert‐adapted taxa. Intermittent streams also had distinct species assemblages, due in part to differences in their hydroperiods, allowing the establishment of distinct winter and summer assemblages in streams with longer‐lived pools. The remaining perennial stream is the only refuge for ancient Gondwanan relict species and the only place in the Wungong Brook catchment where many of these species still persist. The fauna of SWA upland streams is becoming homogenised with that of the wider Western Australian landscape, as drought‐tolerant, widespread species replace local endemics. Flow regime drying caused large, in situ alterations to stream assemblage composition and demonstrates the threat posed to relictual stream faunas in regions where climates are drying. [ABSTRACT FROM AUTHOR]

Key Takeaways: Facing an increase in the size and complexity of wildland interface fires, water utilities must pay more attention to protecting vital infrastructures during potentially catastrophic wildfires. Water utilities can mitigate the impacts of wildfires by using a three‐pronged approach that includes collaborating with fire agencies, protecting infrastructure, and supporting air assets like firefighting helicopters. Gaining situational awareness at the onset of a wildfire helps minimize its impacts. [ABSTRACT FROM AUTHOR]

The Southwestern community of Gilbert, Ariz., chose a proactive approach to addressing dramatic changes in its watershed and resulting treatment challenges. Comprehensive analysis showed that building a new treatment plant was the best way to go. [ABSTRACT FROM AUTHOR]

It is not an understatement to say that a thriving and healthy river system for the Mesopotamian region means a thriving economy for all with a productive agriculture and a sustainable manufacturing base that needs reliable water supply and cheap power. When looked at from a 30,000 feet from the ground, the Mesopotamian region began experiencing a steady decline in the health of its rivers from the 1980s with a series of unfortunate man‐made events ranging from wars to uncoordinated dam development. While there have been many analyses and historical dissection of the current water situation, one question that we all need to ask now is How can we restore the Mesopotamian rivers? Plain Language Summary: We believe we need to think in radical ways and drive our multi‐year and multi‐disciplinary research agenda with the goal of driving sustainable economic development. Research just for research sake and publication of research papers is now an outdated concept that benefits a few in this region in the near term. We call on the key players of the region, such as the national governments, water ministries, US Department of State, and European Government agencies to push for win‐win solutions. It is in their best economic and sovereign interest too to see Mesopotamian rivers restore sooner rather than later. Because, if the Mesopotamian rivers fail, then we as a world fail. Key Points: Mesopotamian rivers have declined steadily over the past 40 years with a reduced flood pulse due to dams by Turkey Iraq and SyriaSuch decline has lead to an unsustainable state of affairs and livelihood for downstream nationsThere are practical solutions to restore the rivers by seeking answer to how much water is really available [ABSTRACT FROM AUTHOR]

An increase in the demand for renewable energy is driving hydropower development and its integration with variable renewable energy sources. When hydropower is produced flexibly from hydropower plants, it causes rapid and frequent artificial flow fluctuations in rivers, a phenomenon known as hydropeaking. Hydropeaking and associated hydrological alterations cause multiple impacts on riverine habitats with cascading effects on ecosystem functioning and structure. Given the significance of its ecological and socio‐economic implications, mitigation of hydropeaking requires an inter‐ and transdisciplinary approach. An interdisciplinary network called HyPeak has been conceived to enrich international research initiatives and support hydropower planning and policy. HyPeak has been founded based on exchange and networking activities linking scientists from several countries where hydropeaking has been widespread for decades and numerous studies dedicated to the topic have been carried out. HyPeak aims to integrate members from other countries and continents in which hydropower production plays a relevant role, and grow to be a reference group that provides expert advice on the topic to policy‐makers, as well as researchers, stakeholders, and practitioners in the field of hydropeaking. [ABSTRACT FROM AUTHOR]