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(Neopho...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.展开更多
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 perfo...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 .展开更多
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 o...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.展开更多
[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 first...[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.展开更多
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 c...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.展开更多
[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 nitroge...[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.展开更多
[Objective] The study aimed at analysing the chemical characteristics of shallow groundwater and causes of formation around Poyang Lake area. [Method] The quality of shallow groundwater under seven counties or cities ...[Objective] The study aimed at analysing the chemical characteristics of shallow groundwater and causes of formation around Poyang Lake area. [Method] The quality of shallow groundwater under seven counties or cities around Poyang Lake was investigated in 2010, and compared different regions from salinity, hardness, conductivity, hydrochemistry types and so forth, so as to reveal the status quo, change characteristics and reasons of shallow groundwater. [Result] Except for pH, other water quality indicators of shallow groundwater around Poyang Lake were better, attaining Class I water quality standards. Among these regions, the salinity, hardness, conductivity, Na+, K+, Ca2+, Mg2+, Cl- and HCO-3 concentration of shallow groundwater in Nanchang city were up to the maximum values, while pH and SO2-4 concentration were the highest in Duchang County; Mg2+ concentration and pH were the lowest in Poyang County, and hardness, K+, Ca2+, SO2-4 and Cl- concentration in Yongxiu County reached the minimum values, while Na+ concentration, salinity and conductivity were the lowest in Jinxian County. In addition, the better quality of groundwater around Poyang Lake was closely related to the low level of economic development in Jiangxi Province. Meanwhile, many water quality indices in Nanchang City reached the maximum values, and even tended to Class Ⅱ water quality standards, which resulted from the high level of economic development and decisive role of human activities. [Conclusion] The research could provide references for the establishment of management strategies for regional shallow groundwater.展开更多
Poyang Lake in the Changjiang(Yangtze)River catchment has undergone frequent spring drought since 2003,and some researchers attributed this phenomenon to sand mining and the lakebed deformation in the outlet channel l...Poyang Lake in the Changjiang(Yangtze)River catchment has undergone frequent spring drought since 2003,and some researchers attributed this phenomenon to sand mining and the lakebed deformation in the outlet channel linking the lake with Changjiang River main channel.However,there is still a lack of high-resolution subaqueous geomorphological evidence of how sand mining led to lakebed deformation in the outlet channel.We examined the bed morphology and sub-bottom sedimentary structure of the outlet channel,using a multibeam echo sounder and sub-bottom profi ler in Poyang Lake.We found that:(1)the subaqueous micro-topography types of the outlet channel are characterized by sand mining disturbance,natural erosional topography,and fl at bed and dunes,accounting for 44.9%,21.4%,28.6%,and 5.1%of the channel area,respectively;and(2)sand mining activity aff ects the local bed topography extensively and signifi cantly.The depth of sandpits caused by sand mining varied from 1.4 m to 12 m deeper than the surrounding bed surface,with 4.41 m of depth increase on average.Hence,the large-scale high-intensity sand mining activities and their signifi cant geomorphic eff ects demand for an improved assessment for future management and longer-term sustainability.Because of the large-scale and ongoing high-intensity sand mining activities in the Poyang Lake outlet channel,these eff ects should raise caution in the future and contribute to monitoring eff orts that are essential to implement sustainable management solutions.The present study and techniques implemented can serve as a scientifi c reference for dam construction and sand mining within the Poyang Lake basin.展开更多
Long-term monthly precipitation data from 1960 to 2008 at 17 rain stations are analyzed to explore spatio-temporal variation of the seasonal and annual precipitation in the Poyang Lake basin, China, using anomaly anal...Long-term monthly precipitation data from 1960 to 2008 at 17 rain stations are analyzed to explore spatio-temporal variation of the seasonal and annual precipitation in the Poyang Lake basin, China, using anomaly analysis, simple linear regressive technique, Mann-Kendall trend test and Continuous Wavelet Transform. The results indicate that: (1) increasing precipitation trend is observed in summer and winter, while decreasing precipitation trend is identified in spring and autumn, and the above mentioned precipitation trends are not statistically significant;(2) changing trend of the areal average annual precipitation is non-significantly increasing, and increasing trend happens in almost the whole basin except in western and south-eastern small parts;(3) the spatial distribution of the seasonal and annual precipitation anomalies between 1991-2008 and 1960-2008 is similar to that of seasonal and annual precipitation trend during 1960-2008;(4) three main time-frequency distributions are observed in annual precipitation series during 1960- 2008, and they are 18 - 26 years, 8 - 14 years and 2 - 8 years, respectively;accordingly, there are three main periods in annual precipitation series, and they are 11-year, 22-year and 5-year respectively. This result will be helpful for further research on availability, scientific management and assessment of the water resources of the Poyang Lake basin.展开更多
Accumulated temperature,which is now widely used in agronomy,is an important ecological factor to the growth of plants,but few relative studies have been found on the vegetation area of floodplain grasslands in Poyang...Accumulated temperature,which is now widely used in agronomy,is an important ecological factor to the growth of plants,but few relative studies have been found on the vegetation area of floodplain grasslands in Poyang Lake.This research used the classification and regression tree(CART)to classify normalized vegetation area index derived from MODIS LAI(Moderate Resolution Imaging Spectroradiometer Leaf Area Index)images from 2008 to 2014,according to different climate indexes,such as mean daily air temperature(n),accumulated temperature(jw),daily maximum temperature(g),daily minimum temperature(d),accumulative precipitation(j),water level(s)and average water level for 20 days preceding(a).The results showed that:(1)The accumulated temperature and the 20-day average WL(water level)were found to have the greatest impact on variation in wetland vegetation area,and they both dominated the classification process twice;(2)Two classification thresholds of accumulated temperature were 790°C and 1784°C,approximately corresponding to the beginning of April and midMay;(3)790°C could also be used as a threshold to select remote sensing images to analysis the annual variability of vegetation,i.e.while accumulated temperature is lower than 790°C,remote sensing images of similar accumulated temperature rather than similar date should be selected from different years for comparison.We also found that,effects of different hydrological factors on area of floodplain grasslands showed stage characteristics:(1)From January to March,water level changes slowly with less rainfall,as a result,the 20-day average WL which can interpret the hydrologic characteristics smoothly showed significant importance in this stage;(2)While entering April,intense rainfall make accumulative precipitation to be the dominating factor of classification;(3)From late April to mid-May,in condition of accumulative precipitation higher than 405 mm,daily water level is of most importance,because to the flood recession process as well as rapid water level fluctuations.展开更多
According to Statistical Yearbook of Jiangxi Province(2001～2006),We analyze the time-space variation of population distribution of Poyang Lake region from the two points of view.The former is quality of population,wh...According to Statistical Yearbook of Jiangxi Province(2001～2006),We analyze the time-space variation of population distribution of Poyang Lake region from the two points of view.The former is quality of population,which involves culture structure,occupational structure,age structure and sex structure of population.The latter is quantity of population,which only involves the amount of population.Furthermore,we can reveal the internal relations and action mechanism of variation of population distribution by analyzing the regional economic development,population urbanization,land use and ecological landscape of Poyang Lake region.It is important to provide help for region planning,ecological landscape planning and environmental protection by correct understanding the man-land relationship of natural-human ecosystem in Poyang Lake region.展开更多
[Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed....[Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed.[Result] Drought occurred frequently in Poyang Lake and the consecutive serious drought occurred now and then.The water level in Poyang Lake since 21st century was lower.The drought in Poyang Lake was due to reduction of precipitation,low water level in Yangtze River and "five lakes",hydraulic project,industrial and agricultural water increase and other aspects.[Conclusion] The study provided theoretical basis for the formulation of drought prevention measures by relevant departments.展开更多
An individual of Anser cygnoides with albinism was found on November 30,2020 in Poyang Lake.Albinism was observed in body part rather than head and neck of the bird.This is the first report of albinism of A.cygnoides ...An individual of Anser cygnoides with albinism was found on November 30,2020 in Poyang Lake.Albinism was observed in body part rather than head and neck of the bird.This is the first report of albinism of A.cygnoides in China.展开更多
The regulation and storage capacity of Poyang Lake is infl uenced by the fl ow from the main stream of the Yangtze River and the fi ve rivers in the Poyang Lake basin.After the operation of the Three Gorges Dam(TGD),h...The regulation and storage capacity of Poyang Lake is infl uenced by the fl ow from the main stream of the Yangtze River and the fi ve rivers in the Poyang Lake basin.After the operation of the Three Gorges Dam(TGD),hydrological changes in the main stream of the Yangtze River impact water exchange between the Yangtze River and Poyang Lake.Based on the analysis of measured data and factors infl uencing outfl ow at Hukou station,a new empirical formula describing outfl ow at Hukou station and critical water level for lake storage capacity is established.The change in monthly storage capacity of Poyang Lake before and after the construction of the TGD is analyzed quantitatively.The results show that the fl ows from the main stream of the Yangtze River and the fi ve rivers in the Poyang Lake basin affect outfl ow and water storage capacity by changing the water level difference between Xingzi and Hukou stations and by changing the water level at Hukou station.But the Yangtze River and the fi ve rivers in the Poyang Lake basin differ in process and degree.If the water level at Hukou station remains consistent,when the fl ow from the fi ver rivers increases by 1,000 m3/s,the outfl ow at Hukou station increases by 304 m3/s.When the fl ow from the main stream of the Yangtze River increases by 1,000 m3/s,the outfl ow at Hukou station decreases by 724 m3/s.In addition,the operation of the TGD affects the water storage capacity of Poyang Lake.The water volume of Poyang Lake decreases by 49.4%in September,but increases by 47.7%in May.展开更多
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 dra...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 distribution, 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 cinerascens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical correspondence 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 –0.5 m above ground to +10.3 m below ground), intermediate in P. australis community(–2.6 m to +7.8 m) and shallowest 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 understandings of the relationship between hydrology and vegetation.展开更多
Achieving water purity in Poyang Lake has become a major concern in recent years, thus appropriate evaluation of spatial and temporal water quality variations has become essential. Variations in 11 water quality param...Achieving water purity in Poyang Lake has become a major concern in recent years, thus appropriate evaluation of spatial and temporal water quality variations has become essential. Variations in 11 water quality parameters from 15 sampling sites in Poyang Lake were investigated from 2009 to 2012. An integrative fuzzy variable evaluation(IFVE) model based on fuzzy theory and variable weights was developed to measure variations in water quality. Results showed that: 1) only chlorophyll-a concentration and Secchi depth differed significantly among the 15 sampling sites(P < 0.01), whereas the 11 water quality parameters under investigation differed significantly throughout the seasons(P < 0.01). The annual variations of all water quality variables except for temperature, electrical conductivity, suspended solids and total phosphorus were considerable(P < 0.05). 2) The IFVE model was reasonable and flexible in evaluating water quality status and any possible ′bucket effect′. The model fully considered the influences of extremely poor indices on overall water quality. 3) A spatial analysis indicated that anthropogenic activities(particularly industrial sewage and dredging) and lake bed topography might directly affect water quality in Poyang Lake. Meanwhile, hydrological status and sewage discharged into the lake might be responsible for seasonal water quality variations.展开更多
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 o...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.展开更多
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...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.展开更多
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 spati...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 charac-teristics 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 coeffi-cient 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".展开更多
基金supported by Science and Technology Service Network Initiative Program of the Chinese Academy of Sciencesthe National Natural Science Foundation of China (41806197)the Exploratory Program of the Natural Science Foundation of Zhejiang Province (ZX2023000154)。
文摘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.
基金funded by the National Natural Science Foundation of China[81961128002].
文摘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 .
基金supported by the National Natural Science Foundation of China(Nos.41961036,41901130).
文摘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.
基金Supported by Horizontal Subject Project of Jiujiang University(2011019)
文摘[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.
基金China National Science Foundation(40730948,41075037,41175063)Special Project of Chinese Academy of Meteorological Sciences(2007Y006)
文摘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.
基金Supported by National Key Project of Water Pollution Control and Management (2008zx07526-008-03)International Science and Technology Cooperation Project (2006DFB91920)+2 种基金National Key Technology R & D Program in the 11th Five-year Plan of China (2007BAB23CO2)National Natural Science Foundation of China (40672159)Technical Assistance Project of China's Economic Reform Implementation (TCC5jxspyhzxh09-03)
文摘[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.
基金Supported by Major Direction Project for Knowledge Innovation Project of Chinese Academy of Sciences (KZCX2-YW-306)Major State Basic Research Development Program (2006CB403200)+1 种基金International Science and Technology Cooperation Project (2006DFB91920)National Key Technology R & D Program in the 11th Five year Plan of China (2007BAB23CO2)
文摘[Objective] The study aimed at analysing the chemical characteristics of shallow groundwater and causes of formation around Poyang Lake area. [Method] The quality of shallow groundwater under seven counties or cities around Poyang Lake was investigated in 2010, and compared different regions from salinity, hardness, conductivity, hydrochemistry types and so forth, so as to reveal the status quo, change characteristics and reasons of shallow groundwater. [Result] Except for pH, other water quality indicators of shallow groundwater around Poyang Lake were better, attaining Class I water quality standards. Among these regions, the salinity, hardness, conductivity, Na+, K+, Ca2+, Mg2+, Cl- and HCO-3 concentration of shallow groundwater in Nanchang city were up to the maximum values, while pH and SO2-4 concentration were the highest in Duchang County; Mg2+ concentration and pH were the lowest in Poyang County, and hardness, K+, Ca2+, SO2-4 and Cl- concentration in Yongxiu County reached the minimum values, while Na+ concentration, salinity and conductivity were the lowest in Jinxian County. In addition, the better quality of groundwater around Poyang Lake was closely related to the low level of economic development in Jiangxi Province. Meanwhile, many water quality indices in Nanchang City reached the maximum values, and even tended to Class Ⅱ water quality standards, which resulted from the high level of economic development and decisive role of human activities. [Conclusion] The research could provide references for the establishment of management strategies for regional shallow groundwater.
基金Supported by the Comprehensive survey of the geological environment along the Changjiang River(No.DD20190260)the Natural Science Foundation of Shandong Province(No.ZR2020QD083)the Postdoctoral Science Foundation(No.2018M642693)。
文摘Poyang Lake in the Changjiang(Yangtze)River catchment has undergone frequent spring drought since 2003,and some researchers attributed this phenomenon to sand mining and the lakebed deformation in the outlet channel linking the lake with Changjiang River main channel.However,there is still a lack of high-resolution subaqueous geomorphological evidence of how sand mining led to lakebed deformation in the outlet channel.We examined the bed morphology and sub-bottom sedimentary structure of the outlet channel,using a multibeam echo sounder and sub-bottom profi ler in Poyang Lake.We found that:(1)the subaqueous micro-topography types of the outlet channel are characterized by sand mining disturbance,natural erosional topography,and fl at bed and dunes,accounting for 44.9%,21.4%,28.6%,and 5.1%of the channel area,respectively;and(2)sand mining activity aff ects the local bed topography extensively and signifi cantly.The depth of sandpits caused by sand mining varied from 1.4 m to 12 m deeper than the surrounding bed surface,with 4.41 m of depth increase on average.Hence,the large-scale high-intensity sand mining activities and their signifi cant geomorphic eff ects demand for an improved assessment for future management and longer-term sustainability.Because of the large-scale and ongoing high-intensity sand mining activities in the Poyang Lake outlet channel,these eff ects should raise caution in the future and contribute to monitoring eff orts that are essential to implement sustainable management solutions.The present study and techniques implemented can serve as a scientifi c reference for dam construction and sand mining within the Poyang Lake basin.
文摘Long-term monthly precipitation data from 1960 to 2008 at 17 rain stations are analyzed to explore spatio-temporal variation of the seasonal and annual precipitation in the Poyang Lake basin, China, using anomaly analysis, simple linear regressive technique, Mann-Kendall trend test and Continuous Wavelet Transform. The results indicate that: (1) increasing precipitation trend is observed in summer and winter, while decreasing precipitation trend is identified in spring and autumn, and the above mentioned precipitation trends are not statistically significant;(2) changing trend of the areal average annual precipitation is non-significantly increasing, and increasing trend happens in almost the whole basin except in western and south-eastern small parts;(3) the spatial distribution of the seasonal and annual precipitation anomalies between 1991-2008 and 1960-2008 is similar to that of seasonal and annual precipitation trend during 1960-2008;(4) three main time-frequency distributions are observed in annual precipitation series during 1960- 2008, and they are 18 - 26 years, 8 - 14 years and 2 - 8 years, respectively;accordingly, there are three main periods in annual precipitation series, and they are 11-year, 22-year and 5-year respectively. This result will be helpful for further research on availability, scientific management and assessment of the water resources of the Poyang Lake basin.
基金This work was supported by the National Natural Science Foundation of China“Study on the dynamic mechanism of grassland ecosystem response to climate change in Qinghai Plateau”under grant number U20A2098the Second Tibet Plateau Scientific Expedition and Research Program(STEP)under grant number 2019QZKK0804.
文摘Accumulated temperature,which is now widely used in agronomy,is an important ecological factor to the growth of plants,but few relative studies have been found on the vegetation area of floodplain grasslands in Poyang Lake.This research used the classification and regression tree(CART)to classify normalized vegetation area index derived from MODIS LAI(Moderate Resolution Imaging Spectroradiometer Leaf Area Index)images from 2008 to 2014,according to different climate indexes,such as mean daily air temperature(n),accumulated temperature(jw),daily maximum temperature(g),daily minimum temperature(d),accumulative precipitation(j),water level(s)and average water level for 20 days preceding(a).The results showed that:(1)The accumulated temperature and the 20-day average WL(water level)were found to have the greatest impact on variation in wetland vegetation area,and they both dominated the classification process twice;(2)Two classification thresholds of accumulated temperature were 790°C and 1784°C,approximately corresponding to the beginning of April and midMay;(3)790°C could also be used as a threshold to select remote sensing images to analysis the annual variability of vegetation,i.e.while accumulated temperature is lower than 790°C,remote sensing images of similar accumulated temperature rather than similar date should be selected from different years for comparison.We also found that,effects of different hydrological factors on area of floodplain grasslands showed stage characteristics:(1)From January to March,water level changes slowly with less rainfall,as a result,the 20-day average WL which can interpret the hydrologic characteristics smoothly showed significant importance in this stage;(2)While entering April,intense rainfall make accumulative precipitation to be the dominating factor of classification;(3)From late April to mid-May,in condition of accumulative precipitation higher than 405 mm,daily water level is of most importance,because to the flood recession process as well as rapid water level fluctuations.
文摘According to Statistical Yearbook of Jiangxi Province(2001～2006),We analyze the time-space variation of population distribution of Poyang Lake region from the two points of view.The former is quality of population,which involves culture structure,occupational structure,age structure and sex structure of population.The latter is quantity of population,which only involves the amount of population.Furthermore,we can reveal the internal relations and action mechanism of variation of population distribution by analyzing the regional economic development,population urbanization,land use and ecological landscape of Poyang Lake region.It is important to provide help for region planning,ecological landscape planning and environmental protection by correct understanding the man-land relationship of natural-human ecosystem in Poyang Lake region.
基金Supported by Nanchang University Science and Technology Fund (Z04862)Jiangxi Province Postgraduates Innovation Program Fund (YC10S037)
文摘[Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed.[Result] Drought occurred frequently in Poyang Lake and the consecutive serious drought occurred now and then.The water level in Poyang Lake since 21st century was lower.The drought in Poyang Lake was due to reduction of precipitation,low water level in Yangtze River and "five lakes",hydraulic project,industrial and agricultural water increase and other aspects.[Conclusion] The study provided theoretical basis for the formulation of drought prevention measures by relevant departments.
基金Supported by FAO/GEF Demonstration Project of Wetland Reserve System in Jiangxi Province(GCP/CPR/052/GFF).
文摘An individual of Anser cygnoides with albinism was found on November 30,2020 in Poyang Lake.Albinism was observed in body part rather than head and neck of the bird.This is the first report of albinism of A.cygnoides in China.
基金National Key R&D Program of China(2018YFC0407201).
文摘The regulation and storage capacity of Poyang Lake is infl uenced by the fl ow from the main stream of the Yangtze River and the fi ve rivers in the Poyang Lake basin.After the operation of the Three Gorges Dam(TGD),hydrological changes in the main stream of the Yangtze River impact water exchange between the Yangtze River and Poyang Lake.Based on the analysis of measured data and factors infl uencing outfl ow at Hukou station,a new empirical formula describing outfl ow at Hukou station and critical water level for lake storage capacity is established.The change in monthly storage capacity of Poyang Lake before and after the construction of the TGD is analyzed quantitatively.The results show that the fl ows from the main stream of the Yangtze River and the fi ve rivers in the Poyang Lake basin affect outfl ow and water storage capacity by changing the water level difference between Xingzi and Hukou stations and by changing the water level at Hukou station.But the Yangtze River and the fi ve rivers in the Poyang Lake basin differ in process and degree.If the water level at Hukou station remains consistent,when the fl ow from the fi ver rivers increases by 1,000 m3/s,the outfl ow at Hukou station increases by 304 m3/s.When the fl ow from the main stream of the Yangtze River increases by 1,000 m3/s,the outfl ow at Hukou station decreases by 724 m3/s.In addition,the operation of the TGD affects the water storage capacity of Poyang Lake.The water volume of Poyang Lake decreases by 49.4%in September,but increases by 47.7%in May.
基金National Natural Science Foundation of China(No.41371062)Collaborative Innovation Center for Major Ecological Security Issues of Jiangxi Province and Monitoring Implementation(No.JXS-EW-00)+1 种基金National Basic Research Program of China(No.2012CB417003)Science Foundation of Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences(No.NIGLAS2012135001)
文摘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 distribution, 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 cinerascens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical correspondence 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 –0.5 m above ground to +10.3 m below ground), intermediate in P. australis community(–2.6 m to +7.8 m) and shallowest 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 understandings of the relationship between hydrology and vegetation.
基金Under the auspices of National Basic Research Program of China(No.2012CB417006)National Natural Science Foundation of China(No.41271500,41571107,41601041)
文摘Achieving water purity in Poyang Lake has become a major concern in recent years, thus appropriate evaluation of spatial and temporal water quality variations has become essential. Variations in 11 water quality parameters from 15 sampling sites in Poyang Lake were investigated from 2009 to 2012. An integrative fuzzy variable evaluation(IFVE) model based on fuzzy theory and variable weights was developed to measure variations in water quality. Results showed that: 1) only chlorophyll-a concentration and Secchi depth differed significantly among the 15 sampling sites(P < 0.01), whereas the 11 water quality parameters under investigation differed significantly throughout the seasons(P < 0.01). The annual variations of all water quality variables except for temperature, electrical conductivity, suspended solids and total phosphorus were considerable(P < 0.05). 2) The IFVE model was reasonable and flexible in evaluating water quality status and any possible ′bucket effect′. The model fully considered the influences of extremely poor indices on overall water quality. 3) A spatial analysis indicated that anthropogenic activities(particularly industrial sewage and dredging) and lake bed topography might directly affect water quality in Poyang Lake. Meanwhile, hydrological status and sewage discharged into the lake might be responsible for seasonal water quality variations.
基金Supported by the National Basic Research Program of China(973Program)(No.2011CB707106)the National Natural Science Foundation of China(Nos.41071261,41023001,41021061,40906092,40971193,41101415)+3 种基金the Opening Foundation of Institute of Remote Sensing and Earth Sciences,Hangzhou Normal University(No.PDKF2010YG06)the Fundamental Research Funds for the Central Universities,the China Postdoctoral Science Foundation(No.20100480861)LIESMARS Special Research Funding,the Natural Science Foundation of Hubei Province,China(No.2009CDB107)the Natural Science Foundation of Zhejiang Province,China(No.Y5090143)
文摘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.
基金supported by the National Natural Science Foundation of China(31460107)Siberian Crane Wetland Project-ChinaConstruction Office of Poyang Lake Water Control Project of Jiangxi Province(KT201401)
文摘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.
基金Key Laboratory of Poyang Lake Ecological Environment and Resource Development, No.PK2004017 National Natural Science Foundation of China, No.40561011
文摘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 charac-teristics 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 coeffi-cient 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".
