Poyang Lake Area Research Articles

Active Surveillance of Avian Influenza in the Southwestern Poyang Lake Area, China: Analyzing Changes in Wholesale and Frozen Fresh Retail Markets Post-Policy Implementation

Active Surveillance of Avian Influenza in the Southwestern Poyang Lake Area, China: Analyzing Changes in Wholesale and Frozen Fresh Retail Markets Post-Policy Implementation

Land Use Simulation and Ecological Network Construction around Poyang Lake Area in China under the Goal of Sustainable Development

The pivotal aspects of enhancing regional ecosystem services and augmenting socioeconomic growth lie in optimizing the land-space development and protection strategies, coupled with the establishment of a robust ecological network (EN). This article examines the Poyang Lake area and employs the MOP model, NSGA-II, and PLUS model to determine the best sustainable land use strategy. Subsequently, the MSPA, InVEST model, circuit theory, complex network, and others are employed to construct and analyze the land-space EN across three time periods. Ultimately, the EN is optimized based on spatial protection priority, ecological obstacle areas, and ecological nodes. The results show the following: (1) From 2005 to 2035, more construction land will be developed around the Greater Nanchang area and other urban centers. In the BAU scenario, construction land will expand faster, while cultivated land, forest, grassland, and bare land will continue to decline. In the SD scenario, the alteration to comparable land is minimal, the growth rate of construction land will slow, cultivated land, forest, grassland, and bare land will all decline little, and the water area will increase slightly; (2) While the area of ecological sources is decreased and ecological corridors become longer and narrower in the BAU scenario, the spatial distribution of ENs in different periods is small, and the quantitative structure and spatial distribution of ecological sources and corridors are essentially unchanged in the SD scenario; (3) Based on the topological structure of ENs, it is found that the clustering of nodes in the SD scenario is more obvious, the importance of ecological sources is enhanced, the efficiency of information transmission is improved, and the radiation range is wider and more stable; (4) The greatest priority ecological sources in each period are concentrated around Poyang Lake. In the SD scenario, the priority of ecological sources improves, and 7025 km2 of ecological obstacle restoration area is identified, with 41, 31, and 36 ecological breakpoints in the first, second, and third levels. The study’s findings can assist and shape theoretical and practical approaches to land governance and sustainable development in great lake areas.

Human activities and ecosystem health: A historical analysis of Poyang Lake

Urbanization, industrialization, land development, and other human activities have led to ecological issues such as shrinking lake wetlands, fragmented cropland, and reduced biodiversity. Taking the Poyang Lake urban agglomeration as the study area, the textual analysis method was used to analyze the typical facts of the historical succession of human activities since 1949, and then the index method and the spatial analysis method were adopted to characterize the spatial and temporal evolution of the ecosystem health and human activities in the period of 2003–2020. On this basis, the spatial spillover effects of human activities on ecosystem health were investigated based on the spatial Durbin model in four dimensions. The results of the study show that since 1949, human activities in the Poyang Lake area have gone through the management path from “agricultural retreat and fishery advancement” and “dike reclamation” to “sand ban” and “returning the lake”. Ecological protection has gone through the sublimation from “enlightenment” to “full implementation” to “strengthening and upgrading”. The ecosystem health of Poyang Lake urban agglomeration from 2003 to 2020 has been in the range of 0.37709 ∼ 0.3709 ∼ 0.3709. 0.37709 ∼ 0.48485, with the spatial characteristics of “low in the center and high in the periphery”. The city expansion and agricultural activities in the county are generally distributed in the pattern of “high center, low periphery”, while the spatial distribution of water body area is characterized by “near-lake” and “near-river”, and the newly registered enterprises show a change from “point” to “surface”. The spatial distribution of water body area is characterized by “proximity to the lake” and “proximity to the river”, and the newly registered enterprises show changes from “point” to “surface”. There is a significant spatial competition effect on the effects of city expansion on ecosystem health, while there is a significant negative spatial collaboration effect on the effects of industrial activities, and agricultural activities show a significant spatial spillover effect. The results of the study can provide more detailed empirical support for the regulation and management of ecosystem health in global lakeside urban agglomerations.

Effect of water Resource utilization in Poyang lake area on carbon emissions based on decoupling theory

The utilization of regional water resources has the potential to impact carbon emissions. Maintaining a decoupled relationship between water resources and carbon emissions facilitates harmonious regional development. Understanding the mechanism of their coordination is conducive to achieving the "Double Carbon" goal and control of regional carbon emissions and water resource consumption. This study examines the decoupling relationship between water resource utilization and carbon emissions in Poyang Lake area, China, employing the Tapio decoupling model and the LMDI(logarithmic mean divisia index) decomposition model. The results indicate that carbon emissions in Poyang Lake area exhibited a gradual increase, accompanied by an annual growth rate of 5.99 %. The water supply exhibited a slow expansion. They have exhibited state of affairs strong negative decoupling and expansive negative decoupling over the past 15 years. Moreover, this situation is most acute and worsening in the secondary industry. The water use structure effect and water economic benefit effect are the primary factors affecting carbon emission increases, contributing 57.93 % and 65.66 %, respectively. Carbon emissions intensity is the largest inhibiting factor, which accounts for a maximum contribution of 42.96 %. The order of potency of the driving factors is as follows: water economic benefit > carbon emission intensity > water use structure > water use efficiency. In summary, this research recognised the enhancement of the water economic efficiency index not only facilitates the decoupling phenomenon but also improves the water-carbon relationship, especially in the secondary industry. It serves as a compelling illustration of the significance of elucidating the interrelationship between regional water and carbon dynamics, and charting the course for the formulation of regional policies that would facilitate the advancement of environmentally conscious and carbon-neutral development, as well as water conservation.

Dynamic Monitoring of Poyang Lake Water Area and Storage Changes from 2002 to 2022 via Remote Sensing and Satellite Gravimetry Techniques

The monitoring of Poyang Lake water area and storage changes using remote sensing and satellite gravimetry techniques is valuable for maintaining regional water resource security and addressing the challenges of global climate change. In this study, remote sensing datasets from Landsat images (Landsat 5, 7, 8 and 9) and three Gravity Recovery and Climate Experiment (GRACE) and Gravity Follow-on (GRACE-FO) mascon solutions were jointly used to evaluate the water area and storage changes in response to global and regional climate changes. The results showed that seasonal characteristics existed in the terrestrial water storage (TWS) and water area changes of Poyang Lake, with nearly no significant long-term trend, for the period from April 2002 to December 2022. Poyang Lake exhibited the largest water area in June and July every year and then demonstrated a downward trend, with relatively smaller water areas in January and November, confirmed by the estimated TWS changes. For the flood (August 2010) and drought (September 2022) events, the water area changes are 3032 km2 and 813.18 km2, with those estimated TWS changes 17.37 cm and −17.46 cm, respectively. The maximum and minimum Poyang Lake area differences exceeded 2700 km2. The estimated terrestrial water storage changes in Poyang Lake derived from the three GRACE/GRACE-FO mascon solutions agreed well, with all correlation coefficients higher than 0.92. There was a significant positive correlation higher than 0.75 between the area and TWS changes derived from the two independent monitoring techniques. Therefore, it is reasonable to conclude that combined remote sensing with satellite gravimetric techniques can better interpret the response of Poyang Lake to climate change from the aspects of water area and TWS changes more efficiently.

Impact of drought on Oncomelania hupensis snails breeding in the Poyang Lake area

To examine the impact of arid climates on distribution of Oncomelania hupensis snails in the Poyang Lake area, so as to provide insights into precision control of O. hupensis snails in the Poyang Lake area. O. hupensis snails-infested grass islands in Hukou County, Lianxi District and Lushan City in the northern Poyang Lake area, and Jinxian County, Nanchang County and Poyang County in the southern Poyang Lake area were selected as the study areas, and the occurrence of frames with living snails and the mean density of living snails were captured from snail surveys in the study areas in spring and autumn each year from 2006 to 2023. Five years 2007, 2011, 2013, 2019 and 2022 were selected as drought years, and the mean daily water levels were collected at the Xingzi hydrological station in the drought years, normal flow year (2012) and flood year (2020). The numbers of days with water levels ranging from the lower elevation (11 m) to the upper elevation (16 m) for snail survival and the numbers of days with water levels of 11 m and below were collected in the Poyang Lake area, and the changes of snail indicators were compared in different grass islands in the Poyang Lake area before and after drought. The numbers of days with water levels ranging from 11 to 16 m were 110, 88, 136 d and 125 d at the Xingzi hydrological station in four drought years 2007, 2011, 2013 and 2019, which were less than in the flow year and flood year, and the days with water levels of 11 m and below were 242, 277, 220 d and 198 d in four drought years 2007, 2011, 2013 and 2019, which were longer than in the flow year and flood year. A total of 416 snails-infested marshlands were surveyed in the Poyang Lake area from 2006 to 2021, and the survey marshlands accounted for 43.12% (307/712) and 46.98% (109/232) of total marshlands in the southern and northern Poyang Lake areas, respectively. The median occurrence of frames with living snails and mean density of living snails were 0.60% (interquartile range, 4.04%) and 0.010 1 snail/0.1 m2 (interquartile range, 0.076 1 snail/0.1 m2) in drought years, which were both lower than those [1.33% (5.19%) and 0.022 8 (0.098 9) snail/0.1 m2] in non-drought years (χ2= 42.170 and 44.911, both P values < 0.01). The proportion of grass islands with a continuous decline in snail indicators was higher in the southern Poyang Lake area than in the northern Poyang Lake area after the next year of drought (24.24% vs. 2.33%; χ2 = 10.633, P < 0.01), and the proportion of grass islands with rebounding snail indicators was higher in the northern Poyang Lake area than in the southern Poyang Lake area (53.49% vs. 15.76%; χ2 = 26.966, P < 0.01). A longitudinal analysis of snail indicators in marshlands with rebounding snail indicators after drought showed 1 to 5 years for return to pre-drought snail status, with a median of 2 (interquartile range, 1) years, and snail status was more likely to rebound if the occurrence of frames with living snails and the mean density of living snails were 2.11% and 0.025 5 snail/0.1 m2 and greater in snails-infested grass islands. Drought causes a remarkable decline in O. hupensis snail indicators in the Poyang Lake area, with a more remarkable impact in the southern Poyang Lake area, and 1 to 5 years are required for return to pre-drought snail status.

Trap or Opportunity: Impact of the Fishing Ban Compensation Policy on the Income of Returning Fishermen in China

The conflict between biodiversity conservation and economic development is intense in developing countries. With the decline in biodiversity, the Chinese government imposed a 10-year fishing ban in the priority waters of the Yangtze River Basin, which resulted in many fishermen losing their livelihood. However, a compensation policy was subsequently introduced. To investigate the impact of the ban, we conducted a two-year study using balanced panel data and the PSM-DID model for 365 households in the Poyang Lake area and introduced fixed effects to discuss the impact of the Yangtze River fishing ban compensation policy on the income of returning fishermen and their choices for alternative income. We also explored the interactive effects of fishing ban compensation and other biodiversity conservation policies on their income. The results showed that the fishing ban negatively impacted the agricultural income of households but not the total household income, and the compensation somewhat subsidized the fishermen’s loss of income. Moreover, this was an opportunity for farmers to adjust their livelihood strategies. These findings improve our understanding of the impact of this fishing ban and compensation policy on the household incomes of returning fishermen and their adaptive strategies for alternative income.

Species-level Microbiota of Biting Midges and Ticks from Poyang Lake.

The purpose of this study was to investigate the bacterial communities of biting midges and ticks collected from three sites in the Poyang Lake area, namely, Qunlu Practice Base, Peach Blossom Garden, and Huangtong Animal Husbandry, and whether vectors carry any bacterial pathogens that may cause diseases to humans, to provide scientific basis for prospective pathogen discovery and disease prevention and control. Using a metataxonomics approach in concert with full-length 16S rRNA gene sequencing and operational phylogenetic unit (OPU) analysis, we characterized the species-level microbial community structure of two important vector species, biting midges and ticks, including 33 arthropod samples comprising 3,885 individuals, collected around Poyang Lake. A total of 662 OPUs were classified in biting midges, including 195 known species and 373 potentially new species, and 618 OPUs were classified in ticks, including 217 known species and 326 potentially new species. Surprisingly, OPUs with potentially pathogenicity were detected in both arthropod vectors, with 66 known species of biting midges reported to carry potential pathogens, including Asaia lannensis and Rickettsia bellii, compared to 50 in ticks, such as Acinetobacter lwoffii and Staphylococcus sciuri. We found that Proteobacteria was the most dominant group in both midges and ticks. Furthermore, the outcomes demonstrated that the microbiota of midges and ticks tend to be governed by a few highly abundant bacteria. Pantoea sp7 was predominant in biting midges, while Coxiella sp1 was enriched in ticks. Meanwhile, Coxiella spp., which may be essential for the survival of Haemaphysalis longicornis Neumann, were detected in all tick samples. The identification of dominant species and pathogens of biting midges and ticks in this study serves to broaden our knowledge associated to microbes of arthropod vectors. Biting midges and ticks carry large numbers of known and potentially novel bacteria, and carry a wide range of potentially pathogenic bacteria, which may pose a risk of infection to humans and animals. The microbial communities of midges and ticks tend to be dominated by a few highly abundant bacteria.

Spatio-temporal evolution and driving factors of regulating ecosystem service value: a case study of Poyang Lake Area, China

Clarifying the driving mechanisms of spatial and temporal changes in the regulating ecosystem service value (RESV) is an important part of realizing the goal of sustainable development. Existing studies have focused on specific factors, ignoring the complex interactions between factors and their regional differences. In this regard, the spatial and temporal changes of RESV and its driving mechanisms in the different zones (core area, fringe area, and peripheral area) were explored in the Poyang Lake Area, China. The results showed that RESV spatially showed the distribution characteristics of fringe area &amp;gt; core area &amp;gt; peripheral area, while the lakes influenced the provision of regulating ecosystem services, showing that RESV per unit area was higher in the core area, and gradually declined with the increase of distance from the lakes, presenting the decreasing trend of fringe area &amp;gt; peripheral area. From 2000 to 2020, the study area lost 70.5988 billion CNY for RESV, in which the core area was the most affected. Further analysis of the driving mechanism of RESV in different areas found that there are regional differences in the paths of the driving factors: Population density mainly affects the core area, precipitation mainly affects the fringe area, and GDP per land mainly affects the peripheral area.

Risk assessment of flood disasters in the Poyang lake area

Floods are one type of common and catastrophic disaster and cause extensive destruction areas, enormous casualties, and huge economic and environmental losses worldwide. Flood risk assessment is crucial to disaster mitigation and prevention, social stability and prosperity, and economic and environmental sustainability. This work establishes comprehensive risk indices of geoenvironmental, disaster-triggering, disaster-vulnerable, and disaster-preventive factors to improve the rationality of risk assessment. Moreover, a novel combined method of context-perception long short-term memory (LSTM), analytic hierarchy process, and entropy weight is suggested to perform relative accurate risk assessment in the Poyang lake region, one of the worst-hit areas in China. The new context-perception LSTM algorithm can adequately learn comprehensive and significant context characteristics and outperforms the context-based convolutional neural network and conventional LSTM algorithms. The test precision reaches 95.7%, 99.1%, 0.958, and 0.981 in Accuracy, TPR, F1-score, and AUC, respectively. Some significant insights into flood risk are suggested as follows. (1) High flood risk mainly occurs in the densely populated regions with gentle topography close to main streams. The concentrated population and intensive town construction have destroyed surface permeability and soil consolidation and caused high flood risk. (2) In the high-risk urban regions, the operational condition of old soil dikes should be continuously monitored, and the construction of high rock dikes are necessary to effective flood prevention in the future. In the densely-populated and high-risk urban regions, more emergency rescue infrastructures, for example hospitals and emergency shelters, are required to arrange or build. Rational planning of emergency shelters can not only protect people against floods but also reduce government investment. (3) Significant hydrological infrastructures require high-frequency or even near real-time monitoring to timely discover engineering diseases and to avoid huge losses caused by unstable prevention infrastructures during flash floods.

Flood Monitoring Using Sentinel-1 SAR for Agricultural Disaster Assessment in Poyang Lake Region

An extensive number of farmlands in the Poyang Lake region of China have been submerged due to the impact of flood disasters, resulting in significant agricultural economic losses. Therefore, it is of great importance to conduct the long-term temporal monitoring of flood-induced water body changes using remote sensing technology. However, the scarcity of optical images and the complex, fragmented terrain are pressing issues in the current water body extraction efforts in southern hilly regions, particularly due to difficulties in distinguishing shadows from numerous mountain and water bodies. For this purpose, this study employs Sentinel-1 synthetic aperture radar (SAR) data, complemented by water indices and terrain features, to conduct research in the Poyang Lake area. The results indicate that the proposed multi-source data water extraction method based on microwave remote sensing data can quickly and accurately extract a large range of water bodies and realize long-time monitoring, thus proving a new technical means for the accurate extraction of floodwater bodies in the Poyang Lake region. Moreover, the comparison of several methods reveals that CAU-Net, which utilizes multi-band imagery as the input and incorporates a channel attention mechanism, demonstrated the best extraction performance, achieving an impressive overall accuracy of 98.71%. This represents a 0.12% improvement compared to the original U-Net model. Moreover, compared to the thresholding, decision tree, and random forest methods, CAU-Net exhibited a significant enhancement in extracting flood-induced water bodies, making it more suitable for floodwater extraction in the hilly Poyang Lake region. During this flood monitoring period, the water extent in the Poyang Lake area rapidly expanded and subsequently declined gradually. The peak water area reached 4080 km2 at the height of the disaster. The severely affected areas were primarily concentrated in Yongxiu County, Poyang County, Xinjian District, and Yugan County.

Intelligent identification of livestock, a source of Schistosoma japonicum infection, based on deep learning of unmanned aerial vehicle images

To develop an intelligent recognition model based on deep learning algorithms of unmanned aerial vehicle (UAV) images, and to preliminarily explore the value of this model for remote identification, monitoring and management of cattle, a source of Schistosoma japonicum infection. Oncomelania hupensis snail-infested marshlands around the Poyang Lake area were selected as the study area. Image datasets of the study area were captured by aerial photography with UAV and subjected to augmentation. Cattle in the sample database were annotated with the annotation software VGG Image Annotator to create the morphological recognition labels for cattle. A model was created for intelligent recognition of livestock based on deep learning-based Mask R-convolutional neural network (CNN) algorithms. The performance of the model for cattle recognition was evaluated with accuracy, precision, recall, F1 score and mean precision. A total of 200 original UAV images were obtained, and 410 images were yielded following data augmentation. A total of 2 860 training samples of cattle recognition were labeled. The created deep learning-based Mask R-CNN model converged following 200 iterations, with an accuracy of 88.01%, precision of 92.33%, recall of 94.06%, F1 score of 93.19%, and mean precision of 92.27%, and the model was effective to detect and segment the morphological features of cattle. The deep learning-based Mask R-CNN model is highly accurate for recognition of cattle based on UAV images, which is feasible for remote intelligent recognition, monitoring, and management of the source of S. japonicum infection.

Nitrogen species and microbial community coevolution along groundwater flowpath in the southwest of Poyang Lake area, China

Nitrate and ammonia overload in groundwater can lead to eutrophication of surface water in areas where surface water is recharged by groundwater. However, this process remained elusive due to the complicated groundwater N cycling, which is governed by the co-evolution of hydrogeochemical conditions and N-cycling microbial communities. Herein, this process was studied along a generalized groundwater flowpath in Ganjing Delta, Poyang Lake area, China. From groundwater recharge to the discharge area near the lake, oxidation-reduction potential (ORP), NO3–N, and NO2–N decreased progressively, while NH3–N, total organic carbon (TOC), Fe2+, sulfide, and TOC/NO3− ratio accumulated in the lakeside samples. The anthropogenic influences such as sewage and agricultural activities drove the nitrate distribution, as observed by Cl− vs. NO3−/Cl− ratio and isotopic composition of nitrate. The hydrogeochemical evolution was intimately coupled with the changes in microbial communities. Variations in microbial community structures was significantly explained by Fe2+, NH3–N, and sulfide, while TOC/NO3− controlled the distribution of predicted N cycling gene. The absence of NH3–N in groundwater upstream was accompanied by the enrichment in Acinetobacter capable of nitrification and aerobic denitrification. These two processes were also supported by Ca2+ + Mg2+ vs. HCO3− ratio and isotopic composition of NO3−. The DNRA process downstream was revealed by both the presence of DNRA-capable microbes such as Arthrobacter and the isotopic composition of NH4+ in environments with high concentrations of NH3–N, TOC/NO3−, Fe2+, and sulfide. This coupled evolution of N cycling and microbial community sheds new light on the N biogeochemical cycle in areas where surface water is recharged by groundwater.

Mapping inundation extents in Poyang Lake area using Sentinel-1 data and transformer-based change detection method

Accurate and timely mapping of inundation extents during flood periods is essential for disaster evaluation and development of rescue strategies. With unique advantages over the optical sensors (e.g., little effect of clouds, and observations at day and night), Synthetic aperture radar (SAR) sensors provide an important data source for mapping inundation, particularly during flood periods. Freely available SAR images from Sentinel-1 have been increasingly used for many applications. This study applied an efficient transformer-based change detection method, bitemporal image transformer (BiT) with bitemporal Sentniel-1 images, to map inundation extents and evolution in Poyang Lake area in 2020. The transformer-based change detection method firstly adopted ResNet for high-level semantic features extraction, and applied a transformer mechanism to refine these features pixel-wise, followed by employing a FCN as the prediction head for generating the results of change detection. Besides, we constructed a water change detection dataset with spatial-and-temporal generalization from bitemporal Sentinel-1 images; this dataset consists of the seasonal variation water samples of Poyang Lake for years. We compared the results from the BiT method with other convolutional neural network (CNN) based methods (STANets and SNUNet). Mapped inundation extents were evaluated with the ground truth visually derived from high spatial resolution images. The evaluation showed the BiT method generated high accurate mapped inundation extents with the F1-score of 95.5%. The BiT model has proven its superior performance in detecting increased water. Based on the results of the BiT method, the variation of inundation extents in Poyang Lake during May-November 2020 was further analyzed. It was found that the water surface coverage of Poyang Lake is the smallest in late May; it gradually increased to the maximum on 14th July, and then began to stabilize and show a significant downward trend before November. The flood distribution map shows that cultivated land has been inundated with the largest area of approximately 600 km2.

Impact of the National Wetland Park in the Poyang Lake Area on Oncomelania hupensis, the Intermediate Host of Schistoma japonicum.

In this study, we aimed to understand the influence of ecotourism on the distribution of Oncomelania hupensis and to provide a scientific basis for formulating effective snail control methods in tourism development areas. Poyang Lake National Wetland Park was selected as the pilot area, and sampling surveys were conducted based on comprehensive and detailed investigations of all historical and suspected snail environments according to map data to determine the snail distribution and analyze the impact of tourism development. The results showed that from 2011 to 2021, the positive rates of blood tests and fecal tests tended to decrease among residents of the Poyang Lake area. The positive rates of blood tests and fecal tests in livestock also tended to decrease. The average density of O. hupensis snails decreased, and no schistosomes were detected during infection monitoring in Poyang Lake. The local economy rapidly grew after the development of tourism. The development of ecotourism projects in Poyang Lake National Wetland Park increased the transfer frequency of boats, recreational equipment, and people, but it did not increase the risk of schistosomiasis transmission or the spread of O. hupensis snails. Prevention and monitoring only need to be strengthened in low-endemic schistosomiasis areas to effectively promote economic development due to tourism activities without affecting the health of residents.

Analysis and Prediction of Poyang Lake’s Navigable Conditions under a New Hydrological Regime

Human activities have profoundly changed the hydrological regime and trends of rivers and lakes, which, in turn, has affected the utilization of their navigable conditions. However, few studies have focused on the effects of changes in hydrological regimes and trends of rivers and lakes on navigable conditions. Thus, this study intensively analyzes and investigates the navigable depth at the major control sections in the lake area during the dry season in the period before 2002, when the Three Gorges Reservoir was not yet constructed, and the period from 2003 to 2019, when the Three Gorges Project was put into operation with impoundment based on the dry-season water level curve in the Poyang Lake area since the operation of the Three Gorges Reservoir. This study also further analyzes the influence of the change in the hydrological regime on the navigable depth in the lake area. The results show that the waterway depth and width could meet the navigation requirements before 2002. From 2003 to 2019, whereas the water level with a 98% guarantee rate of duration at the Xingzi Hydrometric Station decreased, that at the Hukou Hydrometric Station increased. The waterway depth and width at both the Hukou and Xingzi hydrometric stations could meet the requirements of the size of Grade II waterways. This study also performs a simulation prediction of the water regime of Poyang Lake under a new hydrological regime using the mathematical model of water and sediment of the Changjiang River Scientific Research Institute. The results reveal that in 2030 and 2050, after the Three Gorges Reservoir has been in operation for 30–50 years, the water levels at the Hukou, Xingzi, and Wucheng hydrometric stations (Hukou) of Poyang Lake will decline by approximately 0.18–0.66 and 0.10–0.24 m, respectively. Although the overall navigable depth can basically meet the navigation requirements for a period of time, the trend of the long-term declining water level may cause unsafe navigation risks.

Prevalence and genetic diversity of Aeromonas veronii isolated from aquaculture systems in the Poyang Lake area, China.

The area around Poyang Lake is the main aquaculture area in Jiangxi Province, China, and an important base for the supply of freshwater aquatic products. Aquaculture in the Poyang Lake area is severely threatened by diseases caused by bacterial pathogens, and Aeromonas veronii has been the main pathogen in recent years. In this paper, ERIC-PCR genotyping, virulence gene and antimicrobial resistance gene detection, and drug susceptibility tests were carried out on 46 A. veronii isolates obtained from aquaculture systems in the Poyang Lake area from 2016 to 2020. The results showed that the A. veronii strains in the Poyang Lake area had high genetic diversity, and 46 strains produced 36 ERIC genotypes. There were no geographical and temporal differences in the cluster analysis results and no dominant clones. All 13 virulence genes tested were detected, and all isolates had harbored 2 or more virulence genes, with a maximum of 12 virulence genes detected. Among the 22 antimicrobial resistance genes selected, 15 were detected; 97.8% of the isolates contained 2 or more antimicrobial resistance genes, with a maximum of 9 antimicrobial resistance genes. Drug susceptibility tests showed that some strains were resistant to a variety of traditionally effective drugs for Aeromomas, such as enrofloxacin and florfenicol. This study provides a reference for exploring the impact of aquaculture in the Poyang Lake area on public health.

Hydrological Drivers for the Spatial Distribution of Wetland Herbaceous Communities in Poyang Lake

Hydrological processes are known as major driving forces in structuring wetland plant communities, but the specific relationships are not always well understood. The recent dry conditions of Poyang Lake (i.e., the largest freshwater lake in China) are having a profound impact on its wetland vegetation, leading to the degradation of the entire wetland ecosystem. We developed an integrated framework to quantitatively investigate the relationship between the spatial distribution of major wetland herbaceous communities and the hydrological regimes of Poyang Lake. First, the wetland herbaceous community classification was built using a support-vector machine and simultaneous parameter optimization, achieving an overall accuracy of over 98%. Secondly, based on the inundation conditions since 2000, four hydrological drivers of the spatial distribution of these communities were evaluated by canonical correspondence analysis. Finally, the hydrological niches of the communities were quantified by Gaussian regression and quantile methods. The results show that there were significant interspecific differences in terms of the hydrological niche. For example, Carex cinerascens Ass was the most adaptable to inundation, while Triarrhena lutarioriparia + Phragmites australis Ass was the least. Our integrated analytical framework can contribute to hydrological management to better maintain the wetland plant community structure in the Poyang Lake area.

The Measurement of Shear Characteristics of Paddy Soil in Poyang Lake Area

Understanding the shear characteristics of paddy fields is of great significance for the design of high-trafficability paddy wheels and to improve the trafficability of the tiller in paddy fields. Taking the paddy soil in Poyang Lake area of Jiangxi Province as the research object, a simple, self-designed bevameter was constructed to measure the apparent cohesion c and apparent internal friction angle φ of paddy soil with water content of 37% by weight using an annular shear plate. The effects of different shear speeds, shear grouser heights, and shear plate diameters on the measured c and φ were investigated. The measured values of c and φ were 1.89–2.35 kPa and 10.2–11.4°(deg), respectively. With the increase in shear speed, shear plate diameter, and grouser height, the value of c increased. Shear plate diameter and shear speed had small effect on c, whose change rate did not exceed 7.8%. However, shear grouser height had a greater influence on c, and the measured c increased by 24.5%. The influence of the three factors on φ followed the order: shear speed &gt; shear plate diameter &gt; shear grouser height, but the variation in φ did not exceed 1.2°(deg). The optimal operational conditions were: shear plate diameter of 250 mm with inner diameter of 150 mm, shear grouser height of 10 mm, with a shear speed of π/120 rad/s, and the apparent cohesion and apparent internal friction angle are 1887.8 pa and 11.06° (deg), respectively.

Arsenic in groundwater of the Poyang Lake area (China): aqueous species and health risk assessment.

Arsenic is a pervasive pollutant in groundwater, affecting more than 100 million people in 50 countries, including China. Toxicological analysis of As is complicated because As exists in the environment in a variety of forms and redox states. Here, a thermodynamic equilibrium model was used to calculate As speciation, investigate pathways of As accumulation and assess the risk of adverse health effects from oral ingestion of dissolved As from shallow groundwater in the Poyang Lake area (China). The accumulation of As, Fe, and NH4+ in the studied shallow groundwater was found to be the result of the dissolution of As-containing Fe, and probably Mn, (oxyhydr)oxides under reducing conditions due to excess influx of organic matter into the shallow aquifer. Modeling showed that As(III), which is more toxic than As(V), predominated at nearly all sampling sites, regardless of redox conditions. Arsenic tends to accumulate in the highest concentrations as neutral species (As(OH)30, HAsO20) under Eh < 50mV. In the lower reaches of the Ganjiang and Xiushui Rivers, an increased non-carcinogenic risk from oral ingestion of As from drinking water was observed. The elevated cancer risk was found to be present throughout the study area. The lower reaches of the Ganjiang and Xiushui Rivers that have been shown to have the highest risk of both non-carcinogenic and carcinogenic adverse health effects are associated with more toxic As(III) species. Given the As speciation and risk profile, it is recommended to introduce strategies to alter redox conditions in shallow groundwater by adopting safer irrigation practices and managing fertilizer applicationsto avoid the buildup of high As concentrations associated with adverse health effects.