Wetlands are a critical component of the global biogeochemical cycle and have great potential for carbon sequestration under the changing climate. However, previous studies have mainly focused on the dynamics of soil organic carbon while paying little attention to the vegetation carbon storage in wetlands. Poyang Lake is the largest freshwater lake in China, where intra-annual and inter-annual variations in water levels significantly affect the vegetation carbon storage in the floodplain wetland. Therefore, we assessed the seasonal distribution and carbon storage of six typical plant communities (Arundinella hirta, Carex cinerascens, Miscanthus lutarioriparius, Persicaria hydropiper, Phalaris arundinacea, and Phragmites australis) in Poyang Lake wetlands from 2019 to 2024 based on field surveys, the literature, and remote sensing data. Then, we used 16 preseason meteorological and hydrological variables for two growing seasons to investigate the impacts of environmental factors on vegetation carbon storage based on four correlation and regression methods (including Pearson and partial correlation, ridge, and elastic net regression). The results show that the C. cinerascens community was the most dominant contributor to vegetation carbon storage, occupying 12.68% to 44.22% of the Poyang Lake wetland area. The vegetation carbon storage in the Poyang Lake wetland was significantly (p < 0.01) higher in spring (87.75 × 104 t to 239.10 × 104 t) than in autumn (77.32 × 104 t to 154.78 × 104 t). Water body area emerged as a key explanatory factor, as it directly constrains the spatial extent available for vegetation colonization and growth by alternating inundation and exposure. In addition, an earlier start or end to floods could both enhance vegetation carbon storage in spring or autumn. However, preseason precipitation and temperature are negative to carbon storage in spring but exhibited opposite effects in autumn. These results assessed the seasonal dynamics of dominant vegetation communities and helped understand the response of the wetland carbon cycle under the changing climate.

Effective conservation relies on robust assessments; however, the lack of waterbird data in the Yellow River Basin (YRB) has led to an underestimation of key habitat significance. This study addressed this gap by evaluating YRB wetland conservation importance using waterbirds as indicators and applying Ramsar, Important Bird Areas (IBA), and East Asian-Australasian Flyway (EAAF) criteria. We integrated coordinated surveys with citizen science data, creating a framework that tackles data deficiencies along the under-monitored Central Asian Flyway (CAF). Our analysis identified 75 priority wetlands, supporting 15 threatened species and 49 exceeding global/flyway 1% thresholds, highlighting the basin's biodiversity. We observed strong seasonal habitat use, with high-altitude wetlands vital for breeding and migration, and the Yellow River Delta providing year-round refuge. This research also provided data to refine Baer's Pochard population estimates. Alarmingly, one-third of the identified priority areas, primarily rivers and lakes, remain unprotected. To address this, we recommend systematic surveys, enhanced protected areas, OECMs, and targeted wetland restoration. This study underscores the YRB's role in regional conservation and provides essential data for adaptive management, particularly emphasizing the CAF's importance.

Global change, particularly extreme droughts, threatens critical migratory bird habitats like Poyang Lake, a key wintering ground on the East Asian-Australasian Flyway, forcing waterbirds such as geese to increasingly utilize artificial wetlands. Using satellite tracking, ground surveys, and remote sensing, we assessed how wintering geese adjusted their habitat use during an extreme drought year compared to a normal year. Geese expanded their home ranges during drought, with the artificial wetland area composition increased from 1.90 +/- 1.84 km2 to 26.82 +/- 4.58 km2. Habitat use peaked in artificial wetlands during mid-winter, then declined in late winter as natural forage recovered. Diel patterns revealed species-specific strategies: Swan Geese (Anser cygnoides) maintained high day-night reliance on artificial wetlands, Bean Geese (A. fabalis) favored nocturnal use, and Greater White-fronted Geese (A. albifrons) showed minimal dependence, indicating greater ecological risks for the first two species. Vegetation indices confirmed a drought-driven decline and delayed regrowth in natural Carex meadows, closely matching habitat use shifts. These findings demonstrate behavioral plasticity in response to fluctuating resource availability but raise concerns that artificial wetlands, while acting as temporary refuges, may negatively affect waterbirds and lead to human-wildlife conflicts. Although we do not assess fitness consequences directly, our results highlight the potential for ecological mismatch under increasing hydrological variability. We recommend a joined-up effort by prioritizing natural wetland restoration via hydrological management and vegetation recovery, alongside strategic artificial wetlands management to mitigate human disturbances. This study provides essential guidance for adaptive wetland management and waterbird conservation in floodplain ecosystems facing climate change.

1. Floodplain wetlands such as Poyang Lake are increasingly shaped by hydrological extremes, yet the mechanisms linking hydrology to waterbirds' space use remain unclear. We aimed to quantify species-specific distribution, habitat selection and behavioural plasticity across contrasting hydrological conditions to inform conservation and wetland management. 2. We integrated satellite tracking of greater white-fronted goose (Anser albifrons), bean goose (A. fabalis) and swan goose (A. cygnoides) with remote sensing and a hydrological classification derived from long-term water levels and the SPEI. Individual winter home ranges and utilisation intensity were estimated, mapped, and linked to habitat types. Space-use metrics were compared across hydrological categories (normal, drought, extreme drought) to assess species-specific selection. 3. Species differed markedly amongst hydrological years. Greater white-fronted and bean geese had larger home ranges and higher mean utilisation intensity in drought and extreme drought years, whereas swan geese showed the opposite pattern. Hydrology strongly structured habitat selection: differences amongst habitat types were pronounced in normal and drought years but weakened under extreme drought. Fresh, sparse wet meadows dominated in normal and drought years; during extreme drought, use of mudflats and tall sedges increased, with parallel shifts in utilisation intensity. 4. Wintering geese adjusted home range size, utilisation intensity, and habitat preferences under extreme drought, demonstrating pronounced behavioural plasticity and hydrology-dependent space-use strategies. By elucidating species-specific mechanisms linking hydrology to habitat selection in a dynamic Ramsar wetland, this study advances habitat selection theory for floodplain systems and provides actionable guidance for conserving geese and managing Poyang Lake under increasing hydrological extremes.

The establishment of protected areas remains a cornerstone strategy for conserving wetland ecosystems. However, many SIWs in China remain excluded from national conservation frameworks, despite their ecological importance. To address this gap, we developed a rapid assessment model integrating four key indicators — wetland area, waterfowl species richness, waterfowl abundance, and dominant wetland plant richness—to identify and evaluate unprotected SIWs at a national scale. The assessment was supplemented by expert-sourced online questionnaires to enhance data coverage, particularly for regions lacking systematic monitoring. A total of 1,473 unprotected SIWs were identified, encompassing approximately 3.39 million hectares. These wetlands represent critical conservation gaps in the current protected area network. Incorporating them into the national wetland protection system would raise China’s protection level from 50.22% to 58.01%, surpassing the governmental target of 55% by 2035. Many of these SIWs are located along major migratory bird routes and in biodiversity-rich zones, underscoring their strategic ecological value. This study provides the first systematic evaluation of SIWs at the national level in China and proposes a scalable, data-driven framework for prioritizing wetland protection. The results offer actionable guidance for enhancing wetland conservation and contribute to the broader goals of the Global Biodiversity Framework and the Ramsar Convention.

Submerged macrophytes like Vallisneria spinulosa S. Z. Yan play vital roles in aquatic ecosystems by stabilizing sediments, improving water quality, and providing habitat for organisms. However, their populations are declining globally due to environmental stressors like light limitation and bioturbation. This study examined how shading and bioturbation by Procambarus clarkii (Girard, 1852) and Carassius carassius (Linnaeus, 1758) influence V. spinulosa growth and reproduction. Severe shading (50

Wetland hydrological processes have a significant impact on wetland carbon storage.However,the mechanisms by which they affect biomass and carbon storage by regulating soil nutrient content and plant diversity remain underexplored.From June 4th,2018 to April 10th,2019,we conducted daily monitoring of daily water levels,plant diversity and dominance,aboveground and underground plant biomass,as well as soil content of 10 elements(carbon,nitrogen,phosphorus,potassium,sodium,calcium,magnesium,iron,manganese,and zinc)under different elevation gradients in the internationally significant Poyang Lake Wetland,resulting in the formation of a comprehensive dataset.The dataset consists of one Excel file with five sheets,covering plant directory,individual plant numbers,plant biomass,soil element content,and daily water levels for 21 sample plots across seven elevation gradients.The quality of dataset is mainly controlled and evaluated from the aspects of precise design of the plant survey scheme,fine collection of plant and soil samples,laboratory processing and data entry,and third-party calibration.This dataset can provide data support for revealing the process mechanisms among hydrology,soil nutrients,plant biomass,and soil carbon,as well as those between plant dominance,plant biomass soil carbon.It offers an in-depth understanding of how wetland hydrological processes influence vegetation growth and carbon sequestration by regulating nutrient enrichment,thereby laying a new foundation for understanding carbon-water coupling mechanisms.

Changes in migratory birds' habitats are important indicators of the health of global ecosystems. However, the habitat dynamics of the flagship swan species in China's major river basins and the adaptive strategies these species employ to respond to climate change have remained unclear. Using citizen science data, survey data, and species distribution models, we explored how three future climate scenarios for 2040-2060 affect habitat suitability for migratory swans in the Yellow River Basin. We also evaluated the role of protected areas (PAs) in mitigating the negative impacts of climate change. We found that (1) under current climate conditions, the Mute Swan (Cygnus olor), the Bewick's Swan (Cygnus columbianus bewickii), and the Whooper Swan (Cygnus cygnus) occupy substantial suitable habitats, with the Whooper Swan having the most extensive range. (2) the Mute Swan and the Bewick's Swan were predicted to experience the largest habitat loss under the high-emission scenario, while the Whooper Swan would benefit from climate change by gaining suitable habitat, especially under the medium-emission scenario. (3) PAs were most effective in mitigating the adverse effects of climate change on habitat suitability for the Mute Swan, followed by the Whooper Swan, with limited mitigating effect for the Bewick's Swan. These findings highlight the need for species-specific conservation strategies and the critical role of PAs in preserving habitat suitability under climate change.

Climate change and human activities have altered the hydrological patterns of Lake Poyang,leading to lower dry season water levels and extended dry periods.Additionally,extreme events such as the floods of 2020 and the prolonged droughts of 2022 and 2023 have occurred.These changes have significantly impacted the growth and reproduction of floodplain plants.This study in-vestigated the dominant floodplain plant,Carex cinerascens,examining five water level recession timing scenarios:30 days earlier,15 days earlier,normal,15 days later,and 30 days later.The study observed the plant's growth and reproductive responses.The results showed:(1)Water recession timing significantly affected the maximum height of Carex cinerascens.Earlier recession in-creased plant height,while later recession reduced it.The impact on aboveground biomass varied seasonally.In autumn,delayed recession significantly decreased aboveground biomass,while in spring,there was no significant effect.Both spring and autumn un-derground biomass decreased with delayed recession,affecting biomass distribution between seasons.(2)Water level recession timing also significantly influenced vegetative reproduction in the autumn growth stage.Earlier recession increased the number of tillers and the quantity and length of spacers,while delayed recession inhibited tillering and reduced spacers'quantity and length.Both earlier and delayed recession affected the number of flowering stems and inflorescences in spring,but the impact was smaller with earlier recession compared to delayed recession.These findings provide a theoretical basis for the conservation and management of dominant wetland plants under changing hydrological conditions.

BACKGROUND:The degradation and loss of critical nodes in the East Asian-Australasian Flyway (EAAF) migration network could have implications for the migration of shorebirds. The conservation of critical nodes along the EAAF is important for maintaining the stability of migratory networks. However, identifying these nodes remains a major challenge. METHODS:We used a network method that integrates GPS tracking data and remote sensing data to identify critical nodes for three shorebird species (Black-tailed Godwit (Limosa limosa), Eurasian Curlew (Numenius arquata), and Pied Avocet (Recurvirostra avosetta)) in migratory networks along the EAAF and priority conservation areas to facilitate the development of conservation and management plans. RESULTS:A total of 111, 37, and 81 nodes in the migratory networks were identified for the Black-tailed Godwit, Eurasian Curlew, and Pied Avocet, respectively; these included 25, 13, and 16 critical nodes, respectively. Node importance (node betweenness) was higher in the migration period than in the breeding and wintering periods. Habitat loss was observed in most stopover nodes. A total of 23 unprotected critical nodes were identified as priority conservation areas. CONCLUSIONS:Habitat loss was observed in most of the unprotected critical nodes in stopover regions for all three species. The inclusion of these sites such as Haoyao sumu forest farm and Tianjin coast, into flyway site networks (the East Asian-Australasian Flyway Partnership (EAAFP)) should be prioritized, and the habitat quality of nearby alternative nodes should be improved. Future studies should focus on developing new node indexes that integrate ecological variables with each node's role in maintaining network connectivity using data from a larger number of tracked individuals and birdwatching data. Such studies could help identify currently unknown regions with critical habitats.

The population of East Asian geese along migration routes is declining. Accurate understanding of the spatial distribution of wintering geese and estimates of their population numbers are vital for their conservation. Based on satellite tracking data, the migration timing and spatial distribution of geese in Poyang Lake were studied by using time series and home range analysis. We propose a method for estimating goose populations to address the population underestimation in current ground surveys. We found that the utilization intensity of geese is higher within the Protected area than outside, and during the wintering period, spatial overlap in their distributions is evident. This is especially the case in mid-winter, when the overlap area reaches 257.84 km2. There are missing areas in existing ground surveys, resulting in underestimation of the numbers of Greater White-fronted Goose, Bean Goose and Swan Goose by 13,196, 6157 and 3191, respectively. A reevaluation of the numbers using integrated satellite tracking and ground survey data, indicates the high level of importance of Poyang Lake for the protection of East Asian geese, with the numbers of Greater White-fronted Goose, Bean Goose, and Swan Goose wintering there constituting 56.94

Migratory flyways sustain waterbird populations by linking critical habitats across their annual cycle. However, stage-specific impacts of climate change on these habitats remain poorly understood. We integrated species distribution models with annual migration data from 30 Greater White-fronted Geese (Anser albifrons frontalis) to assess changes in habitat suitability, distributional shifts, and suitability fluctuations across breeding, stopover, and wintering stages under mid-century (2040–2060) climate scenarios. Suitability fluctuations were quantified as the coefficient of variation (CV) in habitat suitability between current and future projections. Projected habitat responses varied markedly across stages: breeding areas contracted by 29.9%, wintering areas expanded by 62.7%, and stopover sites showed minimal net change. Centroids of all habitats are projected to shift northward by mean distances of 125–492 km under future climate scenarios. Breeding habitats exhibited the greatest suitability fluctuations (CV=30–45; ~50% area affected under SSP585), followed by stopover and wintering grounds (CV ≈ 11), with 35.8% and 23.3% of their areas falling within high-fluctuation zones. These findings highlight the urgent need to prioritize breeding habitats, implement stage-specific conservation strategies, and enhance international cooperation to ensure the protection of waterbirds along the East Asian Flyway.

Poyang Lake, China's largest freshwater lake, is a critical wintering ground for most of the global Siberian Crane (Grus leucogeranus) population. However, increasingly prolonged dry seasons have degraded the natural wetlands of Poyang Lake, forcing Siberian Cranes to shift to artificial habitats. From 2015 to 2023, field surveys revealed a substantial increase in the number of Siberian Cranes in artificial habitats, with peak counts reaching 3000 individuals, accounting for up to 53% of the species' global population. Satellite telemetry of 13 individuals further confirmed the spatial use of these habitats, highlighting their consistent reliance on artificial sites over multiple years. Seven high-use hotspots were identified outside of Poyang Lake, including two artificial provisioning sites that supported dense foraging flocks for extended periods. Satellite telemetry confirmed this trend, with artificial habitats making up to 64.2% of the occurrence sites in some years. This reliance on artificial habitats was closely linked to the reduced tuber biomass in natural wetlands and low winter water levels in Poyang Lake, which collectively explained 83% of the variance in crane abundance in artificial habitats. Artificial habitat use peaked in December and January, indicating marked seasonal variation. Siberian Cranes also exhibited a pronounced circadian rhythm, foraging in artificial habitats during the day and returning to natural wetlands to roost at night. Despite the shift toward artificial habitats, natural wetlands remain critical for nighttime refuge. The continued dependence on artificial habitats raises concerns about disease transmission owing to dense congregations. Conservation strategies should prioritize both the careful management of artificial provisioning sites and the restoration of natural wetlands to improve food and habitat availability within natural ecosystems, ultimately enabling the return of Siberian Cranes to their traditional natural habitats.

Hydrological connectivity is considered a crucial factor in maintaining the biodiversity of wetland waterbirds, but quantifying this relationship remains challenging. This study uses synthetic aperture radar (Sentinel-1 SAR) to efficiently and cost-effectively quantify the number of surface hydrological connectivity days in large floodplain wetlands. Based on waterbird occurrence data from citizen science platforms and The Maximum Entropy Model (MaxEnt) we simulated habitat suitability for different waterbird families in Poyang Lake. Through a coupled analysis of surface hydrological connectivity and habitat suitability, we found that habitat suitability generally increased with connectivity days up to approximately 36-78 days and then declined, except under extreme hydrological conditions. Extreme floods and droughts were associated with reduced habitat suitability. During normal years, habitat suitability showed little difference between controlled sub-lakes and connected sublakes. However, in years of flood or drought, the habitat suitability of controlled sub-lakes exceeded that of connected sub-lakes by more than 0.15, indicating that moderate hydrological regulation can mitigate the negative impacts of extreme events on waterbird habitats. This study provides a scientific basis for hydrological management strategies in response to the intensified frequency of extreme hydrological events, aiming to enhance wetland resilience under climate warming.

BACKGROUND:Climate change and anthropogenic activities are accelerating environmental changes, challenging wild animals' survival. Behavioral plasticity, such as adjusting habitat selection and foraging activity, is a key mechanism for responding to rapid environmental changes in the Anthropocene era. However, this shift may expose animals to new challenges. Moreover, not all behavioral plasticity is adaptive, as evidenced by ecological traps. This study focuses on Poyang Lake, a Ramsar wetland and a critical wintering ground for waterbirds in the East Asian-Australasian Flyway. Historically, the migratory patterns of waterbirds were synchronized with the plant life cycle. However, recent hydrological regime changes have diminished suitable habitats and food resources, thereby posing significant conservation challenges for waterbirds. METHODS:Utilizing multiyear satellite tracking data, we examined the variations in wintering home range and behaviors of four herbivorous waterbird species between natural and artificial wetlands in Poyang Lake under different hydrological conditions. RESULTS:Our results reveal significant differences in home range area and movement speed among species and across hydrological years. All species demonstrated a marked increase in their use of artificial wetlands under unfavorable conditions. Specifically, the Greater White-fronted Goose (Anser albifrons) shifted its distribution to artificial wetlands during drought years while favoring natural wetlands under normal conditions, indicating a stress-induced adaptation. In contrast, the Bean Goose (A. fabalis) and Swan Goose (A. cygnoid) displayed greater behavioral plasticity. Notably, the Siberian Crane (Leucogeranus leucogeranus) increasingly used artificial wetlands, likely due to human protection, raising concerns about potential ecological traps. Additionally, waterbirds foraging in artificial wetlands generally exhibited higher movement speeds during drought conditions. This behavior suggests maladaptation and a more dispersed distribution. CONCLUSIONS:Our study underscored the critical role of artificial wetlands in supporting migratory waterbirds during drought, though elevated movement speeds observed in these habitats suggest potential maladaptation. Species-specific responses raise concerns about ecological traps if these habitats fail to meet key ecological needs. To ensure long-term conservation, efforts should focus on preserving natural wetlands and enhancing the quality of artificial habitats. Future research should prioritize long-term monitoring to guide habitat management and address species-specific needs in the face of climate change and habitat degradation.

In Poyang Lake, the largest and one of the most important wintering sites in the East AsianAustralasian Flyway, Carex (Carex cinerascens Kuk) meadows provide the primary food source for the wintering geese. However, due to intensified river regulation and more frequent extreme climatic events such as drought, observational evidence suggests that the synchrony of geese migration and Carex phenology could not be maintained without human interventions, imposing a great risk of food shortage during the wintering period. Consequently, the current conservation priority in this Ramsar site is shifted to wet meadow improvement to ensure optimal food quality. Understanding the food preferences of wintering geese is the key for effective wet meadow management. As the growth stage and nutrient level of food plants are the decisive factors influencing the diet selection of herbivores, in this study, we sampled the preferred food items by tracking the foraging paths of the Greater White-fronted Goose (n = 84) and Bean Goose (n = 34) to quantify the "foraging window" in terms of plant height,protein level, and energy content. Further, we established relationships between the above three variables of Carex based on in-situ measurements. The results show that the geese prefer plants with height ranging from 2.4 to 25.0 cm, with protein content from 13.9 to 25.2 %, and energy content from 1440.0 to 1813.6 KJ/100 g. While plant energy content increases with height, the height-protein level relationship is negative. The opposite growth curves signify a conservation challenge to maintain the delicate balance between the quantity and quality requirements of wintering geese. Carex meadow management, such as mowing, should focus on optimizing the timing of action to maximize energy supply while maintaining the right protein level for the long-term fitness, reproduction and survival of the birds.

Wetlands in China's coastal provinces are strategically positioned along migratory flyways for waterbirds, serving as essential habitats and stopover sites due to the expansive land area and abundant wetland resources they offer. This study aimed to introduce a simplified index system to enable rapid assessment and prioritization of unprotected areas for wetlands in China's coastal provinces. A spatial analysis was conducted, combining wetland distribution and existing protected areas data and spatial extent of wetlands extracted by remote sensing data. Results indicate substantial gaps in coverage, covering an area of 108.33 × 104 ha, with 76% being natural wetlands. Over half of these gaps are identified as high-value wetlands with significant ecological functions. The uneven distribution of unprotected wetlands reflects a tension between economic development and wetland conservation. Our findings support the expansion of the existing coastal wetland protected areas' coverage, as well as protecting critical habitats in conservation gaps, and establishing of a network-based waterbird protection system. This research contributes to informed decision-making and policy in wetlands' conservation planning.

Wetlands in the Bohai Sea Rim play an indispensable role in maintaining the stability of waterbird populations on the East Asian-Australian flyway. However, motivated by economic development and urban expansion, coastal wetlands in this region have been extensively reclaimed, leading to a decline in the area and degradation of natural wetlands over the past two decades. We analyzed the temporal and spatial changes of suitable habitats of different groups of waterbirds and quantified habitat connectivity changes and the importance of different patches by using the Probability of Connectivity. The results show that the suitable habitat area of all the different groups of waterbirds decreased sharply from 2000 to 2020. In addition, the utilization ratio by waterbirds of artificial habitats increased. Land use is the primary environmental variable determining the distribution of suitable habitats. Meanwhile, the connectivity of habitats of different groups of waterbirds has also been declining. However, the patches of Tianjin and Hebei in Bohai Bay still have high importance for waterbirds, particularly shorebirds. Expanding existing protection areas to cover the above-mentioned patches is recommended. We also advocate stricter protection measures and necessary ecological restoration activities on both the natural and artificial wetlands.