Abstract: ABSTRACT Thermal refuges in rivers and streams provide critical habitat for cold‐water species during periods of thermal stress. In this study, we created a new cold‐water thermal refuge by pumping cool groundwater to a warm coastal river in Nova Scotia, Canada. Thermal infrared imagery revealed a notable thermal plume, measuring approximately 55 m 2 at the water surface during low‐flow conditions, with mixing limited by the installation of a flow deflector. Above‐water and underwater cameras recorded several fish utilizing the created cold‐water plume during periods of high ambient river temperatures (up to 30°C). Thermal numerical modelling was conducted to interpret the field data and assess the impact of alternative designs and conditions. Model results revealed that the extent of the created thermal plume substantially increased (+202%) with the use of a deflector and that the plume size was controlled by several factors including the river flow rate and temperature, the pumping rate and the groundwater temperature. The study findings demonstrate the efficacy of creating cold‐water habitat in the face of a warming climate and lay the foundation for future proactive thermal management strategies aimed at maintaining thermal diversity in warming rivers.

Abstract: Abstract Changes in water and nitrogen availability can affect the structure and function of arid ecosystems. How these resources affect aboveground primary productivity (ANPP) remains far from clear. We examined the N and water limitation of ANPP from the species to the community level and the response of ANPP to annual precipitation in a Patagonian steppe. We conducted a 7‐year field experiment with water addition (+W), nitrogen addition (+N) and +NW. Destructive methods for grasses and allometric relationships for shrubs were used to assess ANPP and vegetation indices (NDVI and MSAVI2) to estimate community ANPP. An increase in ANPP of one grass species ( Papposstipa humilis ) and a decrease of the grass Poa ligularis under +N were observed. Some shrub species exhibited mortality under nitrogen addition. Nitrogen exerted a positive effect on grass ANPP and amplified the sensitivity of grass ANPP to annual precipitation. However, +N had not effects on the shrub ANPP and shrub ANPP‐precipitation relationship. Water addition by itself had no effect on ANPP for either shrubs or grasses. However, shrubs responded positively to an unusually wet year regardless of treatment and were also more sensitive to changes in annual precipitation than grasses. Total ANPP increased significantly in +N relative to the C and +W but without changes in the sensitivity to annual precipitation. The results suggest that the responses of grasses and shrubs to water inputs are driven by soil moisture redistribution and rooting depth and that grass and community ANPP are more limited by N than by water.

Abstract: Abstract This study provides a new perspective on understanding the intricacies of water‐mediated connectivity in ecosystems, bridging landscape ecology and geomorphology through network science. We highlight dryland and river‐floodplain ecosystems as distinct examples of contrasting water‐controlled systems. We (1) discuss central considerations in developing structural connectivity and functional connectivity networks of water‐mediated connectivity; (2) quantify the emergent patterns in these networks; and (3) evaluate the capacity of network science tools for investigating connectivity characteristics. With a focus on strength (weights) and direction, connectivity is quantified using seven parameters at both network and node levels. We find that link density, betweenness centrality and page rank centrality are highly sensitive to directionality; global efficiency and degree centrality are particularly sensitive to weights; and relative node efficiency remains unaffected by weights and directions. Our study underscores how network science approaches can transform how we quantify and understand water‐mediated connectivity, especially in consideration of the role(s) of weights and directionality. This interdisciplinary perspective, linking ecology, hydrology and geomorphology, has implications for both theoretical insights and practical applications in environmental management and conservation efforts.

Abstract: Abstract Unnatural changes in river flow patterns resulting from peak‐operating hydropower plants adversely impact freshwater ecosystems. In particular, the rapid dewatering of shoreline habitats during artificial flow down‐ramping puts early fish life stages at a high risk of becoming stranded if they fail to follow receding water levels in time. While extensive research has been conducted on the effects of hydropeaking on salmonid species, there is limited knowledge on the diverse cyprinid family, particularly on vulnerable early life stages. Hence, this study aims to compare the larval stranding of two cyprinid species, the common barbel ( Barbus barbus L.) and common nase ( Chondrostoma nasus L.), in response to bank dewatering. We conducted larvae experiments in near‐natural mesocosms, simulating single flow down‐ramping events with varying down‐ramping rates (0.3–1.8 cm·min −1 ) during the day and at night to quantify stranding rates, also including water temperature and fish development. Our results reveal distinct diurnal patterns for both species, with higher stranding rates during the night than during the day in all experimental scenarios. The data also show higher stranding rates at faster down‐ramping, with interaction effects between down‐ramping rates and time of day. The stranding rates between the two species are similar across most of the scenarios. Scenarios with colder water temperatures show that nase larvae tend to strand more frequently than with warmer temperatures. In conclusion, the study results contribute to the ongoing discourse on hydropeaking mitigation by providing new perspectives on flow‐reduction effects on early cyprinid life stages. Mitigation measures should prioritize the periods during early larval development and factor in prevailing water temperatures. Lowering down‐ramping rates, especially during nighttime, will help minimizing negative impacts on aquatic ecosystems, particularly when combining flow rules and habitat restoration measures.

Abstract: Abstract In high mountain areas, snowmelt water is a key—yet fading—hydrological resource, but its importance for soil recharge and tree root water uptake is understudied. In these environments, heterogeneous terrains enhance a highly variable availability of soil and groundwater resources that can be accessed by plants. We conducted a tracer‐based study on a subalpine forest in the Italian Alps. We investigated the isotopic composition ( 2 H and 18 O) of snowmelt, precipitation, spring water, soil water—at different locations and depths—and xylem water of twigs taken from alpine larch, Swiss stone pine and alpenrose plants during bi‐weekly field campaigns (growing seasons of 2020 and 2021). Mixing models based on δ 18 O revealed a large contribution of snowmelt to soil and xylem water, particularly during early summer. We investigated the contribution of water from different soil depths to xylem water, using the sap flow records to date back the end‐member signatures. We found a flexible use of shallow and deeper soil water by the investigated plants, with groundwater more likely used by larger trees and during the late summer. Results based on isotopic data were combined with geophysical observations of the subsurface structure to develop a conceptual model about the different exploitation of water by plants depending on their location (shallow soil on a slope vs. a saturated area). Our study highlights the relevance of snowmelt in high‐elevation terrestrial ecosystems, where heterogeneous substrates shape the water availability at different depths and, in turn, water uptake by plants.

Abstract: Abstract Ecosystem management depends on transforming qualitative observations (e.g., slow‐moving shallow conditions provide nursery refugia for silvery minnow larvae) into management actions to increase habitat quantity or improve habitat quality. To be effective, decision metrics that are developed for management objectives should be validated with field observations. Model assumptions, precision and parameter importance can be refined by comparing the fidelity of selected parameters computed as habitat quality metrics and the correlation of these metrics to real‐world observations. Validated environmental metrics are more credible for management and can be compatible with ecosystem monitoring and project design processes. In this study, streamflow monitoring data and hydraulic modelling are used to quantify fish habitat extent for 15 years of spring runoff. The spring runoff event coincides with larval maturation to a free‐swimming juvenile phase for the silvery minnow, a critical period in Rio Grande habitat management. Different methods to estimate habitat availability (i.e., hydrology statistics, inundation extents based on hydraulic modelling and areal habitat availability based on different formulations of a habitat suitability index curve) were used to test the efficacy of different metrics relative to species population monitoring. This analysis finds that flow–ecology relationships based on hydraulic modelling or hydrology statistics are both effective and highly correlated to larval production. The investigation shows how seasonal hydrologic characterization and hydraulic discretization have varying levels of correlation with seasonal fish production. This study demonstrates how hydraulic modelling data and hydrologic characterization of riverine environments can be used to validate or develop conceptual ecological models.

Abstract: Abstract As one of the responses to the global commitments against climate change, the Ethiopian Government launched a nationwide Green Legacy Initiative (GLI) in 2019, which largely focused on forest tree plantations with some inclusion of fruit trees. Despite its tremendous efforts and investments, its effectiveness and impacts have not been studied. This paper attempted to address this necessity by conducting a cross‐sectional quasi‐experiment in three randomly selected woredas/districts of Lake Hawassa Watershed from August 20 to September 2, 2023. The research hypothesized the likely impacts of GLI on four dependent variables (hydrological regulation, soil stability, nutrient cycling and plant species diversity). To achieve this, the research considered the two variants of GLI practices (plantation with and without soil and water conservation measures) and the corresponding control sites. Having three sites and three treatments with five replications, the study involved a total of forty‐five quadrats of the same size (20 m × 20 m). The first three parameters were analysed using the landscape functionality analysis method, while the fourth employed Shannon's diversity index. Results of ANOVA showed that, on average 87% of randomly selected quadrats were found to significantly improve the local hydrology (runoff potential) (≈ 83.3% with Av. p = 0.012), soil stability (≈100% with Av. p = 0.002), nutrient cycling (≈83.3% with Av. p = 0.017) and plant species diversity (≈83.3% with Av. p = 0.012). The research revealed positive results from the Ethiopian Green Legacy Initiative. The small number of samples is acknowledged as a limitation of the research.

Abstract: Abstract Environmental flows (e‐flows) assessments are a powerful mechanism for enhancing and conserving the ecosystem goods and services rivers provide while allocating water to essential human use. There is a paucity of e‐flows assessments and implementation in water scarce regions such as the Middle East, where limited freshwater resources are under extreme pressure. We conducted a first e‐flows assessment of the Mujib River, a vitally important freshwater resource for biodiversity and people in Jordan. We employed a holistic approach based on the building block method (BBM), using expert knowledge, assessment and integration of the hydrology, hydraulics, fish, macroinvertebrates, vegetation, habitat integrity and benthic diatoms of the Mujib River to perform an e‐flows determination. Several significant threats to its ecology and fresh water supply were identified. The most significant was the absence of flooding and abstraction associated with upstream impoundments, as well as reliance on over‐exploited and severely pressured groundwater‐maintained flows. Overall, this paper presents the first e‐flows assessment for the Mujib River in Jordan, a vital step towards improved water resource monitoring and management in water scarce regions, and serves to highlight the urgent global need for e‐flows to preserve our critical freshwater systems.

Abstract: Abstract Despite their importance in carbon cycling and catchment runoff dynamics, the hydrology of temperate peat swamps in response to changing hydrometeorological conditions is largely understudied. We examined the importance of hydrogeomorphic settings in controlling hydrological connectivity and runoff in a temperate peat swamp in southern Ontario, Canada over two consecutive growing seasons with contrasting conditions (dry and wet years). We chose two different small‐scale hydrogeomorphic settings to investigate: (i) a site with strong wetland‐stream interactions (i.e., an unconfined stream channel; unconfined) and (ii) a site with limited wetland‐stream interactions (confined). During the wet year, the confined site exhibited a consistently gaining stream, maintaining lateral hydrological connectivity and yielding high runoff ratios, while during the dry year, the confined site lost water and experienced low runoff ratios during storm events. Overland flow at the unconfined site maintained a longitudinal hydrological connectivity delivering water to its sub‐catchment outflow, as reinforced by hydrochemical observations. This connectivity was maintained in the wet year but ceased in the dry year despite consistent upstream sub‐catchment water inflow due to high depression storage. Runoff ratios were reduced because of this hydrological disconnection. We highlight the importance of small‐scale hydrogeomorphic setting on peat swamp carbon storage as facilitated by the variation of within‐site hydrological connectivity and runoff, which also has important implications for downstream water quality. The unconfined site maintained a higher water table position in both years and has much greater peat carbon stocks. We suggest peat swamp channelization either naturally or through drainage decreases carbon stocks.

Abstract: Abstract Temporarily consented tracks made from high‐density polyethylene (HDPE) mesh have been used to mitigate both the physical and ecological impacts on peatlands from low‐frequency vehicle usage. However, the impacts of mesh track removal or abandonment at the end of the consented period remain poorly understood. Over a 2‐year period, we studied replicate sections of abandoned mesh track which, at the start of the experiment, had been unused for approximately 5 years, on a UK blanket bog. Some sections were removed (using two treatment methods – vegetation mown and unprepared), whereas others were left in situ. Metrics were compared both between treatments and to undisturbed reference areas. Significant differences in surface soil moisture were found between abandoned and removed tracks depending on season. Control areas had higher volumetric soil moisture than track locations. Compaction was significantly higher across all track locations in comparison to controls ( p < 0.001), but rarefaction was not recorded post‐removal, suggesting long‐term deformation. Overland flow events were recorded in rut sections for a mean of 16% of the time, compared to <1% in control areas. Sediment traps on the tracks collected 0.406 kg compared to 0.0048 kg from the control traps, equating to a per trap value of 7.3 g from track samplers and 0.17 g from control samplers. Erosion and desiccation features occurred on both removed and abandoned track sections. Both abandonment and removal of mesh tracks have a wide range of impacts on the physical properties of peatlands, suggesting that only where access is a necessity should such a track be installed.

Abstract: Abstract Lotic environments are among the most vulnerable aquatic ecosystems, and changes occurring in them happen faster than our capacity to measure the impacts, with the choice of community attributes that best reflect these disturbances still unclear. In this study, we evaluated the response of phytoplankton species and species traits along a gradient of urbanization in lowland streams. To do this, we sampled nine streams in three areas classified as densely populated (DP), low populated (LP), and rural areas (RA) during the four seasons (n = 108), considering relevant limnological variables (including metals, herbicides, and inorganic nutrients) and phytoplankton. Phytoplankton was analysed using taxonomic and morpho‐functional traits approaches. We used several multivariate analyses to assess phytoplankton species and trait distribution among stream groups (DP, LP, RA) and identify their environmental drivers. We found that phytoplankton responded to the urbanization gradient at both taxonomic and functional levels. However, this response was mediated by the land use (urban vs. rural) rather than its intensity. The main stressors detected were eutrophic conditions and organic matter contamination, which differed among groups (DP‐LP and RA). Both approximations indicated eutrophic, organically enriched conditions, but the situation varied among seasons and stream groups. The response of the taxonomic approach was clearer than the traits‐based approach, showing differences in density only between stream groups in the summer and the spring. Phytoplankton was responding to the gradient of urbanization in these subtropical lowland streams, but the seasonality, especially temperature and changes in the water column mixing also mediate the effect.

Abstract: ABSTRACT Methods used to quantify evapotranspiration (ET) from Sphagnum ‐dominated peatlands often assume that soil moisture is not a limiting factor; actual ET (AET) equals potential ET (PET). However, soil moisture can become limiting as peatlands dry, lowering AET below PET and necessitating the use of a surface resistance term in AET estimations. Quantifying and calculating surface resistance is a challenge for the non‐vascular plant surfaces such as those dominated by Sphagnum moss. This paper explores and quantifies the ecohydrological processes that drive Sphagnum resistance to ET. It is hypothesized that a relationship exists between the Sphagnum moss resistance and the ratio of unsaturated to saturated hydraulic conductivity (K‐ratio) for boreal peatlands, where the K‐ratio is a proxy for the hydrophysical properties of the porous medium. An empirical relationship between Sphagnum moss resistance and the K‐ratio was developed from data collected from a boreal peatland and implemented in the cold regions hydrological model. Empirically modelled resistance values (0–800 s m −1 ) did not match well with estimates from inverting observations and the Penman–Monteith (PM) algorithm (0–5000 s m −1 ). Difficulties in validating resistance values were possibly due to lack of moisture limiting conditions although this is seemingly contradicted by the alpha value being less than 1. Priestley–Taylor (PT) and PM algorithms in CRHM were used to estimate AET and compared with each other and with observations from an onsite eddy covariance (EC) system. The PT algorithm, using a site‐specific alpha value (0.75) performed the best with a mean difference of 9.4% (±12.0%) when compared to EC measurements of AET. The PM algorithm consistently overestimated EC measurements with a mean difference of 68.4% (±50.0%), even with a moss resistance incorporated into its use. The performance of PM algorithm is impeded by the uncertainty in quantifying Sphagnum resistance. Reducing this uncertainty should be a focus of future studies, as it does not require the use of a site‐specific alpha value.

Abstract: ABSTRACT The Loess Plateau is one of the most severely eroded areas in the world. A series of ecological measures (e.g., terracing, afforestation and reforestation) have been implemented to rehabilitate the environment. However, consecutive field observations are still inadequate regarding the benefits of eco‐measures on erosion reductions. In this study, surface runoff and soil loss were monitored at the plots of Pinus tabulaeformis with two different terraces and natural slope, including fish scale pits with Pinus tabulaeformis (F–P.t), control slope (natural slope) with Pinus tabulaeformis (C–P.t) and zig terraces with Pinus tabulaeformis (Z–P.t) in the growing season of 2015–2021. Results showed that terraces played a key role in reducing water and soil loss compared to natural slopes. The zig terraces had the greatest runoff and soil loss reduction benefits (43.38% and 67.75%, respectively). Maximum runoff and sediment occurred under the rainfall with high intensity and short duration. Runoff depth was better explained by rainfall depth and rainfall duration compared to soil loss rate. Compared with the natural slope, the degree of explanation of multiple regression models for terrace plots dropped to 36.1%–41.2% for runoff depth and declined to 12.7%–19.5% for soil erosion rate. This study revealed that different terracing measures with afforestation can effectively contribute to soil and water conservation in the Loess Plateau of China. The combination of zig terraces and P. tabulaeformis is recommended as it has the best potential for improving the micro‐topography, storing rainfall and decreasing soil erosion. These results can help evaluate ecological restoration projects on the Loess Plateau and provide a scientific basis for the implementation of terracing projects in similar areas.

Abstract: Abstract Vegetation plays an essential role in the atmospheric and hydrological processes, and vegetation responds differently to climate change in various regions, especially in extreme climates. Therefore, the use of static prescribed vegetation information from past years in numerical models can be a source of biases in hydrological simulations. However, previous studies have mainly focused on the effects of vegetation dynamics on hydrological processes in arid and semi‐arid regions. It remains unclear how static or dynamic vegetation affects hydrological simulations in humid regions, especially under drought conditions. In this study, the Weather Research and Forecasting (WRF) model coupled with Noah‐MP was used to assess the impact of vegetation dynamics on hydrological simulations in the East River basin (ERb) of China, which is a major water source for several major cities in the Pearl River Delta. The model was run with prescribed and dynamic vegetation conditions, respectively. Our model validation based on observed 2‐m temperature (T2) and Leaf Area Index (LAI) showed that the model performance was improved when vegetation dynamics were considered. Our simulations with static or dynamic vegetation showed the impacts of vegetation dynamics on hydrological simulations under droughts. The model with vegetation dynamics simulated a wetter condition with higher soil moisture and runoff and lower T2, compared with the simulations of static vegetation. The results suggested that ignoring vegetation dynamics may overestimate the severity of drought in this humid basin, unlike arid and semi‐arid regions. Therefore, consideration of vegetation dynamics in this humid basin will deepen our research on different types of zones and serve as a reference for other humid regions.

Abstract: Abstract Tropical coastal rivers transport significant amounts of materials, and the dam's retention efficiency can affect hydrological processes generating impacts on reservoirs, such as eutrophication. Nevertheless, climate change projects uneven regional rainfall reduction, affecting surface water circulation and consequently the dam retention efficiency with possible effects on reservoir eutrophication. Here, we investigated the water, suspended particulate matter, and nutrient mass‐balance budgets in a large reservoir under a lowest rainfall year and effects on reservoir eutrophication in a tropical coastal watershed. Under low rainfall condition, the annual water budget showed that the dam water retention was limited, but the dam retained around 75% of the suspended particulate matter fluxes from the rivers. In terms of nutrients, the dam exported TN, TP and D‐Si while retaining PO 4 3− on average; however, these circumstances fluctuated depending on the sample event. The reservoir's trophic state varied from mesotrophic to eutrophic possible reflecting the reduced dam's nutrient retention efficiency under influence of the low rainfall condition. However, 2 years following our sampling period, supereutrophic conditions and algal bloom were measured. Because human activities account for the majority of N and P loads across the watershed, mainly to soils, this biological response has been attributed to a greater rainfall regime that transfers N and P from soils to the reservoir.

Abstract: ABSTRACT Riverine ecosystems exhibit significant spatial variations in their communities, and understanding of these variances is vital to comprehend the mechanisms that maintain biodiversity. This study was conducted to understand pattern of distribution and beta diversity of fish communities in the Bhima River basin in the Deccan Plateau region of India. Fish distribution data from 59 sites across 11 rivers of the Bhima River basin were collected, and pair‐wise β Dissimilarity and site‐wise local contribution to beta diversity (LCβD Sorensen ) and its components (LCβD Turnover and LCβD Nestedness ) were calculated. Power function regression was analysed to understand the decay in community similarity with geographical and environmental distances. Redundancy analysis was performed to investigate the relationship between fish distribution and environmental variables. Results indicated that species richness declined with increasing longitude from west to east. A negative relationship was observed between species richness and LCβD Sorensen . LCβD Turnover formed Ո‐shaped curve at both ends of the species richness gradient, while LCβD Nestedness values exhibited Ս‐shaped curve. No significant difference between mean LCβD Turnover and mean LCβD Nestedness across the sites was observed. The distance decay relationship between community similarity and both geographical and environmental distances follows the power law shape, and the slope of this relationship flattened with increasing distance. Precipitation, topography, temperature variation and dissolved oxygen played a pivotal role in shaping fish assemblages. This study provides insight into the spatial distribution of fish communities in the Bhima River basin, which will be helpful to comprehend the ordination of biodiversity in the riverine ecosystem of the Deccan Plateau region.

Abstract: ABSTRACT Alluvial forests are sensitive to drought induced by climate change and exacerbated by altered flow regimes. Our ability to detect and map their sensitivity to drought is crucial to evaluate the effects of climate change and adjust management practices. Therefore, we explore the potential of multiscale thermal infrared imagery (TIR) to diagnose their sensitivity to droughts. In summer 2022, we sampled leaves and phloem on Populus nigra trees from two sites with contrasted hydrological connectivity along the Ain River (France) to investigate the seasonality of water stress and act as ground truth for airborne TIR images. To map forest sensitivity to drought, we used TIR data from four airborne campaigns and Landsat archives over a larger spatial and temporal extent. Field data showed that stress conditions were reached for both sites but were higher in the site with lower groundwater connectivity, which was also the case for individual tree crown temperatures. At the forest plot scale, canopy temperature was linked to forest connectivity for two of four TIR campaigns, with higher values in the more degraded reaches. Landsat data were used to locate the areas of the riparian forest impacted by a historical drought event and monitor their recovery and proved useful to identify trends. TIR data showed promising results to help detect and map tree water stress in riparian environments. However, stress is not detected in all TIR campaigns, demonstrating that one‐shot TIR acquisitions alone are not enough to diagnose stress and complementary in‐field eco‐physiological measurements are necessary.

Abstract: Abstract Sediment dredging has been an ever‐growing issue, especially in developing nations with high demand for concrete filler material. River systems are adversely affected by sediment mining, resulting in decreased stability of the riverbed and riverbanks. Nature‐based solutions for riverbank erosion have been a research topic that has led to the proposal of vegetation on the riverbanks. However, little is known about the extent of riverbank vegetation required to negate the devastating effects of sediment mining because dense vegetation severely affects the flow structure and becomes a waste trap. This experimental study uses sparsely dense, flexible, and bladed vegetation to study the annulment effects of vegetation against the existing mining pit. Near‐bed turbulence and sediment transport have increased in the test section in the presence of a mining pit. The increase in near‐bed streamwise and transverse Reynolds shear stresses helped us understand the increased sediment movement in streamwise and lateral directions. The morphology of the test section showed increased riverbed erosion at the beginning of the test segment. The entire cross‐section was levelled at the end of the test section, and aggradation was downstream of the test segment. In contrast, in the vegetated riverbank case, the initial profile of the bank was almost unchanged for the same discharge of flow and upstream sand pit. The sparse vegetation overperformed the intended negation effects. This study establishes that sparse vegetation would perform better in maintaining the channel morphology, which otherwise in dense vegetation would have faced a high erosion rate in the main channel while giving the same protection to the riverbanks.

Abstract: Abstract Changes in fish habitat induced by dam construction in the downstream river have been well documented in an increasing body of literature. Fish habitats in the backwater zone of dams have undergone dramatic changes, which have still remained poorly understood. This study aims to provide a more complete understanding of fish habitat distribution and clarify fish habitat utilization patterns in the upstream dam in order to adopt effective remediation activities. This study was conducted in the Three Gorges Dam (TGD) as it is the world's largest installed capacity hydropower station, with a backwater zone length of about 660 km. Four major Chinese carp (FMCC) were selected as target fish species, and fish habitat distribution upstream of TGD was assessed by integrating the swimming ability and environmental preference of different fish species into their critical life stages. Assessment results at different life stages of the target fish species showed that June was a critical period for spawning activities FMCC in the fluctuating backwater zone of TGD. The riverbank was an important feeding habitat for FMCC, and the high‐velocity flow in the centre of the channel exceeded the limits of the swimming ability of target fish. The fish habitat distribution in the fluctuating backwater zone of TGD was heavily affected by runoff from April to September and by dam operation from October to March of the next year. This work provide valuable information about river conservation and management in the upstream of TGD.

Abstract: Abstract Canopy rainfall interception is one key hydrological process, affecting rainwater redistribution and effectiveness in semiarid regions. Canopy rainfall interception loss is jointly influenced by meteorology, vegetation and topography. The canopy water storage capacity (S), rainfall interception depth (I m ) and ratio (I % ) and vegetation characteristics, together with topographic factors of three grassland communities (dominated by Bothriochloa ischaemum , Lespedeza davurica and Artemisia gmelinii , respectively) were investigated on the Loess Plateau of China during the main growing season (June to September). Results showed that I m ranged from 0.55 to 0.89 mm and I % ranged from 6.14% to 12.1%, with the maximum values occurring in August for three communities, and A. gmelinii community had the largest I m (0.89 mm) and I % (12.1%). The I m and I % were positively correlated with aboveground biomass (AGB), coverage (Cov), leaf area index (LAI), community‐weighted mean height (CWMH) and altitude (Alt), but negatively correlated with slope degree and rainfall intensity (RI). Hierarchical partitioning analysis (HPA) showed that AGB had the highest contribution for I m (20.3%), while Alt had the highest contribution for I % (18.2%). The regression models based on forward selection could effectively predict the values of I m (R 2 = 0.802, RMSE = 0.049) and I % (R 2 = 0.546, RMSE = 1.434). Topographic factors (altitude, slope degree and aspect) indirectly influenced both I m and I % by modulating vegetation characteristics (AGB, Cov, etc.). All these indicated that aboveground biomass mainly determines grassland community rainfall interception loss in the semiarid Loess Plateau.

Abstract: ABSTRACT Vegetation in rivers has a significant influence on flow characteristics. A numerical simulation was conducted to study the impact of different vegetation coverage on the flow characteristics in open channels, using ANSYS Fluent for a three‐dimensional computational fluid dynamics analysis. The results showed that as vegetation coverage increased, the water resistance effect was enhanced. In experiments with the same vegetation coverage, the group with more vegetation exhibited a more significant flow resistance effect. Additionally, as vegetation coverage increased, the turbulent kinetic energy also increased, with a range of 35.7%–82.5%. In experiments with the same vegetation coverage, the group with more vegetation had higher turbulent kinetic energy, with an increase ranging from 39.8% to 69.8%.

Abstract: ABSTRACT Plant cultivation is utilized in coastal ecological restoration to cope with shrinking wetlands, and, benefiting from hydrochory, disseminating indigenous plant seeds represents a high‐efficiency strategy. Random displacement model (RDM) is an efficient alternative to simulate seed dispersal progress via wave. Consequently, we investigated the effect of seed properties and wave characteristics on seeds motion in waves by RDM. Errors between the theoretical comprehensive longitudinal diffusion coefficient of the solute and the simulated one by RDM within an acceptable range indicate that the model is applicable for further simulation of particle dispersal in waves. Simulation results demonstrated that seeds with smaller size and density can transport farther in waves; larger wave heights, smaller water depths and longer wavelengths in linear waves and larger relative wave heights and smaller relative water depths in Stokes waves all promote longitudinally seed diffusion. Finally fitting formulas were proposed for the longitudinal propagation position (including mean and variance) of seed dispersal in linear and Stokes waves. Although this work can provide certain scientific guidance for the restoration of coastal vegetation ecology through natural colonization, there is still much work that needs to be conducted to further the research.

Abstract: Abstract Environmental contamination by plastics has been receiving considerable attention from scientists, policy makers and the public during the last few decades. Though some of the models have succeeded in simulating the transport and fate of plastic debris in freshwater systems, a complete model is now being developed to clarify the dynamic characteristics of the plastic budget on a continental scale. Recently, the author linked two process‐based eco‐hydrology models, NICE (National Integrated Catchment‐based Eco‐hydrology) and NICE‐BGC (BioGeochemical Cycle), to a plastic debris model that accounts for both the transport and fate of plastic debris (advection, dispersion, diffusion, settling, dissolution and biochemical degradation by light and temperature) and applied these models on a regional scale and also for global major rivers. The present study was newly modified to incorporate the plastic dynamics in estuaries by extending the previous studies. The model was employed to conduct a 2‐year global simulation aimed at evaluating changes in plastic dynamics in major rivers including 130 tidal estuaries. The model simulated the impact of estuaries on plastic budget and its seasonal variability caused by settling, resuspension and bedload transport during 2014–2015. The model showed that plastics with smaller particle sizes account for more in the water of estuaries than that of rivers, and plastics with larger particle sizes accumulate more on the riverbed. The simulated result also showed that estuaries trap more plastic than lakes and riverbeds (0.218 ± 0.053 Tg/year) although not as much as reservoirs (0.386 ± 0.103 Tg/year). More than 40% of plastics were retained by lakes, reservoirs, riverbeds and estuaries and the riverine plastic transport to the ocean was revised from 1.749 ± 0.371 Tg/year in the author's previous study to 1.000 ± 0.397 Tg/year in the present study. These results aid the development of solutions and measures for the reduction of plastic input to the ocean and help quantify the magnitude of plastic transport under climate change.

Abstract: ABSTRACT To enhance comprehension of current research progress in the field of ecohydrology and to provide valuable references for future related research, policy formulation and international collaboration, this article relies on ecohydrology‐related literature and citation records in four databases: China Knowledge Network (CNKI), Wanfang Database, Web of Science (WOS) and Elsevier, up until the end of 2022. We use publication and citation trends analysis along with keyword hotspot analysis using VOS viewer to investigate publication and citation trends in Chinese and English literature. The study systematically analyse the process of keyword changes and research hotspots in Chinese and international English literature, providing a detailed explanation of the differences in research hotspots and the reasons for their formation. The research indicates that since the inception of the term ‘ecohydrology’, relevant literature has displayed sluggish growth alongside rapid development. Additionally, alterations in primary keywords have differed between Chinese and English literature over time. However, ‘groundwater’ has consistently retained a significant amount of attention within Chinese literature. Groundwater has been extensively studied in Chinese literature, with a particular focus on eco‐hydrological processes, their effects, modelling and techniques. Similarly, English language literature is abundant with keywords denoting pivotal concepts like the environment, hydrology, fauna and rivers. These areas have been the focal points of research for international scholars. Regional characteristics, ecological conditions, economic development level and scientific research priorities, among other factors, are all significant contributors to the development of the field of ecohydrology. Differences in research hotspots can also be attributed to geographical characteristics, ecological environment conditions and scientific research priorities. Over the past decade, there has been a gradual convergence in research between Chinese and English literature. The current hotspots of research in ecohydrology include basic research, theoretical applications and adaptive wide‐area mechanistic research. In the future, the discipline of ecohydrology is likely to face numerous challenges and opportunities related to climate change, resource management, and societal needs. Interdisciplinary collaboration, technological innovation and global cooperation will continue to drive breakthroughs in ecohydrology research.

Abstract: ABSTRACT Vegetation plays an important role in the management of water resources and of the terrestrial vegetation degradation in semiarid regions of China. Detailed descriptions of the actual hydrological process of vegetation root water uptake ( RWU ) are lacking, and the dynamics of interfaces involved in the process of RWU have not received enough attention. A field in situ experiment with bare land and vegetated land was implemented to investigate soil water flow in vadose zones affected by vegetation RWU . The results revealed that, with the influence of RWU , the soil moisture content was redistributed and impacted evaporation and infiltration; therefore, even the roots were driven to utilize groundwater under intense potential evapotranspiration and water stress. Notably, the thicker vadose zones were beneficial for preserving water resources for bare land, but Salix reduced soil water storage by 1191.13 L compared with bare land, which was adverse for water resource development in semiarid regions. The results provide the basis for the protection of the vegetation environment and water resource management in arid regions.

Abstract: ABSTRACT Global warming has led to an increase in the frequency of meteorological drought events, posing a significant threat to ecosystem security, particularly in arid and semi‐arid regions. Previous studies have utilized correlation analyses to examine the relationship between vegetation and meteorological drought; however, a knowledge gap remains regarding the causal process between the two. This study investigates the linkage between solar‐induced chlorophyll fluorescence (SIF) and the standardized precipitation evapotranspiration index (SPEI) in the Yellow River Basin (YRB) from 2001 to 2019 and explores the cumulative and lagged effects of vegetation SIF in response to SPEI. The results indicated that the cumulative and lag effects of vegetation SIF response to meteorological drought varied with the intensity of water stress. Vegetation in arid regions exhibited poor meteorological drought tolerance and high sensitivity, and the cumulative time and lag time of SIF response to SPEI are 6.5 and 2 months, respectively. Forest, compared with cropland and grassland, demonstrated greater meteorological drought tolerance and reduced sensitivity. For forests, the cumulative and lag time of SIF response to SPEI were 8.7 and 7.4 months, respectively. Grassland was more influenced by precipitation, while forests were more affected by temperature. By analysing the response of SIF to SPEI, this study focuses on the cumulative and lag effects of vegetation on meteorological drought, which will strengthen the understanding of the response of vegetation to meteorological drought in arid and semi‐arid areas.

Abstract: ABSTRACT Viticulture is an essential sector in agriculture as wine production plays a vital role in the socio‐economic life of many countries, especially in the Mediterranean area. Grapevines are a valuable, long‐lived species able to grow in hot and dry regions. We currently do not know whether rain‐fed grapevines entirely rely on deep soil water or make substantial use of shallow water from summer precipitation events. Without knowing this, we poorly understand what fraction of summer precipitation inputs contributes to grapevine transpiration. This has implications for how we quantify grapevine‐relevant precipitation budgets and for predicting the impacts of climate change on grape and wine production. We investigated grapevine water use in a vineyard in the Chianti region, central Italy. During the growing season of 2021, we monitored precipitation and soil moisture at 30‐ and 60‐cm depth. We collected over 250 samples for stable isotope analysis from rainfall, soil, and plants. Since traditional plant water sampling is problematic for grapevines, we collected samples from shoots, leaves, and condensed leaf transpiration after sealed plastic bags were wrapped around a shoot. We use these alternative plant samples to reconstruct the isotopic signal in the xylem water and infer the plant's seasonal water origin throughout the growing season. The analysis of the seasonal origin of water revealed that, throughout the growing season, soil water and plant water received disproportional contributions by rain that had fallen in the winter, even when compensating for the Mediterranean climate of the area. Only in late summer did the grapevines use substantial amounts of summer rainfall, whose contribution occasionally became dominant. These results provide a better understanding of ecohydrological interactions and uptake dynamics in valuable socio‐economic agroecosystems such as vineyards.

Abstract: ABSTRACT In recent decades, forest disturbances caused by wildfire, insect and disease‐induced forest mortality and drought have increased in frequency and magnitude, especially in the Western United States. Forest disturbances have been shown to alter water budget partitioning. However, the water budget response to disturbance is inconsistent and is still being characterized within forest disturbance hydrology (FDH) literature. In this review and synthesis, we evaluate how FDH literature has grown in recent decades (2000–2021), and we extract papers discussing compound (or overlapping) forest disturbances in the Western United States. We then compare literature findings with the actual prevalence of forest disturbance (caused by wildfire, insects and disease) in forested catchments in the Western United States, at HUC‐8, −10 and −12 scales. We find that 94% of HUC‐8 basins, 85% of HUC‐10 basins, and 60% of HUC‐12 basins have experienced compound wildfire and insect/disease disturbance over the period 2000–2022, and virtually, no basins remain undisturbed. These figures contrast with recent FDH literature, where relatively few studies evaluate the hydrologic implications of compound disturbances. These findings suggest that FDH literature is not ‘meeting the moment’ and perhaps, more critically, that true control (or ‘static’) basins are nearly nonexistent in the Western United States. We highlight that as a community of ecohydrologists, we must rethink how we assess post‐disturbance water budget partitioning. This will require better tools (e.g., models) to assess post‐disturbance hydrology, more observations and especially cross‐disciplinary collaborations between hydrology and forestry communities.

Abstract: Abstract Verbal accounts, supported by limited ground‐based and satellite images, reveal decreasing riparian woodland and a loss of large trees along the rivers of the Kruger National Park (KNP, South Africa) over the last century. A multi‐decadal analysis was conducted to identify trends in extent and possible drivers of riparian woodland change. Aerial and satellite imagery (1936–2018) were used to quantify changes in the extent of riparian woodland at 18 sites on 14 rivers in KNP. These changes were compared in a multivariate time‐series with river flow and local rainfall. Particular attention was paid to cumulative flow effects, as well as the frequency and magnitude of large infrequent disturbances such as droughts and floods. Riparian tree cover fluctuated over the time period, and the trajectory of change varied between sites. Most (11) sites experienced a decrease in overall riparian tree cover over ~80 years, with these declines being significant at six sites. Peak flow and maximum rainfall events were strongly associated with these decreases, indicating that flood events are potentially the biggest driver of tree loss from the system. Indeed, the mega‐flood event of 2000 and subsequent large floods have resulted in substantial declines in riparian woodland extent in recent decades. Alternatively, flow variability and cumulative rainfall significantly influenced woodland expansion in isolated cases. With global change models predicting more erratic rainfall and an increased likelihood of large infrequent disturbances, together with increasing demands to abstract more water, the long‐term future of these dynamic habitats and their associated biota here is uncertain.