Journal of Hydroecology

Correlation Analysis of Surface Runoff and Landscape Pattern in the Keriya River Basin

In this study, we explored the relationship between changes in surface runoff and changes in landscape pattern in the Keriya River basin, aiming to provide a technical reference for protecting the ecology of the basin. Based on land use/land cover(LULC) data for the study area in five periods(1980,1990, 2000, 2010, and 2020), we extracted landscape pattern index data at the levels of type and landscape. The effects of surface runoff on landscape pattern were then analyzed using ArcGIS and Fragstats 4.2 software, and multi-disciplinary methods including landscape index calculation, Pearson correlation analysis, and Meta analysis. Results show that:(1) From 1980 to 2020, changes in land use type in the basin were clear. Land use consisted primarily of unused land, grassland, and surface water. In 2020, the combined proportion of these three types accounted for 97.79% of the total area, with respective proportions of 75.17%, 20.58%, and 2.04%. The areas of cultivated land and unused land increased by 331.64 km² and 3 838.09 km². respectively, while the areas of surface water and grassland decreased respectively, by 1 147.64 km² and 2 955.13 km².(2) The areas of three land use types(cultivated land, surface water, and unused land) correlated positively with basin runoff, while areas of the three other land use types(forest land, grassland, and construction land) were negatively correlated with basin runoff. At the landscape level, total edge length(TE), edge density(ED), and landscape shape index(LSI) were positively correlated with basin runoff. Moreover, landscape fragmentation and landscape edge length trended upward during the study period.(3) Meta analysis further verified that basin surface runoff significantly impacted the landscape pattern at both the type level and landscape level.

Impacts of Land Use Change on Landscape Patterns and Ecosystem Service Values in the Bosten Lake Basin

The Bosten Lake basin serves as a crucial water source conservation area for the "ecological water transfer" project in the lower reaches of Tarim River. In this study, based on remote sensing image data from 1995 to 2020, we analyzed the dynamic changes in land use, landscape pattern change indices,as well as the variations and spatial distribution of ecosystem service values in the Bosten Lake basin over the 25-year period. We aimed to provide scientific support for ecological security in the basin. Using ArcGis 10.8 software, land types were classified into ten categories, and six periods of land cover data for the Bosten Lake basin were generated for the study. Results show that:(1) The areas of farmland, grass land,surface water, bare land, construction land, wetland and sandy land in the basin presented a fluctuating growth trend, while forest land, glacial snow and saline land showed a fluctuating decrease in area.(2)Within the 25-year period, the patch number(NP) and patch density(PD) of forest land were highest, followed by grassland. In contrast, the NP, PD, and landscape shape index(LSI) of sandy land and saline-alkali land were smaller. This indicates that forest land exhibited a relatively high degree of spatial pattern complexity, while sandy and saline-alkali lands had a low level of patch irregularity and simple landscape shapes.(3) The ecological service value(ESV) of the entire basin first decreased, then increased and decreased again during the 25-year period, with the dominant position of regulating service all the time.Grassland, surface water and glacial snow were the primary contributors and most sensitive factors to changes in the watershed ESV.(4) The distribution of terrestrial ecosystem services in the watershed presented significant spatial positive autocorrelation, with enhanced agglomeration. High ESV areas in the watershed were mainly concentrated in water bodies and the surrounding wetlands, and the low ESV areas were primarily distributed in construction, bare and saline lands. The areas of low-high and high-low aggregation were very small, and the changes were not obvious. The findings of this paper provide a theoretical reference for developing ecological protection and restoration programs in the Bosten Lake basin.

Spatial and Temporal Changes in Vegetation Cover in the Ili River Delta and Influencing Factors

Vegetation along inland rivers in arid zones is sensitive to the dual impacts of climate change and human activities. In this study, the Ili River was selected for a case study, and we systematically analyzed the temporal and spatial characteristics of vegetative cover in the Ili River delta from 1994 to 2022 using remote sensing data, a dichotomous image model, Sen+Mann-Kendall test, the Hurst index and Pearson correlation. Results show:(1) From 1994 to 2022, the mean vegetative cover in the Ili River delta exhibited a fluctuating upward trend, with an average growth rate of 3.6×10^-3/a(R²=0.492). The vegetation cover ranged from 0.30 to 0.47 during this period, with the minimum value occurring in 1996 and the maximum value in 2017.(2) Spatially, areas with increasing vegetative cover were mostly located in the central and northwestern areas of the delta, while areas of decreasing vegetative cover were primarily distributed in the arid edges of the delta. Land with low vegetation cover accounted for the largest proportion in the study area, fluctuating within a wide range(36.37%-63.79%), while land with high vegetation cover exhibited a smaller range(8.97%-23.52%). Vegetative cover in the basin gradually increased from the central delta to the northwest. The central and western delta were characterized by medium-to-high vegetative cover, with wetland(2.97%) and forest land(28.21%) being the primary land use types. In contrast,the northeastern and southwestern regions were dominated by low vegetative cover areas, with bare and desert lands as the primary land uses(62.73%).(3) The overall Hurst index of vegetative cover in the delta was >0.5, with a positive persistence indicating that future vegetative cover will continue the trend of the past 29 years.(4) Correlation analysis showed that runoff volume exerted the greatest influence on vegetative cover, followed by temperature, while precipitation had the least affect. The results of this research support ecological health conservation in the Ili River basin, sustainable development of regional water resources and the protection of soil and water quality in central Asia.

Spatial Differentiation of Landscape Pattern and Water Quality in Beidasha River Basin of Jinan City

Beidasha River is a large river flowing through Jinan City, with typical characteristics of a river flowing along a “village-town-city” gradient. In this study, Beidasha River was selected for a case study, and we explored the impact of land use changes on water quality in the Beidasha River basin along the urban-rural gradient, aiming to provide a scientific basis for optimizing land use and improving water quality in the study area. A total of 19 sampling points were set in the Beidasha River basin, and ArcGIS software was used to analyze the hydrology and land use. Water quality analysis, the landscape pattern index, and correlation analysis were used to explore the relationship between watershed land use and water quality. Results show that along the village-town-urban gradient, patch density initially increased and then decreased. The higher the degree of urbanization, the greater the degree of landscape fragmentation. The river section in the urban community region exhibited the highest land use richness, along with the highest landscape diversity and stability. The spatial heterogeneity of water pollution in the Beidasha River basin was significant. Water quality in the mainstem of Beidasha River was better than that in the tributaries,and improved along the village-town-urban gradient. Farmland was the primary land use type in the Beidasha River basin and its proportional area steadily decreased along the village-town-urban gradient. Land use composition and landscape patterns were the important factors affecting water quality in the basin,and the landscape index exerted a substantial impact on ammonia nitrogen and nitrate levels. Our results indicate that the impact of urbanization and human activities on water quality can be mitigated by strengthening rational planning and management of land use in the watershed and optimizing the land use pattern of the watershed.

Sustainability Evaluation of the Shaanxi Section of Weihe River Basin Based on Game Theory and a Weighted Fuzzy Matter Element Model

The Shaanxi section of the Weihe River basin was selected for research, and we evaluated its sustainability, explored evolutionary patterns and identified key factors influencing sustainability. Our aim was to provide a scientific basis for water resource management and high-quality development. Considering the existing situation and development needs in the basin, we selected evaluation indicators related to water security and resources, ecological health, water quality, water economy, and water culture to develop an evaluation system based on relevant data from 2012 to 2021. First, the G1 method and entropy weight method were used for determining the subjective and objective weights of indicators, and the comprehensive index weight of each indicator was then determined using a combinatorial weighting method based on game theory. Next, a fuzzy matter-element model was constructed, and finally the improved TOPSIS-RSR-Fuzzy method was used to evaluate watershed sustainability and analyze model sensitivity. Indicator weights for watershed runoff regulation and watershed biological integrity ranked high: the weight for watershed runoff regulation was 0.156 and that for watershed biological integrity was 0.108. The evaluation results of the model were consistent with the existing situation. From 2012 to 2014, the river basin was at the preliminary sustainable level, and the evaluation score for sustainability increased steadily from 2015 to 2021, with the highest score of 0.699 in 2021. Analysis showed that the sensitivity of indicators varied by year, and the dike compliance rate, eutrophication rate, and urban flood control compliance rate fluctuated dramatically. Based on our findings, we make the following suggestions: ensure water security in the basin, rationally manage water resources, promote coordinated development of the economy,culture, and environment, and improve the happiness of residents. These suggestions provide a basis for rational water resource management and sustainable development in the Shaanxi section of Weihe River basin.

Effects of Microplastics with Different Particle Sizes on the Bioaccumulation and Oxidative Stress of Lead(Pb) in Zebrafish

The Henan section of the Yellow River， as a critical water resource area in the Yellow River Basin， plays an essential role in the surrounding environment and socio-economic development. The region， with its high population density， faces multiple environmental pressures， including domestic wastewater， agricultural non-point source pollution， and industrial wastewater discharges. Therefore， the water quality of diverted water from the Henan section urgently requires greater attention. Microplastics and heavy metal lead (Pb) are prevalent pollutants in the Henan section， and existing studies have shown that both can cause a range of adverse effects on aquatic organisms， such as growth inhibition， oxidative stress， and neurotoxicity. However， current research has mostly focused on the single toxicity of microplastics or lead， or the simple combined effects of both. There is a lack of comprehensive understanding regarding how microplastic particle size influences the bioaccumulation of lead and its toxic mechanisms in organisms. In this study， three different particle sizes of microplastics (30 mesh， 300 mesh， and 2000 mesh) were exposed to zebrafish for 21 days， either alone or in combination with 100 μg/L lead， to evaluate their effects on lead bioaccumulation and oxidative stress. The results indicated that exposure to 2000 mesh (ultrafine) microplastics in combination with lead significantly enhanced the bioaccumulation of lead in zebrafish， leading to a significant reduction in the fish's condition factor. Furthermore， combined exposure significantly inhibited the total antioxidant capacity (T-AOC) activity and glutathione (GSH) levels in zebrafish liver， resulting in increased reactive oxygen species (ROS) accumulation and elevated malondialdehyde (MDA) levels， thereby inducing oxidative stress damage. The study revealed that the toxicity of combined microplastic and lead pollution in zebrafish exhibited a significant particle size dependence， with smaller microplastic particles being more effective in promoting lead bioaccumulation and exacerbating its toxicity compared to larger particles. This study provides a new perspective for understanding the toxicological mechanisms of combined pollution from microplastics and heavy metals， and offers fundamental data and insights for the water environmental management of the water diversion projects in the Henan section of the Yellow River.

The causal analysis of blue-green algal bloom and research on prevention and control measures in Lang River Debouchure

To address the frequent occurrence of cyanobacterial blooms in Lang River Debouchure， this study conducted water quality and algal monitoring at six sections during the 2021 peak bloom period. By comprehensively applying methods such as pollution index， trophic state index， and redundancy analysis， the study revealed the causative mechanisms of cyanobacterial blooms and proposed control strategies. Results indicated that The water quality of Langhe Debouchure was generally at a mild pollution level， with severe pollution observed at the Bowan Bridge (X2) and Lang River Middle School (X1) sections， where total nitrogen， total phosphorus， and permanganate index were the primary pollutants. The X2 section exhibited characteristics of “high temperature， high pH-high DO， high nutrients， and low transparency”， with cyanobacterial density peaking at 1.2×10⁸ cells/L and a trophic state index reaching a mildly eutrophic level. Redundancy analysis revealed that pH had the highest independent explanatory power for cyanobacterial distribution (69.6%)， followed by COD_Mn and total nitrogen. Cyanobacterial blooms resulted from the synergistic effects of exogenous nutrient input， slow flow hydrodynamic conditions (HRT approximately 18 hours， flow velocity 0.05 m/s)， and the positive feedback of “high pH-high DO”. Based on the causative analysis， a “source-travel-converge” integrated management strategy was proposed， including upgrading wastewater treatment plants， constructing low weir systems to enhance water flow， introducing filter-feeding fish， and establishing an online monitoring and early warning system. This study aims to provide references for eutrophication control in the inflow rivers of the South-to-North Water Diversion Project's central water source area.

Dynamic Coupling Response of Dissolved Oxygen and Chlorophyll-a in Eutrophic Lakes Driven by Ecological Water Diversion

To clarify the regulatory mechanism of ecological water diversion on the dynamic coupling relationship between chlorophyll a and dissolved oxygen in eutrophic lakes， and to provide quantitative basis and scientific support for optimizing lake water diversion schemes and enhancing the long-term effectiveness of ecological restoration. Taking Lake Taihu， an eutrophic lake， as the research object， focusing on the "Diverting Yangtze River Water to Taihu" ecological water diversion project， 2 sampling points were set up in the water diversion area (Gonghu Bay) and the reference area (lake center) respectively. Based on the monitoring data of 2011 (high-intensity water diversion)， 2014 (medium-intensity water diversion)， and 2016 (low-intensity water diversion)， the temporal and spatial variation characteristics of chlorophyll a， dissolved oxygen and key environmental factors under different water diversion intensities were systematically analyzed， and the coupling response laws and driving mechanisms of the two were analyzed. The results showed that after the implementation of ecological water diversion， the concentration of chlorophyll a in the water body and the risk of cyanobacterial blooms significantly (P < 0.01) decreased， and the concentration of chlorophyll a in the water diversion area (Gonghu Bay) decreased from 24.35 μg/L to 12.51 μg/L. At the same time， ecological water diversion changed the algal growth environment in the water diversion area and reshaped the restrictive environment for algal growth， resulting in that total phosphorus might not be the main influencing factor of chlorophyll a concentration in the study area. During the ecological water diversion period， although the concentration of dissolved oxygen showed an increasing trend， the dissolved oxygen saturation showed a decreasing trend， from 96% to 85%， indicating that water diversion might weaken the photosynthetic oxygen production capacity of the water body by inhibiting algal biomass， thereby changing the balance of dissolved oxygen income and expenditure. In addition， ecological water diversion not only changed the coupling relationship between chlorophyll a and dissolved oxygen， but also indirectly affected the change of dissolved oxygen by increasing the input of exogenous nutrients. This study clarifies the regulatory mechanism of ecological water diversion on the coupling process of lake algal biomass and dissolved oxygen production and consumption， and provides a quantitative basis and scientific support for optimizing lake water diversion schemes and enhancing the long-term effectiveness of ecological restoration.

A comparative analysis of the structural changes in algae in shallow water bodies based on photocatalytic integrated restoration technology

Ponds and small lakes are a kind of shallow water ecosystems distributed widely in the world. Based on transparency， total nitrogen (TN)， total phosphorus (TP)， planktic algae， and chlorophyll-A， an in-situ comparative experiment for ecological restoration was conducted to analyze the changes of planktic algae structure in Luhu Lake， a typical small shallow water in Nanning， Guangxi. The advantageous functional groups with and without restoration treatment were identified with FG classification method， and the effect of an UV-photocatalytic integrated restoration (UVPIR) system on algae habitat was discussed. As a result， the UVPIR system reduced averagely the growth rate and survival rate of algae by 70%， decreased chlorophyll a content by 46%， and increased transparency by 30%. After restoration treatment， the advantageous functional groups have shifted from M， N， W1 to M，C， B， and the main functional groups from S1， F， P， J to W1， H1. Consequently， planktonic algae habitat has changed from the mixed eutrophic water with low transparency to the stable eutrophic water with high transparency. The growth of algae was also affected by suspended clay which either obstructs photosynthesis or adsorbs or release P available in the water column.

Response of Plankton Communities to Environmental Changes over the Past Two Centuries in Typical Alpine Lakes of Northwestern Yunnan

To reveal the response patterns of biological communities in typical alpine lakes to environmental changes over the past 200 years， clarify the response differences among lakes of different types and organisms at different trophic levels， and provide a scientific reference for environmental protection and future ecological prediction in high-altitude areas， this study selected three alpine lakes (Gaigong Cuona， Wodi Co and Bigu Tianchi) with distinct altitudes， water depths and watershed vegetation coverage in northwestern Yunnan as the research objects. By comparatively analyzing the variation characteristics of major geochemical indicators， Cladocera and diatom communities in lake sediments， we explored the correlation and driving mechanisms between environmental changes and biological communities over the past 200 years. The results showed that the trophic levels and primary productivity of the two deep lakes (Gaigong Cuona and Wodi Co) increased significantly， while the primary productivity of the shallow lake Bigu Tianchi showed a declining trend due to the significant photolysis of sediment pigments caused by its shallow water environment. Obvious differences in Cladocera community composition were observed among lakes of different types: Bigu Tianchi was dominated by the littoral species Chydorus sphaericus (with its relative abundance exceeding 60% since the 1920s); the relative abundance of the planktonic species Bosmina longispina increased along with the rise in cladoceran flux in Wodi Co since the 1960s and in Gaigong Cuona since the 1980s. Primary productivity was a common factor driving the changes in Cladocera communities in the three lakes， and climate change played a more prominent role in driving the evolution of Cladocera communities in deep lakes. Analyses by STARS and CUSUM indicated that the community structure shift of Cladocera occurred later in lakes with higher altitudes， greater water depths and relatively lower watershed vegetation coverage. The magnitude of regime shift of Cladocera communities was weaker than that of diatom communities in all the three lakes; the shift of Cladocera communities in deep lakes was slightly later than that of diatom communities， while the opposite was true for the shallow lake Bigu Tianchi. The response of alpine lake ecosystems to climatic and environmental changes is comprehensively regulated by the lakes' own physicochemical characteristics (altitude and water depth) and watershed attributes. Low-altitude shallow lakes exhibit higher sensitivity to climatic and environmental changes， with earlier regime shifts of plankton communities， whereas deep lakes show an obvious lag effect in their responses.

Progress of River Restoration Research at Home and Abroad

Research Progress of River Restoration Research at Home and Abroad

Plant Function and Selection for Constructed Wetlands

Fish Swimming Performance Related to Fishway Design

With the habitat destruction and fishery resources dwindling,fishway and other facilities have become important measures to mitigate the disadvantages of water conservancy construction.While early worldwide fishway construction mostly became decorations without consideration of fish.The re-rise of fishway construction in China need more reliable biological informations.The fish swimming performance is related to fishway design and determines its success or failure.Aiming at the fishway design,paper reviewed the decades of research achievements of fish swimming performance at home and abroad.Fish swimming performance has been classified into three distinct categories:sustained speed,prolonged speed and burst speed,among which the latter two are closely related to fishway design.Fish swimming speeds are affected by biological and physical constraints,including tail beat,length,time to exhaustion,temperature and oxygen consumption etc.Finally,the article describes the application of fish swimming performance in fishway design.Fish swimming performance research has been seldom reported in China,so that summary of research method and experience abroad can provide biological basis for our fish facilities construction and promote its development.

A Summary of Hydrology and Hydrodynamics Conditions of Four Chinese Carps' Spawning

Four Chinese Carps(FCC)are very important economy fishes in China,and the Yangtze River is their nature germplasm library.The scale of FCC's natural reproduction is of great significance to the protection of their resources.The spawning of FCC has closely relations with the hydrology and hydrodynamics conditions in rivers.In this paper,a comprehensive represent of the relations between the FCC's spawning and the water temperature and swelling is given,and a brief description of the distribution of FCC's spawning grounds and their hydrodynamics characters is also given.This work can provide some technical support for reservoir operation to the FC's spawning and also for the restoration of FCC's spawning grounds,which is very important to the protections of FCC's germplasm resources and aquatic ecosystems。

Progress of River Restoration Research at Home and Abroad

Research Progress of River Restoration Research at Home and Abroad

Plant Function and Selection for Constructed Wetlands

Research Progress on Ecological Restoration Technology Based on River Ecosystem Health

With the large-scale exploitation of river, river ecosystem is suffering serious damage. So river ecological restoration has become a big concern for public and the work has made considerable progress in recent years. In this paper, at first we analyzed the characteristics of river ecological system and the stresses it is facing at present, introduced the concept of river health and its evaluation methods, and reviewed the related research development of river ecological restoration home and abroad. Then, the technologies and typical practice cases of river ecological restoration were summed up in relation to water flow, connectivity, water quality and aquatic organisms. Finally, we put forward three suggestions on the further research of river ecological restoration: combining different restoration technologies; decision making from the aspect of river basin; monitoring and effect evaluation after ecological restoration. The study will provide reference and guidance for the restoration practice in future.