In the face of global warming and increasing impervious surfaces,quantifying the change of climate potential productivity(CPP)is of great significance for the food production planning.Targeting the Dongting Lake Basin...In the face of global warming and increasing impervious surfaces,quantifying the change of climate potential productivity(CPP)is of great significance for the food production planning.Targeting the Dongting Lake Basin,which is a key area for food production in China,this paper uses meteorological data,as well as Climate Change Initiative Land Cover,and Shuttle Radar Topography Mission digital elevation model to investigate the CPP and its changes from 2000 to 2020.The suitability of land for cultivation(SLC),and the land use/land cover change(LUCC)are also considered.The results showed that the CPP varied from 9,825 to 20,895 kg ha^(-1).Even though the newly added impervious surfaces indirectly resulted in the decrease of CPP by of 9.81×10~8 kg,overall,the CPP increased at an average rate of 83.7 kg ha^(-1)a^(-1).Global warming is the strongest driver behind CPP increase,and CPP has played an important role in the conversions between cultivated land and other land types.The structure of land types tends to be optimized against this challenge.展开更多
Full operation of the Three Gorges Dam(TGD) reduces flood risk of the middle and lower parts of the Yangtze River Basin. However,Dongting Lake, which is located in the Yangtze River Basin, is still at high risk for po...Full operation of the Three Gorges Dam(TGD) reduces flood risk of the middle and lower parts of the Yangtze River Basin. However,Dongting Lake, which is located in the Yangtze River Basin, is still at high risk for potentially severe flooding in the future. The effects of the TGD on flood processes were investigated using a hydrodynamic model. The 1998 and 2010 flood events before and after the operation of the TGD, respectively, were analyzed. The numerical results show that the operation of the TGD changes flood processes, including the timing and magnitude of flood peaks in Dongting Lake. The TGD can effectively reduce the flood level in Dongting Lake, which is mainly caused by the flood water from the upper reach of the Yangtze River. This is not the case, however, for floods mainly induced by flood water from four main rivers in the catchment. In view of this, a comprehensive strategy for flood management in Dongting Lake is required. Non-engineering measures, such as warning systems and combined operation of the TGD and other reservoirs in the catchment, as well as traditional engineering measures, should be further improved. Meanwhile, a sustainable philosophy for flood control, including natural flood management and lake restoration, is recommended to reduce the flood risk.展开更多
Floodplains are important and distinctive ecosystems around the world,and the recruitment of ichthyoplankton from river to floodplain lakes is crucial to maintain this unique ecosystem.However,this process has not bee...Floodplains are important and distinctive ecosystems around the world,and the recruitment of ichthyoplankton from river to floodplain lakes is crucial to maintain this unique ecosystem.However,this process has not been well documented.In this study,ichthyoplankton were sampled to investigate the details of ichthyoplankton recruitment from the Changjiang(Yangtze)River to the Dongting Lake via a floodway channel,the Songzi River,from May to July in 2013 and 2014.During the study period,41 species of eggs and larvae were sampled.Among the samples,16 were river-lake migratory species(RL),representing 23.5%of the species in the Dongting Lake.In 2013,an estimated 130 million eggs and 3180 million larvae drifted through the sampling section,and in 2014,an estimated 1 060 million eggs and 1040 million larvae drifted through the sampling section.The amount of eggs and larvae of RL reached 3 210 million in 2013 and 1 850 million in 2014,respectively.These results demonstrated the importance of ichthyoplankton recruitment from the river to the lake,as species diversity will decrease sharply without this recruitment.Canonical correspondence analysis(CCA)showed that water temperature and water flow are the two most important factors influencing the spawning activities of fish.To maintain the high fish diversity in the Changjiang floodplain,we suggest to irrigate the channel to increase water discharge and increase the transport of ichthyoplankton from the Changjiang mainstream into the Dongting Lake.展开更多
From nitrogen and phosphorus,chemical oxygen demand,phytoplankton,and eutrophication,this article analyzes the current situation of water quality in the Dongting Lake area,and discusses the factors influencing the wat...From nitrogen and phosphorus,chemical oxygen demand,phytoplankton,and eutrophication,this article analyzes the current situation of water quality in the Dongting Lake area,and discusses the factors influencing the water quality of Dongting Lake. Based on the actual production,geographic characteristics and outstanding problem of grim water pollution situation in the Dongting Lake area,some specific proposed measures are put forward in order to provide the basis and reference for the future pollution control in the Dongting Lake area,such as strengthening the industrial pollution control,developing ecological agriculture,and enhancing ecological restoration and water quality early warning.展开更多
The sediments of the Dongting Lake come from four channels (one of them was closed in 1959), connected with the Yangtze River, four tributaries (Lishui, Yuanjiang, Zishui and Xiangjiang) and local area, and some of th...The sediments of the Dongting Lake come from four channels (one of them was closed in 1959), connected with the Yangtze River, four tributaries (Lishui, Yuanjiang, Zishui and Xiangjiang) and local area, and some of them are transported into the Yangtze River in Chenglingji, which is located at the exit of the Dongting Lake, some of them deposit into drainage system in the lake region and the rest deposit into the lake. The annual mean sediment is 166,555x104 t, of which 80% come from the four channels, 18% from the four tributaries and 2% from local area, whereas 26% of the total sediments are transported into the Yangtze River and 74% deposited into the lake and the lake drainage system. Based on topographic maps of 1974, 1988 and 1998, and the spatial analysis method with geographic information system (GIS), changes in sediment deposition and erosion are studied in this paper. By overlay analysis of 1974 and 1988, 1988 and 1998, erosion and sediments deposition areas are defined. The main conclusions are: (1) sediment rate in the lake is larger than erosion rate from 1974 to 1998. The mean deposition in the lake is 0.43 m; (2) annual sediment deposition is the same between 1974-1988 and 1988-1998, but the annual volume of deposition and erosion of 1988-1998 is bigger than that in 1974-1988; (3) before the completion of the Three Gorges Reservoir, there will be 7.82x108 m3 of sediments deposited in the lake, which would make the lake silted up by 0.33 m; (4) in the lake, the deposition area is found in the north of the east Dongting Lake, the south-west of the south Dongting Lake, and the east of the west Dongting Lake; while the eroded area is in the south of the east Dongting Lake, the middle of the south Dongting Lake, the west of the west Dongting Lake, as well as Xiangjiang and Lishui river flood channels.展开更多
This study developed a hierarchical Bayesian(HB)model for local and regional flood frequency analysis in the Dongting Lake Basin,in China.The annual maximum daily flows from 15 streamflow-gauged sites in the study are...This study developed a hierarchical Bayesian(HB)model for local and regional flood frequency analysis in the Dongting Lake Basin,in China.The annual maximum daily flows from 15 streamflow-gauged sites in the study area were analyzed with the HB model.The generalized extreme value(GEV)distribution was selected as the extreme flood distribution,and the GEV distribution location and scale parameters were spatially modeled through a regression approach with the drainage area as a covariate.The Markov chain Monte Carlo(MCMC)method with Gibbs sampling was employed to calculate the posterior distribution in the HB model.The results showed that the proposed HB model provided satisfactory Bayesian credible intervals for flood quantiles,while the traditional delta method could not provide reliable uncertainty estimations for large flood quantiles,due to the fact that the lower confidence bounds tended to decrease as the return periods increased.Furthermore,the HB model for regional analysis allowed for a reduction in the value of some restrictive assumptions in the traditional index flood method,such as the homogeneity region assumption and the scale invariance assumption.The HB model can also provide an uncertainty band of flood quantile prediction at a poorly gauged or ungauged site,but the index flood method with L-moments does not demonstrate this uncertainty directly.Therefore,the HB model is an effective method of implementing the flexible local and regional frequency analysis scheme,and of quantifying the associated predictive uncertainty.展开更多
In order to ascertain the soil carbon flux characteristics of poplar plantations and crop communities in the Dongting Lake area during the growing season and their correlation with hydrothermal conditions,soil respira...In order to ascertain the soil carbon flux characteristics of poplar plantations and crop communities in the Dongting Lake area during the growing season and their correlation with hydrothermal conditions,soil respiration rate was monitored at fixed sites and time points with an LI-8100 A automated soil flux system.Meanwhile,the surface temperature and soil temperature and humidity were measured. The soil respiration variation in the two different vegetation types and its correlation with environmental factors were analyzed. The results showed that in the growing season,the diurnal variation curves of soil respiration rate in the two different vegetation types showed a single peak variation,but there was certain difference in the appearance time of the peak. The peak of the crop appeared around11: 00 am,while the peak of soil respiration in the poplar appeared around 13: 00. The soil respiration rate of the poplar was also significantly higher than that of the crop,and the average difference of soil respiration rate between the two was 3. 09 and 3. 55 μmol/( m^2·s) in April and August,respectively. Temperature and soil moisture were the main factors affecting soil respiration of the poplar plantation and crop community. Temperature had a greater effect on the soil respiration of the crop community,and soil humidity had a greater impact on soil respiration in the poplar plantation,showing a correlation coefficient reaching 0. 952.展开更多
The Dongting Lake Estuary is migration pathways for some river-lake migratory and semi-migratory fishes. In the present study, an annual survey of fish was conducted from January to November 2018 covering a total of 6...The Dongting Lake Estuary is migration pathways for some river-lake migratory and semi-migratory fishes. In the present study, an annual survey of fish was conducted from January to November 2018 covering a total of 6 sites in Dongting Lake Estuary. A total of 57 freshwater species and subspecies belonging to 5 orders and 10 families were recorded. The catches at the Dongting Lake Estuary were mainly composed of Lake settled fish. The biomass of Cyprinus (Cyprinus) carpio Linnaeus was the highest, accounting for 25.53% of the total catches, followed by Hypophthalmichthys molitrixs, Culter alburnus Basilewsky and Ctenopharyngodon idellus, accounting for 10.41%, 8.99% and 7.10% of the total catches, respectively. The four major domestic carps accounted for 26.13% of the total catch. The range of richness of species varied between 40 and 51 species. The trend was fewer species in spring, with the arrival of summer and autumn gradually increasing, peaking at the turn of summer and autumn, and then gradually decreasing with the arrival of winter, to the lowest in spring. The Shannon, Simpson, Pielou and Margalef indices showed the consistent trends with richness of species.展开更多
On the basis of water-balance equation in Dongting Lake and Xiang Zi Yuan-Li River drainage areas, a possib1e flood height relating to the rainfall precipitation in these areas has been inferred. According to the floo...On the basis of water-balance equation in Dongting Lake and Xiang Zi Yuan-Li River drainage areas, a possib1e flood height relating to the rainfall precipitation in these areas has been inferred. According to the flood simulation, some synthetic maintenance strategies to prevent future catastrophic f1oods in Dongting Lake drainage area have been also presented.展开更多
There is a close relationship between occurrence of nonmetallic minerals and tectonic evolution of geosyncline, platform and diwa (geodepression) on the western margin of the Dongting diwa. Some results that (1) diwa ...There is a close relationship between occurrence of nonmetallic minerals and tectonic evolution of geosyncline, platform and diwa (geodepression) on the western margin of the Dongting diwa. Some results that (1) diwa tectonics is berfeficial for formation and preservation of nonmetallic minerals and (2) volcano-sedimentary altered ore deposits, saline deposits and organo-sedimentary ore deposits can be often found in diwa basins are gained.展开更多
[Objective] The research aimed to study influences of the weather and climate on wintering migratory bird in Dongting Lake. [Method] Bird analysis data provided by East Dongting Lake National Nature Reserve and winter...[Objective] The research aimed to study influences of the weather and climate on wintering migratory bird in Dongting Lake. [Method] Bird analysis data provided by East Dongting Lake National Nature Reserve and wintering migratory bird monitoring data in big and small west lakes in recent 5 years were used. By combing water level data and various meteorological factors in Chenglingji, wintering migratory bird in Dongting Lake was analyzed. [Result] Abnormal precipitation led to drought or flood in Dongting Lake, causing significant adverse effect on the birds. Abnormal climate was important reason for that wintering migratory bird greatly reduced, such as high temperature and later going south of the strong cold air. Extreme weather and climate events led that some birds in Dongting Lake significantly reduced. Meteorological element had certain influence to bird survey. We should select a reasonable investigation time based on weather and climate. In Birding Festival, weather had little effect on bird species observation. In the migratory season of bird, we could see many birds in fine cold weather after a strong cold air, which suitable for observing bird. When it was low temperature or less rain in autumn, and was high temperature or more rain and sunshine in early winter, it was suitable for migratory birds wintering in Dongting Lake. Ardea cinerea, Anser fabalis and Anser erythropus were more in sunny days while Phalacrocorax carbo was more in rainy weather. Grus grus was more in heavy wind weather while Recurvirostra avosetta was more in small wind weather. [Conclusion] The research provided scientific basis for studying migratory bird in east Dongting Lake.展开更多
Wetland is a transition zone between terrestrial and aquatic ecosystems,and is the source and sink of various biogenic elements in the earth’s epipelagic zone.In order to investigate the driving force and coupling me...Wetland is a transition zone between terrestrial and aquatic ecosystems,and is the source and sink of various biogenic elements in the earth’s epipelagic zone.In order to investigate the driving force and coupling mechanism of carbon(C),nitrogen(N)and phosphorus(P)migration in the critical zone of lake wetland,this paper studies the natural wetland of Dongting Lake area,through measuring and analysing the C,N and P contents in the wetland soil and groundwater.Methods of Pearson correlation,non-linear regression and machine learning were employed to analyse the influencing factors,and to explore the coupling patterns of the C,N and P in both soils and groundwater,with data derived from soil and water samples collected from the wetland critical zone.The results show that the mean values of organic carbon(TOC),total nitrogen(TN)and total phosphorus(TP)in groundwater are 1.59 mg/L,4.19 mg/L and 0.5 mg/L,respectively,while the mean values of C,N and P in the soils are 18.05 g/kg,0.86 g/kg and 0.52 g/kg.The results also show that the TOC,TN and TP in the groundwater are driven by a variety of environmental factors.However,the concentrations of C,N and P in the soils are mainly related to vegetation abundance and species which influence each other.In addition,the fitted curves of wetland soil C-N and C-P appear to follow the power function and S-shaped curve,respectively.In order to establish a multivariate regression model,the soil N and P contents were used as the input parameters and the soil C content used as the output one.By comparing the prediction effects of machine learning and nonlinear regression modelling,the results show that coupled relationship equation for the C,N and P contents is highly reliable.Future modelling of the coupled soil and groundwater elemental cycles needs to consider the complexity of hydrogeological conditions and to explore the quantitative relationships among the influencing factors and chemical constituents.展开更多
Architectural design of Dongting Lake Museum takes "River dolphin ripples in the Dongting Lake" as the theme, tries to integrate into the local wetland environment and ecological resources of the Dongting La...Architectural design of Dongting Lake Museum takes "River dolphin ripples in the Dongting Lake" as the theme, tries to integrate into the local wetland environment and ecological resources of the Dongting Lake, in order to realize the dream of "making a great museum for the most gorgeous lake". The overall layout follows the concept of "coexistence of real and virtual, integration of exterior and interior", and the architectural image symbolizes "the river dolphin ripples", which is extremely harmonious in the whole natural environment. The design integrates planning, building, landscape and interior spaces, adopts technical means and ecological green to integrate the building into the environment, and presents us a tremendous ecological wetland museum that floats on the lake like a fish, an islet, a sail or a hill.展开更多
To analyze the efficiency of the agro-ecosystem of Dongting Rim in Hunan Province,this paper adopted the emergy theory to study the agricultural output of this region during 2001 to 2010.The results showed that the va...To analyze the efficiency of the agro-ecosystem of Dongting Rim in Hunan Province,this paper adopted the emergy theory to study the agricultural output of this region during 2001 to 2010.The results showed that the value of regional agricultural emergy output increased by44.68%to(6.50 E)sej,but lower than the growth of non-agricultural industry output.Compared with 2001,the emergy output of planting industry was(4.10E)sej in 2010 which occupied 63.09%of the total agricultural emergy output and got an increase of 2.93 percentage points,while the emergy output of stock farming got a decrease of 2.87 percentage points.The growth of fishery emergy output was not in conformity with the characteristics of Dongting Rim in Hunan.From the contrast between emergy output and economic output,we could find that the economic return ratio of planting industry and fishery industry were lower than those of forestry industry and stock farming industry,which indicated that it is necessary to improve the economic benefits of planting industry and fishery industry which were the traditional industries with advantages of the Dongting Rim in Hunan.展开更多
Confucian ethics, idea and behavior criterion were embodied in "everything" of life, especially in the building as an important tool for moralizing. Taking a case study on vernacular houses of Dongting East ...Confucian ethics, idea and behavior criterion were embodied in "everything" of life, especially in the building as an important tool for moralizing. Taking a case study on vernacular houses of Dongting East Mountain and West Mountain, this paper reveals the "moderate", "etiquette" and "benevolence" as moral contents in the building's layout, form, space, decoration and so on. The moralizing reflects a subtle way of guidance, as well as diversified and systematic characteristics. Vernacular houses deeply mingled with daily life, had unique influence as physical environment, thus realizing the implementation and manifestation of Confucian moralizing ideas that have been converted to folk customs. In sum, the Confucian moralizing function carried by vernacular houses is the product of institutions and rules, and it is also the manifestation of conscious inheritance of cultural identity.展开更多
Wetlands provide vital ecological services for both humans and environment,necessitating continuous,refined and up-to-date mapping of wetlands for conservation and management.in this study,we developed an automated an...Wetlands provide vital ecological services for both humans and environment,necessitating continuous,refined and up-to-date mapping of wetlands for conservation and management.in this study,we developed an automated and refined wetland mapping framework integrating training sample migration method,supervised machine learning and knowledge-driven rules using Google Earth Engine(GEE)platform and open-source geospatial tools.We applied the framework to temporally dense Sentinel-1/2 imagery to produce annual refined wetland maps of the Dongting Lake Wetland(DLW)during 2015-2021.First,the continuous change detection(CCD)algorithm was utilized to migrate stable training samples.Then,annual 10 m preliminary land cover maps with 9 classes were produced using random forest algorithm and migrated samples.Ultimately,annual 10 m refined wetland maps were generated based on preliminary land cover maps via knowledge-driven rules from geometric features and available water-related inventories,with Overall Accuracy(OA)ranging from 81.82%(2015)to 93.84%(2020)and Kappa Coefficient(KC)between 0.73(2015)and 0.91(2020),demonstrating satisfactory performance and substantial potential for accurate,timely and type-refined wetland mapping.Our methodological framework allows rapid and accurate monitoring of wetland dynamics and could provide valuable information and methodological support for monitoring,conservation and sustainable development of wetland ecosystem.展开更多
Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in D...Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.展开更多
Although the Three Gorges Project(TGP)may have affected the population structure and distribution of plant and animal communities,few studies have analyzed the effect of this project on small mammal communities.Theref...Although the Three Gorges Project(TGP)may have affected the population structure and distribution of plant and animal communities,few studies have analyzed the effect of this project on small mammal communities.Therefore,the present paper compares the small mammal communities inhabiting the beaches of Dongting Lake using field investigations spanning a 20-year period,both before and after the TGP was implemented.Snap traps were used throughout the census.The results indicate that the TGP caused major changes to the structure of the small mammal community at a lake downstream of the dam.First,species abundance on the beaches increased after the project commenced.The striped field mouse(Apodemus agrarius)and the Norway rat(Rattus norvegicus),which rarely inhabited the beach before the TGP,became abundant(with marked population growth)once water was impounded by the Three Gorges Reservoir.Second,dominant species concentration indices exhibited a stepwise decline,indicating that the community structure changed from a single dominant species to a more diverse species mix after TGP implementation.Third,the regulation of water discharge release by the TGP might have caused an increase in the species diversity of the animal community on the beaches.A significant difference in diversity indices was obtained before and after the TGP operation.Similarity indices also indicate a gradual increase in species numbers.Hence,a long-term project should be established to monitor the population fluctuations of the Yangtze vole(Microtus fortis),the striped field mouse and the Norway rat to safeguard against population outbreaks(similar to the Yangtze vole outbreak in 2007),which could cause crop damage to adjacent farmland,in addition to documenting the succession process of the small mammal community inhabiting the beaches of Dongting Lake.展开更多
Water level fluctuation of is an important ecological character of lakes in monsoon climate zone.It is the key driver to seasonal change of the wetlands and associated habitats,which provide vital inhabiting condition...Water level fluctuation of is an important ecological character of lakes in monsoon climate zone.It is the key driver to seasonal change of the wetlands and associated habitats,which provide vital inhabiting conditions for different species in summer and winter,or,wet season and dry season.Due the hydrologic regime changes in the recent years after the operation of Three Gorges Dam,in 2012,the government of Hunan province proposed Chenglingji Hydraulic Project,aiming at water level control in dry season at Chenglingji,where the outlet of Dongting Lake located.Through different operations on water retreat process,five scenarios on the water level control from 21 m to 24 m were set in the plan.The potential ecological impacts of the project are under enormous public concern.To analyze potential impacts from different scenarios of water level control on the wetlands,this paper studied the topography of Dongting Lake bed and wetlands in dry season,by using Digital Elevation Model（DEM）and 15 images from HJ satellite and 1 image from Landsat TM.The wetlands at water levels of 19 m to 27 m were analyzed.The study revealed that there were 4 terrain steps on Dongting Lake bed from the West Dongting Lake to East Dongting Lake.Water level control at Chenglingji would increase area of open water in East Dongting Lake and Hengling Lake areas,while its effect on South Dongting Lake and West Dongting Lake areas due to higher terrain was weaker.Particularly,the area percentages of South Dongting Lake area did not change with water level fluctuation,due to its 2 elevation steps.The area percentages of various types of the wetlands in Dongting Lake area during the processes of water level rising and retreating were quite different,even in the relatively close water level interval.The retreating area of open water in autumn was larger than that during the spring flooding.The 23 m was the key water level,a turning point of the area change of the wetlands in Dongting Lake area.Areas of open water,mudflat,meadows and their percentages changed significantly at water levels above 23 meters,with increasing of open water area and shrinking of meadow area,their areas would decrease 30 000 ha.As the key habitats for wintering geese,the area of meadows was from near 70 000 ha to 10 000 ha.Among 5 scenarios,the impact of the scenario at 21 m elevation on wetlands was the weakest.However,water level dropping was still postponed than that of natural hydrological process in the scenarios.It resulted in longer inundation of large area of lakebed at elevation of 22-23 m,increasing habitats for aquatic biodiversity but reducing area of the meadows,where is the key habitat for wintering geese.All the other water level control scenarios would cause large area of inundation of lakebed in dry season and dramatic change of wetlands.To maintain the natural wetlands in Dongting Lake area,the Chenglingji Hydraulic Project should be considered in a more cautious way and further researches were needed on the response of aquatic biodiversity and wintering water birds.展开更多
Identifying the spatiotemporal dynamics of the water body in Dongting Lake,the second largest freshwater lake in China,is crucial for water resource management.In this study,the variations of the water body were compr...Identifying the spatiotemporal dynamics of the water body in Dongting Lake,the second largest freshwater lake in China,is crucial for water resource management.In this study,the variations of the water body were comprehensively analyzed based on remote sensing images and in situ measurements from 2000 to 2019.Four breakpoint detection approaches were integrated to analyze the change trends and explore the related driving forces behind the changes.The results showed that significant intra-and inter-annual fluctuations of the water body were found from 2000 to 2019.The water area and volume decreased at rates of 1.26 km^(2)/a and 16.65×10^(6)m^(3)/a,respectively.During the entire study period,the outflow at Chenglingji station(CLJ),the inflow from three outlets of the Yangtze River(Inflow2),and the inundation conditions during the last period(Arealag)made the largest relative contributions to the water area variation(around 25%,27%and 24%,respectively).A breakpoint was detected around 2004,corresponding to the operation period of the Three Gorges Dam(TGD).The regulation of TGD profoundly affected the hydrological characteristics at the three outlets and CLJ,and may have indirectly caused the water area to expand by 2.41 km^(2)/a during the dry seasons between 2004 and 2019.These results provide valuable insight into how natural and anthropogenic factors affect water body variation and may offer a practical reference for the local government to adjust management strategies.展开更多
基金funded by the National Natural Science Foundation of China(Grant No.72174211)the Natural Science Foundation of Hunan Province(Grant No.2023JJ30693)。
文摘In the face of global warming and increasing impervious surfaces,quantifying the change of climate potential productivity(CPP)is of great significance for the food production planning.Targeting the Dongting Lake Basin,which is a key area for food production in China,this paper uses meteorological data,as well as Climate Change Initiative Land Cover,and Shuttle Radar Topography Mission digital elevation model to investigate the CPP and its changes from 2000 to 2020.The suitability of land for cultivation(SLC),and the land use/land cover change(LUCC)are also considered.The results showed that the CPP varied from 9,825 to 20,895 kg ha^(-1).Even though the newly added impervious surfaces indirectly resulted in the decrease of CPP by of 9.81×10~8 kg,overall,the CPP increased at an average rate of 83.7 kg ha^(-1)a^(-1).Global warming is the strongest driver behind CPP increase,and CPP has played an important role in the conversions between cultivated land and other land types.The structure of land types tends to be optimized against this challenge.
基金supported by the National Basic Research Program of China(973 Program,Grant No.2012CB417000)
文摘Full operation of the Three Gorges Dam(TGD) reduces flood risk of the middle and lower parts of the Yangtze River Basin. However,Dongting Lake, which is located in the Yangtze River Basin, is still at high risk for potentially severe flooding in the future. The effects of the TGD on flood processes were investigated using a hydrodynamic model. The 1998 and 2010 flood events before and after the operation of the TGD, respectively, were analyzed. The numerical results show that the operation of the TGD changes flood processes, including the timing and magnitude of flood peaks in Dongting Lake. The TGD can effectively reduce the flood level in Dongting Lake, which is mainly caused by the flood water from the upper reach of the Yangtze River. This is not the case, however, for floods mainly induced by flood water from four main rivers in the catchment. In view of this, a comprehensive strategy for flood management in Dongting Lake is required. Non-engineering measures, such as warning systems and combined operation of the TGD and other reservoirs in the catchment, as well as traditional engineering measures, should be further improved. Meanwhile, a sustainable philosophy for flood control, including natural flood management and lake restoration, is recommended to reduce the flood risk.
基金Supported by the National Key Research and Development Program of China(No.2016YFC0402005)the Three Gorges Project EcoEnvironmental Monitoring System(No.JJ [2017]-011)+1 种基金the National Natural Science Foundation of China(No.NSFC31400359)the China Three Gorges Corporation(No.0704097)
文摘Floodplains are important and distinctive ecosystems around the world,and the recruitment of ichthyoplankton from river to floodplain lakes is crucial to maintain this unique ecosystem.However,this process has not been well documented.In this study,ichthyoplankton were sampled to investigate the details of ichthyoplankton recruitment from the Changjiang(Yangtze)River to the Dongting Lake via a floodway channel,the Songzi River,from May to July in 2013 and 2014.During the study period,41 species of eggs and larvae were sampled.Among the samples,16 were river-lake migratory species(RL),representing 23.5%of the species in the Dongting Lake.In 2013,an estimated 130 million eggs and 3180 million larvae drifted through the sampling section,and in 2014,an estimated 1 060 million eggs and 1040 million larvae drifted through the sampling section.The amount of eggs and larvae of RL reached 3 210 million in 2013 and 1 850 million in 2014,respectively.These results demonstrated the importance of ichthyoplankton recruitment from the river to the lake,as species diversity will decrease sharply without this recruitment.Canonical correspondence analysis(CCA)showed that water temperature and water flow are the two most important factors influencing the spawning activities of fish.To maintain the high fish diversity in the Changjiang floodplain,we suggest to irrigate the channel to increase water discharge and increase the transport of ichthyoplankton from the Changjiang mainstream into the Dongting Lake.
基金Supported by International Science&Technology Cooperation Program of China(2012DFB30030)Special Program of national forestry Public Welfare Industry(201104065)+2 种基金Natural Science Foundation of Hunan Province(11JJ5021)Science and Technology Plan Project of Hunan Provincial Department of Science and Technology(2013FJ42082012WK4010)
文摘From nitrogen and phosphorus,chemical oxygen demand,phytoplankton,and eutrophication,this article analyzes the current situation of water quality in the Dongting Lake area,and discusses the factors influencing the water quality of Dongting Lake. Based on the actual production,geographic characteristics and outstanding problem of grim water pollution situation in the Dongting Lake area,some specific proposed measures are put forward in order to provide the basis and reference for the future pollution control in the Dongting Lake area,such as strengthening the industrial pollution control,developing ecological agriculture,and enhancing ecological restoration and water quality early warning.
基金Under the auspices of the project of Chinese Academy of Sciences No. KZCX2-31+1 种基金 The World Wide Fund of Nature No. CN008802-YZ04-1
文摘The sediments of the Dongting Lake come from four channels (one of them was closed in 1959), connected with the Yangtze River, four tributaries (Lishui, Yuanjiang, Zishui and Xiangjiang) and local area, and some of them are transported into the Yangtze River in Chenglingji, which is located at the exit of the Dongting Lake, some of them deposit into drainage system in the lake region and the rest deposit into the lake. The annual mean sediment is 166,555x104 t, of which 80% come from the four channels, 18% from the four tributaries and 2% from local area, whereas 26% of the total sediments are transported into the Yangtze River and 74% deposited into the lake and the lake drainage system. Based on topographic maps of 1974, 1988 and 1998, and the spatial analysis method with geographic information system (GIS), changes in sediment deposition and erosion are studied in this paper. By overlay analysis of 1974 and 1988, 1988 and 1998, erosion and sediments deposition areas are defined. The main conclusions are: (1) sediment rate in the lake is larger than erosion rate from 1974 to 1998. The mean deposition in the lake is 0.43 m; (2) annual sediment deposition is the same between 1974-1988 and 1988-1998, but the annual volume of deposition and erosion of 1988-1998 is bigger than that in 1974-1988; (3) before the completion of the Three Gorges Reservoir, there will be 7.82x108 m3 of sediments deposited in the lake, which would make the lake silted up by 0.33 m; (4) in the lake, the deposition area is found in the north of the east Dongting Lake, the south-west of the south Dongting Lake, and the east of the west Dongting Lake; while the eroded area is in the south of the east Dongting Lake, the middle of the south Dongting Lake, the west of the west Dongting Lake, as well as Xiangjiang and Lishui river flood channels.
基金supported by the National Natural Science Foundation of China(Grants No.51779074 and 41371052)the Special Fund for the Public Welfare Industry of the Ministry of Water Resources of China(Grant No.201501059)+3 种基金the National Key Research and Development Program of China(Grant No.2017YFC0404304)the Jiangsu Water Conservancy Science and Technology Project(Grant No.2017027)the Program for Outstanding Young Talents in Colleges and Universities of Anhui Province(Grant No.gxyq2018143)the Natural Science Foundation of Wanjiang University of Technology(Grant No.WG18030)
文摘This study developed a hierarchical Bayesian(HB)model for local and regional flood frequency analysis in the Dongting Lake Basin,in China.The annual maximum daily flows from 15 streamflow-gauged sites in the study area were analyzed with the HB model.The generalized extreme value(GEV)distribution was selected as the extreme flood distribution,and the GEV distribution location and scale parameters were spatially modeled through a regression approach with the drainage area as a covariate.The Markov chain Monte Carlo(MCMC)method with Gibbs sampling was employed to calculate the posterior distribution in the HB model.The results showed that the proposed HB model provided satisfactory Bayesian credible intervals for flood quantiles,while the traditional delta method could not provide reliable uncertainty estimations for large flood quantiles,due to the fact that the lower confidence bounds tended to decrease as the return periods increased.Furthermore,the HB model for regional analysis allowed for a reduction in the value of some restrictive assumptions in the traditional index flood method,such as the homogeneity region assumption and the scale invariance assumption.The HB model can also provide an uncertainty band of flood quantile prediction at a poorly gauged or ungauged site,but the index flood method with L-moments does not demonstrate this uncertainty directly.Therefore,the HB model is an effective method of implementing the flexible local and regional frequency analysis scheme,and of quantifying the associated predictive uncertainty.
基金Supported by National Key Research and Development Program(2016YFD0600402)Key Research and Development Program of Hunan Province(2016NK2160)Forestry Science and Technology Program of Hunan Province(XLK201657)
文摘In order to ascertain the soil carbon flux characteristics of poplar plantations and crop communities in the Dongting Lake area during the growing season and their correlation with hydrothermal conditions,soil respiration rate was monitored at fixed sites and time points with an LI-8100 A automated soil flux system.Meanwhile,the surface temperature and soil temperature and humidity were measured. The soil respiration variation in the two different vegetation types and its correlation with environmental factors were analyzed. The results showed that in the growing season,the diurnal variation curves of soil respiration rate in the two different vegetation types showed a single peak variation,but there was certain difference in the appearance time of the peak. The peak of the crop appeared around11: 00 am,while the peak of soil respiration in the poplar appeared around 13: 00. The soil respiration rate of the poplar was also significantly higher than that of the crop,and the average difference of soil respiration rate between the two was 3. 09 and 3. 55 μmol/( m^2·s) in April and August,respectively. Temperature and soil moisture were the main factors affecting soil respiration of the poplar plantation and crop community. Temperature had a greater effect on the soil respiration of the crop community,and soil humidity had a greater impact on soil respiration in the poplar plantation,showing a correlation coefficient reaching 0. 952.
文摘The Dongting Lake Estuary is migration pathways for some river-lake migratory and semi-migratory fishes. In the present study, an annual survey of fish was conducted from January to November 2018 covering a total of 6 sites in Dongting Lake Estuary. A total of 57 freshwater species and subspecies belonging to 5 orders and 10 families were recorded. The catches at the Dongting Lake Estuary were mainly composed of Lake settled fish. The biomass of Cyprinus (Cyprinus) carpio Linnaeus was the highest, accounting for 25.53% of the total catches, followed by Hypophthalmichthys molitrixs, Culter alburnus Basilewsky and Ctenopharyngodon idellus, accounting for 10.41%, 8.99% and 7.10% of the total catches, respectively. The four major domestic carps accounted for 26.13% of the total catch. The range of richness of species varied between 40 and 51 species. The trend was fewer species in spring, with the arrival of summer and autumn gradually increasing, peaking at the turn of summer and autumn, and then gradually decreasing with the arrival of winter, to the lowest in spring. The Shannon, Simpson, Pielou and Margalef indices showed the consistent trends with richness of species.
文摘On the basis of water-balance equation in Dongting Lake and Xiang Zi Yuan-Li River drainage areas, a possib1e flood height relating to the rainfall precipitation in these areas has been inferred. According to the flood simulation, some synthetic maintenance strategies to prevent future catastrophic f1oods in Dongting Lake drainage area have been also presented.
文摘There is a close relationship between occurrence of nonmetallic minerals and tectonic evolution of geosyncline, platform and diwa (geodepression) on the western margin of the Dongting diwa. Some results that (1) diwa tectonics is berfeficial for formation and preservation of nonmetallic minerals and (2) volcano-sedimentary altered ore deposits, saline deposits and organo-sedimentary ore deposits can be often found in diwa basins are gained.
基金Supported by Special Item of the Climate Change,China Meteorological Administration(CCSF201205)Key Item of the Hunan Meteorological Bureau(201202)
文摘[Objective] The research aimed to study influences of the weather and climate on wintering migratory bird in Dongting Lake. [Method] Bird analysis data provided by East Dongting Lake National Nature Reserve and wintering migratory bird monitoring data in big and small west lakes in recent 5 years were used. By combing water level data and various meteorological factors in Chenglingji, wintering migratory bird in Dongting Lake was analyzed. [Result] Abnormal precipitation led to drought or flood in Dongting Lake, causing significant adverse effect on the birds. Abnormal climate was important reason for that wintering migratory bird greatly reduced, such as high temperature and later going south of the strong cold air. Extreme weather and climate events led that some birds in Dongting Lake significantly reduced. Meteorological element had certain influence to bird survey. We should select a reasonable investigation time based on weather and climate. In Birding Festival, weather had little effect on bird species observation. In the migratory season of bird, we could see many birds in fine cold weather after a strong cold air, which suitable for observing bird. When it was low temperature or less rain in autumn, and was high temperature or more rain and sunshine in early winter, it was suitable for migratory birds wintering in Dongting Lake. Ardea cinerea, Anser fabalis and Anser erythropus were more in sunny days while Phalacrocorax carbo was more in rainy weather. Grus grus was more in heavy wind weather while Recurvirostra avosetta was more in small wind weather. [Conclusion] The research provided scientific basis for studying migratory bird in east Dongting Lake.
基金supported by National Natural Science Foundation of China(No.42077176,No.41976057)Natural Science Foundation of Shanghai(No.20ZR1459700).
文摘Wetland is a transition zone between terrestrial and aquatic ecosystems,and is the source and sink of various biogenic elements in the earth’s epipelagic zone.In order to investigate the driving force and coupling mechanism of carbon(C),nitrogen(N)and phosphorus(P)migration in the critical zone of lake wetland,this paper studies the natural wetland of Dongting Lake area,through measuring and analysing the C,N and P contents in the wetland soil and groundwater.Methods of Pearson correlation,non-linear regression and machine learning were employed to analyse the influencing factors,and to explore the coupling patterns of the C,N and P in both soils and groundwater,with data derived from soil and water samples collected from the wetland critical zone.The results show that the mean values of organic carbon(TOC),total nitrogen(TN)and total phosphorus(TP)in groundwater are 1.59 mg/L,4.19 mg/L and 0.5 mg/L,respectively,while the mean values of C,N and P in the soils are 18.05 g/kg,0.86 g/kg and 0.52 g/kg.The results also show that the TOC,TN and TP in the groundwater are driven by a variety of environmental factors.However,the concentrations of C,N and P in the soils are mainly related to vegetation abundance and species which influence each other.In addition,the fitted curves of wetland soil C-N and C-P appear to follow the power function and S-shaped curve,respectively.In order to establish a multivariate regression model,the soil N and P contents were used as the input parameters and the soil C content used as the output one.By comparing the prediction effects of machine learning and nonlinear regression modelling,the results show that coupled relationship equation for the C,N and P contents is highly reliable.Future modelling of the coupled soil and groundwater elemental cycles needs to consider the complexity of hydrogeological conditions and to explore the quantitative relationships among the influencing factors and chemical constituents.
基金Sponsored by National Natural Science Foundation of China(51278070)Open Fund of National Key Laboratory of Subtropical Architectural Science,South China University of Technology(2016ZB14):Climate Adaptability Spatial Design and Strategy Research of Subtropical Architecture
文摘Architectural design of Dongting Lake Museum takes "River dolphin ripples in the Dongting Lake" as the theme, tries to integrate into the local wetland environment and ecological resources of the Dongting Lake, in order to realize the dream of "making a great museum for the most gorgeous lake". The overall layout follows the concept of "coexistence of real and virtual, integration of exterior and interior", and the architectural image symbolizes "the river dolphin ripples", which is extremely harmonious in the whole natural environment. The design integrates planning, building, landscape and interior spaces, adopts technical means and ecological green to integrate the building into the environment, and presents us a tremendous ecological wetland museum that floats on the lake like a fish, an islet, a sail or a hill.
基金Supported by National Social Science Fund Project(11BJY029)Hunan Provincial Conditions and Decision-making Advisory Research Project(2012BZZ16)Arts Tender Project of Central South University of Forestry and Technology(2011ZB003)
文摘To analyze the efficiency of the agro-ecosystem of Dongting Rim in Hunan Province,this paper adopted the emergy theory to study the agricultural output of this region during 2001 to 2010.The results showed that the value of regional agricultural emergy output increased by44.68%to(6.50 E)sej,but lower than the growth of non-agricultural industry output.Compared with 2001,the emergy output of planting industry was(4.10E)sej in 2010 which occupied 63.09%of the total agricultural emergy output and got an increase of 2.93 percentage points,while the emergy output of stock farming got a decrease of 2.87 percentage points.The growth of fishery emergy output was not in conformity with the characteristics of Dongting Rim in Hunan.From the contrast between emergy output and economic output,we could find that the economic return ratio of planting industry and fishery industry were lower than those of forestry industry and stock farming industry,which indicated that it is necessary to improve the economic benefits of planting industry and fishery industry which were the traditional industries with advantages of the Dongting Rim in Hunan.
基金Sponsored by the Philosophical and Social Science Research Project in Colleges and Universities of Jiangsu Province(2010SJB760012)
文摘Confucian ethics, idea and behavior criterion were embodied in "everything" of life, especially in the building as an important tool for moralizing. Taking a case study on vernacular houses of Dongting East Mountain and West Mountain, this paper reveals the "moderate", "etiquette" and "benevolence" as moral contents in the building's layout, form, space, decoration and so on. The moralizing reflects a subtle way of guidance, as well as diversified and systematic characteristics. Vernacular houses deeply mingled with daily life, had unique influence as physical environment, thus realizing the implementation and manifestation of Confucian moralizing ideas that have been converted to folk customs. In sum, the Confucian moralizing function carried by vernacular houses is the product of institutions and rules, and it is also the manifestation of conscious inheritance of cultural identity.
基金supported by the National Natural Science Foundation of China(grant numbers 42071393,U1901219 and U21A2022).
文摘Wetlands provide vital ecological services for both humans and environment,necessitating continuous,refined and up-to-date mapping of wetlands for conservation and management.in this study,we developed an automated and refined wetland mapping framework integrating training sample migration method,supervised machine learning and knowledge-driven rules using Google Earth Engine(GEE)platform and open-source geospatial tools.We applied the framework to temporally dense Sentinel-1/2 imagery to produce annual refined wetland maps of the Dongting Lake Wetland(DLW)during 2015-2021.First,the continuous change detection(CCD)algorithm was utilized to migrate stable training samples.Then,annual 10 m preliminary land cover maps with 9 classes were produced using random forest algorithm and migrated samples.Ultimately,annual 10 m refined wetland maps were generated based on preliminary land cover maps via knowledge-driven rules from geometric features and available water-related inventories,with Overall Accuracy(OA)ranging from 81.82%(2015)to 93.84%(2020)and Kappa Coefficient(KC)between 0.73(2015)and 0.91(2020),demonstrating satisfactory performance and substantial potential for accurate,timely and type-refined wetland mapping.Our methodological framework allows rapid and accurate monitoring of wetland dynamics and could provide valuable information and methodological support for monitoring,conservation and sustainable development of wetland ecosystem.
基金jointly supported by the National Natural Science Foundation of China (Nos. 51622901 , 51709225 )the Young Scientific Research Innovation Team Project of Xi'an University of Technology (No. 104/256051715 )。
文摘Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.
基金The National Natural Science Foundation of China(30870402,31170396,51009129)Hunan Natural Science Foundation(14JJ2136)the Chinese Academy of Sciences(KSCX-EW-N-05)provided financial support for this study.
文摘Although the Three Gorges Project(TGP)may have affected the population structure and distribution of plant and animal communities,few studies have analyzed the effect of this project on small mammal communities.Therefore,the present paper compares the small mammal communities inhabiting the beaches of Dongting Lake using field investigations spanning a 20-year period,both before and after the TGP was implemented.Snap traps were used throughout the census.The results indicate that the TGP caused major changes to the structure of the small mammal community at a lake downstream of the dam.First,species abundance on the beaches increased after the project commenced.The striped field mouse(Apodemus agrarius)and the Norway rat(Rattus norvegicus),which rarely inhabited the beach before the TGP,became abundant(with marked population growth)once water was impounded by the Three Gorges Reservoir.Second,dominant species concentration indices exhibited a stepwise decline,indicating that the community structure changed from a single dominant species to a more diverse species mix after TGP implementation.Third,the regulation of water discharge release by the TGP might have caused an increase in the species diversity of the animal community on the beaches.A significant difference in diversity indices was obtained before and after the TGP operation.Similarity indices also indicate a gradual increase in species numbers.Hence,a long-term project should be established to monitor the population fluctuations of the Yangtze vole(Microtus fortis),the striped field mouse and the Norway rat to safeguard against population outbreaks(similar to the Yangtze vole outbreak in 2007),which could cause crop damage to adjacent farmland,in addition to documenting the succession process of the small mammal community inhabiting the beaches of Dongting Lake.
基金Under the auspices of National Key R&D Program of China(2017YFC0405300)
文摘Water level fluctuation of is an important ecological character of lakes in monsoon climate zone.It is the key driver to seasonal change of the wetlands and associated habitats,which provide vital inhabiting conditions for different species in summer and winter,or,wet season and dry season.Due the hydrologic regime changes in the recent years after the operation of Three Gorges Dam,in 2012,the government of Hunan province proposed Chenglingji Hydraulic Project,aiming at water level control in dry season at Chenglingji,where the outlet of Dongting Lake located.Through different operations on water retreat process,five scenarios on the water level control from 21 m to 24 m were set in the plan.The potential ecological impacts of the project are under enormous public concern.To analyze potential impacts from different scenarios of water level control on the wetlands,this paper studied the topography of Dongting Lake bed and wetlands in dry season,by using Digital Elevation Model（DEM）and 15 images from HJ satellite and 1 image from Landsat TM.The wetlands at water levels of 19 m to 27 m were analyzed.The study revealed that there were 4 terrain steps on Dongting Lake bed from the West Dongting Lake to East Dongting Lake.Water level control at Chenglingji would increase area of open water in East Dongting Lake and Hengling Lake areas,while its effect on South Dongting Lake and West Dongting Lake areas due to higher terrain was weaker.Particularly,the area percentages of South Dongting Lake area did not change with water level fluctuation,due to its 2 elevation steps.The area percentages of various types of the wetlands in Dongting Lake area during the processes of water level rising and retreating were quite different,even in the relatively close water level interval.The retreating area of open water in autumn was larger than that during the spring flooding.The 23 m was the key water level,a turning point of the area change of the wetlands in Dongting Lake area.Areas of open water,mudflat,meadows and their percentages changed significantly at water levels above 23 meters,with increasing of open water area and shrinking of meadow area,their areas would decrease 30 000 ha.As the key habitats for wintering geese,the area of meadows was from near 70 000 ha to 10 000 ha.Among 5 scenarios,the impact of the scenario at 21 m elevation on wetlands was the weakest.However,water level dropping was still postponed than that of natural hydrological process in the scenarios.It resulted in longer inundation of large area of lakebed at elevation of 22-23 m,increasing habitats for aquatic biodiversity but reducing area of the meadows,where is the key habitat for wintering geese.All the other water level control scenarios would cause large area of inundation of lakebed in dry season and dramatic change of wetlands.To maintain the natural wetlands in Dongting Lake area,the Chenglingji Hydraulic Project should be considered in a more cautious way and further researches were needed on the response of aquatic biodiversity and wintering water birds.
基金funded by the National Natural Science Foundation of China(grant numbers 41975044,41801021,41871019,41672355).
文摘Identifying the spatiotemporal dynamics of the water body in Dongting Lake,the second largest freshwater lake in China,is crucial for water resource management.In this study,the variations of the water body were comprehensively analyzed based on remote sensing images and in situ measurements from 2000 to 2019.Four breakpoint detection approaches were integrated to analyze the change trends and explore the related driving forces behind the changes.The results showed that significant intra-and inter-annual fluctuations of the water body were found from 2000 to 2019.The water area and volume decreased at rates of 1.26 km^(2)/a and 16.65×10^(6)m^(3)/a,respectively.During the entire study period,the outflow at Chenglingji station(CLJ),the inflow from three outlets of the Yangtze River(Inflow2),and the inundation conditions during the last period(Arealag)made the largest relative contributions to the water area variation(around 25%,27%and 24%,respectively).A breakpoint was detected around 2004,corresponding to the operation period of the Three Gorges Dam(TGD).The regulation of TGD profoundly affected the hydrological characteristics at the three outlets and CLJ,and may have indirectly caused the water area to expand by 2.41 km^(2)/a during the dry seasons between 2004 and 2019.These results provide valuable insight into how natural and anthropogenic factors affect water body variation and may offer a practical reference for the local government to adjust management strategies.
