Spatiotemporal Differentiation of Urban Spatial Form and Carbon Emissions in Poyang Lake City Group

In response to the inherent requirements of low-carbon land spatial planning in Jiangxi Province and the lack of existing research,this paper explored the mechanism of spatial form elements of Poyang Lake urban agglomeration on urban carbon emissions.Based on generalized linear regression and geographically weighted regression models,this paper analyzed the spatiotemporal distribution characteristics of carbon emissions,the spatiotemporal relationship between urban form index and carbon emissions,and the spatial differentiation of the intensity of dominant factors from 63 county-level administrative units in the Poyang Lake city group from 2005 to 2020.The results showed that:①The carbon emissions of urban agglomerations around Poyang Lake are generally increasing,and the spatial distribution of carbon emissions is characterized by high-value concentration in the middle and low-value agglomeration in pieces;②The main driving factor for the spatial heterogeneity of carbon emissions was the expansion of built-up area;③Improving urban compactness and optimizing urban form could effectively reduce urban carbon emissions.The results showcased the correlation between urban spatial landscape pattern and the spatiotemporal distribution of carbon emissions,which could make the low-carbon land spatial planning in the Poyang Lake city group more reasonable and practical.

Metagenomic Analysis of Environmental Samples from Wildlife Rescue Station at Poyang Lake, China

Objective To improve the understanding of the virome and bacterial microbiome in the wildlife rescue station of Poyang Lake,China.Methods Ten smear samples were collected in March 2019.Metagenomic sequencing was performed to delineate bacterial and viral diversity.Taxonomic analysis was performed using the Kraken2 and Bracken methods.A maximum-likelihood tree was constructed based on the RNA-dependent RNA polymerase(RdRp)region of picornavirus.Results We identified 363 bacterial and 6 viral families.A significant difference in microbial and viral abundance was found between samples S01–S09 and S10.In S01–S09,members of Flavobacteriia and Gammaproteobacteria were the most prevalent,while in S10,the most prevalent bacteria class was Actinomycetia.Among S01–S09,members of Myoviridae and Herelleviridae were the most prevalent,while the dominant virus family of S10 was Picornaviridae.The full genome of the pigeon mesivirus-like virus(NC-BM-233)was recovered from S10 and contained an open reading frame of 8,124 nt.It showed the best hit to the pigeon mesivirus 2 polyprotein,with 84.10%amino acid identity.Phylogenetic analysis showed that RdRp clustered into Megrivirus B.Conclusion This study provides an initial assessment of the bacteria and viruses in the cage-smeared samples,broadens our knowledge of viral and bacterial diversity,and is a way to discover potential pathogens in wild birds .

Anthropogenic activity,hydrological regime,and light level jointly influence temporal patterns in biosonar activity of the Yangtze finless porpoise at the junction of the Yangtze River and Poyang Lake,China

Under increasing anthropogenic pressure,species with a previously contiguous distribution across their ranges have been reduced to small fragmented populations.The critically endangered Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis),once commonly observed in the Yangtze River-Poyang Lake junction,is now rarely seen in the river-lake corridor.In this study,static passive acoustic monitoring techniques were used to detect the biosonar activities of the Yangtze finless porpoise in this unique corridor.Generalized linear models were used to examine the correlation between these activities and anthropogenic impacts from the COVID-19 pandemic lockdown and boat navigation,as well as environmental variables,including hydrological conditions and light levels.Over approximately three consecutive years of monitoring(2020–2022),porpoise biosonar was detected during 93%of logged days,indicating the key role of the corridor for finless porpoise conservation.In addition,porpoise clicks were recorded in 3.80%of minutes,while feeding correlated buzzes were detected in 1.23%of minutes,suggesting the potential existence of localized,small-scale migration.Furthermore,both anthropogenic and environmental variables were significantly correlated with the diel,lunar,monthly,seasonal,and annual variations in porpoise biosonar activities.During the pandemic lockdown period,porpoise sonar detection showed a significant increase.Furthermore,a significant negative correlation was identified between the detection of porpoise click trains and buzzes and boat traffic intensity.In addition to water level and flux,daylight and moonlight exhibited significant correlations with porpoise biosonar activities,with markedly higher detections at night and quarter moon periods.Ensuring the spatiotemporal reduction of anthropogenic activities,implementing vessel speed restrictions(e.g.,during porpoise migration and feeding),and maintaining local natural hydrological regimes are critical factors for sustaining porpoise population viability.

Do Geographically Isolated Grasslands Follow the Principle of Island Biogeography in a Landscape Scale? Taking Poyang Lake Grassland as an Example

As one of the basic theories of biodiversity conservation,island biogeography has been widely accepted in the past decades.Originally,island biogeography was put forward and applied in oceanic environments.But later on,it was found out that the application was not only limited to oceanic islands,but also in terrestrial environments with relatively isolated conditions.In terms of biodiversity level,island biogeography generally focuses on a small scale,such as species diversity and genetic diversity.The studies of biodiversity on a large-scale based on island biogeography,such as ecosystem and landscape scales,were seldomly conducted.Taking Poyang Lake,the largest fresh water lake in China as case study area,30 grasslands were randomly selected to study whether island biogeography can be applied to grasslands at a landscape level from three island attributes(area,distance and shape),and the most important ecological variable(flooding)in Poyang Lake.The results showed that in general,grasslands have the property of an island,and follow the basic principle of island biogeography.We found the area and flooding duration were the two most important determinants of landscape diversity.There was a significant positive correlation between the grassland area and the landscape diversity,which could be well expressed by logarithmic function model(R2=0.73).There was a negative correlation between flooding duration and landscape diversity,which could be described by an inverse model(R2=0.206).The distance to mainland and the shape of grassland were correlated with landscape diversity,but the fitting result of the models was not as good as expected.The possible reason could be that Poyang Lake is a seasonal lake,the water level varies with hydrological conditions,so that the grasslands are not strongly isolated and their shape is not stable enough required by island biogeography.Furthermore,it indicates that besides area,distance and shape attributes,flooding strongly affects the biodiversity of grassland vegetation,and should not be ignored when applying island biogeography theory to Poyang Lake.This study is expected to be a supplement for island biogeography in terrestrial environments,and the results are expected to benefit for the biodiversity conservation in Poyang Lake.

Vertical Distribution Characteristic of Nitrogen in the Core Sediments of Three Rivers Estuary in Poyang Lake

The vertical profile distribution characteristics of nitrogen in core sediments of Three Rivers Estuary in Poyang Lake were studied.The results showed that TN content in core sediments ranged from 480.0 to 1 900.0 μg/g with the change of depth,which was divided into three distribution types as follows:TN content decreases gradually with the increase of depth,TN content increases gradually with the increase of depth or higher content in the middle but lower content in two ends.NH4+-N content ranged from 8.7 ...

Study on Regionalization of High Efficiency Eco-agriculture in Eco-economic Zone of Poyang Lake

The high efficient eco-agricultural zone in Eco-economic Region of Poyang Lake was divided into three different areas. 12 indicators including per capita cultivated land,forest coverage,comprehensive utilization rate of straw,the ratio of the effective irrigation area to the arable land,amount of pesticide usage per unit area of arable land,the output value ratio of planting industry,the output value ratio of forestry and fruit industry,the output value ratio of stock farming,the output value ratio of fishery,the proportion of sown area of crop,proportion of sown area of oil plants and the proportion of sown area of vegetable were screened to construct the indicator system of regionalization of high efficient eco-agriculture. The average index values of the high efficient eco-agricultural regionalization of three regions were obtained,the development direction of the efficient eco-agriculture construction of three areas were analyzed according to the natural resources characteristics f eco-agricultural and requirements of high efficient eco-agricultural development of the regions.

Foundation for the Formation and Development of Lushan-Poyang Lake Eco-civilization

Lushan-Poyang Lake Eco-civilization is the joint product of natural process and regional characteristics in the evolution of history, the formation factors and status of Lushan-Poyang Lake eco-civilization were clarified by understanding its natural geographical foundation, regional culture foundation, environmental philosophy foundation and production practice foundation, to provide theoretical support for the future construction of Lushan-Poyang Lake eco-civilization.

Research of Informatization Demands of New Countryside in Poyang Lake Ecological Economic Zone and Related Countermeasures

[Objective] The aim was to survey and analyze informatization demand in new countryside in Poyang Lake Ecological Economic Zone and to propose counter- measures, [Method] A questionnaire was made among farmers on informatization de- mands in different regions in Poyang Lake Ecological Economic Zone and the re- sults were analyzed to propose countermeasures promoting informatization. [Result] With strengthening of information awareness, information demands in rural areas in Poyang Lake Ecological Economic Zone change as follows： Information demand car- rier changes from traditional media to modern media; demand on information content changes from one-way to diversified one; demand of information service changes from one-way transmission to interaction and exchange. However, some problems still exist in informatization process, such as poor infrastructure, dispersed information resources, higher information expense and shortage of information-based talents. Hence, the countermeasures were proposed, as follows： Rational security systems should be established; financing should be as diversified as possible; informatization infrastructure should be reinforced; agricultural economic information and informatiza- tion service system should be established. [Conclusion] The research lays foundation for construction of informatization in new countryside in Poyang Lake Ecological Economic Zone.

Tourism Development Strategy in Poyang Lake Eco-economic Area from the Perspective of Industrial Cluster

As a regional tourism development strategy, tourism industrial cluster can promote the core competitiveness of tourism industry in advantageous regions and the great-leap-forward development of regions with less-developed tourism industry. The conditions of forming tourism industrial cluster in Poyang Lake Eco-economic Area was analyzed, the development strategies for tourism industry from the perspective of industrial cluster was put forward.

Study on Artificial Propagation and Embryonic Development of Poyang Lake Catfish

Poyang Lake catfish （Silurus asotus Linnaeus） is native to Poyang Lake Basin. Artificial propagation of Poyang Lake catfish was carried out by using artificial insemination. Under water temperature of 18-26 ℃, embryonic development of Poyang Lake catfish in impounded water was observed and recorded in detail. Embryonic development of Poyang Lake catfish encountered seven stages, and it last- ed for 47.08 h from the fertilized egg stage to the stripping stage. The hatching time of Silurus meridionalis Chen was shortest, followed by that of Poyang Lake catfish, and the hatching time of Pelteobagrus vachelli was longest.

Effects of Water-table Depth and Soil Moisture on Plant Biomass, Diversity, and Distribution at a Seasonally Flooded Wetland of Poyang Lake, China

Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dramatic changes in hydrological conditions in last decade, which greatly influenced the wetland vegetations. To explore the relationships between hydrology and vegetation distri- bution, water-table depth, soil moisture, species composition, diversity and biomass were measured at a seasonally flooded wetland section at Wucheng National Nature Reserve. Three plant communities, Artemisia capillaris, Phragmites australis and Carex cineras- cens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical corre- spondence analysis （CCA）, spearmen correlation and logistic regression were adopted to analyze the relationships between vegetation characteristics and hydrological variables of water-table depth and soil moisture. Results show that significant hydrological gradient exist along the wetland transect. Water-table demonstrates a seasonal variation and is consistently deepest in A. capillaris community （ranging from q）.5 m above ground to ＋10.3 m below ground）, intermediate in P. australis community （-2.6 m to ＋7.8 m） and shallow- est in C. cinerascens community （-4.5 m to ＋6.1 m）. Soil moisture is lowest and most variable in A. capillaris community, highest and least variable in P. australis community, and intermediate and moderate variable in C. cinerascens community. The CCA ordination indicated that variables of water-table depth and soil moisture are strongly related to community distribution, which explained 81.7% of the vegetation variations. Species diversity indices are significantly positively correlated with soil moisture and negatively correlated with moisture variability, while above- and belowground biomass are positively correlated with moisture. Above- and belowground biomass present Gaussian models along the gradient of average water-table depth in growing season, while species diversity indices show bimodal patterns. The optimal average water-table depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively, and are 2.2 m and 2.4 m for species richness and Shannon-Wiener indices, respectively. Outcomes of this work improved the under- standings of the relationship between hydrology and vegetation.

Study of heavy metal speciation in branch sediments of Poyang Lake

This study concentrates on the environmental pollution level of sediments in the six branches of Poyang Lake, the biggest fresh water lake in China. This is the first systematic report on the speciation analysis of heavy metals （Cu, Co, Cd, Pb, and Ni） in the six branches of the lake. A reported analytical procedure involving a five-step sequential extraction is used for the partition of particulating heavy metals. The sediment samples are analyzed using flame atomic absorption spectroscopy （FAAS）. Experimental results obtained from five replicate samples of fluvial bottom surface sediments at the sampling points demonstrated that the relative standard deviation of the sequential extraction procedure was generally better than 10% （Cd except）. The average extracted contents of the five elements, analyzed after all five steps, are found to be （mg/kg） for Cu： 26.89, Co： 16.25, Cd： 1.08, Pb： 37.98, and Ni： 20.46. The content of the exchangeable species was generally lower. Except Cu, the percentage of the species bond to organic matter was lower than 20%. The fractions containing the most metal for Cu, Co, and Ni were the residues （52.26%, 45.28%, and 74.82%, respectively）.

Farmers＇ vulnerability to flood risk： A case study in the Poyang Lake Region

This paper quantitatively explores farmers＇ vulnerability to flood in the Poyang Lake Region （PLR） with the supports of GIS spatial functions. The analysis consists of three major steps, which is based on the spatial unit of township. Firstly, the spatial extent and characteristics of flood risk areas were determined using a digital elevation model （DEM） derived from the 1：50,000 topographic map. Secondly, for each of the township, six indices indicating the economic activities of local farmers were calculated. These indices are： rural population proportion, cultivated land proportion, GDP per unit area, employment proportion of primary industry, net rural income per capita and agricultural income proportion. These six indices were then normalized and used for later vulnerability assessment. Thirdly, the normalized indices （as GIS data layers） were overlaid with the flood risk areas to produce the risk coefficient for each township and to calculate the overall vulnerability for each township. The analysis results show that in the PLR there are high flood risk areas where the farmers＇ livings are seriously influenced or threatened. About 55.56% of the total 180 townships in the flood risk areas have a high degree of flood vulnerability. The townships under flood risk are mainly distributed in the areas around the Poyang Lake and the areas along the ＂five rivers＂.

Assessment of total suspended sediment concentrations in Poyang Lake using HJ-1A/1B CCD imagery

We explored the potential of the environment and disaster monitoring and forecasting small satellite constellations (HJ-1A/1B satellites) charge-coupled device (CCD) imagery (spatial resolution of 30 m, revisit time of 2 days) in the monitoring of total suspended sediment (TSS) concentrations in dynamic water bodies using Poyang Lake, the largest freshwater lake in China, as an example. Field surveys conducted during October 17-26, 2009 showed a wide range of TSS concentration (3-524 mg/L). Atmospheric correction was implemented using the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) module in ENVI with the aid of aerosol information retrieved from concurrent Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) surveys, which worked well at the CCD bands with relatively high reflectance. A practical exponential retrieval algorithm was created between satellite remote sensing reflectance and in-situ measured TSS concentration. The retrieved results for the whole water area matched the in-situ data well at most stations. The retrieval errors may be related to the problem of scale matching and mixed pixel. In three selected subregions of Poyang Lake, the distribution trend of retrieved TSS was consistent with that of the field investigation. It was shown that HJ-1A/1B CCD imagery can be used to estimate TSS concentrations in Poyang Lake over synoptic scales after applying an appropriate atmospheric correction method and retrieval algorithm.

Patterns of change in the population and spatial distribution of oriental white storks (Ciconia boyciana) wintering in Poyang Lake

Using total counts in simultaneous annual surveys, we monitored the population size and spatial distribution of oriental white storks （Ciconia boyciana） wintering in Poyang Lake between 1998 and 2011. Results showed that Poyang Lake wetland is an important wintering ground for oriental white storks, with an annual average population number of 2 305＋326. The population sizes in 2004, 2005, 2010, and 2011 were higher than the highest-ever estimate of its global population. In 2005, we recorded 3 789 individuals, which was the maximum population number within the period of 1998-2011. The storks inhabited 52 lakes, with the greatest distance between these lakes being 180.3 km. The storks presented a clustered distribution pattern in the Poyang Lake wetland, irrespective of the number of individuals or occurrence frequencies. Shahu, Dahuchi, Banghu, and Hanchihu were most frequently used lakes and had the largest annual average numbers of storks. There was a significant positive correlation between occurrence frequency and annual average number of storks in the lakes. Most of the lakes important for storks were covered by existing nature reserves, though some lakes outside the reserves were also frequently used. About 64.9%＋ 5.5% of the storks were found in nature reserves. In addition, the storks more frequently used and clumped in significantly larger flocks in lakes within nature reserves than lakes outside.

STATISTICAL ANALYSIS AND NUMERICAL SIMULATION OF POYANG LAKE'S INFLUENCE ON TROPICAL CYCLONES

Based on the Tropical Cyclone(TC briefly thereafter)Yearbook 1980-2009,this paper first analyzes the number and intensity change of the TCs which passed directly over or by the side of Poyang Lake(the distance of TC center is less than 1°longitude or 1°latitude from the Lake)among all the landfalling TCs in China during the past 30 years.Two cases are examined in detail in this paper.One is severe typhoon Rananim with a speed of 3.26 m/s and a change of 1 hPa in intensity when it was passing the Lake.The other is super typhoon Saomai with a faster moving speed of 6.50 m/s and a larger change in intensity of 6 hPa.Through numerical simulation experiments,this paper analyzes how the change of underlying surface from water to land contributes to the differences in intensity,speed and mesoscale convection of the two TCs when they passed the Lake.Results show that the moisture and dynamic condition above the Lake were favorable for the maintenance of the intensity when Rananim was passing through Poyang Lake,despite the moisture supply from the ocean was cut off.As a result,there was strong convection around the lake which led to a rainfall spinning counter-clockwise as it was affected by the TC movement.However,little impact was seen in the Saomai case.These results indicate that for the TCs coming ashore on Poyang Lake with a slow speed,the large water body is conducive to the sustaining of the intensity and strengthening of the convection around the TC center and the subsequent heavy rainfall.On the contrary,a fast-moving TC is less likely to be influenced by the underlying surface in terms of intensity and speed.

Study on Control Countermeasures of Agricultural Non-point Source Pollution in Lakeside Belt of Poyang Lake——Taking Duchang Section in the Lower Reaches of Poyang Lake as Example

[Objective] The aim was to study the control countermeasures of agricultural non-point source pollution in lakeside belt of Poyang Lake.[Method] The current situation of water quality of Poyang Lake was analyzed firstly,then the causes of agricultural non-point source pollution in Duchang section of Poyang Lake were studied,finally corresponding control countermeasures were put forward.[Result] Agricultural non-point source pollution in Duchang section of Poyang Lake was mainly related to the rapid development of pearl industry and livestock industry,aggravated soil erosion and excessive utilization of fertilizer.Based on analysis of current environmental situation and bearing capability of resources in Poyang Lake basin,agricultural non-point source pollution would be controlled through the reduction of external source pollution load,restoration of river wetland and construction of aquatic ecosystem.After the primary implementation of agricultural non-point source pollution control project,the amount of agricultural non-point source pollution in demonstration plot was reduced,and the quality of effluent met the first Class (Class A) of state Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).Meanwhile,biodiversity index in river wetland increased by about 30%,so the pollution load entering Poyang Lake was decreased.[Conclusion] The study could provide technology integration and demonstration for the environmental remediation in lakeside belt of Poyang Lake.

Variation Characteristics of Water Environmental Capacity in Poyang Lake under the Scheduling of Three Gorges Reservoir

[Objective] The aim was to study the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir.[Method] Choosing chemical oxygen demand (COD),total nitrogen (TN) and total phosphorus (TP) as the control indexes of pollutants in Poyang Lake,the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir were analyzed based on the water environment mathematical models of organic compounds and nutrients.[Result] After the operation of Three Gorges Project,high water level in Poyang Lake lasted for a long time in flood season when Three Gorges Reservoir increased discharge volume,while water level went down obviously with the accelerating of recession flow when reservoir decreased discharge volume to store water,so Three Gorges Project had obvious effects on the hydrological regime of Poyang Lake.In 2009,when Three Gorges Reservoir stored water,the water environmental capacity of COD,TN and TP in Poyang Lake in October decreased by 14.0%,15.4% and 15.4% compared with those before operation,while they increased by 3.64%,4.88% and 4.88% in August when reservoir discharged water to prevent flood.[Conclusion] The study could provide scientific foundation for the water pollution control and water environment management of lakes.

Spatiotemporal Comparative Analysis of Ecological Footprint of Poyang Lake Area and Five River Watersheds in Jiangxi Province

The Jiangxi province was divided into seven parts according to the concept of watershed,namely Poyang lake area,Fuhe,Xinjiang,Ganjiang,Xiuhe,Raohe and other river watersheds.The ecological supply and demands status of the former six parts from 2000 to 2006 was computed based on the ecological footprint model and a spatiotemporal comparative analysis to them was conducted.The result showed that:①all the studied areas had an increasing ecological deficit and they were in the status of unsustainable development;② the arable land footprint's demand were about 80% of their total footprint's demand respectively,so it was of great significance to protect and exploit arable land resources scientifically;③ the ecological deficit of grassland and forest resources can not be ignored.

Wetland vegetation biomass estimation and mapping from Landsat ETM data: a case study of Poyang Lake

Poyang Lake is the largest freshwater lake in China. This paper conducted a digital and rapid investigation of the lake’s wetland vegetation biomass using Landsat ETM data acquired on April 16, 2000. First, utilizing the false color composite derived from the ETM data as one of the main references, the authors designed a reasonable sampling route for field measurement of the biomass, and carried it out on April 18–28, 2000. Then after both the sampling data and the ETM data were geometrically corrected to an equal-area projection of Albers, linear relationships among the sampling data and some transformed data derived from the ETM data and the ETM 4 were calculated. The results show that the sampling data is best relative to the band 4 data with a high correlation coefficient of 0.86, followed by the DVI and NDVI data with 0.83 and 0.80 respectively. Therefore, a linear regression model, which was based on the field data and band 4 data, was used to estimate the total biomass of entire Poyang Lake, and then the map of the biomass distribution was compiled.