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.
The invasion of Spartina alterniflora (Smooth Cordgrass) in coastal wetlands has emerged as a pressing ecological challenge, significantly threatening native biodiversity and impairing critical ecosystem functions such as sediment stabilization, carbon sequestration, and habitat provision for migratory species. In response, comprehensive investigations into the spatiotemporal dynamics of this invasive species are urgently needed to inform effective ecosystem management and resource conservation strategies. This study addresses this imperative by developing an innovative biomass-based cellular automaton (CA) model specifically tailored to simulate the complex expansion patterns of S. alterniflora in salt marsh environments. Traditional CA models for vegetation dynamics often suffer from oversimplification, typically reducing vegetation presence to binary ‘on/off’ states without accounting for growth intensity or physiological responses. Our model advances this framework by incorporating biomass as a continuous variable, enabling nuanced representations of vegetation health, growth stages, and stress responses. The model employs Moore’s neighborhood rules for spatial iteration, which consider eight surrounding cells to more realistically capture seed dispersal and vegetative spread patterns. Key environmental and physiological constraints are integrated as dynamic correction factors: water depth (quantifying hydrodynamic stress), growth macrocycle (mapping individual developmental stages), and seasonal phenological changes (accounting for dormancy and active growth periods). This multi-parameter approach allows for accurate simulation of vegetation area and density distribution across heterogeneous wetland landscapes. The model was applied to the Jiangsu Yancheng Wetland National Nature Reserve, a representative coastal ecosystem, using May 2000 distribution data as initial conditions to simulate a 15-year expansion period. Validation against October 2015 remote sensing data demonstrated exceptional performance, with a Pearson correlation coefficient of
Wetlands in the source region of the Yellow River are critical for water regulation and serve as a key water supply for the river, playing a strategic role in ensuring the economic, social, and ecological security of the basin. The MSPA-Conefor-MCR model was applied to construct the wetland ecological network in this region, and its functional characteristics were analyzed by quantifying the groundwater recharge volume and value provided by the wetlands. The structural characteristics were evaluated using the connectivity robustness index. The results show that the wetland ecological network in the Yellow River source region comprises of 74 ecological nodes and 670 ecological corridors. Larger wetland patches, excluding water bodies, exhibit higher groundwater recharge volumes and greater recharge value. Among the patches with the highest recharge values, most are located in cold calcareous soils, meadow soils, and black felt soils. Functionally, wetland patches with higher groundwater recharge values are better connected to surrounding wetlands. These patches also have a wider range of ecological resistance values, and the weight sizes of the wetland patches they connect to show some degree of randomness. Structurally, wetland patches in the northeastern and southeastern regions have a stronger potential for connection, while those in the northwestern region have weaker connectivity.
Qinghai Province is one of the main summering and breeding grouds of Black-necked Cranes (Grus nigricollis), a national first-class protect species in China and a Near Threatened (NT) species on the IUCN Red List. However, systematic and comprehensive research on the spatiotemporal distribution of this high plateau crane species in Qinghai remains inadequate. To address this gap, we integrated multi-source data to clarify its spatial and temporal distribution patterns and potential habitat, providing a scientific basis for targeted conservation. A total of 1 178 valid distribution points from field research and citizen science platforms were used to predict habitat suitablity of Blanc-necked Crane by conducting MaxEnt model. Meanwhile, we used the point density analysis tool in ArcMap (with a 100 km radius) to characterize temporal distribution dynamics. The results show that spatially, suitable habitat of Black-necked Cranes in Qinghai Province are mostly distributed along rivers and lakes, specifically include areas around Qinghai Lake, south slope of the Qilian Mountains, upper reaches of the Yellow River in eastern Qinghai Province, Sanjiangyuan area and the east extension of Qaidam Basin. Total potential suitable habitat is 116 831 km2, it accounts for 16.7% of the total area of Qinghai Province, among which there are 2 626.6 km2 of highly suitable habitat, accounting for 0.4% of the area of the whole province. Gangca county, Qilian county, Haiyan county, Tianjun county, and Gonghe county are the top five administrative regions with the largest highly suitable areas, each exceeding 300 km2. Temporally, April to September constitutes the main residence period for Black-necked Cranes in Qinghai. The surrounding areas of Qinghai Lake, Qilian Mountains and Yushu are the three areas with the highest concentration of records. The distribution from July to August is the most scattered. Notably, 18 records (including single individuals and small groups) confirm that some cranes remain in Qinghai during the overwintering period (December–February), primarily in the Qinghai Lake vicinity and the Sanjiangyuan area. We considered this this previously unreported phenomenon may relate to the physical condition of individuals, local environmental conditions, Climate change, and population migration patterns. Jackknife test results revealed that altitude (contribution rate 31.8%), annual precipitation (18.8%), distance from rivers (16.3%), slope (8.2%), and land cover (7.7%) are the five most influential environmental factors shaping habitat suitability. Annual precipitation positively correlates with habitat suitability, likely by regulating wetland area and water depth. Wetlands and water bodies are the most preferred land cover types, while artificial surfaces (including farmland) also show relatively high suitability, reflecting the cranes’ adaptation to foraging on residual crops. Notably, highly suitable habitats overlap significantly with areas of high grazing intensity, highlighting the need for in-depth research on the coexistence mechanisms between grazing activities and cranes. Although there are potential suitable habitat in every county of Qinghai Province, the black-necked crane still faces multiple conservation challenges: only 28.06% of suitable areas are within existing protected areas; habitat degradation and fragmentation persist due to climate change and anthropogenic activities, and migration connectivity is threatened by power line collisions, a major cause of juvenile mortality. Additionally, the functional roles of most habitats (e.g., stopover, roosting or breeding sites) remain uncharacterized, limiting the effectiveness of conservation measures. To address these issues, we recommend to carry out continuous monitoring based on the spatiotemporal distribution of Black-necked cranes, clarify the functions of each distribution area, build a migration network and identify problems and barriers in the network.
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.
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.
Dissolved organic matter (DOM) in wetland soil is a sensitive indicator reflecting the change of soil organic carbon pool, and its variation characteristics and driving factors have been a research hotspot at home and abroad. However, there is little research on whether it has regional differences. In this study, we selected marsh wetlands in four typical climatic regions of Da Hinggan Mountains, Inner Mongolia, Qinghai, and Xizang, and used ultraviolet-visible spectroscopy (UV-Vis) and three-dimensional fluorescence excitation-emission matrix (3D-EEM) techniques to investigate the effects of climate change on the wetland ecosystem, combined with PARAFAC analysis, the spatial variation of soil DOM and its environmental driving mechanism were systematically explored. The results showed that the content and spectral characteristics of soil DOM were significantly different in different regions. The content of soil DOM was the highest in Da Hinggan Mountains, and the aromatization and humification of soil DOM were higher in Qinghai affected by high altitude and extreme climate, the soil DOM of the marsh wetland on the Qinghai-xizang plateau was dominated by abiotic characteristics, and the abiotic index (BIX) value was the highest. In addition, the spatial distribution of DOM was significantly correlated with latitude and longitude, showing a zonal pattern. With the increase of latitude, the content of DOM increased and the degree of humification decreased, reflecting the cooperative regulation of the climate-vegetation-microorganism system. Soil pH was negatively correlated with DOM content, but positively correlated with aromatic components. Structural equation modeling showed that geospatial location was the main controlling factor for DOM differentiation at large regional scales, and that soil pH could be used as a proxy for DOM variability at large regional scales, and vegetation biomass played a dominant role at the local scale.
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.
The Yilong Lake, one of the nine major plateau lakes in Yunnan Province, is currently facing severe threats from water eutrophication. To investigate the adaptive mechanisms of dominant riparian wetland plants under eutrophic conditions, this study focused on reeds (Phragmites australis) and cattails (Typha orientalis) along the lakeshore of the Yilong Lake. We analyzed the characteristics of leaf nitrogen (N) and phosphorus (P) resorption in response to different chemical oxygen demand (COD) gradients: high (45.23-51.47 mg/L), medium (23.04-31.76 mg/L), and low (3.10-18.50 mg/L). Plant and surface water samples were collected synchronously during the peak growing season. The N and P concentrations in both mature and senescing leaves were measured to calculate resorption efficiency. The results showed that the N and P contents in reed leaves declined over the seasons. Leaf N decreased from 24.64 mg/g in spring to 12.25 mg/g in winter, with a reduction of 50.28%, while leaf P peaked in spring (2.70 mg/g), decreased in summer (1.72 mg/g), and reached its lowest in winter (0.61 mg/g). In contrast, cattail leaf N and P initially increased and then decreased with seasonal changes. Leaf N and P were relatively low in spring (20.93 mg/g and 1.84 mg/g), increased in summer (33.56 mg/g and 2.01 mg/g), began to decline in autumn (26.35 mg/g and 1.96 mg/g), and reached the lowest values in winter. The mean N and P resorption efficiencies of reed leaves were 41.93% and 57.85%, respectively, while those of cattail leaves were 42.87% and 63.53%. Across different COD concentrations, the N and P resorption efficiencies were highest under low COD, followed by medium and then high COD. N resorption efficiency differed significantly among COD levels, whereas P resorption efficiency showed no significant variation. Nutrient contents in mature leaves were significantly positively correlated with those in senescent leaves, indicating coordinated nutrient dynamics between the two stages. Moreover, leaf N resorption was significantly negatively correlated with COD concentration, suggesting that higher environmental COD levels reduce leaf N resorption efficiency. Both N and P resorption efficiencies were significantly negatively correlated with nutrient contents in senescent leaves; the greater the nutrient transfer from senescent to young tissues, the longer nutrients are retained within the plant, thereby reducing nutrient leaching during litter decomposition and slowing nutrient loss from the system. This study elucidates the ecological adaptation mechanisms by which wetland plants respond to eutrophication stress through nutrient resorption strategies, providing a theoretical basis for wetland restoration and eutrophication control in the Yilong Lake.
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.
The construction of water diversion projects and cascade dams drastically alters the hydrological regimes of rivers, inducing changes in the habitats of riparian zones and exerting varying degrees of impacts on the interspecific relationships and community stability of riparian plants. Based on the zonal distribution characteristics of plant communities along elevation and moisture gradients in the middle and lower reaches of the Hanjiang River, this study conducted field vegetation surveys by dividing sampling sites into three parallel transects: Transect 1 (near-water vegetation zones), Transect 2 (intermediate zones), and Transect 3 (farthest vegetation zones from the water). Methods including niche breadth, niche similarity ratio, chi-square (χ2) test, Pearson correlation analysis, and Spearman’s rank correlation test were employed to investigate the ecological niches and interspecific relationships of dominant riparian plants, aiming to explore the effects of water diversion and cascade dams operations on plant interspecific interactions and community succession mechanisms. The results showed that there were 44 herbaceous plant species in the study area, predominantly belonging to the Poaceae and Asteraceae families. The species with the highest importance values in Transects 1, 2, and 3 were Typha angustifolia, Phragmites australis, and P. australis, respectively. Meanwhile, the species with the largest niche breadths were Erigeron canadensis, E. canadensis, and Cynodon dactylon in the three transects. The species pairs with the highest niche similarity ratios were T. angustifolia & P. australis (Transect 1), Equisetum arvense & Imperata cylindrica (Transect 2), and Lolium perenne & I. cylindrica (Transect 3). Across all three transects, more than 70% of species pairs exhibited a niche similarity ratio below 0.2, indicating low overlap in resource utilization and relatively independent interspecific relationships among riparian plants in the middle and lower reaches of the Hanjiang River. The χ2 test revealed that over 80% of species pairs showed non-significant correlations in each transect, with Transect 3 presenting the loosest interspecific network structure. Further results from Pearson and Spearman’s rank correlation tests demonstrated that negatively associated species pairs dominated in all three transects, suggesting weak interspecific linkages, relative independence among dominant species, and an unstable successional stage of the plant community. Based on these findings, we recommend selecting mutualistic plant species as pioneer species for the conservation and habitat restoration of riparian plant communities in the middle and lower reaches of the Hanjiang River. This strategy will contribute to enhancing the stability of riparian plant communities and maintaining the overall functionality of the riparian ecosystem.
To further investigate the numbers, species, and distribution of waterbirds during their spring migration, a coordinated survey was conducted in April 2023 across 25 wetlands along the Yellow Bohai Sea coast. This survey, carried out in collaboration with 30 organizations, employed a combination of line transects and point count methods. A total of 1 115 772 waterbirds from 126 species, belonging to 8 orders and 18 families, were recorded. Among these, shorebirds accounted for the highest number of individuals, with 855 485 individuals, representing 76.67% of the total population. Among the 126 waterbird species recorded, 12 were classified as national first-class key protected species, and 20 as second-class key protected species. Additionally, 44 species of waterbirds accounted for more than 1% of their global populations based on individual numbers. The highest numbers of waterbird individuals were recorded in the Liaoning Liaohekou Wetland, Jiangsu Yancheng Wetland, Shandong Yellow River Delta Wetland, and Liaoning Dandong Yalujiangkou Wetland. Among these, Jiangsu Yancheng Wetland had the greatest species diversity, with 107 species identified. The wetlands were assessed based on Criteria 5 and 6 of the Convention on Wetlands of International Importance. Of the surveyed wetlands, 23 met either Criterion 5 or Criterion 6, accounting for 92% of the total area, while 15 wetlands met both Criteria, representing 60% of the surveyed area. However, 10 wetlands have not yet been included in the national wetland protection system.
Understanding both taxonomic and functional dimensions of biodiversity is essential for revealing how aquatic communities respond to environmental disturbances. Taxonomic diversity reflects the structural attributes of a community, whereas functional diversity provides insight into ecological strategies, resource utilization patterns, and resilience mechanisms. In recent years, extreme hydrological events have become more frequent in northern China, yet the impacts of catastrophic floods on macroinvertebrate communities in mountain rivers remain insufficiently studied. We investigated benthic macroinvertebrates in the mountain section of the Yongding River in Beijing during the spring preceding the Haihe River Basin ‘23·7’ extraordinary regional flood event and during the autumn following the flood. Our objectives were to examine seasonal variations in taxonomic and functional diversity and to explore the relationships between macroinvertebrate communities and key environmental variables, thereby elucidating the response patterns of mountain river ecosystems to large-scale flood disturbances. A total of 76 species of benthic macroinvertebrates were identified across both seasons, belonging to 3 phyla, 6 classes, 18 orders, 44 families, and 60 genera. The assemblage was dominated by Arthropoda, Annelida, and Mollusca, with aquatic insects representing a major proportion of the taxa. Despite this rich composition, the results indicated no significant seasonal differences in taxonomic diversity indices. In contrast, functional diversity exhibited notable temporal variation, functional evenness showed a significant decline during autumn, suggesting a reduction in the uniformity of trait distribution within the community after the flood disturbance. Correlation analyses revealed that water depth, water transparency, and chlorophyll-a concentration were the most influential environmental factors shaping functional diversity patterns. The substantial decrease in chlorophyll-a in autumn implied reduced primary productivity, which likely constrained food resource availability for benthic consumers. Following the flood, the benthic community shifted toward strongly dominance by small-bodied, fast-developing arthropods with high dispersal capacities- traits that confer advantages for rapid recolonization and survival in unstable environments. In contrast, mollusks, which typically exhibit limited mobility and slower life-history strategies, showed a sharp decline in both abundance and diversity, reflecting their considerably slower recovery after disturbance. These findings highlight that evaluating both taxonomic and functional aspects of macroinvertebrate diversity provides a more comprehensive understanding of community dynamics under extreme hydrological disturbances. While species richness alone may mask substantial ecological shifts, functional metrics capture subtle yet ecologically meaningful changes related to species’ ecological roles, niche complementarity, and adaptive strategies. Our results further demonstrate that large floods can reorganize community structure by selectively favoring taxa with traits that enhance resilience and recolonization potential, ultimately altering functional composition even when species diversity appears unchanged. Overall, this study deepens our understanding of seasonal changes and flood responses in mountain river macroinvertebrate communities. The insights gained contribute to a more integrative perspective on maintaining ecosystem function and stability in river systems experiencing increasing hydrological variability. These findings also provide scientific support for ecological protection and restoration efforts within the Yongding River Basin and similar mountainous river ecosystems.
Spartina alterniflora, a typical invasive plant in wetlands, poses serious threats to biodiversity and ecological security in coastal wetlands. Effective control of S. alterniflora has therefore become a crucial issue in coastal wetland management. A field experiment was conducted in the Tiaozini Wetland, Dongtai, Yancheng City, Jiangsu Province, using a two-factor interactive design to investigate the effects of different physical control measures: namely, control (no treatment), mowing, mowing plus coverage with white plastic film, and mowing plus coverage with black plastic film+across different treatment timings (end of the current growing season, beginning of the next growing season, and peak of the next growing season) on the growth and reproduction of S. alterniflora, the recovery of the native plant Suaeda salsa, macrozoobenthos communities, and soil physicochemical properties. The results indicated that physical control measures had significant effects on all growth indicators of S. alterniflora except belowground biomass. Among these measures, the combination of mowing and black film coverage demonstrated increasingly pronounced control efficacy over time. Moreover, the density of the native plant S. salsa significantly increased under mowing plus film coverage treatments. No significant changes were observed in the density and biomass of macrozoobenthos under the mowing plus coverage treatments; however, both macrozoobenthic density and biomass were significantly higher at the end of the current growing season compared to other periods. Soil moisture content significantly increased after the mowing plus coverage treatments and recovered more rapidly compared to mowing alone. In conclusion, mowing combined with black film coverage proved highly effective in controlling S. alterniflora, while exhibiting minimal impact on macrozoobenthic density and other related indicators. Furthermore, this treatment facilitated the recovery of the native plant S. salsa.
Alnus cremastogyne is a predominant tree species in subtropical mountain swamp ecosystems, recognized for its considerable ecological and economic importance. This fast-growing species exhibits a pronounced capacity for carbon sequestration, playing a vital role in regional carbon cycling. Accurate assessment of its biomass is essential for understanding and projecting the carbon sink potential of mountain swamp ecosystems under ongoing regional climate change. In this study, field surveys and laboratory analyses were conducted to measure the biomass of various components of standard A. cremastogyne specimen trees. Using multivariate nonlinear least squares regression, we developed and compared two categories of predictive models: relative growth models and compatible biomass models, designed to estimate biomass at both the component and whole-tree levels. Each model’s predictive accuracy was rigorously evaluated using statistical metrics such as root mean square error (RMSE), mean absolute error (MAE), and the coefficient of determination (R2). Results indicate that relative growth models achieved higher accuracy for estimating specific biomass components, including leaves, roots, branches, stems, crowns, wood, and bark, when modeled independently. Among these, leaf biomass was best represented by a univariate power function of the form
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.
Under the background of global change, to explore the mechanism of wetland vegetation response to nitrogen deposition, we selected Deyeuxia purpurea which is one of the dominant plants of Sanjiang Plain Wetland as the research object, through controlled experiments to study the effects of nitrogen addition level and nitrogen addition time on its functional traits, asexual reproduction and biomass allocation. In this controlled experiment, five nitrogen addition levels were set, CK[0 g/(m2·a)], N1[2 g/(m2·a)], N2 [4 g/(m2·a)], N3[6 g/(m2·a)]and N4[8 g/(m2·a)], and the experimental period was 2 years. The research results indicated that nitrogen addition time, nitrogen addition level and their interaction had extremely significant impacts on plant height, base diameter, and number of branches of D. purpurea (p<0.01). Nitrogen addition increased the number of branches, decreased the leaf length, and significantly reduced the plant height and base diameter of D. purpurea in the first year (p<0.01), while showed opposite trends in the second year. Nitrogen addition time and levels had significant effects on the number of dormant buds and sprouting buds at the tillering nodes of D. purpurea (p<0.01), and their interaction had extremely significant effects on the number of established individuals, the number of elongating rhizome branches, and the number of sprouting buds of rhizomes (p<0.01). Nitrogen addition increased the number of established individuals, the number of sprouting buds at tillering nodes, and the number of dormant buds, but decreased the length and number of elongating rhizome branches. Total biomass, above-ground biomass, and below-ground biomass of D. purpurea gradually increased with the increase of nitrogen addition concentration, and the results of the second year were significantly higher than those of the first year (p<0.01). The allocation proportion of root and leaf biomass gradually increased, while the allocation proportion of stem biomass decreased. Our study demonstrated that the addition of nitrogen increased the number of branches, tillering buds, sprouting buds of rhizomes, and the number of established individuals of D. purpurea, decreased the leaf length, the number and length of elongating rhizome branches, and promoted the biomass accumulation. At nitrogen addition levels of 6 g/(m2·a) and 8 g/(m2·a), and with an additional period of two years, it effectively regulated the growth and asexual reproduction of D. purpurea. The results showed that D. purpurea through an ‘intensive’ growth strategy to expand its population number under the the nitrogen addition background.
The sustainable management of aquatic ecosystems faces growing challenges due to the accumulation of plant-derived biomass waste in polluted lakes and reservoirs. Issues such as impaired plant growth, uncontrolled proliferation, seasonal die-off, and rapid decomposition of vegetation contribute to significant accumulations of organic residues. These materials not only deteriorate water quality by releasing nutrients and accelerating eutrophication but also disrupt the ecological balance of freshwater habitats. Without timely and systematic intervention, such residual biomass can cause secondary pollution, further compromising aquatic biodiversity and ecosystem services. Against the backdrop of China’s Zero-Waste City initiative, there is a pressing need to transition from conventional disposal methods toward sustainable, resource-oriented strategies consistent with circular economy principles. To address the challenge of selecting appropriate treatment pathways, this study developed a multi-criteria decision framework based on the Analytic Hierarchy Process (AHP). The framework integrates five fundamental dimensions, including technical economic, environmental, social, and policy criteria, supported by 17 sub-criteria that systematically reflect sustainability priorities and local operational conditions. The model was applied to assess typical forms of aquatic waste, such as cyanobacterial blooms and water hyacinth (Pontederia crassipes) in Suzhou City, a representative urban area in China confronting eutrophication and aquatic vegetation management challenges. The AHP-based weighting results highlighted technical feasibility as the most influential criterion, accounting for 51% of the total decision weight. Among environmental sub-criteria, carbon emissions emerged as a dominant factor with a weight of 17.94%, underscoring the growing importance of low-carbon considerations in technology selection. Using a normalized scoring mechanism, aerobic composting received the highest comprehensive evaluation score (7.215), attributable to its strong compatibility with high-fiber feedstock, steady market demand for compost products, and operational adaptability to local infrastructure. Anaerobic digestion ranked second (6.416), offering appreciable energy recovery benefits though limited by process stability requirements and capital investment. Co-incineration (5.549) scored lower, constrained by its reliance on auxiliary fuels, higher emissions, and public acceptance challenges, positioning it mainly as a contingency option. Based on these findings, the study proposes an integrated and hierarchical management system centered on aerobic composting, supplemented by anaerobic digestion, and incorporating co-incineration as a contingency option. This multi-technology framework is designed to enhance flexibility, resource output, and environmental performance. Further analysis emphasizes the importance of region-specific policy support, industrial symbiosis models, and regulatory incentives to enable technology adoption and scalling. By combining scientific assessment with practical policy insights, this research provides a robust and transferable decision-support tool for advancing sustainable resource utilization of aquatic plant residue in urban and peri-urban contexts.
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.
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.
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.
