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ABSTRACT Sound is critical in fish behaviours, including reproduction, feeding, predator avoidance and habitat selection. To investigate the impact of underwater soundscape on the distribution of Cobitidae fishes, we surveyed the status of Cobitidae fish resources and the underwater soundscape along with related environmental factors at 12 sampling sites downstream of the Songxin Hydropower Station in the Heishui River, a major tributary of the Jinsha River in China. Generalised additive models (GAMs) were employed to identify the primary environmental factors influencing the distribution of Cobitidae fishes and we analysed the correlation between the abundance of Cobitidae fish and primary environmental factors. The study revealed that the water depth, flow velocity, water temperature and sound pressure level (SPL) all had highly significant effects on the distribution of Cobitidae fishes (p < 0.001), with SPL showing the lowest relative importance among these factors. Water depth positively correlated with Cobitidae fish abundance, whereas water temperature, SPL and flow velocity showed negative correlations. This study preliminarily explored the response relationship between the distribution of Cobitidae fish and four main environmental factors, offering a technical foundation for predicting the distribution of Cobitidae fishes in rivers and for implementing conservation measures of fish such as suitable habitat creation. [ABSTRACT FROM AUTHOR]

Research on the runoff and sediment reduction effects of soil and water conservation measures has always been a topic of interest, which is of great significance for carrying out sustainable strategies for soil and water conservation in the Yellow River Basin. This study aims to find the threshold years of soil and water conservation measures for reductions in runoff and sediment. Through the analysis of various soil and water conservation measures, runoff, sediment, and rainfall data in the Sanchuan River Basin from 1960 to 2019, we determined the threshold years of soil and water conservation measures on runoff and sediment processes using the Hydrology and Lagrange Multiplier method. The results are as follows: The trend in flood season rainfall and annual rainfall in the Sanchuan River Basin is consistent. The 1990s was a turning period in the annual rainfall and flood season rainfall of the Sanchuan River Basin. The 2000s was a turning period of the runoff in the Sanchuan River Basin, while the sediment entered a stable period after 2000. The best periods for reducing runoff and sediment were the initial treatment period (1967–1979) and the centralized treatment period (1980–1996). The runoff and sediment reduction effects of each soil and water conservation measure during the initial treatment period (1967–1979) were terrace (32.8%) > dam (30.1%) > grass (18.6%) > forest (18.5%), while their effects during the centralized treatment period (1980–1996) were grass (53.7%) > terrace (20.7%) > dam (14.6%) > forest (11.0%). The runoff and sediment reduction effects of various soil and water conservation measures during different treatment periods indicate that the runoff reduction effect reached its peak in 2003–2005, while the sediment reduction benefit reached its peak in 2013–2015. Based on the comprehensive benefits of runoff and sediment regulation, 2013–2015 are considered to be the threshold years for various soil and water conservation measures, with the measures covering respective average areas of 4.85 × 104, 17.80 × 104, 1.15 × 104, and 0.82 × 104 hm2. These research results will have a certain significance for the reasonable allocation of soil and water conservation measures and sustainable development in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

Cooperative governance of water pollution is an effective initiative to implement the strategy for the protection of the Yangtze River Basin. Based on the stakeholder theory, this paper constructs a tripartite evolutionary game model of water pollution in the Yangtze River Basin from the perspective of "cost–benefit". This paper analyzes the stability of possible equilibrium points of the evolutionary game system by scenarios and further explores the influence of key factors on the evolution of the cooperative governance system of water pollution in the Yangtze River Basin using numerical simulation. According to the findings, (1) the watershed system comprises three key stakeholders: local governments, enterprises, and the public. Each stakeholder's behavioral strategy choice is influenced by its unique factors and the behavioral strategy choices of the other two stakeholders. (2) Equilibrium points represent the potential strategic equilibrium presented by each stakeholder. When the net income of a particular behavioral strategy within the set exceeds zero, stakeholders will be more inclined to choose that behavioral strategy. (3) The key influencing factors in the evolutionary game are regulatory costs, reputation loss, material rewards, and violation fines. Therefore, this paper proposes to construct a cooperative governance mechanism for water pollution in the Yangtze River Basin from three aspects: an efficient regulatory mechanism, a dynamic reward and punishment mechanism, and a multi-faceted incentive mechanism, with a view to promoting a higher-quality development of the ecological environment in the Yangtze River Basin. [ABSTRACT FROM AUTHOR]

Rivers play important roles in ecological biodiversity, shipping trade and the carbon cycle. Owing to human disturbances and extreme climates in recent decades, river extents have altered frequently and dramatically. The development of sequential and fine-scale river extent datasets, which could offer strong data support for river protection, management and sustainable use, is urgently needed. A literature review revealed that annual river extent datasets with fine spatial resolutions are generally unavailable for China. To address this issue, the first Sentinel-derived annual China river extent dataset (CRED) from 2016 to 2023 was produced in our study. We first produced annual water maps by combining the dynamic world (DW), ESRI global land cover (EGLC) data and the multiple index water detection rule (MIWDR). For the DW and MIWDR water time series, the mode algorithm, which calculates the most common values, was used to generate yearly water maps. Then, an object-based hierarchical decision tree based on geometric features and auxiliary datasets was developed to extract rivers from the water data. The results indicated that the overall accuracies (OAs) of the CRED were greater than 96.0 % from 2016 to 2023. The user accuracies (UAs), producer accuracies (PAs) and F1 scores of the rivers exceeded 95.3 %, 91.3 % and 93.7 %, respectively. A further data intercomparison indicated that our CRED shared similar patterns with the wetland map of East Asia (EA_Wetlands), China land use/cover change (CNLUCC) and China water covers (CWaC) datasets, with correlation coefficients (R) greater than 0.75. Moreover, our CRED outperformed the three datasets in terms of small river mapping and misclassification reduction. The area statistics indicated that the river area in China was 44,948.78 km2 in 2023, which was mostly distributed in coastal provinces of China. From 2016 to 2023, the river areas were characterized by an initial increase, followed by a decrease and then a slight increase. Spatially, the decreased rivers were located mainly in Southeast China, whereas the increased rivers were distributed mainly in Central China and Northeast China. In general, the CRED explicitly delineated river extents and dynamics in China, which could provide a good foundation for improving river ecology and management. The CRED dataset is publicly available at https://doi.org/10.5281/zenodo.13841910 (Peng et al., 2024a). [ABSTRACT FROM AUTHOR]

The paper aims to verify whether volunteering and environmentalism are two phenomena that overlap both conceptually and empirically. The actions for the protection and enhancement of rivers in Italy are taken as a testing ground. Two packages of literature are used to understand the overlap between volunteering and environmentalism, one on neo-institutionalism and the other on new social movements. The starting framework is a general typology of voluntary organisations, which is then adapted to the environmental movement. The hypothesis of growing disintermediation and light commitment by the new generations of volunteers finds original answers in river volunteering. Alongside classic environmentalist militancy, forms of popular action in favour of rivers are emerging that show detachment from politics and attraction to intrinsic benefits, such as the pleasure of recreation and collective memory recovery. This raises new questions about the role of organised civil society in maintaining democracy and helping the ecological transition. [ABSTRACT FROM AUTHOR]

Analytical and semi‐analytical models for stream depletion with transient stream stage drawdown induced by groundwater pumping are developed to address a deficiency in existing models, namely, the use of a fixed stream stage condition at the stream–aquifer interface. Field data are presented to demonstrate that stream stage drawdown does indeed occur in response to groundwater pumping near aquifer‐connected streams. A model that predicts stream depletion with transient stream drawdown is developed based on stream channel mass conservation and finite stream channel storage. The resulting models are shown to reduce to existing fixed‐stage models in the limit as stream channel storage becomes infinitely large, and to the confined aquifer flow with a no‐flow boundary at the streambed in the limit as stream storage becomes vanishingly small. The model is applied to field measurements of aquifer and stream drawdown, giving estimates of aquifer hydraulic parameters, streambed conductance, and a measure of stream channel storage. The results of the modeling and data analysis presented herein have implications for sustainable groundwater management. [ABSTRACT FROM AUTHOR]

Water conservation (WC) is a critical ecological service function in the Yellow River Basin (YRB). There is currently a lack of detailed exploration of WC development processes and the impact mechanisms of driving factors at spatiotemporal scales in the YRB. By collecting data on DEM, land use, soil, meteorology, reservoirs, and observed discharge, this study established a large-scale WC model using the soil and water assessment tool (SWAT). The abrupt change test, empirical orthogonal function (EOF), wavelet analysis, hierarchical partitioning analysis (HPA), geodetectors, and aridity index were employed to analyze the multi-spatiotemporal characteristics and driving forces of WC calculated using the water balance method. The results are as follows: (1) The average WC among the YRB was 9.11 mm (74.68 × 108 m3) from 1960 to 2020. Pasture and forests contributed to 48.65% and 22.05% of the average annual WC, respectively. (2) WC exhibited four forms: less/more in the YRB, more in the southeast (northwest), and less in the northwest (southeast). (3) Forests and pastures in land use had higher average WC capacity, while Gansu, Shaanxi, and Qinghai ranked in the top three for average WC among the nine provinces. (4) Precipitation was the major driving force affecting WC variations, with the interaction between precipitation and actual evapotranspiration being the most significant. (5) Drought was a significant cause of negative WC. Protecting and managing crucial WC areas was essential for improving the ecological environment. This research elucidates the driving forces of WC in the YRB, providing scientific support for improving regional WC and promoting sustainable development. [ABSTRACT FROM AUTHOR]

This article explores different definitions of river, and in doing so, considers how our efforts to define rivers illuminate aspects of the human condition. Through an exploration of our definitions of river, through the human imagination, in poetry, music, and human's actions, this article considers how our nature is reflected back by rivers—how we in turn are defined by rivers—such as their role in determining borders, movement, escape, the locations of cities, trade, communication, and in the shaping of cultures and societies. This article specifically highlights three definitions of river using examples predominately from North America. River as boundary, exploring how in the reaches of some river basins, rivers act not only as a border, or boundary between two nations or cultures, but also as a line of demarcation between the known and unknown landscapes and the tamed and untamed lands. The definition of river as pathway includes exploration of how the Mississippi River served as a natural highway for people escaping slavery to travel North and reach Underground Railroad routes toward freedom, while also forcibly moving hundreds of thousands of enslaved people in the United States from the Upper South to the Lower South as they were "sold down the river." Third, this article examines how rivers have been defined as a resource through examples, such as the US government and Bonneville Power Administration's (BPA) efforts, to encourage support of large dam construction and water development projects by hiring Woody Guthrie in 1941 to write songs that would prompt public support for the water projects. Through this discussion of three river definitions, the article considers how rivers have been conceptualized over time and how those different knowledges inform our understanding and treatment of rivers. The article argues that it is vital to include knowledge from across scales, time, boundaries, and ways of knowing in order to improve the protection of rivers and their ecosystems. If we do not, we will continue to lose freshwater biodiversity, wetland and riverine habitat, and their immeasurable qualities that inspire life and imagination at a staggering rate. [ABSTRACT FROM AUTHOR]

The Normalized Difference Vegetation Index (NDVI) is affected by various environmental factors, and its relationship with these factors is complex. In order to explore the complex relationship between NDVI and environmental factors, this paper adopts the complex network method to construct a correlation fluctuation network and analyze the interaction between them. It is found that temperature, precipitation, soil moisture, sunshine duration, and PM2.5 are all correlated with NDVI to varying degrees, and their combined correlation with NDVI varies over time. The correlation typically takes 3 to 6 months to change, and it tends to persist to some extent. Moreover, we fuse a generalized regression neural network (GRNN) with a long-short-term memory (LSTM) network combining phase space reconstruction (PSR) to propose a GRNN-PSRLSTM prediction model. The model achieves the prediction of monthly NDVI using the five environmental factors of the fluctuation network. The results indicate that the averages of root mean squared error (RMSE) and mean absolute percentage error (MAPE) predicted by the GRNN-PSRLSTM model in the nine provinces are 0.0232 and 0.0564 respectively. This model performs better in the assessment metrics for monthly NDVI forecasts. These findings are significant for evaluating vegetation changes and have some theoretical value for the ecological protection of the Yellow River Basin. [ABSTRACT FROM AUTHOR]

This article examines the construction of the land-water binary in the Sundarbans delta in colonial South Asia. It argues that this division was racially motivated and used to justify colonial rule. The article criticizes current river studies scholarship for perpetuating this divide and calls for a reevaluation of approaches to environmental studies. It also highlights the need to analyze the social dynamics and power structures surrounding water resources, particularly in relation to caste-based oppression. The article concludes by emphasizing the importance of understanding the complexities of water access and usage beyond the traditional land-water binary. [Extracted from the article]

Background. Colorado River Cutthroat Trout (CRCT; Oncorhynchus clarkii pleuriticus) conservation populations may be at risk from wildfire and post-fire debris flows hazards. Aim. To predict burn severity and potential post-fire debris flow hazard classifications to CRCT conservation populations before wildfires occur. Methods. We used remote sensing, spatial analyses, and machine learning to model 28 wildfire incidents (2016-2020) and spatially predict burn severity from pre-wildfire environmental factors to evaluate the likelihood (%) and volume (m³) hazard classification of post-fire debris flow. Key results. Burn severity was best predicted by fuels, followed by topography, physical ecosystem conditions, and weather (mean adjusted R² = 0.54). Predictions of high or moderate burn severity covered 1.1 (15% of study area) and 1.5 (19% of study area) million ha, respectively, and varied by watershed. Combined high or moderate debris flow hazard classification included 80% of stream reaches with conservation populations and 97% of conservation population point nodes. Conclusions. Predicted burn severity and potential post-fire debris flow indicated moderate to high hazard for CRCT conservation populations native to the Green and Yampa rivers of the Upper Colorado River Basin. Implications. Future management actions can incorporate predicted burn severity and potential post-fire debris flow to mitigate impacts to CRCT and other at-risk resource values before a wildfire occurs. [ABSTRACT FROM AUTHOR]

This study examined the location preferences and changes in pollution-intensive firms by analyzing the spatiotemporal distribution and drivers in the Yangtze River Economic Belt, a transitional manufacturing region in China. To analyze the distribution of firms under natural growth conditions prior to the implementation of the national "Great Protection of the Yangtze River" policy in 2016, this study utilized data on newly expanded industrial land use from 2007 to 2016. The results indicated that new pollution-intensive firms predominantly focused on water pollution, occupying over 40% of the total area annually. The new pollution-intensive firms preferred the geographic agglomeration siting strategy, mostly along the Yangtze River or in urban agglomerations, while gradually moving westward. The total area and number of new pollution-intensive firms in the Yangtze River Economic Belt showed an overall trend of "inverted U-shaped" variation during the study period, and the average size of the pollution-intensive firms gradually decreased. GeoDetector analysis revealed that geographical factors have always been significant. Local economic factors attracted new pollution-intensive firms, but later in the study period, these factors showed some inhibitory effect on the increase in pollution-intensive firms in the lower reaches. Government intervention worked less effectively but was significantly enhanced after interaction with other factors. Finally, the results suggested that local governments should build a stronger synergy between industrial land policies and environmental regulations to ensure sustainable growth and rational allocation of pollution-intensive firms. [ABSTRACT FROM AUTHOR]

Damming profoundly affects downstream flow‐sediment regimes, altering channel bar dynamics and thereby affecting floods and riverine biodiversity. Here, we investigate the response of bars to upstream damming by examining patterns, mechanisms, and impacts in the Middle Yangtze River (∼1,000 km). Over a decade of post‐damming observational data reveal substantial increases in bar revegetation and Leaf Area Index. Shorter flood duration and stable bar size collectively drive bar greening. Consequently, denser vegetation has slowed flow velocity by 17% ± 2% and increased flow resistance by 21% ± 5%, offsetting the water‐level decrease from channel expansion due to scouring and even causing a slight rise in floodwater levels. Furthermore, damming has markedly altered river connectivity, thermal regimes, and solute dynamics, detrimentally affecting fish habitats and aquatic life. These findings, along with refined river stage simulation considering flow‐sediment‐vegetation interactions, facilitate sustainable reservoir operation and river management in big river systems. Plain Language Summary: Dams significantly impact downstream river systems, affecting bar dynamics, flood risks, and biodiversity. This study focuses on the Middle Yangtze River, which spans nearly 1,000 km, to show how upstream damming changes vegetation growth on bars. Over a decade, we observe increases in vegetated area and Leaf Area Index, with shorter floods and stable bar area leading to greener bars. Denser vegetation slows flow velocity and increases flow resistance, which balances the water level changes caused by channel deepening. Damming also disrupts river connectivity and water quality, harming fish habitats and aquatic life. These insights can help improve reservoir management and river conservation in the face of global change. Key Points: Damming operation boosts downstream bar greeningShorter flood duration and stable bar size drive plant expansionChannel bar greening increases flow resistance, reshaping flood and ecological patterns [ABSTRACT FROM AUTHOR]

Climate change and human activities have significantly impacted the long-term growth of vegetation, thereby altering the ecosystem's response mechanisms. The Yellow River Water Conservation Area (YRWCA) is a critical ecological functional zone in China. Since 1982, the vegetation in the YRWCA has changed significantly, and the primary drivers of vegetation which changed before and after 2000 were identified as climate change and human activities, respectively. However, the extent to which different drivers contribute to the vegetation dynamics of the YRWCA remains uncertain. In this study, we introduced a modified deep Convolutional Long Short-Term Memory (ConvLSTM) model to quantify the contributions of climate change and human activities to vegetation change while considering the spatiotemporal heterogeneity. We identified areas with minimal human activity before 2000 using the residual trend method, and used the regional data from these areas to train the model. Subsequently, we applied the trained deep ConvLSTM model to perform an attribution analysis after 2000. The results show that the deep ConvLSTM effectively captures the impacts of climate change on vegetation growth and outperforms the widely used Random Forest model (RF). Despite the fact that the input data of RF were optimized, ConvLSTM still distinctly outperformed RF, achieving R2, MAE, and RMSE values of 0.99, 0.013, and 0.018, respectively, compared to RF's corresponding values of 0.94, 0.038, and 0.045. Since 2000, the regional normalized difference vegetation index (NDVI) has shown a broad increasing trend, particularly in dryland, primarily induced by human activities from 2006 to 2015. Furthermore, an analysis of changes in regional land use, particularly in drylands, revealed that the highest magnitude of conversion of farmland back to forest or grass was recorded from 2000 to 2005. However, the most significant contributions from human activities occurred from 2006 to 2015, indicating a time lag in vegetation recovery from these ecological programs. The attribution results provide valuable insights for the implementation of ecological programs, and the introduced deep ConvLSTM proves the suitability of deep learning models that capture spatiotemporal features in vegetation growth simulations, allowing for broader applications. [ABSTRACT FROM AUTHOR]

Two new African minnow species, Enteromius cerinus sp. nov. and Enteromius ruforum sp. nov., are described for science from the Angadiko River, a left‐bank sub‐affluent of first order of the Nepoko River, draining the north‐eastern part of the Okapi Wildlife Reserve (OWR). Both new species belong to the group of Enteromius for which the last unbranched dorsal‐fin ray is flexible and underrated. Within this morphological group, both are most similar to Enteromius kamolondoensis, especially in life colour pattern characteristics. However, Enteromius cerinus sp. nov. differs from E. kamolondoensis by its low number of circumpeduncular scales, 10–11 (vs. 12), low maximum body depth, 22.8%–25.7% standard length (Ls) (vs. 26.1%–30.0%), and long anterior and posterior barbel lengths, 32.6%–35.3% head length (LH) (vs. 23.6%–27.2%) and 41.6%–43.9% LH (vs. 30.3%–34.9%), respectively. Further, E. ruforum sp. nov. is also easily distinguished from E. kamolondoensis by its high maximum body depth, 30.6%–33.3% Ls (vs. 26.1%–30.0%), and small, isometric, eye diameter, 26.2%–28.0% LH (vs. 29.1%–31.9%). A barcoding study (mtDNA, cytochrome oxidase subunit I [COI]) revealed that specimens of both new species form lineages well differentiated from those of other available species. As such, (i) E. cerinus sp. nov. diverges from E. kamolondoensis by a K2P genetic distance (GD) of 10.3% and (ii) E. ruforum sp. nov. by a K2P GD of 11.2%. To the present day, the fish fauna of the left‐bank sub‐affluents of the Nepoko River, in general, remains poorly known or undocumented. Unfortunately, at the same time, multiple anthropogenic impacts are affecting this fauna, such as (i) the destruction of habitats along the river banks for agriculture and fishing and (ii) the use of illegal fishing practices, such as fishing with plant‐based ichthyotoxins during ecopage, which is combined with dam building. As a result of the demographic growth, this ecopage results in overfishing and thus is threatening both new species in particular, but all other co‐occurring fish species as well. Both new species, E. cerinus sp. nov. and E. ruforum sp. nov., should thus be considered Vulnerable (VU) according to IUCN criterion D2. It is therefore hoped that their discovery highlights the urgent need for a better protection and further in situ exploration of the reserve's freshwater (fish) biodiversity, in general, and that of those small sub‐affluents, in particular. [ABSTRACT FROM AUTHOR]

Atlantic salmon (Salmo salar), brown trout (Salmo trutta), and steelhead trout (Oncorhynchus mykiss) kelts have important conservation value for population resilience. Nonetheless, relative to other salmonid life-stages, knowledge on their behavior and survival is poor. This is especially true for kelt downstream migration in rivers fragmented by hydropower plants (HPP), even though the physiological and survival consequences are severe when functional connectivity is not provided. Here, the existing information about kelt downstream migration past HPP was summarized, beginning with an overview of iteroparous salmonid lifecycles. Then, the importance of kelts for conservation and the threats they encounter while migrating was discussed. Finally, the current corpus of peer-reviewed literature and reports focused on kelt migration in these systems was presented. Kelt studies have focused on five main themes: (1) postspawning survival, (2) migration delays before dam passage, (3) passage selection and guidance efficiency, (4) passage mortality, and (5) the swimming behaviors of kelts during migration. Overall, there was a paucity of information about kelts and several information gaps and needs for future research. This work should inform scientists and river managers on the conservation of salmonids in regulated rivers, including the development of passage solutions for safe downstream migration. [ABSTRACT FROM AUTHOR]

[Objective] Habitat quality is the potential of ecosystems to provide the necessary conditions for species survival and reproduction, and is the key to improving ecosystem functions. Studying the habitat quality of the Yangtze River Basin is of great significance for national major strategies such as green development of the Yangtze River Economic Belt and the protection of the Yangtze River. [Methods] Based on land use data from 1980 to 2018 in the middle and lower reaches of the Yangtze River, the InVEST model was used to study the spatiotemporal changes in land use change, habitat quality, and habitat degradation in the middle and lower reaches of the Yangtze River from 1980 to 2018. [Results] (1) As the main type of land use in the study area, woodland was decreasing, mainly turning to construction land and water area, which greatly reflected the driving effect of population growth, economic development and environmental protection on the change of land use structure. (2) The overall habitat quality of the study area was at a high level. showing a trend of low in the east and middle, and high in the south, which was consistent with the land use pattern that most of the cities along the Yangtze River in the east and middle of the study area were dominated by construction land, and the south was dominated by woodland and grassland. (3) In the study area, the degree of habitat degradation was higher in the central area and lower in the surrounding area. The change of the degree of habitat degradation showed an upward trend in time, and the areas where the degree of habitat degradation changes were more concentrated in space, such as the urban agglomeration along the river, urban and rural areas and other population agglomerations. [Conclusion] The habitat evolution in the middle and lower reaches of the Yangtze River is in a process of degradation. The process of urbanization makes a large number of woodland, grassland and cultivated land in land use turn to construction land, which leads to the continuous decline of habitat quality, especially the problem of the urban agglomeration. along the Yangtze River. We should develop construction land more reasonably and draw the ecological protection red line, gradually restore and improve the habitat quality of the middle and lower reaches of the Yangtze River, and make a positive contribution to the process of the Yangtze River protection. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrate abundance and taxa richness associated with environmental variables were monitored monthly from September 2015 to August 2016 in the Nyamuhinga River. The benthic macroinvertebrate samples were collected using a D-frame aquatic net employing the man-time method. Environmental variables including pH, temperature, conductivity, and total dissolved solids (TDS) were measured using a Combo HI 98129 and GREISIN-GER 020 multimeters, and water flow was assessed using the Float Method procedure. The Shannon–Wiener and equitability indices were then calculated to assess diversity and richness, facilitating the comparison of diversity within sites or stations. A total of 35,142 macroinvertebrate individuals were collected from the 12 sampling sites belonging to 29 genera, 27 families, and 9 orders. Diptera were the most abundant (71.83%) followed by Odonata (9.13%) and Ephemeroptera (7.11%). The findings showed that taxa richness decreased from upstream to downstream. At the same time, absolute abundance increased from downstream to upstream due to riparian vegetation, substrate type, plant debris, and organic matter which are habitats for benthic macroinvertebrates in the river. Environmental variables such as flow, pH, temperature, conductivity, and TDS varied between sites and stations because of habitat disturbances, contaminant discharges into the catchment, and inflow of tributary waters into the river. The canonical correspondence analysis (CCA) results displayed that Eristalis and Chironomus were strongly associated with the flow, conductivity, TDS, temperature, and pH at the downstream sites related to anthropogenic activities from the catchment. From our results, the Nyamuhinga River needs conservation master plan/guidelines and increased awareness to reduce environmental impacts in Bukavu River catchments in the Lake Kivu basin. [ABSTRACT FROM AUTHOR]

The impacts of landscape patterns on river water quality are commonly acknowledged, but understanding the complex processes by which landscape patterns affect water quality is still limited, especially in densely populated urban areas. Exploring the mechanisms through which landscape characteristics influence water quality changes in urbanized rivers will benefit regional water resource protection and landscape-scale resource development and utilization. Utilizing daily water quality monitoring data from rivers in the urbanized area of the Pearl River Delta in 2020, our research employed canonical analysis and partial least squares structural equation modeling (PLS-SEM) to explore the processes and mechanisms of the influence of urbanized river landscape patterns on surface water quality. The results indicated that total nitrogen (TN) was the critical indicator limiting the water quality of rivers in the Pearl River Delta. The landscape composition and configuration indexes exhibited non-linear variations with scale, and the landscape fragmentation was higher closer to the river. Landscape patterns had the most significant influence on water quality under the characteristic scale of a 5.50 km circular buffer zone, and landscape composition dominated the change of water quality of urbanized rivers, among which 30.64% of the percentage patch area of construction (C_PLAND) contributed 46.40% to the explanation rate of water quality change, which was the key landscape index affecting water quality. Moreover, landscape patterns had a higher interpretive rate of 39.29% on water quality in the wet season compared to 36.62% in the dry season. Landscape composition had an indirect negative impact on water quality, with a value of 0.47, by affecting the processes of runoff and nutrient migration driven by human activities, while landscape configuration had an indirect negative impact on water quality, with a value of 0.11. Our research quantified the impacts of landscape patterns driven by human activities on surface water quality and proposed management measures to optimize the allocation of landscape resources in riparian zones of urbanized rivers. The results provide a scientific basis for water quality management and protection in urbanized rivers. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrates play a crucial role in river ecosystems. The cascading dams had altered the characteristics of the river environment, consequently impacting the spatial distribution of these organisms. We compared water physicochemical and benthic macroinvertebrates collected in July 2021 among sites located above and below a series of dams. The impact of high-density cascading dams on benthic macroinvertebrates and physicochemical characteristics were analyzed in the Oujiang River mainstem. Our results revealed a noticeable change in the benthic macroinvertebrates from upstream to downstream in the Oujiang River. Due to the construction of dams, with the increase of water depth, the ecologically sensitive taxa (Ephemeroptera, Plecoptera, Trichoptera) disappeared as we moved from the natural river sections to the upstream sections of the dams. In contrast, Bivalves and Oligochaetes, which are well-suited for still water, exhibited an increasing trend. However, the species number, biomass, and biodiversity index significantly decreased. The downstream sections of dams affected by the discharge of low-temperature water had a relatively low number of Oligochaete species. The CCA analysis revealed that total nitrogen, water depth, and water temperature were the main factors influencing benthic macroinvertebrates in the mainstream of Oujiang River. The contribution rates of these factors were 21.1, 16.4, and 4.5%, respectively. These findings can be valuable for supporting ecological management and biodiversity conservation in mountainous rivers with high-density barrage dams. [ABSTRACT FROM AUTHOR]

In the streaming era, the very thing that defines it is what threatens to impede access to important media history and cultural heritage. Streaming's barriers to entry and its interim content catalogs challenge the actual collection and preservation of it for research and teaching purposes. If researchers and libraries do not work together to document and preserve these, we will keep losing important sources and data. From a collection perspective, we argue that streaming services consist of their catalog, metadata, and graphical user interfaces. First, we map the large-scale legal deposit collection of streaming at a national library as well as a media researcher's small-scale targeted collection. Second, we compare the resulting collections of web sites and graphical user interfaces in order to discuss methodological challenges. The findings of this comparative analysis indicate the existing deficiencies in both collections and suggest potential improvements in the collection and preservation of streaming services. [ABSTRACT FROM AUTHOR]

The growing population and expansion of rural activities, along with changing climatic patterns and the need for water during drought periods, have led to a rise in the water demand worldwide. As a result, the construction of water storage structures such as dams has increased in recent years to meet the water needs. However, dam construction can bring significant alterations to the natural flow regime of rivers, and it is therefore essential to understand the potential effects of human structures on the hydrological regime of rivers to reduce their destructive impacts. This study analyzes the hydrological changes in the Shahrchai River in response to the Shahrchai Dam construction in Urmia, Iran. The study period was from 1950 to 2017 at the Urmia Band station. The Indicators of Hydrological Alteration (IHA) were used to analyze the hydrological changes before and after regulating, accounting for land use changes and climatic factors. The results revealed the adverse effects of the Shahrchai Dam on the hydrological indices. The analysis showed an increase in the average flow rate during the summer season and a decrease in other seasons. However, the combined effects of water transferring for drinking purposes, a decrease in permanent snow cover upstream of the dam, and an increase in water use for irrigation and agricultural purposes resulted in a decrease in the released river flow. Furthermore, the minimum and maximum daily flow rates decreased by approximately 85% and 65%, respectively, after the construction of the Shahrchai Dam. Additionally, the number of days with maximum flow rates increased from 117 days in the pre-dam period to 181 days in the post-dam period. As a concluding remark, the construction of the Shahrchai Dam, land use/cover changes, and a decrease in permanent snow cover had unfavorable effects on the hydrological regime of the river. Therefore, the hydrological indicators should be adjusted to an acceptable level compared to the natural state to preserve the river ecosystem. The findings of this study are expected to guide water resource managers in regulating the sustainable flow regime of permanent rivers.

Riverine fishes face many challenges including habitat degradation and climate change, which alter the productivity of the riverscapes in which fish live, reproduce, and feed. Understanding the watershed portfolio of foraging and growth opportunities that sustain productive and resilient fish populations is important for prioritizing conservation and restoration. However, the spatiotemporal distribution and availability of fish food are poorly understood relative to other factors such as abiotic habitat quantity and quality (e.g., water temperature). In this paper, we build on the concept of “foodscapes,” and describe three components of food for fish, including abundance, accessibility, and quality. We then discuss methodological advances to help address three key questions: (1) Why is food availability hard to estimate? (2) What are the consequences of uncertainty in food availability estimates? and (3) What approaches are available or emerging for quantifying food available to fish? To address the first question, we characterize data acquisition and analytical challenges; for the second, we demonstrate the importance of evaluating and communicating potential consequences of uncertainty; and for the third, we posit opportunities for future work. Collectively, we highlight the need for greater appreciation of the role food plays in stream fish conservation, especially given its critical influence on responses to warming temperatures.This article is categorized under: Water and Life > Nature of Freshwater Ecosystems Water and Life > Conservation, Management, and Awareness Water and Life > Methods [ABSTRACT FROM AUTHOR]

Freshwater streams are frequently fragmented by infrastructure that has the potential to alter stream fish assemblage structure. However, separating natural vs anthropogenically derived assemblage structuring mechanisms within fragmented riverscapes can be challenging. Riverscape concepts such as the river continuum concept (RCC), serial discontinuity concept (SDC), and network dynamics hypothesis (NDH) conceptualize the roles of natural and anthropogenic regulators of assemblage structure along longitudinal gradients in streams. Each of these theories approaches the influence of stream continuity and discontinuity differently, and their application to metacommunity ecology might identify natural vs anthropogenic drivers of assemblage structure. Over 3 y, we surveyed fish assemblages and habitat variables from 40 sites along the longitudinal dimension of White Creek, a headwater stream in College Station, Texas, USA, to test theory-based hypotheses regarding the structuring of fish metacommunities. To achieve this goal, we constructed asymmetric eigenvector maps (AEMs) that integrated aspects of the RCC, NDH, and SDC theories and used these AEMs to test 3 hypotheses: (H1) fish species richness increases longitudinally downstream, but fragmentation by road–stream crossings causes repeated disruptions to this increase, as predicted by the SDC; (H2) spatial contexts based on the SDC explain more variation in metacommunity structure compared with RCC, NDH, or a neutral model; and (H3) distinct fish assemblages exist within fragments of stream created by impassable road–stream crossings. Competing generalized additive models based on stream theories indicated the SDC was the top-ranked model for predicting longitudinal increase in species richness, supporting H1. Spatial variables from the theory-integrated AEMs explained more variation in assemblage structure relative to the neutral model (particularly for the SDC model), supporting H2. Assemblage clustering and ordination showed unique assemblage structure in 3 of the 4 fragments, providing partial support for H3. Our results advance the goal of bridging the gap between theory and conservation of stream fishes by indicating that integration of stream ecosystem theories provides insight to the origins of spatial processes that regulate assemblage structure. Moreover, our results highlight that management of fragmented stream ecosystems might benefit from perspectives that frame anthropogenic alterations within the context of the natural architecture of riverscapes. [ABSTRACT FROM AUTHOR]

Environmental flows (e-flows) aim to mitigate the threat of altered hydrological regimes in river systems and connected waterbodies and are an important component of integrated strategies to address multiple threats to freshwater biodiversity. Expanding and accelerating implementation of e-flows can support river conservation and help to restore the biodiversity and resilience of hydrologically altered and water-stressed rivers and connected freshwater ecosystems. While there have been significant developments in e-flow science, assessment, and societal acceptance, implementation of e-flows within water resource management has been slower than required and geographically uneven. This review explores critical factors that enable successful e-flow implementation and biodiversity outcomes in particular, drawing on 13 case studies and the literature. It presents e-flow implementation as an adaptive management cycle enabled by 10 factors: legislation and governance, financial and human resourcing, stakeholder engagement and co-production of knowledge, collaborative monitoring of ecological and social-economic outcomes, capacity training and research, exploration of trade-offs among water users, removing or retrofitting water infrastructure to facilitate e-flows and connectivity, and adaptation to climate change. Recognising that there may be barriers and limitations to the full and effective enablement of each factor, the authors have identified corresponding options and generalizable recommendations for actions to overcome prominent constraints, drawing on the case studies and wider literature. The urgency of addressing flow-related freshwater biodiversity loss demands collaborative networks to train and empower a new generation of e-flow practitioners equipped with the latest tools and insights to lead adaptive environmental water management globally. Mainstreaming e-flows within conservation planning, integrated water resource management, river restoration strategies, and adaptations to climate change is imperative. The policy drivers and associated funding commitments of the Kunming–Montreal Global Biodiversity Framework offer crucial opportunities to achieve the human benefits contributed by e-flows as nature-based solutions, such as flood risk management, floodplain fisheries restoration, and increased river resilience to climate change. [ABSTRACT FROM AUTHOR]

The loss of lateral hydrological connectivity (LLHC) in freshwater ecosystems is increasingly threatening biodiversity; however, studies reporting this situation are limited, especially those assessing multi‐measure biodiversity features at large spatial scales.Here, and using one the most threatened taxonomic groups in freshwater ecosystems, we examined the possible influence of LLHC on the species diversity, density, and biomass of mussel assemblages and the genetic diversity and structure of Nodularia douglasiae (a common and widespread native species) in the Yangtze River floodplain.Results showed that the species diversity of freshwater mussels (α and β diversity) significantly differed between the connected and the disconnected areas, with higher α diversity and lower β diversity in the connected areas. At the same time, relative abundance, density, biomass, and genetic diversity of freshwater mussels were higher in the connected areas. High genetic differentiation and low gene flow were found among the 18 analysed N. douglasiae populations, indicating that LLHC is affecting genetic structure of this particular freshwater mussel species.Overall, results indicated that river–lake connectivity is affecting freshwater mussel biodiversity. In addition, this study highlights that multi‐measure biodiversity features provide distinct information about biodiversity dynamics, and are essential to evaluate the effects of floodplain disconnection. We advocate that an integrative approach to floodplain management embracing species and genetic diversity is needed for effective biodiversity conservation in large river ecosystems. [ABSTRACT FROM AUTHOR]

The security of the environment in the headwaters is vital to the whole basin. This study focused on the main ion composition, spatial distribution characteristics, and sources of river water and surface sediments in the source regions of the Lancang River and the Yangtze River and analyzed hydrochemical type and control factors. The results showed that the main cations in the water of the source region were Ca2+ and Na+, with a combined proportion of over 89%. The main anions were Cl-, SO42-, and HCO3-, with a combined proportion of over 97%. There were some differences in the content of metallic elements in the water. The average contents of As, Cu, Pb, Cr, Cd, Ni, and Ti in the river water of the source region of the Yangtze River (SRYR) were higher than those in the source region of the Lancang River (SRLR). The main hydrochemical types in the source region were Na-Cl and Ca-SO4•HCO3, which were controlled by rock weathering and evaporating crystallization. The ions in the river water of the source region were less affected by atmospheric transport and human activities, but more affected by rock weathering. In the SRLR, the water ions were mainly affected by evaporites and carbonate rocks. And in the SRYR, those were mainly affected by evaporites, silicates, and carbonate rocks. The average contents of Ti, Mn, Fe, Sr, and Ba in the surface sediments of rivers were higher than those of other metallic elements. The metallic elements in sediments were controlled by natural and traffic pollution. The study could provide basic data and a scientific basis for the study of the geochemical processes of the water environment and the protection of river ecological environments in plateau rivers. [ABSTRACT FROM AUTHOR]

A low-level river crossing is an economic means of providing access for lower-order roads during high-frequency flood events. Conventionally, culverts are employed to enable the flow to traverse the road, albeit with allowance for overtopping. This overtopping flow from the approach roads, however, possesses the potential to cause erosion of the downstream embankment, thereby jeopardising the foundational integrity of the structure. A physical modelling study was undertaken to investigate the hydraulic performance of stepped chutes in terms of flow patterns, air-water flow properties, and energy dissipation. Various types of stepped chutes were investigated, namely horizontal steps with a chute wall, horizontal steps without a chute wall but with riprap placed directly downstream of each chute, step-inclined steps (backward sloping), steps with pooled cascades, and steps with baffle blocks. Notably, chutes with horizontal steps were the most efficient configuration in terms of relative energy dissipation. Furthermore, this research culminated in the formulation of a new regression formula to establish a quantifiable relationship between the required step length and the overflow depth and discharge, thereby offering a valuable tool for design purposes. [ABSTRACT FROM AUTHOR]

River bank protection is vital in hydraulic river engineering to preserve natural rivers, lands, and critical constructions such as bridges. Spur dikes are erosion-protective structures that protrude outward from the river bank in different orientations to deflect the flow away from the riverbank. The present experimental study provides insight into the temporal variation in bed morphology and scours around rectangular-shaped spur dikes with different orientations, such as 60º, 90º, and 120º. Also, maximum scour depth (MSD) is developed compared to the condition when downward seepage is applied. The experiments examined the suitability of various spur dike orientation configurations and the scour development over time, specifically at intervals of 2, 12, and 24 hours, and compared with 24 hours (Seepage). Results showed that the orientation angle of 90º generated the highest scour depth, while the least scour depth was found with an orientation angle of 120º. The downward seepage intensifies the motion of sediment particles and leads to an escalated particle detachment, resulting in deeper scour depressions. The development of scour depth is initiated from the spur dike tip and reaches its maximum there. The deposition of sand particles shifted downstream, and a dune-like structure formed near the second spur dike. [ABSTRACT FROM AUTHOR]

The growing population and expansion of rural activities, along with changing climatic patterns and the need for water during drought periods, have led to a rise in the water demand worldwide. As a result, the construction of water storage structures such as dams has increased in recent years to meet the water needs. However, dam construction can bring significant alterations to the natural flow regime of rivers, and it is therefore essential to understand the potential effects of human structures on the hydrological regime of rivers to reduce their destructive impacts. This study analyzes the hydrological changes in the Shahrchai River in response to the Shahrchai Dam construction in Urmia, Iran. The study period was from 1950 to 2017 at the Urmia Band station. The Indicators of Hydrological Alteration (IHA) were used to analyze the hydrological changes before and after regulating, accounting for land use changes and climatic factors. The results revealed the adverse effects of the Shahrchai Dam on the hydrological indices. The analysis showed an increase in the average flow rate during the summer season and a decrease in other seasons. However, the combined effects of water transferring for drinking purposes, a decrease in permanent snow cover upstream of the dam, and an increase in water use for irrigation and agricultural purposes resulted in a decrease in the released river flow. Furthermore, the minimum and maximum daily flow rates decreased by approximately 85% and 65%, respectively, after the construction of the Shahrchai Dam. Additionally, the number of days with maximum flow rates increased from 117 days in the pre-dam period to 181 days in the post-dam period. As a concluding remark, the construction of the Shahrchai Dam, land use/cover changes, and a decrease in permanent snow cover had unfavorable effects on the hydrological regime of the river. Therefore, the hydrological indicators should be adjusted to an acceptable level compared to the natural state to preserve the river ecosystem. The findings of this study are expected to guide water resource managers in regulating the sustainable flow regime of permanent rivers. [ABSTRACT FROM AUTHOR]

Stocking density has a significant influence on animal homeostasis, and so is a crucial factor in the management of organisms in captivity and an important role in ex situ conservation of endangered species. Hypancistrus zebra is an endemic fish species from the Xingu River, Brazil—considered Critically Endangered since the early 2000s due to fishing pressure and, more recently, due to habitat changes resulting from the construction of the Belo Monte Hydroelectric Dam. The implementation of appropriate management in captivity is of utmost importance for its conservation, particularly in enhancing ex situ breeding techniques. This study aimed to evaluate the growth of juvenile H. zebra in aquaria with three different stocking density levels. The juveniles were distributed between three treatments, each with three replicates. We found no correlation between biomass and aquarium volume. The highest correlation coefficients were found between growth rates and densities related to the number of individuals per shelter area. Mortality rate was directly related to the initial number of fish in the aquariums, with larger populations showing higher mortality rates. The treatment with lower stocking density displayed the highest growth rate, while the treatment with higher density had the lowest growth rate, with a 23.38% difference between them. [ABSTRACT FROM AUTHOR]

The Karamnasa River, originating in Bihar's Kaimur district, serves as a vital water resource in the region. This research, conducted at coordinates 25°30'54''N latitude and 83°52'30" E longitude, aimed to identify optimal sites for water conservation structures within the Karmanasa River Basin (KRS) using Remote Sensing and GIS techniques. By analysing morphometric parameters (MP) of the basin, including slope, stream length, and drainage density, the study delineated the basin into seven sub-watersheds and five stream orders. The comprehensive analysis revealed SW2 as the most critical sub-watershed, necessitating immediate conservation efforts. Assigning ranks to parameters like bifurcation ratio and circulatory ratio, SW2 emerged as the priority sub-watershed. Fifteen potential conservation sites were identified, comprising 9 farm ponds, 3 percolation tanks, and 3 check dams. The research underscores the significance of prioritizing sub-watersheds based on morphometric characteristics, with lower parameter values indicating higher priority. The study's drainage network analysis, conducted through remote sensing and GIS, enhances understanding of the KRS hydrological features. This research highlights sustainable development through effective water resource use and targeted conservation in the Karamnasa River Basin, emphasizing community engagement and participatory methods for enduring, resilient environmental stewardship and successful land management. [ABSTRACT FROM AUTHOR]

Rivers represent naturally dynamic ecosystems that require diligent preservation efforts to maintain ecological balance and biodiversity. Understanding the evolutionary movements of rivers is crucial for effective conservation and management strategies. Geographic information systems (GISs) have emerged as indispensable tools in this domain and provide detailed spatial analysis and visualization capabilities. This paper explores the development and application of a specific set of GIS tools called RiverMetrics, which was designed to monitor and analyze rivers' changes over time. By leveraging these advanced tools, researchers and environmental managers can gain deeper insights into river dynamics, enabling informed decision-making to safeguard these vital ecosystems. This paper details the functionalities and benefits of these GIS tools and demonstrates their critical role in river conservation efforts. The Paglia River in Central Italy serves as a case study for demonstrating the validity of RiverMetrics tools in monitoring long-term trends. The tools offer significant advantages for monitoring and calculating various indexes such as the sinuosity, braiding index, and profile trend. They also provide researchers with a simple way to process spatial data with precision and efficiency, increasing their ability to perform correct environmental monitoring. [ABSTRACT FROM AUTHOR]

Managing water resources amidst the pressures of climate change and human activities is a significant challenge, especially in regions experiencing shrinking lakes, deteriorating water quality, and ecological degradation. This review focuses on achieving integrated river basin management by learning from the governance experiences of typical watersheds globally, using the Hulun Lake Basin as a case study. Hulun Lake, China's fifth-largest lake, experienced severe ecological problems from 2000 to 2009 but saw improvements after comprehensive management efforts from 2012 onward. This review systematically explores methods to address water resource, environment, and ecological challenges through the lenses of data acquisition, mechanism identification, model simulation, and regulation and management. Drawing lessons from successful basins such as the Rhine, Ganges, Mississippi, and Murray–Darling, the review proposes key goals for comprehensive management, including establishing extensive monitoring networks, developing predictive models, and creating contingency plans for routine and emergency management. Leveraging advanced technologies like satellite imagery and IoT sensors, alongside continuous improvement mechanisms, will ensure the sustainable use and protection of river basins. This review provides a detailed roadmap for achieving comprehensive watershed management in Hulun Lake, summarizing effective strategies and outcomes from data acquisition to regulation, thus serving as a model for similar regions globally. [ABSTRACT FROM AUTHOR]

Ecological protection in the Yellow River Basin (YRB) is a major strategy for China's sustainable development. Amid global warming, droughts have occurred more frequently, severely affecting vegetation growth. Based on the Standardized Precipitation Evapotranspiration Index (SPEI) and Normalized Difference Vegetation Index (NDVI) at different time scales from 2003 to 2020, this study employed the linear trend method and the Spearman correlation coefficient method to calculate the trends and correlation coefficients of NDVI and SPEI at different scales at the pixel scale and explored the spatial distribution pattern of the sensitivity of vegetation growth in the YRB to drought. The results show that: (1) NDVI and SPEI are positively correlated in 77% of the area, negatively correlated in 9%, and are positively correlated in the arid and semi-arid areas, while negatively correlated in the humid and subhumid areas. The significant negative correlation between NDVI and drought at high altitudes may be due to the fact that Gramineae vegetation is more sensitive to drought, with heat being more affected than water. (2) Urbanization has a relatively obvious impact on the distribution of drought. Extreme drought mainly occurs in the middle and upper reaches of the Wei River; severe drought mainly occurs in the central area of the Guanzhong Plain centered on Xi'an; the central area of the Loess Plateau; and the surrounding areas of the Zhengzhou-centered Central Plains City Group. (3) The NDVI showed an upward trend from 2003 to 2020, indicating an increase in vegetation density or an expansion of vegetation coverage. From the temporal trend, SPEI decreased at a rate of −0.17/decade, indicating that the entire watershed has a drought trend on an annual scale. (4) Spring NDVI is more sensitive to the water supply provided by SPEI-1, while the positive correlation between SPEI and NDVI begins to rise in June and reaches its peak in July, then starts to decline in August. In autumn and winter, NDVI is more sensitive to 3–6-month accumulated drought. (5) From the dynamic transmission laws of different levels of positive correlation, the positive impact of the 3-month accumulated drought on NDVI is most significant, and the influence of SPEI-1 on the negative correlation between SPEI and NDVI is most significant. This paper aims to clarify the sensitivity of vegetation to different time-scale droughts, provide a basis for alleviating drought in the YRB, and promote sustainable development of ecological environmental protection. The research findings enable us to gain a profound insight into the responsiveness of vegetation growth to drought in the context of global warming and offer a valuable theoretical foundation for devising pertinent measures to alleviate stress on vegetation growth in regions prone to frequent droughts. [ABSTRACT FROM AUTHOR]

Rivers are constantly disturbed by anthropogenic stressors. Developing robust biotic indicators to assess river environments across large spatial scales is important. In the subtropical Liuxi River of China, 34 native fish indicators, including 4 genera and 30 species, were selected from 108 fish species by linear discriminant analysis. These indicators were grouped into 19 ecological items and assigned evaluation scores according to the roles they played in the food web (e.g., keystoneness and trophic level) and their positive feedback on the environment (e.g., requirements for feeding, spawning/nursing, and migrating). Three formulae for calculating the index of fish indicators (IFI) were developed based on the scoring of each indicator and weighted by relative abundance (individual number, i.e., IFI[INF]N[/INF]) and relative biomass (wet weight, i.e., IFI[INF]B[/INF]). Spearman correlation analysis showed that IFI[INF]B[/INF], which had positive (P< 0.05) correlations with elevation (m), dissolved oxygen (mg/L), flow velocity (cm/s), Shannon-Wiener diversity, benthic index of biotic integrity, exhibited a more powerful explanation of biodiversity and environmental factors than IFI[INF]N[/INF] and unweighted IFI. Therefore, IFI[INF]B[/INF] was most suitable for constructing a scoring system to evaluate ecological status (e.g., water and habitat quality). These results suggested that fish indicator-based scoring and evaluation system was effectively in not only assessing the siteor region-specific ecological status bot also reflecting the fluvial biodiversity and food web integrity. Further application and promotion of this indicator-based evaluation method may improve field investigation efficiency and contribute greatly to the conservation and management of river ecosystems. [ABSTRACT FROM AUTHOR]

Water conservation is a crucial indicator that measures the available water resources needed for maintaining regional ecological services and socioeconomic development. The Yiluo River Basin plays an essential role in water conservation in the Yellow River Basin, which is one of the most important river basins with vulnerable ecological conditions and a large population in China. However, previous studies have a limited understanding of the distribution of water conservation in the Yiluo River Basin. To address this knowledge gap, we developed a SWAT model to evaluate water conservation in the Yiluo River Basin with high spatial and temporal details on a monthly scale. From a monthly perspective, water conservation accumulation primarily took place in July (54.6 mm), August (23.5 mm), and September (33.2 mm), which are in the flood season. From 1966 to 2018, we found a significant 47% reduction in basin-wide water conservation, and the reduction was primarily influenced by meteorological conditions and underlying surface dynamics. The results of the temporal correlation analysis identified precipitation as the most significant factor influencing water conservation, while the spatial correlation analysis revealed that potential evapotranspiration, vegetation, and elevation had the highest spatial correlation with water conservation. By combining SWAT outputs on the HRU (hydrological response unit) scale with the spatial distribution of HRUs, the study achieved the visualization of the spatial distribution of water conservation, identifying Luonan County, Luanchuan County, and Luoning County as the key regions that experienced water conservation decline over the past decades. These findings advance our understanding of the distributions of water conservation and their key driving factors in the study area and provide valuable policy implications to support ecological protection and water resource management in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

The protection of Chile's rivers is a matter of ongoing public and constitutional interest in the wake of Chile's failed 2019–2024 constitutional reforms. In this article we review and evaluate opportunities for greater legal protection and restoration of rivers in Chile. The legal analysis was complemented by a survey of social attitudes about river protection needs and several interviews with key experts and stakeholders, which found strong concern for enhanced river protection mechanisms in Chile. We conclude by outlining critical pathways towards durable legal protections for the future of Chile's rivers. [ABSTRACT FROM AUTHOR]

Endangered trout populations can be monitored with a variety of methods, the selection of which should consider social constraints and environmental variables known to affect method effectiveness. Here, we confront the effectiveness of four monitoring methods (removal with electrofishing, ELE; underwater camera survey, UCS; streamside visual survey, SVS; visual surveys with angling, VSA) to estimate the relative abundance of three populations of the endangered Mediterranean brown trout. The trout counts obtained via different methods were well correlated (r = 0.65–0.72), providing a coherent description of the relative pool abundance across the methods. However, the methods were differently affected by environmental variables, depending on the age classes of trout. Specifically, the adult and subadult counts provided by ELE and VSA were negatively and positively affected by the maximum pool depth, respectively; adult and subadult counts of VSA and the SVS were positively affected by pool area; the juvenile counts provided by the UCS were positively affected by pool shade and negatively affected by water turbidity; juvenile counts provided by VSA were positively affected by shade. Variables such as pool depth, area, shading, water turbidity and proportion of age classes can be hardly controlled in monitoring programs, and their bias could be modelled. Different sampling methods provided similar information about relative abundance and appeared equivalent. While ELE could be selected to collect samples and biometric data, monitoring relative abundance with the UCS, VSA, and SVS appears more suited and can also involve citizen scientists. [ABSTRACT FROM AUTHOR]

The Ib River is an important tributary of the Mahanadi River. The aim of the present study was to establish a reliable barcoding reference database for fish in Ib River. A total of 134 specimens, belonging to 42 species within 32 genera, 18 families, and 11 orders, were subjected to PCR amplification of the target region of mitochondrial genome and sequenced. The average length of the 134 barcodes was 648 bp. The average K2P distances within species, genera, and families were 0.13, 9.94, and 16.79%, respectively. The average interspecific distance was approximately 76.46 times higher than the mean intraspecific distance. The Barcode Index Number (BIN) discordance report showed that 134 specimens represented 42 BINs, of which 13 were singletons, 29 were taxonomically concordant while no species taxonomically discordant in our dataset. The barcode gap analysis demonstrated that 100% of the fish species examined could be discriminated by DNA barcoding. These results provide new insights into fish diversity in the Ib River and can provide a basis for the development of further studies on fish fauna. [ABSTRACT FROM AUTHOR]

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Understanding the dynamics of water bodies is crucial for managing water resources and protecting ecosystems, especially in regions prone to climatic extremes. The Tumen River Basin, a transboundary area in Northeast Asia, has seen significant water body changes influenced by natural and anthropogenic factors. Using Landsat 8 and Sentinel-1 data on Google Earth Engine, we systematically analyzed the spatiotemporal variations and drivers of water body changes in this basin from 2015 to 2023. The water body extraction process demonstrated high accuracy, with overall precision rates of 95.75% for Landsat 8 and 98.25% for Sentinel-1. Despite observed annual fluctuations, the overall water area exhibited an increasing trend, notably peaking in 2016 due to an extraordinary flood event. Emerging Hot Spot Analysis revealed upstream areas as declining cold spots and downstream regions as increasing hot spots, with artificial water bodies showing a growth trend. Utilizing Random Forest Regression, key factors such as precipitation, potential evaporation, population density, bare land, and wetlands were identified, accounting for approximately 81.9–85.3% of the observed variations in the water body area. During the anomalous flood period from June to September 2016, the Geographically Weighted Regression (GWR) model underscored the predominant influence of precipitation, potential evaporation, and population density at the sub-basin scale. These findings provide critical insights for strategic water resource management and environmental conservation in the Tumen River Basin. [ABSTRACT FROM AUTHOR]

In southwest Florida, the Caloosahatchee River flows from Lake Okeechobee into a biologically productive tidal estuarine system. A combination of excess water during the wet season, insufficient fresh water in the dry season, and poor quality of the river water are damaging the estuarine ecosystem. To better control the quality and quantity of the water entering the estuary, reservoirs are being constructed to store excess, poor quality water during the wet season and return it to the river for discharge into the estuary at an appropriate time. This stored water is enriched in nutrients and organic carbon. Because of the subtropical nature of the climate in southwest Florida and potential increases in temperature in the future, the return flow of water from the reservoirs must be treated before it can be returned to the river. Hence, an experimental water treatment system was developed and operated to compare biological treatment processes consisting of solely wetland plants versus adding some engineered processes, including slow sand filtration and a combination of slow sand filtration and ultraviolet (UV) treatment. These three treatment trains were operated and monitored through a seasonal cycle in 2021–2022. All three treatment methods significantly reduced the concentrations of nutrients and total organic carbon. While the enhanced engineered wetlands' treatment trains did slightly outperform the wetland train, a comparison of the three process trains showed no statistically significant difference. It was concluded that upscaling of the slow sand filtration and UV process could improve the treatment efficiency, but this change would have to be evaluated within a framework of long-term economic benefits. It was also concluded that the Caloosahatchee River water quality is quite enriched in nutrients so that reservoir storage would increase the organic carbon concentrations, making it imperative that it be treated before being returned to the river. It was also discovered that the green alga Cladophora sp. grew rapidly in the biological treatment tubs and will present a significant challenge for the treatment of the reservoir discharge water using the currently proposed alum treatment. [ABSTRACT FROM AUTHOR]

Arid and semi-arid areas are among the most threatened ecosystems on the planet. The Tehuacán-Cuicatlán Biosphere Reserve (TCBR), in southeastern Mexico, is an arid and semi-arid area with high biological diversity and human settlements of eight ethnic groups. Two rivers drain the reserve, Río Grande (RG) and Río Salado (RS), which are not subject to water quality monitoring by government agencies; however, measures of water quality of these rivers are needed to focus conservation actions on this resource. This work aimed to test the effectiveness of participatory water quality monitoring with the participation of three actors: Reserve management leaders, local communities, and academics, to monitoring water quality in the rivers of the TCBR. Ninety-two residents were trained to carry out water quality biomonitoring using the Biological Monitoring Working Party (BMWP) index calibrated for the reserve. The BMWP uses macroinvertebrate families to display numerical and categorical water quality scores. Additionally, the Water Quality Index (WQI) was assessed and the Normalized Difference Vegetation Index (NDVI) of the riparian zones was estimated in each study site. The mean WQI scores were 69.24 for RS (no treatment necessary for most crops and necessary treatment for public water supply) and 75.16 for RG (minor purification for crops requiring high-quality water and necessary treatment for public water supply). The BMWP showed five water quality categories (Excellent, Very Good, Good, Fair, and Poor), showing higher water quality scores in the upper portion of the basins and capable of discriminating study sites with lower scores close to human settlements. At one study site, data from participatory monitoring impelled actions taken to address a pollution source and influenced policy focus, reaching the maximum level of participatory-based monitoring. This led to avoid the discharge of wastewater into the river to conserve and protect the water resource. WQI is closely related to BMWP; however, the latter was far more sensitive to detecting areas affected by domestic water discharges. The NDVI presented low values for the TCBR, being lower in RS (the driest area). Although the NDVI showed a weak relationship with BMWP values, areas with higher NDVI values generally achieved higher BMWP values. The results of this study highlight the high sensitivity of the BMWP to detect several water quality conditions in the rivers running through the TCBR when compared to WQI. In addition, the usefulness of biomonitoring using the BMWP index was evident, as well as the importance of the participation of local inhabitants contributing to the knowledge of water quality in biosphere reserves and carrying out timely measures that allow the rivers in these reserves to be maintained in good condition. [ABSTRACT FROM AUTHOR]

A dynamic global vegetation model based on the annual land- use change data was used to quantify water conservation capacity with respect to grassland changes in the Yellow River above Lanzhou between 1980 and 2020 using different scenario simulations. The results showed that the average annual water conservation in this region was approximately 24. 21 billion cubic meters, with grassland ecosystems contributing approximately 20. 28 billion cubic meters, accounting for 83. 8% of the total water conservation. Before 2002, the water conservation capacity exhibited a decline trend (- 0. 51 billion cubic meters per year). However, an increasing trend was observed after 2002 (0. 35 billion cubic meters per year). Changes in the grassland in the Yellow River above Lanzhou, while having negligible negative impacts and no discernible regional differences, resulted in an annual reduction of 0. 67 billion cubic meters in the regional water conservation volume between 2015 and 2020. Simulations were performed under scenarios representing different degrees of grassland degradation. The results showed that mild degradation caused changes in the components of grassland evapotranspiration, which in turn led to a slight increase in the regional water conservation volume; however, this effect decreased significantly as the degree of degradation increased. [ABSTRACT FROM AUTHOR]

It is of great significance to study the spatial and temporal distribution characteristics and influencing factors of national key cultural relics protection units in the Yangtze River Delta region. Taking the national key cultural relics protection units in the Yangtze River Delta as an example, the spatial and temporal distribution characteristics and influencing factors of the sites were studied by using the methods of nearest proximity index, spatial density, standard deviation ellipse, and geographic detector. It can be concluded that the number of key cultural relics under protection in the Yangtze River Delta region is concentrated in the Song, Yuan, Ming and Qing Dynasties and since modern times, with the main types of ancient buildings, and the largest number in the 100-year time scale since modern times. On the whole, the spatial density of the national insurance unit has formed contiguous areas dominated by "Shanghai, Suzhou, and Wuxi,""Nanjing, Yangzhou,""Hangzhou and Shaoxing" and single core areas dominated by Ningbo and Huangshan, with the spatial distribution characteristics of "three contiguous areas and two single cores." During the eight periods from prehistoric period to modern times, the national security units showed a state of agglomeration in spatial distribution, showing the transfer trend of "Southwest-northwest-southeast-southeast-southeast-northwest-northeast" and the evolution process of "agglomeration—dispersion—agglomeration—dispersion—agglomeration—agglomeration." Natural environmental factors such as altitude and river network density, and socio-economic factors such as economic development level, abundance of scenic spots, abundance of intangible cultural heritage resources and total population have a significant impact on the spatial distribution of national protection units in the Yangtze River Delta. Plain language summary: It is of great significance to study the spatial and temporal distribution characteristics and influencing factors of national key cultural relics protection units in the Yangtze River Delta region. Taking the national key cultural relics protection units in the Yangtze River Delta as an example, the spatial and temporal distribution characteristics and influencing factors of the sites were studied by using the methods of nearest proximity index, spatial density, standard deviation ellipse, and geographic detector. It can be concluded that the number of key cultural relics under protection in the Yangtze River Delta region is concentrated in the Song, Yuan, Ming and Qing Dynasties and since modern times, with the main types of ancient buildings, and the largest number in the 100-year time scale since modern times. On the whole, the spatial density of the national insurance unit has formed contiguous areas dominated by "Shanghai, Suzhou, and Wuxi,""Nanjing, Yangzhou,""Hangzhou and Shaoxing" and single core areas dominated by Ningbo and Huangshan, with the spatial distribution characteristics of "three contiguous areas and two single cores." Natural environmental factors such as altitude and river network density, and socio-economic factors such as economic development level, abundance of scenic spots, abundance of intangible cultural heritage resources and total population have a significant impact on the spatial distribution of national protection units in the Yangtze River Delta. [ABSTRACT FROM AUTHOR]

In Mediterranean climate regions, intermittent rivers (IRs) harbor highly dynamic communities with species and trait composition changing over time and space. Simultaneously considering multiple biodiversity facets and a spatiotemporal perspective is, therefore, key to developing effective conservation strategies for these ecosystems. We studied the spatiotemporal dynamics of aquatic macroinvertebrates in rivers of the western Mediterranean Basin by analysing (1) the taxonomic and functional richness and the local contribution to beta diversity (LCBD; measured considering taxonomic and functional facets) of perennial rivers and IRs over five sampling times, and (2) their relation with flow intermittence, local environmental uniqueness, and the number of anthropogenic impacts. Both analyses were also conducted for the subset of data including only IRs to compare values between their flowing and disconnected pool phases. According to our results, taxonomic and functional richness tended to be higher in perennial rivers than in IRs, while taxonomic and functional LCBD tended to be higher in IRs than in perennial rivers. When comparing IR sites over time, higher values of taxonomic and functional LCBD corresponded mostly to their disconnected pool phase. Flow intermittence, the number of anthropogenic impacts and the environmental uniqueness were significant predictors of taxonomic and functional richness, but only flow intermittence was an important predictor of taxonomic LCBD. For the IR-only data subset, disconnected pool permanence was the main predictor explaining spatiotemporal patterns. Our results highlight the importance of IRs to biodiversity conservation of Mediterranean climate rivers, especially during the disconnected pool phase, suggesting that these ecosystems cannot be ignored in conservation planning strategies. [ABSTRACT FROM AUTHOR]