Lake wetlands serve as critical carbon reservoirs and sources/sinks within the terrestrial biosphere, playing a crucial role in the global carbon cycle. China is endowed with extensive lake wetland resources, and enhancing the capability to monitor and estimate their carbon source/sink dynamics is critical for achieving the national goals of carbon peak and carbon neutrality. However, considerable uncertainties remain due to limited research on carbon flux monitoring and mechanistic understanding of carbon cycling processes in these ecosystems. To improve the understanding of carbon dioxide (CO₂) flux research in Chinese lake wetlands and enhance the accuracy of carbon source/sink assessments in terrestrial ecosystems, this review classifies inland lakes of China into five distinct regions, according to the geographical regionalization framework; they are Tibetan Plateau lakes, Eastern Plain lakes, Inner Mongolia-Xinjiang lakes, Yunnan-Guizhou Plateau lakes, and Northeast Plain and Mountain lakes. For each region, we synthesize the characteristic patterns of CO₂ fluxes and identify key drivers influencing CO₂ emissions, such as climate conditions, hydrological properties, sediment characteristics, vegetation coverage, and anthropogenic impacts. Also, we provide an overview of widely applied methodologies for monitoring and estimating CO₂ fluxes, e.g. eddy covariance systems, floating chambers, and remote sensing-based models. Furthermore, this study outlines the major challenges in current research, including spatial and temporal data gaps, methodological inconsistencies, and scaling issues from site-level measurements to regional estimates. We propose future research directions aimed at strengthening long-term monitoring networks, integrating multi-source data, developing mechanistic models, and improving carbon sequestration strategies. This synthesis is expected to offer a scientific foundation for the conservation and sustainable management of lake wetlands, as well as the enhancement of their carbon sequestration potential in the context of climate change mitigation.

Investigating the characteristics and mechanisms of soil organic carbon storage in the drawdown zone of reservoirs under periodic water level variations is of great significance for accurately understanding the eco-environmental effects of reservoirs and assessing their carbon sink function. Water level fluctuations in the drawdown zone of reservoirs could disrupt the formation and stability of soil aggregates, and also affect the binding of soil minerals and organic carbon as well as the structure and function of microbial communities, thereby regulating organic carbon sequestration. However, the soil organic carbon content in the drawdown zone is influenced by complex environmental factors, and the dominant mechanisms of soil organic carbon sequestration in the drawdown zone vary under different environmental conditions. Currently, no consensus has been reached on the storage and distribution patterns of soil organic carbon in drawdown zones under periodic inundation and exposure. Research on the soil carbon sequestration mechanisms of reservoir drawdown zones remains relatively insufficient, while it is particularly necessary to elaborate on the dynamics of organic carbon and its regulatory mechanisms in these areas. This review summarizes the impact of water level fluctuations on the storage and distribution of soil organic carbon in the drawdown zone, and analyzes the physical, chemical, and microbiological mechanisms of soil organic carbon sequestration in the context of the special hydrological features of the drawdown zones. Future research should combine field sampling surveys with in-situ controlled experiments to deeply elucidate the mechanisms of soil organic carbon sequestration and their interactions in reservoir drawdown zones, thereby providing a scientific basis for the development of carbon sequestration models and carbon sink accounting in drawdown areas of reservoir.

Under the background of environmental protection, constructed wetland, an ecological technology, is widely used in advanced treatment and ecological purification of various surface water bodies because of its low carbon, low consumption and high efficiency. Plants are considered to be important parts of constructed wetlands and play an important role in the process of water purification. Due to the growth characteristics of wetland plants, if the withered wetland plants can not be harvested in time, they will lead to secondary pollution, and even cause wetland blockage, which will affect the stable operation of wetland system. This paper summarized the influence of plant harvesting on the operation effect of constructed wetland system, analyzed the mechanism of plant harvesting affecting pollutant removal, and finally summarized the harvesting management strategies of different kinds of plants. This paper makes up the blank of this part through narration, which will better guide the harvesting process of constructed wetland plants. The seasonal fluctuation of plant harvesting on water quality is significant. Harvesting in spring and summer can stably improve the removal effect of pollutants such as chemical oxygen demand and total nitrogen in the system, while harvesting in autumn and winter is beneficial to the removal of total phosphorus and ammonia nitrogen, but the impact on chemical oxygen demand and total nitrogen fluctuates greatly. In terms of plant species, harvesting submerged plants is more conducive to removing four conventional pollutants (chemical oxygen demand, total nitrogen, total phosphorus, and ammonia nitrogen) compared to emergent plants, which facilitates better purification of constructed wetland water bodies. At the same time, through the second excavation of the article, it is found that there is a certain correlation between wetland plant species and seasons during harvesting. In addition, harvesting not only directly affects the productivity and biological characteristics of plants, but also indirectly affects the physical and chemical environment and microbial metabolism process of wetlands by changing the oxygen secretion level of plant roots and the activity of substrate enzymes, thus affecting the plant-microorganism-substrate coupling effect and the geochemical cycle process of pollutants, which makes the change of water purification efficiency in constructed wetlands. The influence of plant harvesting on the operation of constructed wetland mainly depends on harvesting time, harvesting mode, harvesting frequency, harvesting degree and plant species. When harvesting plants, appropriate harvesting strategies should be selected according to plant types and actual conditions of constructed wetlands, striving to achieve the optimal solution.

In the context of "carbon peaking and carbon neutrality goals", the energy consumption of wastewater treatment process has gradually been paid attention, and the chemical energy contained in the wastewater has huge development potential. Constructed wetland-microbial fuel cell (CW-MFC) technology has the dual functions of reducing pollution and generating electricity, which was considered to be a promising water treatment technology. Taking advantage of the electrochemical performance of metal mineral matrix, improving CW-MFC to enhance power generation and pollution reduction has become the focus of research. Based on introducing the operating principles, advantage and disadvantage of CW-MFC and the main influencing factors, the strengthening effects of metal minerals on CW and MFC were analyzed respectively in this review. The enhancement mechanism of CW-MFC modified by metal mineral matrix in pollutant adsorption and removal by metal redox cycle, and metal minerals played a significant role in reducing internal resistance to enhance conductivity, enriching electroactive bacteria, and establishing microscopic mechanism to improve electrochemical performance through interspecies electron transfer. We revealed the phenomenon of organic carbon fixation by metal minerals in wetland, and proposed theoretical paths for organic carbon fixation in CW-MFC. Focusing on reducing the cost of CW-MFC and improving efficiency of power generation, pollution reduction and carbon sequestration, the exploration of improving CW-MFC with metal minerals was proposed, which provides a reference for the promotions and applications of CW-MFC.

Spartina alterniflora is a widely recognized invasive species that poses significant threats to native ecosystems. Its successful invasion is closely linked to its allelopathic effects, which involve the release of chemical compounds that influence the growth and physiological processes of neighboring organisms. This review comprehensively summarizes the classification of allelochemicals produced by Spartina alterniflora and explores the multiple mechanisms through which its allelopathic effects operate. The allelopathic substances secreted by Spartina alterniflora include organic acids, flavonoids, coumarins, alkaloids, and other secondary metabolites, primarily released through root exudates, leaching, and decomposition of plant residues. These compounds interfere with nutrient and water uptake in native plants by disrupting root function, thus limiting their access to essential growth resources. Moreover, Spartina alterniflora allelochemicals inhibit photosynthesis and respiration by damaging chloroplast ultrastructure and reducing photosynthetic pigments, stomatal conductance, and transpiration rates in native plants such as mangroves and herbaceous species. Additionally, these chemicals affect enzyme activities and cell membrane permeability, altering antioxidant enzyme systems (e.g., superoxide dismutase and peroxidase) and increasing lipid peroxidation markers, thereby compromising plant physiological function. The allelopathic effects extend beyond plants, impacting soil microbial communities by reducing the colonization of beneficial mycorrhizal fungi and altering microbial biomass and nutrient cycling processes, particularly carbon and nitrogen dynamics. These microbial changes negatively affect soil health and nutrient availability, further influencing plant community structure.The invasion of Spartina alterniflora also disrupts benthic animal communities in coastal wetlands, leading to declines in species diversity and richness of mollusks and nematodes. This is partly attributed to chemical changes in the sediment environment induced by allelochemicals released into the rhizosphere and litterfall, which alter food web dynamics and nutrient cycling in these habitats.Interestingly, Spartina alterniflora exhibits autotoxicity, where some allelochemicals produced inhibit its own seed germination and seedling growth, affecting its population dynamics. However, most research has focused on its heterospecific allelopathic interactions, and further studies are required to elucidate the mechanisms and implications of its autotoxicity.The allelopathic interaction between Spartina alterniflora and native plants is bidirectional. Certain native species such as Phragmites australis (common reed) and mangroves release compounds that suppress Spartina alterniflora growth, indicating complex chemical interactions that could be leveraged for ecological management. In addition to ecological impacts, Spartina alterniflora allelochemicals have practical applications. Extracts from this species demonstrate inhibitory effects on harmful algal blooms, such as Microcystis aeruginosa and Prorocentrumdonghaiense, through oxidative stress induction and disruption of photosynthetic systems. Moreover, flavonoids isolated from Spartina alterniflora possess anti-inflammatory properties and have been explored for cosmetic applications, suggesting potential economic value.Future research should broaden the scope to include effects on lower plants, fungi, soil biochemical properties, and animals, and investigate environmental factors influencing allelochemical production and release. Advanced analytical methods are needed to isolate and identify allelochemicals, while genetic and molecular studies could clarify regulatory mechanisms. Exploring integrated management strategies combining biological, chemical, and physical methods is essential to control Spartina alterniflora invasions while harnessing its beneficial properties. Overall, this review provides a comprehensive understanding of the allelopathic roles of Spartina alterniflora in invaded ecosystems, offering critical insights for ecological restoration and invasive species management.

Turbidity, as a key optical parameter measuring the scattering and absorption of light by suspended substances (including organic/inorganic particles, phytoplankton, and microorganisms), is one of the core indicators in water quality assessment. In recent years, frequent pollution events in inland water bodies, such as tailings leakage, abnormal turbidity discharges from reservoirs, and industrial runoff, have heightened the need for efficient and accurate water quality monitoring technologies. Traditional turbidity monitoring methods rely on field sampling and laboratory analysis. Although these techniques provide high-accuracy results, they are inherently limited in spatial coverage and temporal frequency, while also being labor-intensive and time-consuming. With the advancement of remote sensing technology, the acquisition of multispectral data via satellite or aerial platforms has emerged as a promising and cost-effective approach for large-scale and periodic turbidity retrieval. Remote sensing-based turbidity estimation offers several advantages, including wide-area coverage, temporal consistency, and the ability to monitor inaccessible regions. A bibliometric analysis of 574 relevant research articles indexed in the Web of Science reveals a clear upward trend in the number of turbidity-related remote sensing studies. Moreover, the diversity of satellite data sources continues to expand. Among them, the Landsat series stands out as the most commonly used due to its 30 m spatial resolution and extensive historical archive spanning over four decades. Other widely adopted sensors include MODIS (Moderate Resolution Imaging Spectroradiometer), which is suited for large-scale observations; MERIS (Medium Resolution Imaging Spectrometer), known for its ocean color-specific spectral bands; and Sentinel-2 MSI and Sentinel-3 OLCI, which strike a balance between spatial and spectral resolution. In terms of retrieval methodologies, early studies primarily employed linear or polynomial regression models. Over time, more sophisticated approaches have emerged, forming a diverse methodological framework. These include empirical models such as single-band threshold methods and band ratio algorithms, semi-analytical models that incorporate water optical properties, and data-driven machine learning algorithms that offer improved flexibility and adaptability. However, accurately estimating turbidity in optically complex inland waters remains a challenge, primarily due to the heterogeneous absorption and scattering effects of different water constituents. Looking forward, future research should prioritize three key directions: integrating multi-source remote sensing data to overcome limitations in spatial and temporal resolution; improving atmospheric correction algorithms to effectively eliminate interference from aerosols and atmospheric particles; and developing classification-based retrieval frameworks that account for the variability of water optical properties across different inland water types. These efforts will collectively enhance the accuracy, robustness, and general applicability of turbidity remote sensing in complex inland aquatic environments.

As a critical natural ecotone and barrier between marine and terrestrial ecosystems, mangrove wetlands play an indispensable role in the capture and sequestration of atmosphere carbon dioxide (CO₂), as well as organic carbon in the marine environment. Carbon within mangrove wetland ecosystems is ultimately fixed through a series of biological processes and biogeochemical reactions and sequestered in three primary and stable forms: vegetation biomass (i.e., plant aboveground and belowground biomass), plant litters (such as leaves, branches and root, etc.), and soil organic carbon (SOC). In contrast, the export and emission of organic carbon from mangrove wetlands occur mainly through three dominant pathways: the fluxes of greenhouse gas (mainly CO₂ released via soil respiration and litter decomposition, and methane (CH₄) produced under anaerobic soil conditions), the feeding and activities of benthic fauna (such as crabs and snails, etc.), and the hydrological export of dissolved organic carbon (DOC) and particulate organic carbon (POC) into adjacent coastal waters via tidal flow and runoff. By synthesizing the research findings reported in relevant domestic and international publications over the past six years (2018—2023), we reviewed the advances in three key processes of mangrove wetland carbon cycling, including carbon sequestration (i.e., carbon storage, carbon density and carbon sequestration rate) and its influencing factors (e.g., plant, soil physical and chemical properties), as well as the main organic carbon processes (i.e., carbon input and carbon export) in the carbon cycle of mangrove wetlands. Based on the review, we propose two urgent scientific and practical issues that need to be addressed in the current ecological restoration of mangrove wetlands. The first issue is the restoration and enhancement of the carbon sink capacity of degraded mangrove wetlands. The second issue is the need to balance the relationship between conservation (which have high and stable carbon sink capacities and should be protected from disturbance) and the ecological restoration of degraded mangrove areas. To address these gaps, future research should: in-depth exploration of the interactive effects of biotic and abiotic factors on mangrove carbon processes; systematic investigation of the transformation mechanisms of carbon pools; quantitative evaluation of the carbon sink benefits of vegetation restoration; detailed evaluation of restoration processes of carbon sinks; research on the priming effects and roles of consumers (e.g., benthic fauna) in carbon dynamics. Our review could provide a scientific support for the protection and restoration of mangrove wetlands, mitigation of greenhouse effect, and achieving the goals of carbon emissions peaking and carbon neutrality.

Spartina alterniflora is a common invasive species in coastal wetlands of China. Rapid and accurate identification of S. alterniflora has been one of the key focuses in coastal wetland ecological research. Traditional identification methods primarily rely on manual field surveys, which are labor-intensive, time-consuming, and costly. Moreover, existing remote sensing-based identification studies largely depend on a single normalized vegetation index, which often fails to adequately address the spectral confusion between S. alterniflora and co-occurring vegetation species. To address these limitations, taking the Xiangshan Port in Ningbo City, Zhejiang Province as the study area, this research utilized the Red Edge Index (REI) generated from the red-edge bands of Sentinel-2 remote sensing imagery, combining with the phenological characteristics of S. alterniflora during its peak growth season (from June to July 2022) and senescence period (from December 2022 to January 2023), constructed an identification model integrating temporal spectral and phenological information. Through the Google Earth Engine platform, obtain and preprocess image data to identify S. alterniflora in the study area, and systematically optimize the number of decision trees to improve model performance. The results showed that compared with the commonly used Normalized Difference Vegetation Index (NDVI), REI provided better identification performance for S. alterniflora. Furthermore, compared with remote sensing identification methods without phenological features, incorporating the phenological characteristics of S. alterniflora reduced the misidentification rate of surrounding plants. When the number of random forest decision trees was set to 7, the overall identification accuracy combining S. alterniflora vegetation phenological features reached 99.18%, with a Kappa coefficient of 0.981 7. The results were significantly better than the classification results using only NDVI or single-phase data. Spatial analysis further indicated that this method could effectively suppress spectral confusion caused by seasonal phase changes and reduce misjudgment between the edge area of the tidal ditch and the remaining reed plant area. This study verified the potential of the red-edge band of sentine1-2 in the identification of vegetation phenology, providing an efficient and feasible technical approach for high-precision remote sensing monitoring of invasive plants in coastal wetlands.

As ecosystems with the highest biodiversity and ecological roles in the world, wetlands are confronted with a growing number of environmental pollution problems, especially heavy metal contamination, which has emerged as a crucial area of study. As a result, it has become essential to preserve wetland ecosystems. Plants, the fundamental component of constructed wetlands, are extensively utilized in the treatment of heavy metals in effluent, industrial wastewater, and residential sewage since they are low cost, low risk of secondary environmental damage, and superior ecological benefits for the environment. They play an important role in the purification of water bodies. Applying phytoremediation technology effectively requires an understanding of the mechanisms behind plant-based heavy metal remediation. This is crucial for improving the effectiveness of heavy metal pollution remediation in wetlands and lowering ecological concerns. This study examines recent local and international studies on the use of wetland plants for heavy metal pollution remediation. The importance of phytoremediation in wetland restoration is highlighted as it explores the capacities and processes of common wetland plants in the buildup and removal of heavy metals. Research shows that common plants in China and overseas, such as Phragmites australis, Typha orientalis, Thalia dealbata, and Myriophyllum verticillatum, have potent remediation abilities for wetland soils contaminated with heavy metals. Through a multitude of processes, including the release of root exudates (Res) into the rhizosphere environment, the formation of iron plaques on root surfaces, and radial oxygen loss (ROL), plants improve their capacity to accumulate heavy metals. Specifically, by releasing root exudates and causing radial oxygen loss, plants change the rhizosphere's pH, redox potentials, and microbial activities. It alters the solubility and mobility of heavy metals and encourages plant absorption of them. In addition, plants can form iron plaques on their roots to fix heavy metals and prevent them from entering the plant and causing toxicity. Heavy metals enter plant tissues, bind to phytochelatins to form heavy metal-phytochelatin complexes, and are subsequently carried into vacuoles by specific metal transporters, among which are cation diffusion facilitators (CDF), metal transporter P1B-ATPases, and iron-regulated transporter-like protein (ZIP). Furthermore, by controlling the activity of antioxidant enzymes like superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidases (APX), and catalase (CAT), plants can be used to increase their resistance to heavy metal toxicity under heavy metal stress conditions. This provides an efficient antioxidant defense mechanism that eliminates an excessive amount of reactive oxygen species (ROS), reducing the oxidative harm that reactive oxygen species inflict. Future research should focus on the application of genetic engineering and integrated remediation technologies that will enhance both the effectiveness of phytoremediation and its practicality when dealing with wetland heavy metal contamination.

Dietary ecology is fundamental to understanding wildlife-habitat interactions, serving as a cornerstone for assessing environmental carrying capacity, habitat quality, habitat selection behavior, trophic structure, and interspecific competition/mutualism in community ecology. It remains a pivotal focus in endangered species conservation and biodiversity management. Ornithologists have long recognized the significance of dietary studies; for waterbirds-key indicator taxa in wetland ecosystems-dietary data elucidate species-environment energy/material linkages and critically inform ex situ conservation strategies and captive breeding optimization, particularly for threatened species. Methodologically, waterbird dietary research employs diverse approaches. Traditional techniques (direct observation, gizzard/crop content analysis, fecal microscopy) historically dominated the field. Technological advances now highlight DNA metabarcoding for its high taxonomic resolution, though constrained by sample DNA degradation and cost-intensive procedures. Conversely, stable isotope analysis demonstrates broader utility: beyond resolving dietary composition, it enables migration tracking, quantification of seasonal dietary dynamics, trophic-level mapping, and evidence-based population management and wetland restoration. Amid accelerating climate change and pervasive habitat loss/fragmentation, the scope of waterbird dietary research now transcends conventional boundaries. Objectives have expanded from basic diet characterization to multidimensional investigations of spatiotemporal foraging patterns, habitat restoration efficacy, and migratory ecology. Methodologically, interdisciplinary integration (ecology, genetics, physiology, molecular biology) drives advances in: climate-driven dietary adaptation mechanisms, gut microbiota-diet interactions, paleo-dietary evolution from fossil evidence, migration-resource phenology alignment, precision wetland rehabilitation. High-throughput, information-rich analytical tools (e.g., DNA metabarcoding, stable isotopes) provide unprecedented resolution for quantifying dietary seasonality, migration-stage shifts, and species-distribution-environment relationships. With persistent technological advancements and scientific inquiry, waterbird dietary ecology will increasingly underpin biodiversity conservation, ecosystem governance, and global change mitigation.

Nectar plants have great potential use value, and they are also important components of urban ecosystem. In order to identify the diversity of nectar plant species in the area and the important functions in ecosystem construction, we carried out extensive field work and analysis on the diversity of nectar plant species of Haizhu National Wetland Park of Guangzhou City. A total of 71 species of nectar plants were recorded, belonging to 48 genera and 61 families. Among them, there were 11 species (belonging to 9 families 10 genera) of major nectar plants, and 60 species (39 families 51 genera) of auxiliary nectar plants. At the families level, Rosaceae (7 species) and Myrtaceae (6 species) were the dominant components. The results showed that there was no significant difference in the distribution of main nectar plants in different seasons based on the different flowering periods in four seasons. However, the auxiliary nectar plants were mainly distributed in spring and summer, both accounting for 43.33% of the total auxiliary nectar plants species. In terms of life form, the main nectar plants were mainly arbors, including 8 species of arbors, 2 species of herbs and 1 species of vine. Among the auxiliary nectar plants, there were 30 species of trees (50.0% of the total auxiliary nectar plants species), 7 species of shrubs (11.67%), 17 species of herbs (28.33%), and 6 species of vines (10.0%). It was suggested that 1 genus and 27 species of commonly distributed local of nectar plants should be added to this wetland park, and 6 configuration modes of plant community dominated by nectar plants were constructed based on the local zonal plant community structure. The results will be benifit for the conservation and sustainable utilization of urban biodiversity in this area.

Extracellular enzymes are essential for mediating the biogeochemicalcycling of carbon, nitrogen, and phosphorus in wetland sediments, influencing nutrient dynamics and environmental quality. To explore the variations in extracellular enzyme activity in sediments of naturally restored wetlands across different restoration periods and to identify the driving factors, this study was conducted in the Hongze Lake Wetland National Nature Reserve. Sediment samples were collected from wetlands with varying restoration durations (0, 2, 3, 5, and 10 years since restoration). Enzyme activities were measured by fluorescence measurement technology, and sediment chemical properties were analyzed using conventional chemical methods. The results showed that in wetlands restored for 3 years or longer (≥3a), extracellular enzyme activity in the 0-10 cm sediment layer significantly increased compared to degraded wetlands (0 years of restoration, 0 a). In contrast, enzyme activity in sediments of wetland restored for less than 3 years (<3 a) remained relatively unchanged. Additionally, in wetlands restored for 3 years or longer (≥3a), enzymes activities (except for phosphatase) were significantly higher in the surface sediment layer (0-10 cm)than in deeper layers (>10-20 cm and >20-30 cm). Furthermore, enzyme activity in deeper sediments exhibited a lagged response to restoration duration, indicating that surface sediments are more sensitive to restoration-induced changes. During natural restoration of 3 years or longer, the organic matter and total nitrogen content in sediments increased progressively, Correspondingly, enzymes involved in carbon cycling such as cellobiohydrolase (CBH), β-1,4-xylanase (βX) and β-Glucosidase (βG), and phosphatase involved in phosphorus cycling (PHOS), showed increasing trends with restoration time. Among nitrogen (N)-cycling enzymes, N-acetyl-β-D-glucosaminidase (NAG) activity increased, while leucine aminopeptidase (LAP) activity remained stable between 5 and 10 years of restoration. Except for phosphatase, all measured enzymes exhibited higher activity in surface sediments (0-10 cm) compared to deeper layers, highlighting the stratification of microbial and enzymatic processes in sediment profiles. Correlation analysis revealed that in wetlands restored for 3 years or longer, the activities of carbon- and nitrogen-transforming enzyme (CBH, βX, βG, NAG, and LAP) were significantly correlated with sediment properties, including organic matter, total nitrogen, total phosphorus, available phosphorus, and pH. However, in wetlands restored for 10 years, phosphatase activity showed no significant correlation with organic matter, total nitrogen, total phosphorus, or available phosphorus, suggesting that phosphorus cycling may become less dependent on sediment nutrient status in long-term restored wetlands. These findings indicate that wetland restoration enhances sediment enzyme activity and promotes the accumulation of organic matter and total nitrogen, thereby facilitating carbon and nitrogen sequestration in sediments.

The quantitative assessment of wetland water purification functions is important for wetland restoration and water environment management. Based on the literature review, the purification mechanisms of wetlands for suspended solids, organic matter and nutrients have been summarized. The types, advantages and disadvantages, and limiting factors of constructed wetlands were analyzed. The functions of constructed wetlands in purifying new pollutants and reducing greenhouse gas emissions need to be further enhanced. In addition, the quantitative assessment methods for the water purification function of natural wetlands have been summarized, and the driving factors and limiting factors of the hydrological, hydrodynamic and vegetation modules in the numerical simulation have been sorted out. Additionally, a notable contribution of this review is its focus on the advantages of assessing water purification functions from the perspective of wetland complexes within a watershed. This approach provides valuable insights for establishing appropriate pollutant concentration control thresholds, which are particularly relevant in the context of wetland ecological restoration projects, comprehensive water quality improvement efforts across entire watersheds, and the planning and implementation of water transfer projects for lake wetlands. Finally, the review proposes future research directions based on an analysis of current research trends and identified gaps in the field of wetland water purification studies. It suggests a strategic shift in focus from single wetland research to a broader watershed scale perspective that considers wetland complexes. The review also advocates for increasing the density of data monitoring in key water quality areas, establishing long-term and large-scale ecological databases, and developing integrated models of large-scale wetland complexes. These initiatives are conducive to enhancing the ecological construction level of the entire river watershed in China and the water purification capacity of wetlands.

The estuary of the Dafeng River in Guangxi, situated along the East Asian-Australasian Flyway, serves as a crucial habitat for a multitude of migratory birds along the coast of the Beibu Gulf. Currently, systematic research on waterbirds at the Dafeng River Estuary remains scarce. Understanding the community structure and diversity of waterbirds in this region is of great significance for the conservation of coastal migratory birds. From January to December 2022, we conducted surveys of waterbird communities in six sampling sites across four habitat types, using the method of sampling sites and direct counting in the Dafeng River Estuary wetlands. The survey recorded a total of 87 waterbird species from 12 families and 7 orders, with a cumulative count of 74 394 individuals. Among these species, four were national first-class protected species, including Spoon-billed Sandpiper(Calidris pygmaea), Spotted Greenshank(Tringa guttifer), Black-faced Spoonbill (Platalea minor) and Saunders's Gull (Saundersilarus saundersi). And eight were national second-class protected species. One globally critically endangered (CR) species, four globally endangered (EN) species, five globally vulnerable (VU) species and eight near threatened (NT) species were observed. The waterbird diversity showed significantly seasonal variation, with more species and numbers of waterbirds in autumn and winter. The dominant species were Black-headed Gull (Chromocephalus ridibundus), Dunlin (Calidris alpina) and the Lesser Sand Plover (Charadrius mongolus). In Dafeng River Estuary, the maximum monthly numbers of Grey Plover(Pluvialis squatarola), Kentish Plover(Charadrius alexandrinus), Lesser Sand Plover and Dunlin were recorded to exceed 1% of the population size along the East Asian-Australasian Flyway, meeting the criteria for an internationally important wetland. The composition of waterbird communities varied in different habitats, with the highest number of recorded waterbird species at 51 in aquaculture ponds and fewest at 21 in farmland. In conclusion, coastal mudflat wetlands along the Dafeng River estuary in Guangxi satisfy the international criteria for significant wetlands, and is an important stopover site and wintering area for migrating waterbirds on the East Asian-Australasian Flyway. Urgent measures are needed to enhance their management and protection.

To systematically elucidate the spatio-temporal variations of nitrogen contents in both soil and water body, as well as soil nitrogen transformation rates in estuarine wetlands of eastern China, this study compiled and analyzed relevant data collected from 18 major estuarine wetlands spanning latitudes from 19°07′12″N to 41°08′46″N. The investigation focused on the concentrations of different forms of nitrogen, including total nitrogen, ammonium nitrogen, and nitrate nitrogen in both soil and aqueous environments, alongside key nitrogen transformation processes such as denitrification, nitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA). The primary objective was to elucidate the spatial patterns and seasonal dynamics of these variables. The results showed that the contents of different forms of nitrogen in soils were significantly higher than those in water bodies, and showed a spatial distribution pattern of higher in the south and lower in the north (p<0.05), and the soil nitrogen content in winter was significantly higher than that in other seasons. There was no obvious spatial pattern of different forms of nitrogen in water bodies, but it had higher seasonal variation characteristics in spring and autumn (p<0.05). The soil nitrogen conversion rates did not exhibit significant spatial distribution pattern (p>0.05). Specifically, soil transformation rates were significantly higher during spring compared to other seasons. The random forest model showed that several soil properties, including total organic carbon, ammonium nitrogen, nitrate nitrogen and salinity in estuarine wetlands significantly affected the spatiotemporal distribution of nitrogen conversion rates, suggesting that carbon and nitrogen content and salinity were the main driving factors of nitrogen conversion rates in estuarine wetlands in China. However, compared with other ecosystems, the nitrogen contents of different forms in soils of estuarine wetlands were low, and the nitrogen content of different forms in water bodies were lower than those in river ecosystems. Nevertheless, the nitrogen transformation rates in estuarine wetlands exceeded those measured in farmland, forest, and grassland ecosystems in different climate zones in China. Moreover, the rates were significantly higher than the global average level of wetlands. Collectively, the above results underscore the high potential of estuarine wetlands in nitrogen removal and provide an important scientific basis for evaluating the nitrogen reduction capacity of estuary wetlands in China.

Carbon (C), nitrogen (N), and phosphorus (P) are fundamental components of soil nutrients in wetlands. Their ecological stoichiometric characteristics serve as critical indicators that reflect the soil fertility supply capacity and quality, which is of great significance to nutrient cycling in wetland ecosystems. Water and salt conditions are recognized as key environmental factors governing nutrient cycling in estuarine wetlands. However, their specific impacts on the ecological stoichiometric characteristics of soil C, N, and P remain poorly understood. In this study, the freshwater wetland of the Yellow River Estuary were selected as the research object. A simulated incubation experiment was conducted using an interactive design with three water levels (surface flooding at +10 cm, surface drainage at −10 cm, and dry-wet alternation from −10 cm to +10 cm) and four salinity gradients (blank control, 5‰, 10‰ and 15‰) to investigate the effects of water-salt conditions on the stoichiometric characteristics of C, N and P. The results showed that soil C, N, and P contents over 16-weeks incubation period under different water-salt conditions ranged from 2.67 g/kg to 9.14 g/kg, 0.43 g/kg to 0.72 g/kg, and 0.54 g/kg to 0.67 g/kg, respectively. Nutrient concentrations in the control treatment were consistently higher than those in the salinity treatments. Specifically, soil C and N contents were higher under flooding conditions, whereas the water level exhibited a relatively weaker influence on soil P content. Under different water-salt conditions, the soil C:N, C:P, and N:P ratios ranged from 5.67 to 16.85, 12.21 to 36.68, and 1.65 to 2.78, respectively. Elevated salinity exerted a suppressive effect on these ratios, compared to the control, the C:N, C:P and N:P ratios in the high-salinity treatment (15‰) decreased by 14.3%, 23.2% and 10.5%, respectively. Furthermore, these stoichiometric ratios were consistently highest in the flooding treatment and lower in the drainage and dry-wet alternation treatments. Correlation analysis indicated that soil C, N, and P contents and their ecological stoichiometric ratios were positively correlated with soil water content, pH, and plant biomass, but presented negative correlations with electrical conductivity. Salinity was identified as the dominant factor controlling the variations of soil C:N and C:P in the freshwater wetlands of the Yellow River Estuary, while the variation of N:P was more strongly influenced by hydrological conditions. These findings suggest that in the context of global climate change, the declining water levels and increasing salinity in estuarine wetlands may alter the ecological stoichiometric characteristics of soil C, N and P, thereby affecting soil nutrient cycling processes.

As an important water source for human activities and economic development, the protection of lake water quality is crucial, and the mechanisms by which different types of agricultural activities affect lake water quality is urgently needed further in-depth study. With the continuous expansion of agricultural reclamation activities, processes such as farmland fertilization, pesticide use, and changes in land cover have significantly altered the patterns of material input and energy transfer in lakes, necessitating an in-depth study of their quantitative relationship with lake water quality parameters. Although existing studies have focused on the impact of agricultural activities on lake water quality, the mechanisms by which different types of cultivation, spatial patterns, and climatic conditions affect lake optical water quality parameters are still not well understood. Lake optical water quality parameters (such as chlorophyll-a (Chl-a), total suspended particulate matter (TSM), and colored dissolved organic matter (CDOM)) not only reflect the nutrient status and biological productivity of the water body, but also serve as important inputs and validation indicators for remote sensing-based water quality models. Based on recent domestic and international research results, this paper uses a combination method of bibliometrics and case analysis to review the current research status of inversion models for lake optical water quality parameters, including inversion techniques and progress of key optical water quality parameters such as chlorophyll a, inorganic suspended solids, and colored soluble organic matter. It also systematically reviews the latest research results on the impact of agricultural reclamation on optical water quality parameters of lakes, revealing the mechanisms by which agricultural activities affect lake water quality through pathways such as nutrient input, particulate matter input, and organic matter accumulation. Furthermore, through typical lake case studies (e.g., lakes in different climate zones, land use structures, and reclamation history backgrounds), the specific impacts of heterogeneity in agricultural reclamation structures on lake optical water quality parameters is explored, providing a scientific reference for lake ecological protection and sustainable agricultural development.

Mangroves are a pivotal component of blue-carbon ecosystems, and the stability of soil organic carbon (SOC) in these systems exerts a critical control on their carbon-sink function. Along a latitudinal gradient from Fujian to Guangdong and Hainan, we collected surface (0–20 cm) and subsurface (40–60 cm) soils dominated by two representative mangrove species, Kandelia obovata and Avicennia marina. After 90 d of laboratory incubation, cumulative SOC mineralization (used as a proxy for SOC stability) was measured and related to different soil carbon fractions. Results showed no significant difference in cumulative SOC mineralization among latitudes or plant communities. SOC in deeper layers was more stable than in surface layers. Fine-particle content was positively correlated with the proportion of mineral-associated organic carbon (MAOC) to SOC, whereas the MAOC/SOC ratio was negatively correlated with cumulative mineralization. On average, MAOC accounted for 54.00% of SOC, whereas microbial residue carbon (MRC) represented only 14.27%. SOC was significantly correlated with both particulate organic carbon (POC) and MAOC, but the relationship was stronger for POC. These findings suggest that SOC stability in mangroves is primarily governed by soil texture, and the influence of latitude and community type requires further investigation. Microbial residue carbon is unlikely to be the main source of stable MAOC, whereas the labile POC fraction may be a key driver of SOC accumulation in mangrove soils.

To explore the trophic structure and food web structure of the fish community in the Xiaoxi'ergenqi River, an investigation of its fish resources was conducted in the summer (June) and autumn (September) of 2023. By analyzing the carbon and nitrogen stable isotope values (δ¹³C, δ¹⁵N) of various organisms, the SIBER and MixSIAR packages in R were used for relevant calculations and analysis to determine the seasonal differences in the trophic structure of the catch community, and a preliminary food web of the river was constructed. The results showed that the δ¹³C values of fish in summer ranged from (−36.53‰±0.09‰) to (−28.15‰±0.08‰), and the δ¹⁵N values ranged from (6.33‰±0.24‰) to 10.23‰. In autumn, the δ¹³C values of fish ranged from (−33.08‰±0.76‰) to (−28.75‰±0.68‰), and the δ¹⁵N values ranged from (6.43‰±0.76‰) to 10.13‰. Statistical analysis indicated no significant seasonal differences in δ¹³C and δ¹⁵N values between summer and autumn (p>0.05). There was no significant difference in δ¹³C values between carnivorous and omnivorous fish (p>0.05), but the δ¹⁵N values of carnivorous fish were significantly higher than those of omnivorous fish (p<0.05). The trophic level ranges of the fish samples collected in summer and autumn were 2.63-3.77 and 2.66-3.75, respectively, with no significant seasonal differences in the trophic positions of each fish species (p>0.05). The food chain lengths of the Xiaoxi'ergenqi River in summer and autumn were 3.77 and 3.75, respectively. For the six isotope quantitative indices, the values in summer were all higher than those in autumn, indicating that the trophic diversity of the fish community was higher in summer than in autumn, while the degree of trophic redundancy was lower in summer. The study also found that among the three carbon sources, sedimentary particulate organic matter (SOM) contributed the most to the entire food web in both summer and autumn, while the contributions of suspended particulate organic matter (POM) and phytoplankton were relatively lower. According to the food web characteristics of the Xiaoxi'ergenqi River predicted by the Bayesian mixing model, the benthic food chain dominated the entire river ecosystem in both summer and autumn.

The wetland requisition-compensation balance policy, an important ecological conservation strategy in China, mandates equivalent-area compensation for development-occupied wetlands to maintain regional wetland inventory. However, widespread functional heterogeneity exists among wetland types. Since China formally institutionalized the concept of ecological products in 2006, scholarly focus has shifted toward quantifying wetland ecological product values encompassing provisioning services, regulating services, and cultural services to comprehensively reflect intrinsic wetland functions. In order to investigate the effects of current wetland requisition-compensation balance policy on ecological profit and loss of regional wetland functions, this study calculated and evaluated the values of wetland ecological product in Yancheng in 2022 based on gross ecosystem product (GEP) accounting model. The results demonstrated that the wetland in Yancheng was classified into 5 types, including coastal wetland, marshy wetland, riverine wetland, lacustrine wetland, and human-made wetland, of which the total area was 5 678.36 km². The total value of wetland ecological product in Yancheng reached 140.094 billion yuan, comprising provisioning services (26.632 billion yuan), regulating services (107.576 billion yuan), cultural services (5.886 billion yuan). The mean value of unit-area wetland ecological products averaged 22.30 yuan/(m²·a). In terms of different types of wetland, their values from high to low were: coastal wetland [32.65 yuan/(m²·a)], lacustrine wetland [24.57 yuan/(m²·a)], riverine wetland [19.97 yuan/(m²·a)], human-made wetland [19.22 yuan/(m²·a)], and marshy wetland [15.08 yuan/(m²·a). Different wetland types exhibit divergent functional orientations and ecological function values. Coastal wetland provided unique coastal protection [3.66 yuan/(m²·a)]. As to different types of wetland ecological function, value for flood regulation was highest [14.13 yuan/(m²·a)], while value for carbon sequestration was lowest [0.01 yuan/(m²·a)]. Functional equivalence analysis reveals that uniform ecological value can be achieved when the area ratios of coastal wetland: lacustrine wetland: riverine wetland: human-made wetland reach 1.00:1.33:1.63:1.70:2.17. Consequently, it is suggested that when implementing the requisition-compensation balance mechanism across different wetland types, the equivalent value conversion from requisitioned area to ecological compensation can be calculated based on the unit-area wetland ecological product value. This approach can ensure zero net loss of regional ecological product value.

Agricultural nitrogen pollution has become a leading cause of non-point source pollution, resulting in widespread water quality deterioration including eutrophication, nitrate contamination of groundwater, and the formation of black and odorous water bodies. These adverse environmental impacts threaten aquatic ecosystems, public health, and hinder the advancement of rural ecological civilization. As agricultural production intensifies and expands, especially in rural areas lacking centralized treatment infrastructure, developing effective and sustainable nitrogen removal technologies is imperative for environmental protection. Constructed wetlands (CW) have been widely adopted as cost-effective, eco-friendly wastewater treatment systems that integrate physical, chemical, and biological processes for pollutant removal. Their low operational cost, landscape compatibility, and ability to support plant-microbe interactions make them particularly suitable for decentralized rural wastewater treatment. However, traditional CW often exhibit limited nitrogen removal efficiency and instability due to variable hydraulic loading, seasonal temperature fluctuations, and low carbon-to-nitrogen (C/N) ratios, which impede microbial nitrogen transformation processes. This review focuses on overcoming the challenges of nitrogen removal in CW by integrating functional substrates, including biochar, iron-based materials, and microbial fuel cells (MFC). These substrates enhance CW performance by improving substrate physicochemical properties, stimulating microbial communities, and facilitating nitrogen transformation under diverse environmental conditions. Biochar, produced by pyrolysis of biomass, is a porous carbonaceous material with high surface area and abundant functional groups, promoting pollutant adsorption and providing habitats for microorganisms. It improves redox potential and simultaneously supports aerobic nitrification and anaerobic denitrification. Iron-based materials, such as zero-valent iron and ferrous oxides, play crucial roles in redox reactions, facilitating denitrification and anaerobic ammonium oxidation (anammox). They also aid phosphorus adsorption and immobilize heavy metals, improving overall water quality. Combined application of biochar and iron synergistically enhances substrate stability and microbial diversity, promoting efficient nitrogen cycling and stronger plant-microbe interactions. MFC introduce bioelectrochemical functions by enabling extracellular electron transfer and electricity generation through microbial metabolism. They increase nitrogen removal efficiency, especially under low carbon availability, by stimulating microbial cooperation and redox activity. Though MFC effects on plant growth are limited, they provide added value by generating renewable energy to support system operation in off-grid rural settings. Furthermore, the use of these functional substrates helps to mitigate greenhouse gas emissions commonly associated with nitrogen cycling in wetlands, thereby contributing to climate change mitigation efforts. Their incorporation into CW design not only improves nitrogen removal but also enhances the overall ecological sustainability of treatment systems. Recent advances have demonstrated that combining these substrates with optimized operational parameters can significantly extend the lifespan and effectiveness of constructed wetlands, reduce maintenance costs and improve resilience to environmental fluctuations. his review synthesizes recent advances in the use of functional substrates for CW enhancement, elucidating their mechanisms, advantages under stress conditions, and practical implementation strategies. The integration of biochar, iron, and MFC offers a comprehensive and innovative approach to mitigate agricultural non-point source nitrogen pollution. Ultimately, this strategy improves nitrogen removal efficiency, system resilience, and sustainability, contributing significantly to water resource protection and rural ecological civilization development across diverse geographical regions worldwide with sustainable way.

In order to analyze the influence of river-lake connection project on the carrying capacity of water and soil resources in western Jilin Province, and promote the optimal allocation of regional water and soil resources. Based on the ecological footprint model, this paper analyzed the dynamic changes of the spatial and temporal patterns of ecological footprint and ecological carrying capacity of water and soil resources in the western region of Jilin Province from 2016 to 2020. According to the results, the coupling coordination degree model was used to quantitatively analyze the coupling coordination status of ecological carrying capacity of water and soil resources. And the impact of river and lake connectivity projects on the carrying capacity of water and soil resources is discussed. The results show that the ecological footprint of per capita water resources in western Jilin Province shows a downward trend from 2016 to 2020. The overall ecological carrying capacity is on the rise, with an average value of 0.39 hm²/person. The ecological environment of water resources is seriously deteriorated and the water resources are tight. The ecological footprint of per capita land resources in western Jilin Province increased from 0.355 hm²/person in 2016 to 0.403 hm²/person in 2020, and the ecological carrying capacity increased slowly, the land resources have a larger space for use. The river-lake connectivity project has played a positive role in the ecological carrying capacity of water resources in western Jilin Province. However, in the implementation process, the coordination between water resources and land resources is insufficient, resulting in a certain degree of decline in the coupling coordination degree of ecological carrying capacity of water and soil resources. It can be seen that in the future planning, the western part of Jilin Province needs to pay more attention to the comprehensive management of water and soil resources, and gradually realize the efficient allocation of water and soil resources according to local conditions.

Characteristics of mangrove community structure and species diversity serve as crucial indicators for assessing mangrove ecosystem health. Based on field survey data from three major mangrove areas in Shenzhen, this study comprehensively analyzed and compared community characteristics including arbor species composition, community types, dominant species, and species diversity at a holistic scale, aiming to provide scientific basis for biodiversity conservation and sustainable development of mangroves in Shenzhen. The Futian Mangrove National Nature Reserve, Xiwan Mangrove in Bao'an District, and Luzui Mangrove in Dapeng District represent three typical mangrove distribution areas located in southern, western, and eastern Shenzhen, respectively. To elucidate the community characteristics of Shenzhen’s mangroves, these three representative mangrove distribution areas were selected as study areas. The results demonstrated that in terms of community types, Luzui Mangrove exhibited richer diversity with seven community types, compared to five types each in Futian Mangrove and Xiwan Mangrove. Regarding dominant species, Kandelia obovata, Sonneratia caseolaris, and Sonneratia apetala served as foundational and dominant species widely distributed across all three mangrove areas. Bruguiera gymnorrhiza functioned as an important associated species in Futian Mangrove, while Laguncularia racemosa, Excoecaria agallocha, and Rhizophora stylosa formed locally dominant communities as characteristic species in Luzui Mangrove. Aegiceras comiculatum and Avicennia marina significantly contributed to species diversity as key components in both Futian and Lujiazhuang Mangroves. Population age structure analysis revealed stable patterns in Futian and Xiwan Mangroves, whereas Luzui Mangrove showed a younger population with overall growth potential. In species diversity assessment, Luzui Mangrove demonstrated higher diversity indices with more prominent dominant species and more even species distribution. For mangrove restoration and reconstruction, we recommended adopting an integrated approach combining native and introduced species to enhance ecological stability and landscape value. Native species including Excoecaria agallocha, Avicennia marina, and Bruguiera gymnorrhiza were particularly recommended as they pose no ecological invasion risks while effectively increasing biodiversity. These species represented excellent candidates for transforming Kandelia obovate dominated communities or establishing mixed mangrove forests in Shenzhen, contributing to both ecological resilience and aesthetic value of the mangrove ecosystems. The findings provide valuable insights for developing science-based conservation strategies, highlighting the importance of maintaining species diversity and appropriate species composition in urban mangrove management. The spatial variation observed across different locations underscores the need for site-specific management approaches that consider local ecological conditions and community characteristics. This study establishes a fundamental framework for ongoing monitoring and adaptive management of Shenzhen’s valuable mangrove resources.

The coastal tidal flats of the South Yellow Sea are an important stopover for global bird migration and have been listed as World Natural Heritage Site. However, they have been in the process of turning change under the influence of river diversion, marine dynamics and human activities. This study selected seven tidal flat sections, including Sheyang Estuary, Xinyanggang, Chuandonggang, the inner and outer sides of radial sandbars, and the inner and outer sides of Jinggang in the World Natural Heritage Site of Yellow (Bohai) Sea Migratory Bird Habitat (Phase I) along South Yellow Sea. By using Landsat images from 1984 to 2020, the exposed width of the tidal flats was obtained, and the positions and shapes of the tidal flats in different periods were reconstructed based on the tide level information during the imaging period, thereby obtaining the evolution trend of the tidal flats. The results show that, except for Jinggang section, the tidal flats along the coast of this natural heritage site have been in a shrinking state since the beginning of this century, with the width of the tidal flats narrowing and the slope becoming steeper. This trend is more obvious on the northern side than on the southern side. The tidal flats on both sides of the radial sandbar outside the coast also show a significant retreat trend. The tidal flat sections on the inner and outer sides of Jinggang in the south, however, showed a significant siltation and extension trend during the second decade of this century. The retreat of tidal flat wetlands is a threat to the habitat space of rare birds and the stability of the tidal flat ecosystem within the natural heritage site. In order to cope with this challenge, it is necessary to strengthen the unified management of coastal wetlands, promote the subsequent application for World Natural Heritage status of the coastal wetlands, build artificial wetlands and take engineering protection measures to protect the coastal wetland environment, and expand the habitat space for rare birds.

It is an important prerequisite for ensuring regional sustainable development to attach importance to the ecological value and ecological functions of wetland resources. Based on Landsat remote sensing images from 2010 to 2020, the spatio-temporal evolution characteristics of the ecological environment quality of the Sugan Lake Wetland were analyzed by constructing the Remote Sensing Ecological Index (RSEI), and the driving factors affecting the regional ecological environment quality were explored in combination with the geographical detector. The research results showed that among the four indicators of the RSEI of the Sugan Lake Wetland in 2010, 2015 and 2020, there was a positive correlation between NDVI and RSEI, and between WET and RSEI, while there was a negative correlation between NDBSI and RSEI, and between LST and RSEI. The average values of RSEI in the three periods were 0.469, 0.402 and 0.460, respectively. The RSEI decreased by 14.29% from 2010 to 2015; and increased by 14.43% from 2015 to 2020. Overall, the RSEI decreased by 1.92% from 2010 to 2020, and the ecological environment quality of the Sugan Lake Wetland generally showed a slightly deteriorating trend. The areas with poor and relatively poor ecological environment quality were basically consistent in distribution, mainly located on the east side, in the central part of the wetland, and on the north side of the Xiaosugan Lake, with land use types such as bare land, saline-alkali land, and salt marsh land. The analysis of the RSEI difference showed that from 2010 to 2020, the ecological environment quality of the study area was dominated by the deteriorating grade, with the area of the deteriorating grade region reaching 196.01 km², and the area of the improving grade region being 138.07 km². The Moran’s I values of RSEI in 2010, 2015 and 2020 were 0.322, 0.236 and 0.149, respectively, showing a positive spatial correlation, but with a significant trend of weakening aggregation, and the polarization of the ecological environment quality in the study area had been alleviated. The results of the hot spot analysis showed that the cold spots mainly gather on the east side of the study area, with the land use types mainly being saline-alkali land and sandy land; the hot spots mainly gather in the central part of the study area, and after 2010, they moved to the south side of the Xiaosugan Lake and the area around Huahaizi. The analysis of the results of the geographical detector showed that the ecological environment quality of the Sugan Lake wetland was jointly affected by natural factors and human factors. Among them, the dryness index was the single factor with the greatest driving force affecting the ecological environment quality; in the interactive detection, the interactive influence of elevation, land use type and air temperature was dominant. The influence of human factors was significantly weaker than that of natural factors. The research results can provide certain data support and reference for the sustainable development of wetland resources in arid regions.

The investigation of soil stoichiometry characteristics, spatial patterns and driving factors in coastal wetlands is of great significance in revealing soil nutrient cycling in coastal wetlands and elucidating their response mechanisms to environmental changes. This study analyzed the elemental contents and stoichiometric characteristics of carbon (C), nitrogen (N), phosphorus (P), and silicon (Si) in the coastal wetlands soils in China, exploring their variations and driving mechanisms at a large spatial scale. By examining relationship between soil stoichiometric ratios and net primary productivity (NPP), the study revealed the interaction between soil nutrients and vegetation productivity in coastal wetlands. The results showed that the contents of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and available silicon (ASi) in coastal wetlands were (11.43±0.76) g/kg, (0.96±0.05) g/kg, (0.58±0.01) g/kg, and (0.03±0.001) g/kg, respectively. Soil C:N, C:P, C:Si, N:P, N:Si, and Si:P were 11.44±0.36, 22.28±2.10, 366.32±18.18, 1.76±0.10, 33.13±1.52 and 0.06±0.001, respectively. The growth of wetland soils and vegetation was mainly under N limitation. Soil stoichiometric characteristics showed a decreasing trend with increasing soil depth, which may be influenced by surface vegetation and active environmental factors. Mean annual temperature (MAT) and mean annual precipitation (MAP) were identified as key drivers of the quadratic distribution patterns of soil stoichiometric characteristics along latitudinal gradients. The coastal wetlands in southern China had higher C:N, C:P, and N:P, indicating that the rate of SOC mineralization, the availability of soil N and P, and the degree of soil N limitation were lower than those in the northern region. pH was the most important factor affecting the stoichiometric characteristics of coastal wetland soils in China, followed by soil electrical conductivity (EC), specific surface area (SSA), and particle size composition. In coastal wetlands, soil C:P and N:P ratios significantly increased with rising NPP (p<0.05). The NPP of salt marshes was primarily influenced by soil Si:P, while mangrove NPP was predominantly regulated by soil C:P. This research contributes valuable insights into the soil characteristics of China’s coastal wetlands, offering a scientific foundation for informed management strategies aimed at enhancing the carbon sequestration potential of these vital blue carbon ecosystems.

In order to investigate the differences in population characteristics of Protosalanx hyalocranius in different lakes of Lianhuan Lake, Heilongjiang, we estimated key growth and mortality parameters of P. hyalocranius by using the electronic body length frequency method based on fish samples (n=2 801) collected from May to November 2022 in four primary P. hyalocranius-producing lakes of Lianhuan Lake. The current status of P. hyalocranius resource utilization was assessed by constructing the Beverton-Holt dynamic integrated model, and the trend of P. hyalocranius population resources under different fishing strategies was analyzed, so as to formulate a scientific fishing management strategy for P. hyalocranius in Lianhuan Lake. The results showed that there were both supplementary and residual populations of the second age in the Lianhuan Lake. The ELEFAN_SA method yielded an asymptotic length (L_∞) ranging from 173.3 mm to 205.5 mm, an asymptotic body mass (W_∞) from 12.78 g to 25.64 g, and a growth coefficient (k) from 1.9 to 2.3 per year. The total coefficient of mortality (Z) was from 6.32/a to 7.63/a, the coefficient of natural mortality (M) was from 2.07/a to 2.27/a, the coefficient of fishing mortality (F) was from 4.18/a to 5.36/a, and the exploitation rate (E) was from 0.65 to 0.70. Based on the Beverton-Holt dynamic model, the biomass of the residual breeding population accounted for approximately 18%-21% of the total resource. Comparison of the living environment and population resource status indicated that population density and food abundance were the primary factors contributing to growth retardation and miniaturization in P. hyalocranius. By constructing the relative Y'/R of P. hyalocranius in relation to exploitation rate and body length, the results showed that the mean capture body length of HSH Lake, XHL Lake, EBG Lake and NSD Lake were adjusted to 103.98 mm, 123.30 mm, 120.30 mm, 113.58 mm, and the Y'/R value increased by an average of 12.25%. When the exploitation rate of P. hyalocranius was maintained at E_0.1, the residual breeding population biomass could be guaranteed. When the exploitation rate was close to or exceeded the E_max, it was necessary to consider appropriate releases of fertilized eggs. The key factors for the sustainable development of P. hyalocranius resources include adequate food organisms, balanced intraspecific and interspecific relationships, and rational control of resource quantity. The results of this study can be used as a reference for managing P. hyalocranius aquaculture in northern cold-region waters.

Mangrove wetlands are critical ‘blue carbon’ ecosystems that harbor diverse soil microbial communities playing essential roles in biogeochemical cycling. Within these communities, microorganisms can be categorized into generalists (broad ecological niches) and specialists (narrow ecological niches). However, the differential responses of these bacterial groups to infrastructure development, specifically bridge construction, and their underlying assembly mechanisms remain largely underexplored. This knowledge gap hinders our understanding of soil bacterial community evolution under anthropogenic disturbances and the development of effective mitigation strategies. Based on high-throughput 16S rRNA gene sequencing and bioinformatics analysis, this study investigated the impacts of bridge construction by comparing soil bacterial communities in two construction disturbance zones [Sheet Pile Cofferdam (SP) and Steel Casing Pipe (SC)] with those in an adjacent Undisturbed (UD) mangrove habitat. The results demonstrated a distinct divergence in how generalists and specialists responded to disturbance. In the undisturbed ecosystem, bacterial specialists exhibited significantly higher species richness (Mean=98.5) compared to generalists (Mean=49.4). However, bridge construction imposed a significant negative impact on specialists. Compared to the UD habitat, the species richness of specialists decreased notably by 38.73% in SP and 29.14% in SC sites, whereas generalist richness remained relatively stable. Moreover, the UD habitat harbored a higher number of indicator species than the SC and SP habitats, with 62.2% of them being specialists. Furthermore, construction activities profoundly altered the community structure of specialists (p<0.05), with soil organic carbon (SOC) and pH identified as the primary environmental drivers shaping these shifts. Community assembly analysis, utilizing the Modified Stochasticity Ratio (MST), revealed contrasting ecological strategies: generalist assembly was dominated by stochastic processes, suggesting high adaptability to environmental fluctuations; conversely, specialist assembly was governed predominantly by deterministic processes (environmental filtering). Notably, although bridge construction altered community composition and diversity, it did not change the community assembly processes of these bacterial groups. This indicates that the environmental stress induced by construction (e.g., carbon loss and pH alteration) acts as a strong filter, selectively eliminating taxa with narrow niche breadths. In conclusion, the impact of bridge construction on mangrove soil bacterial specialists was significantly greater than on generalists, highlighting the vulnerability of specialists and their potential utility as bio-indicators for monitoring anthropogenic disturbance. These findings provide a scientific basis for ecological management and biodiversity conservation. Therefore, conservation efforts during infrastructure development should prioritize minimizing soil physicochemical alterations to preserve the functional stability of specialist communities. Additionally, eco-friendly construction techniques, such as Steel Casing Pipes, which showed a relatively lower ecological impact compared to Sheet Pile Cofferdams, should be promoted to reduce environmental selection pressure on soil microorganisms.

Ecological sensitivity assessment plays a crucial role in regional environmental protection and the formulation of functional zoning. Using GIS, an ecological sensitivity assessment was conducted on the Longfeng Wetland. Eight indicators elevation, slope, slope aspect, vegetation cover, water body buffer zone, land use type, road buffer zone, and settlement were selected to construct an ecological sensitivity evaluation system. The Analytic Hierarchy Process (AHP) and GIS spatial analysis were employed to assess the ecological sensitivity of the study area. The results indicate that the overall ecological sensitivity of the Longfeng Wetland is relatively low, with a predominance of moderately sensitive areas; vegetation cover and water body buffer zones have the greatest influence on ecological sensitivity; non-sensitive, moderately sensitive, and highly sensitive areas account for 39.5%, 46.4%, and 14.1% of the Longfeng Wetland's total area, respectively; highly sensitive areas are concentrated in the northeastern and central parts of the study area, primarily in reed marsh wetlands, with additional concentrations in the southwestern part's bog wetlands. Moderately sensitive areas are distributed around the periphery of highly sensitive areas, while the remaining areas are non-sensitive, primarily located along the edges of the study area. The basic spatial pattern of sensitivity is a gradual decrease from the central water body of the protected area outward. Based on the evaluation results, relevant recommendations for environmental protection and ecological construction are proposed to provide reference for the protection of wetland ecology and the planning of wetland landscapes.

To safeguard water quality for ecological water replenishment in the Yongding River and address the potential water quality non-compliance issues caused by direct recycled water discharge, a subsurface flow constructed wetland was established within Beijing Yongding River Leisure Forest Park, aiming for advanced purification of recycled water. Based on daily water quality monitoring data throughout a complete water supply period (Mar. to Nov.) in 2022, this study systematically evaluated the continuous purification efficiency of the subsurface flow constructed wetland on recycled water. Results demonstrate that the subsurface flow constructed wetland effectively purified the quality of recycled water, with chemical oxygen demand (COD) and pollutant concentrations, including suspended solids (SS), total nitrogen (TN) and total phosphorus (TP), were significantly reduced (p<0.001) compared to the influent. The treated effluent water also exhibited greater stability. The removal rates for SS and TP were particularly high, reaching 68.35% and 57.78%, respectively, while removal rates for COD and TN were 29.49% and 15.29%, respectively. In terms of purification mechanisms, pollutant removal in this system primarily relied on filtration and adsorption by the substrate, whereas plant uptake and microbial decomposition played a more limited role. To address existing issues, future improvements can prioritize the construction of surface flow wetland units to optimize hydraulic condition, the selection of highly efficient purifying plants to establish diverse communities, and the inoculation of functional microorganisms to enhance biodegradation performance. These multidimensional strategies will strengthen the water purification capacity of the subsurface flow constructed wetland, enabling it to better support ecological restoration of the Yongding River.

Barnacles, as common fouling organisms in mangrove forests, seriously harm the growth of mangrove plants. The massive attachment of barnacles often leads to the death of mangrove seedlings in newly planted forests. The Scylla paramamosain and barnacles share a predator-prey relationship, with the crab serving as a significant predator of barnacles. We aim to investigate the predatory behavior and predation efficiency of the Scylla paramamosain on barnacles. We employed Scylla paramamosain of four body mass classes (100 g, 140 g, 180 g, and 260 g) in predation experiments where they were exposed to barnacles. We conducted predation experiments using Scylla paramamosain to target barnacles (Euraphia withersi and Amphibalanus amphitrite) attached to twigs of the mangrove plant Avicennia marina. Through video surveillance, we observed that Scylla paramamosain detach barnacles from twigs using their chelae, then transfer them to their mouthparts to crush the shells and consume the soft tissue within. The results indicate that both the body mass of Scylla paramamosain and the size of barnacles exert highly significant influences on the crabs' predation efficiency (p<0.01). All body mass classes of Scylla paramamosain exhibited a predation preference for larger barnacles (mean shell length: 6.81 mm). By measuring prey consumption as an indicator of predation efficiency (y), we observed that Scylla paramamosain reached their maximum predation efficiency on barnacles at Day 1 of the experiment. Moreover, the relationship between predation efficiency (y) and Scylla paramamosain body mass (x) can be modeled by the regression equation: y=-112.790+2.146x-0.006x² (R²=0.868, p<0.01). The regression equation reveals that the predation efficiency of Scylla paramamosain on barnacles initially increases but subsequently declines as crab body mass rises, exhibiting a distinct unimodal trend. On Day 3 of the experiment, the 180 g body mass class demonstrated the highest cumulative predation efficiency (94.4%), while the 260 g group showed the lowest efficiency (35.4%). Field experiments likewise confirmed the effective biocontrol potential of Scylla paramamosain against barnacle colonization on mangrove seedlings, with over 70% of seedlings achieving barnacle clearance rates exceeding 50%.

The construction of cascaded reservoirs is a pivotal strategy for global water resource utilization, hydropower generation, and flood control. However, the cumulative effects of cascaded reservoirs, including river fragmentation, alteration of natural flow regimes and sediment retention, pose significant threats to the structure and function of riverine ecosystems.To investigate the impact of cascade reservoir construction on riverine aquatic ecosystems and to provide technical and data support for ecological monitoring, early warning, protection, and restoration, this study employed the Phytoplankton Index of Biotic Integrity (P-IBI) to assess the aquatic ecological health of the Tongzi River at 9 sampling sites from March to May 2024. Based on three aspects—phytoplankton community diversity, species richness, and evenness—20 candidate indicators were analyzed in terms of their distribution range, discriminative power, and Pearson correlation, resulting in the selection of seven core indicators: the number of Bacillariophyta taxa, Shannon-Wiener diversity index of phytoplankton, phytoplankton evenness index, phytoplankton richness index, cell density, the percentage of Chlorophyta cell density, and dominant species cell density. These parameters were used to construct a spring-specific P-IBI evaluation system for the Tongzi River. A ratio-based method was applied to establish a five-tier grading standard: Excellent, Good, Fair, Poor, and Very Poor, corresponding to the health status of the ecosystem. The results revealed that, during spring, a total of 77 phytoplankton genera from 7 phyla were identified in the cascade reservoirs of the Tongzi River. These included 29 genera of Chlorophyta, 25 genera of Bacillariophyta, 14 genera of Cyanophyta, and 4 genera of Euglenophyta. The phytoplankton community was predominantly of the Bacillariophyta-Chlorophyta-Cyanophyta type, with Bacillariophyta as the dominant group. Overall, the aquatic ecosystem of the Tongzi River during spring was found to be in a sub-healthy state. A distinct spatial trend was observed: ecological health conditions improved progressively from upstream to downstream, with downstream sites exhibiting better ecological status. Among the nine sampling sites, 1 site was classified as “fair”, 5 as “sub-healthy”, and 3 as “healthy”. The construction of cascade reservoirs exerted a noticeable influence on the river’s aquatic ecological health. Significant differences in phytoplankton community structure were observed between upstream and downstream of dams and among reservoirs, with P-IBI scores generally lower upstream of dams. Furthermore, P-IBI parameters showed significant correlations with key physicochemical factors such as pH, chlorophyll-a concentration, and the permanganate index, indicating that P-IBI has potential as an effective indicator of water quality pollution in the Tongzi River. Based on these results, it is strongly recommended that water resource managers authorities strengthen efforts to control pollution sources within the watershed, particularly in the upstream and reservoir regions. Moreover, optimizing the operation schedules of the cascaded reservoirs to mimic more natural flow patterns and enhancing wastewater treatment systems in the surrounding areas are critical steps toward mitigating ecological impacts and restoring the Tongzi River's aquatic ecosystem to a healthier state.

Investigating the impact of hydrological connectivity on waterbird diversity is crucial for optimizing waterbird habitat structure and maintaining wetland ecological functions. Using Xianghai National Nature Reserve in Jilin Province as the study area, this study systematically analyzed the response characteristics of waterbird diversity to changes in wetland hydrological connectivity from 2014 to 2023, employing field surveys and a connectivity assessment model. By evaluating waterbird community characteristics and diversity during periods of differing hydrological connectivity, the influence of wetland hydrological conditions on waterbird diversity was explored. The results indicate that: Between 2014 and 2023, waterbirds of the orders Charadriiformes and Anseriformes constituted approximately 52.59% of the waterbird community within Xianghai Reserve. The overall trend in waterbird diversity indices showed an initial increase followed by a decline. Significant temporal variations were observed in the Simpson diversity index, Shannon-Wiener diversity index, Margalef species richness, and Pielou evenness. A significant coupling relationship exists between waterbird diversity and wetland hydrological connectivity. Waterbird diversity was higher during periods of high hydrological connectivity. As connectivity decreased, waterbird populations became unevenly distributed, community diversity declined, and community structure tended towards simplification. Enhancing the management of wetland hydrological connectivity is therefore essential for improving waterbird diversity and sustaining wetland ecological functions.

Compensatory growth following disturbance is a prevalent phenomenon in clonal plants within natural ecosystems, and the bud bank serves as a crucial source for population regeneration in clonal plants. This study focused on Carex brevicuspis, a dominant species in the Dongting Lake wetlands, and established two experimental groups (severe clipping and mild clipping) along with one control group. By collecting and analyzing data on growth performance, regenerative potential, and reproductive strategy, the responses of the C. brevicuspis population and its bud bank to different clipping intensities were investigated. The results demonstrated that, clipping led to a decline in the growth performance of the C. brevicuspis population. Compared with the control group, severe clipping significantly reduced plant density, height, aboveground biomass, and belowground biomass, while mild clipping significantly decreased plant height and aboveground biomass. Clipping impaired the regenerative potential of the C. brevicuspis population; basal bud density was significantly reduced under all clipping treatments, and apical bud density was also significantly decreased following severe clipping. Mild clipping had no effect on the reproductive strategy of C. brevicuspis, whereas severe clipping altered its reproductive strategy, shifting it from guerrilla-type growth to phalanx-type growth. Overall, the C. brevicuspis population exhibited a certain degree of resistance to clipping stress; however, excessively high clipping intensity adversely affected the regenerative capacity of the C. brevicuspis population. This study provides a scientific basis for plant species conservation, waterbird habitat management, and the development of ecological restoration strategies in the context of habitat changes in the Dongting Lake wetlands.

In the northwestern arid areas with severe shortage of water resources, the comprehensive use of recycled water is one of the important means to effectively alleviate the shortage of water resources. For Yinchuan City, which is relatively rich in lake wetland resources, it is of great significance to carry out ecological rehydration of natural rivers and lakes, but the ecological risks of recycled water used for ecological rehydration of rivers and lakes cannot be ignored. Taking Yuehai Lake, a typical lake in Yinchuan City, as the research object, through indoor simulation experiments, the effects of different proportions of recycled water replenishment on water quality and microorganisms of Yuehai Lake were studied. The research results showed that with the increase of the proportion of recycled water replenishment, the concentrations of total nitrogen, nitrate nitrogen and total phosphorus increased significantly, but gradually decreased in the later stage of the experiment. Dissolved oxygen as a whole showed a downward trend, while the chemical oxygen demand showed the characteristics of first decrease, then rise and then decrease. The turbidity first decreased and then increased, and pH gradually stabilized after a sharp rise in the middle of the experiment, and the electrical conductivity was on the rise and there was a stratification phenomenon. Amorphous phylar was the dominant phylar, and its proportion increased significantly with the increase of the proportion of rehydration and the hydration time. The proportion of mycobacterium phyllus and the wart microphyll gradually decreased. When the ratio of recycled water replenishment was 50%-60%, although the concentration of total nitrogen and total phosphorus increased in the early stage, it decreased rapidly in the later stage under the action of microbial assimilation and self-cleaning. The dissolved oxygen stabilized above 6 mg/L, and the turbidity and chemical oxygen demand changed the least. At the same time, the richness and diversity of microbial species under this ratio were high, the proportion of metamorphic phylar was maintained at about 85%, and the community structure was rich and stable. Redundancy analysis showed that nitrate nitrogen, pH and total phosphorus had a significant impact on the microbial community structure, but the three fluctuations were the weakest and the ecological position was the most stable in the 50%-60% groups. Comprehensive water quality safety and biodiversity, the ratio of 50% to 60% recycled water replenishment is the optimal range for the ecological replenishment of Yuehai Lake, which can realize the efficient recycling of water resources while ensuring the landscape function.

Riverine wetlands underpin regional socio-economic development by sustaining critical ecosystem functions and services, including water provision and regulation, ecosystem maintenance, and biodiversity conservation. Accordingly, a rigorous assessment of riverine wetland ecosystem health is essential for guiding rational water-resource utilization and supporting sustainable regional development. Anchored in the concept of ecological integrity, this study developed an integrated framework for evaluating riverine wetland health through the systematic classification, reorganization, and synthesis of widely used river-health indicators into a coherent, multi-dimensional index system. The framework comprises three complementary indicator domains, aquatic biological, physical (habitat), and chemical (water-quality) indicators, designed to capture biological community condition, habitat structure and stability, and the physicochemical environment, respectively. To ensure that the relative diagnostic value of these domains was explicitly represented in the assessment, the Analytic Hierarchy Process (AHP) was used to derive criterion-level weights. The weighting scheme assigned the highest importance to aquatic biological indicators, followed by physical indicators, with chemical indicators weighted lowest, reflecting the premise that biotic assemblages and habitat attributes often integrate cumulative environmental effects and could be more responsive to disturbance than routine chemistry at reach-to-river scales. Because the differential importance of individual metrics within each domain is difficult to determine objectively, equal weights were assigned to metrics within the same domain. The finalized framework includes 18 metrics, encompassing attributes of benthic macroinvertebrate communities, channel morphology and riparian condition, and key water-quality variables (e.g., nutrients and dissolved oxygen). Metric scores were standardized and aggregated to generate an integrated health index, which classified riverine wetland condition into five grades ranging from ‘very poor’ to ‘healthy’. The framework was applied to riverine wetlands in the southern section of the Gaoligong Mountains, Yunnan Province, China. Field investigations were conducted in November 2018, integrating assessments of channel form and riparian habitat, measurements of water physicochemical properties, and standardized collection and identification of benthic macroinvertebrates. Application of the integrated index indicated that the study area could be partitioned into two major basins, the Dulong River Basin and the Nu River Basin, both of which were evaluated as healthy at the basin scale. At the river scale, five of the six investigated rivers were classified as healthy, whereas one river was rated good. Relative to previous assessments conducted in the same region, the restructured and reweighted framework yielded results judged to be more reasonable, with improved interpretability and greater sensitivity. By prioritizing biological integrity while retaining essential habitat and water-quality information for diagnosis and management, this framework provides a scientifically robust tool for riverine wetland health evaluation, conservation and restoration planning, and evidence-based water-resource management.

To understand the water quality status and plankton community characteristics in the Huolin River Basin under the influence of different land-use structures and landscape patterns, water samples were collected from 20 monitoring sections in October 2023. Eight water quality parameters were measured, and plankton community characteristics were investigated. During the survey, 88 zooplankton species (4 categories) and 98 phytoplankton species (6 phyla) were identified. Rotifers dominated the zooplankton community, while Bacillariophyta and Chlorophyta constituted the primary phytoplankton groups. Land-use structures and landscape patterns significantly influenced water quality. Specifically, grassland and woodland effectively filtered and intercepted pollutants, with higher Largest Patch Index (LPI) values enhancing their water purification capacity. Conversely, construction land and cultivated land exerted negative effects on river water quality. These land-use structures and landscape configurations indirectly shaped plankton community characteristics by altering physicochemical water parameters. Key environmental factors affecting dominant zooplankton species abundance included: the proportion of grassland and cultivated land in the buffer zone, LPI, Shannon’s Diversity Index, as well as ammonia nitrogen and permanganate index in water. For dominant phytoplankton species, critical factors were the proportion of cultivated land, nitrate nitrogen, ammonia nitrogen, alkalinity, and dissolved oxygen. These findings provide a scientific basis for rational land-use planning and landscape pattern optimization in the Huolin River Basin, and offered essential data support for riverine ecological conservation and restoration.

To explore the characteristics of phytoplankton community structure and their relationships with influencing factors in the trunk stream and main tributaries of the Tanjiang River, the phytoplankton, land use types and water environmental factors of 23 sampling sections were investigated in December 2021 and June 2022. A total of 6 phyla and 288 species of phytoplankton were detected, and the number of phytoplankton species in dry season was higher than those in wet season. Scenedesmus bicauda, Scenedesmus quadricauda, Scenedesmus bijuga, Chlorella vulgaris, Cyclotella catenata, Microcystis aeruginosa, Cryptomonas ovata were dominant species during study periods. Average density (14.79×10⁶ cell/L) and biomass (12.18 mg/L) of phytoplankton in wet season were higher than those in dry season (10.92×10⁶ cell/L, 7.69 mg/L). Phytoplankton diversity index showed that water quality in wet season was better than that in dry season. Redundancy analysis (RDA) showed that land use type and environmental factors from 600 m buffer zone had the greatest explanatory ability for phytoplankton community in dry season (61.14%), while land use type and environmental factors from 1200 m buffer zone could explain the changes of phytoplankton in wet season to the greatest extent (59.90%). The results of RDA analysis showed that main influencing factors of dominant species in dry season were nitrogen and phosphorus nutrient salts, water temperature, turbidity, building land and fish ponds area ratio, while main influencing factors of dominant species in wet season were nitrogen and phosphorus nutrient salts, water temperature, turbidity, building land, cultivated land and woodland area ratio. Reasonable allocation of land use types from riparian buffer zone will help to reduce the amounts of pollutant into the river and improve water ecosystem quality.

The dynamic process of lateral hydrological connectivity is a key driving factor in maintaining the functional stability of wetland ecosystems and holds significant implications for wetland conservation and ecological restoration. This study focuses on the coastal wetlands of the Yellow River Delta and employs a combination of field monitoring and laboratory experiments to systematically analyze the dynamics of surface and subsurface water levels as well as soil structural properties. The study reveals the spatiotemporal variation patterns and driving mechanisms of lateral hydrological connectivity. The main findings are as follows both surface and subsurface lateral connectivity indices (LC) show a significant decreasing trend with increasing distance from tidal creeks. However, subsurface connectivity exhibits greater intensity and longer duration compared to surface connectivity. The hydrological connectivity response to tidal fluctuations weakens progressively with increasing distance from the coastline or tidal creeks, although similar dynamic patterns are observed across different creeks. Soil structure exhibits significant spatial variability in its influence on hydrological connectivity. Surface soil properties (e.g., saturated water content, field capacity) mainly regulate the duration of lateral connectivity (p<0.05), while subsurface soil properties (e.g., non-capillary porosity) primarily determine the intensity of connectivity (p<0.05), with non-capillary porosity identified as a key factor. Soil bulk density and capillary porosity influence the spatiotemporal dynamics of hydrological connectivity by altering the soil's water infiltration and storage capacity. This study provides new insights into the dynamic patterns of lateral hydrological connectivity and the regulatory role of soil properties in the Yellow River Delta wetlands. The findings offer a theoretical basis for coastal wetland ecological restoration and water resource management. Future research should integrate longer time series data, multi-scale spatial sampling, and factors such as tidal creek morphology. A combined approach involving field experiments and model simulations is recommended to further elucidate the mechanisms underlying hydrological connectivity.