Search Results (629)

Soil salinisation and periodic flooding jointly shape coastal wetland ecosystems, but how coexisting halophytes differ in their rhizosphere bacterial communities under these conditions remains insufficiently understood. Here, we investigated rhizosphere bacterial communities associated with Suaeda glauca Bunge and Tamarix chinensis Lour. in saline–alkaline habitats of the Yellow River Delta, China. Twenty quadrat-level rhizosphere samples were collected across four plant–habitat groups, and near-full-length 16S rRNA gene amplicons were sequenced using Pacific Biosciences single-molecule real-time sequencing. Our analysis revealed that hydrological habitat and plant identity together contributed to differences in rhizosphere bacterial community composition. Across the dataset, 2325 bacterial operational taxonomic units were identified. T. chinensis showed higher Shannon and Gini–Simpson diversity, whereas richness patterns depended on habitat and the metric examined. Meanwhile, exploratory genus-level association networks revealed host- and habitat-dependent differences in node number, network density and average degree. PICRUSt2-based functional prediction suggested contrasting predicted functional response patterns: the S. glauca rhizosphere showed 19 significantly altered predicted pathways between flooded and non-flooded habitats, whereas the T. chinensis rhizosphere showed no significant pathway shifts after multiple-testing correction. These findings suggest that coexisting halophytes are associated with divergent rhizosphere bacterial community patterns under saline–alkaline and flooding-associated habitat conditions. Full article

River regulation creates reservoir shorelines with hydrological regimes that differ from those of adjacent riparian wetlands, but it remains unclear whether wetland setting and geomorphic region are reflected similarly in aggregate community attributes and species composition. We examined plant community attributes, species composition, dominant-species patterns, and their associations with soil and topographic conditions across 20 wetlands in the Han River basin, China. No community attribute differed significantly between riparian and reservoir shoreline wetlands, whereas lowland wetlands had greater plant cover than mountain wetlands. Of the 28 species recorded on reservoir shorelines, 24 also occurred in riparian wetlands. Species composition showed modest differentiation between mountain and lowland wetlands but not between wetland settings, and the ordination showed considerable overlap among groups. Cynodon dactylon dominated all groups, while the frequency and cover of other common species varied spatially. Slope, fine substrate, and distance to water were significantly associated with species composition, but explained a limited proportion of the variation. Slope contributed most within the explained component. These findings indicate that spatial and seasonal variation may be expressed differently across aggregate community attributes and species patterns. Reservoir shoreline assessment may therefore benefit from considering species composition and dominant-species structure alongside vegetation cover and richness. Full article

The Jianghan Plain is one of the important freshwater aquaculture regions in China. Accurate information on the spatial distribution and spatiotemporal dynamics of aquaculture ponds is essential for regional ecological management. However, large-scale and accurate identification remains challenging for aquaculture ponds because they have spectral and seasonal hydrological characteristics similar to those of rice fields, rivers, canals, and lakes. In this study, we developed a framework for mapping inland aquaculture ponds using multi-source remote sensing data from Sentinel-2, Sentinel-1, and PlanetScope. The framework integrated elevation-zoned Otsu thresholding for candidate water extraction, phenological features for rice field removal, and object classification based on a Gradient Boosting Decision Tree (GBDT) model using 12 shape and spatial-context features. It was applied to identify aquaculture ponds in the Jianghan Plain from 2016 to 2025. Overall accuracy exceeded 93%, and the F1-score exceeded 0.93 in all validations. Results from different sensors also showed high spatial consistency. In 2025, aquaculture ponds covered 2365.17 km² in the Jianghan Plain and were mainly concentrated in the central and eastern parts of the plain, especially near Honghu Lake and along the Yangtze and Hanjiang river meanders. Over the ten-year period, the aquaculture pond area fluctuated between 2033.58 and 2383.52 km², showing an initial decline followed by recovery. Lost aquaculture ponds were mainly located around lakes, while newly added ponds were mostly distributed along the margins of existing clusters. The decade dataset generated in this study can support freshwater aquaculture management and wetland conservation. Full article

Climate change and global warming are increasingly affecting freshwater bodies both locally and globally, resulting in fluctuating water levels. Understanding how Cladocera communities are organized across different water body types is important for ecological assessment and conservation. In this study, we compared Cladocera assemblages between different wetland types with different water body types and evaluated the role of physicochemical characteristics and spatial structuring in shaping the community distribution patterns. Six water bodies were selected for our study; each contained three sampling points spaced at least 75–100 m apart. Cladocera specimens in the filtrate samples were identified at the species level. Homogeneity of multivariate dispersions (PERMDISP) and PCA analysis of site-related spatial effects were used to test differences in community composition. Based on previous studies and results, we concluded that the water body type significantly influenced the composition of Cladocera communities among the wetlands investigated. Full article

Poyang Lake is a typical floodplain lake hydrologically linked to the middle-lower Yangtze River. Its peripheral saucer-shaped sub-lakes undergo seasonal hydrological alternation between isolation and connectivity driven by annual water level fluctuations. To date, the coupling between seasonal hydrological rhythms and zooplankton metacommunity assembly in these saucer floodplain lakes remains poorly understood. In this study, four representative saucer sub-lakes within the Poyang Lake National Nature Reserve (Banghu, Zhonghuchi, Shahu and Dahuchi) were selected as research objects. Seasonal quantitative zooplankton surveys and synchronous hydro-physicochemical monitoring were conducted across four hydrological phases from 2012 to 2013: low-water isolation (spring), high-water connectivity (summer), water recession transition (autumn), and extreme low-water closure (winter). We systematically explored how water level fluctuations regulate zooplankton metacommunity assembly processes. In total, 95 zooplankton species were identified, among which rotifers (68 species) constituted the absolute dominant taxon, and 15 species were identified as year-round absolute dominants exhibiting regular seasonal succession in response to hydrological shifts. Our results demonstrate that hydrological connectivity plays a strong role in regulating the relative strength of species dispersal and environmental filtering. During spring and winter, complete hydrological isolation blocked inter-lake species exchange, making local environmental filtering the main driver of metacommunity assembly. Isolated sub-lakes harbored fewer total species but abundant endemic taxa, accompanied by pronounced spatial community heterogeneity. When water levels exceeded the 17.3 m threshold in summer, full water exchange between sub-lakes and the main lake coincided with widespread species dispersal, which appeared to represent the primary assembly process. The four sub-lakes shared 23 co-occurring species during this period, with highly homogenized community structures and minimal spatial differentiation (Global test: R = 0.47, p = 0.001). In autumn, receding water levels weakened inter-lake connectivity, such that environmental filtering and dispersal jointly structured zooplankton metacommunities; significant spatiotemporal differences were detected in zooplankton density, biomass and α-diversity (p < 0.05). Critical hydro-physicochemical factors of environmental filtering included water temperature, chlorophyll a, pH, electrical conductivity and turbidity, yet the dominant limiting factor varied spatially across sub-lakes due to divergent basin topography and water residence time. Species co-occurrence network analysis revealed that zooplankton communities achieved the highest stability during the fully connected summer phase. In early autumn water drawdown, species association networks became fragmented, and community stability reached its annual minimum. This study elucidates the mechanistic link between floodplain lake hydrological rhythms and zooplankton metacommunity assembly, providing theoretical support and baseline data for wetland biodiversity conservation and ecosystem management of Poyang Lake floodplains. Full article

Urban wetlands and agricultural lands are among the most important socio-ecological systems in urban areas. They support food production, biodiversity conservation, water regulation, climate resilience, and human well-being. However, rapid urbanization negatively affects wetland–agricultural coexistence (WAC) by destroying habitats, fragmenting landscapes, and intensifying land-use conflicts. Our study proposed a Wetland–Agriculture Coexistence Index (WACI) to assess the spatial pattern of WAC in Colombo, Sri Lanka. We considered four components for the WACI framework: wetland condition (WC), agricultural condition (AC), urban pressure (UP), and hydrological connectivity (HC). The WACI was developed using Landsat 8/9, Sentinel-1 Synthetic Aperture Radar (SAR), and Advanced Land Observing Satellite (ALOS) data, along with road network, population, and hydrological network data. Variables used in this study include land surface temperature (LST), Enhanced Vegetation Index (EVI), Modified Soil-Adjusted Vegetation Index (MSAVI), Bare Soil Index (BSI), soil moisture, elevation, slope, population density, distance to roads, hydrological connectivity, and built-up %, which were normalized and integrated into four dimensions using an equal-weighted approach to develop the WACI. The results showed substantial spatial heterogeneity in WAC across Colombo. The average WACI was 0.51, indicating a moderate WAC. This study further identified that favorable environmental conditions, rich hydrological connectivity, and low urban pressure increased coexistence potentials. The spatial pattern of WACI identified priority areas for conservation, restoration, and sustainable urban planning implications in Colombo. Our WACI framework provides a practical and transferable method for assessing WAC in urban areas. The findings of this study support balanced urban wetland–agricultural management, conservation, food security, and long-term sustainability of rapidly urbanizing cities. Full article

Wetland ecosystems in large lake basins play a critical role in maintaining regional water security and ecological balance. Despite their importance, the long-term spatiotemporal dynamics of basin wetlands and their effects on lake water quality under intensive human disturbance remain elusive. This study leveraged multi-source satellite archives from 1986 to 2025 to construct a framework for extracting and classifying potential wetlands in the Chaohu Lake basin, Anhui province, China, and examined its evolution and its relationship with water quality. The resulting wetland maps are highly reliable, with overall accuracy ranging from 81.63% to 94.22% and precision approaching 99%, effectively addressing spectral confusion and boundary instability caused by hydrological fluctuations. In total, the basin contains approximately 2139.9 km² of potential wetlands (16%), which are spatially concentrated along the lake and river corridors. Over the 36-year period, wetlands underwent distinct phases of “relative stability—rapid decline—Emerging recovery,” with shrinkage primarily in the west and relative stability in the east, while ponds and paddy fields experienced the most frequent conversions. In recent years (2010–2025), changes in the water environment of Lake Chaohu showed strong spatiotemporal consistency with wetland dynamics. As partial wetland recovery emerged after 2015, concentrations of total nitrogen (TN), total phosphorus (TP), and chlorophyll-a (Chla) declined and stabilized, and the area affected by cyanobacterial blooms decreased by 46%, suggesting a potential role of wetland recovery in improving water quality and mitigating non-point-source pollution. This study provides a comprehensive characterization of wetland dynamics and their influence on water quality, offering valuable data and guidance for wetland conservation, ecological restoration, and integrated lake management in the Chaohu Lake Basin. Full article

Alternanthera philoxeroides (A. philoxeroides) is one of the worst invasive alien species in the world and poses serious threats to both ecological security and agricultural production in China. However, the effects of environmental factors on its growth across different habitat types remain insufficiently understood. To reveal the determining natural factors influencing the growth of A. philoxeroides, fieldwork, including 50 sample quadrats in six field sites, was conducted in the Yangtze River Basin of Hubei Province. In every quadrat, soil properties, soil moisture, pH, soil temperature, soil nutrients (N, P, and K), light intensity, plant cover, and aboveground plant fresh biomass were measured. Cluster analysis showed that A. philoxeroides habitats can be divided into five cluster groups: wetland, grassland, forest understory, farmland and aquatic communities. The results showed that both total community biomass and A. philoxeroides biomass were positively correlated with water content, whereas no significant relationships were found between biomass and soil nutrients, including N, P, and K. The biomass of A. philoxeroides was significantly higher in aquatic habitats, while no significant differences were observed among the other four terrestrial habitats. These findings suggest that hydrological management, together with early control in aquatic habitats, may be an effective strategy to limit the spread of A. philoxeroides. Full article

Accurate evapotranspiration (ET) estimates are essential for hydrological assessment, water-resource management, and wetland conservation, yet global ET products often disagree in heterogeneous coastal environments. This study compared ERA5-Land, GLDAS Noah, TerraClimate, MERRA-2, MOD16A2GF, and PML_V2 across Hong Kong during 2001–2020 and examined their applicability to the Mai Po Marshes. The products were standardized to annual water-depth equivalents and evaluated using descriptive statistics, the Friedman repeated-measures test, Holm-adjusted Wilcoxon signed-rank tests, lag-1 autocorrelation analysis, and standard and Hamed–Rao modified Mann–Kendall tests. Spatial uncertainty was quantified using the inter-product coefficient of variation and summarized by land-cover class. Mean annual ET ranged from 530.09 mm yr⁻¹ for GLDAS to 1182.80 mm yr⁻¹ for ERA5-Land. Product differences were significant (χ²(5) = 94.74, p < 0.001; Kendall’s W = 0.947), and all pairwise contrasts remained significant after Holm correction. GLDAS was the only product with a significant increasing trend (Sen’s slope = 4.88 mm yr⁻², p < 0.001), while the remaining products showed no significant trends. Within Mai Po, ET estimates differed among products but showed negligible variation among aggregated wetland habitat classes. The findings support uncertainty-aware, multi-product interpretation for regional ET monitoring and cautious application to compact coastal wetlands. Full article

Ecological niche modeling (ENM) is widely used to predict species distributions and support biodiversity conservation under environmental change, yet its application to Amazonian wetland plants has not been systematically synthesized. We conducted a systematic review following the PRISMA 2020 guidelines to evaluate methodological approaches, environmental predictors, model performance, and research gaps. Literature searches were performed in Web of Science, Scopus, and Consensus (as a complementary AI-assisted academic search platform), yielding 1789 records, of which 48 met the eligibility criteria. Correlative models predominated, with MaxEnt, Random Forest, and ensemble frameworks being the most frequently applied algorithms. Across studies, integrating hydrological and edaphic predictors consistently improved model performance and ecological realism compared with climate-only approaches. Future climate projections indicated greater vulnerability for habitat-specialist species, whereas western Amazonia and the Andean foothills were repeatedly identified as potential climatic refugia. Major limitations included geographically biased occurrence records, limited high-resolution environmental datasets, and the underrepresentation of several Amazonian wetland ecosystems. Overall, the evidence indicates that reliable ENMs for Amazonian wetlands require integrating climatic, hydrological, and edaphic drivers rather than relying solely on macroclimate. Future research should prioritize geographically representative sampling, improved environmental datasets, transparent workflows, and process-informed modeling to strengthen ecological forecasting and conservation planning under climate and land-use change. Full article

The escalating frequency of extreme hydrological events under environmental uncertainty poses a severe socio-economic threat to floodplains such as the Brazilian Pantanal, the world’s largest tropical wetland. Mitigating dynamic flooding and drying cycles is highly challenging due to a critical scarcity of in situ monitoring, leaving flood risks poorly understood. To address these data gaps, this study presents an advanced deep learning forecasting framework that integrates multisource environmental data, fusing satellite-derived precipitation (CHIRPS) and global land data assimilation evapotranspiration (GLDAS) data with historical river gauge telemetry. Multi-layered neural network architectures were optimized and combined with progressive moving average filters (10− and 15−day windows) to capture the complex hydrometeorological patterns of the data-scarce Miranda River Watershed. The optimal deep learning configuration, utilizing a robust two-hidden-layer topology (15 and 60 neurons), consistently outperformed standard baselines. Although purely exogenous data blocks successfully minimized satellite noise and captured seasonal trends (NSE ≥ 0.92), structural underestimation of peak flows was observed. When incorporating the previous day’s streamflow (lag t−1) as a physical anchor, this limitation was noticeably alleviated, increasing both the Nash–Sutcliffe Efficiency (NSE) and Coefficient of Determination (R²) values above 0.99. While this performance surge is driven by the strong temporal persistence inherent to the autoregressive lag, it introduces an operational trade-off by restricting the forecast to a reactive 24 h window. In this regard, an evaluation of the operational forecast horizons revealed that the exogenous deep learning blocks maximize warning lead times, providing a vital tool for proactive civil defense and disaster risk reduction. Ultimately, this multisource framework establishes a methodological foundation for automated decision support systems, providing the high-accuracy streamflow forecasting capability required to support future flood mitigation frameworks. Full article

The Laspias River and Lissos River sustain the hydrological and ecological functioning of the Vistonida Lake wetland complex, a protected Natura 2000 site and Ramsar Convention Wetland of International Importance, by regulating nutrient transport and supporting aquatic biodiversity. Thus, the water quality of the rivers Laspias and Lissos and their adjacent coastal zones located in the prefectures of Xanthi and Rhodope (NE Greece) respectively was monitored regarding key metal concentrations for a period of two years. The monitoring of these watersheds and coastal zones was based on seven sampling stations in the Laspias River, twelve stations in the Lissos River and four stations in each river’s coastal zone. During water monitoring of both rivers, a wide range of chemical elements was analyzed to assess water quality. In the present work, the heavy metal pollution index (HPI) and the heavy metal evaluation index (HEI) were assessed in both rivers and their coastal area for four successive seasons. The mean HPI and HEI values for the Laspias River were 54.66 ± 10.82 and 1.45 ± 0.22, whereas the respective indices in the Lissos River were 14.43 ± 4.14 and 0.39 ± 0.14. The mean HPI and HEI values for the adjacent coastal zones of the Laspias and Lissos Rivers were 7.42 ± 1.52 and 0.14 ± 0.05, as well as 10.39 ± 0.83 and 0.23 ± 0.02, respectively. Therefore, the average HPI values for both rivers and their coastal zones were below the proposed threshold (<100), while the HEI of the Laspias River classified the water quality in the second category (slightly affected, HEI from 1.0 to 2.0 due to the effect of Mn) and the Lissos River in the first category (very pure/pure, HEI < 1), respectively, considering drinking water thresholds. The HEI indices of their coastal zones characterized the water quality as very pure/pure. Full article

The Mississippi River Delta region is of national and international relevance in terms of agriculture, energy, river navigation, and fisheries. Being one of the most engineered rivers in the world, the Mississippi River has been intensively altered over the past 150 years. The river alterations included the construction of dams, levees, diversions, channelization, spillway flood control systems, and many others. These engineering practices have significantly modified the natural hydrology and sediment dynamics of the river and its deltaic region. While these interventions have provided critical benefits such as flood protection, improved navigation, and economic development, they have also led to profound environmental and ecological consequences. The reduction in sediment delivery to the Mississippi River Delta has accelerated land loss, contributing to the disappearance of coastal wetlands at an alarming rate. The land loss has diminished critical habitats for wildlife, reduced storm surge protection for coastal communities, and disrupted the delta’s natural ability to adapt to fast subsidence. The long-term sustainability of the delta is further threatened by the compounding effects of climate change, including rising sea levels, increased storm intensity, and extreme precipitation and drought conditions. This paper examines the effects, consequences, and future risks of the major river engineering practices on the Mississippi River Delta and provides strategic recommendations that balance human needs with changing natural conditions to ensure sustainability. Specific recommendations include river diversion upstream of New Orleans, better strategies to deal with floods and droughts, strategic maintenance or removal of portions of levees, hybrid coastal-inland human migration, improved transportation connections between coast and inland, and better preparation for future ecosystem shifts. This review is needed because river engineering has made the Mississippi River Delta economically vital yet increasingly vulnerable to sediment loss, wetland collapse, saltwater intrusion, flooding, and population decline. By synthesizing these linked natural and human consequences, it provides a timely framework for rethinking delta sustainability under climate change. Full article

Invasive species represent a major threat to global biodiversity, highlighting the need for continuous monitoring and research to better understand their ecology, distribution, and invasion dynamics. Among freshwater leeches (Hirudinea), Helobdella europaea is considered one of the most successful and widespread invasive taxa. This study provides an updated assessment of the distribution of H. europaea in Morocco and identifies the main environmental factors influencing its occurrence and spread across the country. Field surveys were conducted between 2014 and 2024 in northern Morocco, with particular focus on protected wetlands, including Ramsar sites, and major biogeographical barriers such as the Middle Atlas Mountains and the Sebou and Moulouya river basins. Specimens were collected using Surber samplers (20 × 25 cm, 400 μm mesh), while physicochemical water parameters and other abiotic variables were simultaneously recorded. Since its first detection in Morocco in 2014, H. europaea has significantly expanded its geographic range. The species exhibited broad ecological tolerance, occurring in a wide variety of habitats, including environmentally degraded sites, and enduring substantial variation in water conditions. Among the environmental variables examined, water velocity and salinity were identified as the primary factors constraining the species’ distribution and abundance. Nevertheless, additional studies are required to better predict the future expansion dynamics of H. europaea, particularly under ongoing hydrological alterations and climate change scenarios. Full article

Increased herbicide use in agriculture is a major threat to adjacent aquatic and wetland ecosystems. In Morocco, the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) poses a risk to temporary ponds found in agricultural landscapes. This study used mesocosm experiments to assess the effects of 2,4-D concentration (0, 0.10, 0.20, and 0.30 mg·L⁻¹) and application timing (early vs. late in the hydrological cycle) on water quality and aquatic plant communities from forest ponds not previously exposed to herbicides. At the highest concentration (0.30 mg·L⁻¹), conductivity increased from 206 to 274 µS and pH from 7.5 to 8.4 under early application. At the same time, species richness and total abundance significantly decreased with increasing 2,4-D concentrations, with the strongest effects observed under early application. Community composition shifted markedly in response to 2,4-D, with annual and submerged species showing greater sensitivity, whereas perennial and emergent species were relatively tolerant. These findings highlight the need to adopt more sustainable agricultural practices to conserve pond biodiversity. Specifically, herbicide applications should be avoided near ponds, at high application rates, and during periods early in the hydroperiod. Lastly, land-use strategies should balance agricultural productivity with the conservation of biodiversity in temporary pond ecosystems. Full article