Climate Evolution Recorded by Organic Carbon Stable I sotope since 5 kaB.P.in Poyang Lake Area, China

Based on the data of organic carbon stable isotope ratios and magnet ic susceptibility, climate evolution in the past 5 kaB.P. in Poyang Lake plain (in Jiangxi Province) has been reconstructed. The results of the research indicate that the climate evolution can be divided into nine stages in the past 5 kaB.P.. Comparisons of different regional environmental records suggest that the intens ity and the temporal spatial changes of monsoon in China mainly controlled the climate evolution.

Analysis on Change of the Vegetation Cover in Poyang Lake Area from 1991 to 2005

[Objective] The reseamh aimed to analyze variation of the vegetation cover in Poyang Lake area from 1991 to 2005. [Method] Based on Landsat TM remote sensing images of 1991 and 2005 in Poyang Lake area, NDVI dimidiate pixel model was used to calculate vegetation cover- age. By transfer matrix, temporal-spatial change of the vegetation cover grade in the area was analyzed. [ Result] Vegetation cover in this region overall presented increase trend from 1991 to 2005, and forestry area increased somewhat. But at the same time, farmland area decreased to some extent. Sandlot and bare land also increased slightly. [ Conclusion] Governments and relevant departments should reasonably allocate land re- sources and protect natural ecology environment.

Emergy Analysis of Agro-ecosystem in Poyang Lake Area

By using emergy analysis theory and methods, we conduct quantitative analysis on the input and output of emergy, and sustainable development of agro-ecological system in Poyang Lake Area. The results show that compared with the national average, the environmental loading ratio is relatively low in this area; the net emergy yield rate is high; the sustainable development ability is strong. Finally according to the results of emergy analysis, corresponding countermeasures are put forward as follows: develop agriculture based on the existing rich natural resources; increase technological inputs; develop circular agriculture; promote sustainable agricultural development.

Development of Ecological Fishery in Poyang Lake Area

Through in-depth analysis on history and current situations of fishery development in Poyang Lake area,this paper presents location,resource and environment advantages in development of ecological fishery.According to orientation of leading functions,Poyang Lake can be divided into breeding development,capture operation,enhancement protection and ecological rehabilitation functional zones.In accordance with industrial foundation and ecological advantages of cities and counties in Poyang Lake,it determines the reasonable distribution of 8 leading industries:river crabs,shrimps(Procambarus clarkia),eels,Pengze crucian carp,Siniperca chuatsi,Channa argus,Ietalurus Punetaus,and pearl.On the basis of systematically summing up exploration experience,it comes up with the development path"ecology oriented fishery and industrialization oriented ecological fishery"for ecological fishery in Poyang Lake area.It proposes a series of key technological measures,including reducing fertilizer and drugs,increasing output and benefits,low consumption and emission,high quality and safety,and standardization,to realize a benign cycle of"cost saving,benefit increasing,quality improving and low carbon"and the multi-win objective of coordination between ecology,economy and society.

Ecological Footprint and Endogenous Economic Growth in the Poyang Lake Area in China Based on Empirical Analysis of Panel Data Model

In this paper, ecological footprint methods were used to calculate the ecological footprint of six cities （Nanchang, Jingdezhen, Jiujiang, Xinyu, Yingtan and Fuzhou） in the Poyang Lake Area, Jiangxi, China from 1991 to 2010. Ecological footprint was the input factor for ecological resources and the contribution of this and other factors such as labor and capital to economic growth were analyzed. The results showed that, from 1991 to 2010, ecological footprints in the six cities increased year by year. The amount of land for fossil energy, under cultivation and grassland influenced total ecological footprint in each city. The contribution of ecological resources, labor factors and capital factors to economic growth showed regional differences. Nanchang, Jiujiang, Xinyu, and Yingtan are capital-orientated and capital factor had a great influence on the economic growth rates, whereas, Jingdezhen and Fuzhou were labor-orientated. The contribution of ecological resources to economic growth in the six cities was the lowest of all three factors, meaning that efficiency of ecological resource utilization is low. Total productivity plays a key role in economic development; however, the overall level of total factor productivity for the six cities was low and indicates that the technological content of Poyang Lake Area’s economic growth is low and the utilization of input factors extensive. In summary, we suggest changing the mode of economic growth and developing tertiary industry in the region.

Spatial Behavior Characteristics of Land Use based on Fractal Theory:Taking Poyang Lake Area as an Example

Landscape morphology can reflect the spatial behavior of land use.Using the Poyang Lake area as an example,the landscape pattern characteristics in 1995,2000,2015,and 2018 are determined by calculating the fractal dimension,fractal stability,patch density,patch shape fragmentation,and landscape isolation,and fractal theory is used to analyze the spatial behavior of land use.The results show that building land was the land use type which consistently had the highest fractal dimension,but the fractal dimension of building land shows a downward trend,indicating that the spatial form of building land gradually developed in an orderly direction under the action of land use spatial behavior.Paddy,dryland,and forested land were the land use types which always had the lowest fractal dimension,and they are in unstable states.The calculation results of patch density,patch shape fragmentation index,and landscape isolation index supported the conclusions of the fractal analysis.One recommendation for realizing the rational layout of the land is to reduce the fractal dimension of building land through scientific and reasonable planning and to guide the orderly development of building land.For natural landscapes such as forested land,shrub forest land,high-coverage grassland,and water area,their fractal dimensions should be increased to reduce human interference and maintain their stability.Finally,the results of this study suggest that the fractal dimension should be introduced into the National Spatial Planning,and used as an index for evaluating the rationality of the regional land use pattern.

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

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

Research on the Development of Leisure Agriculture Tourism in the Area around Poyang Lake

Leisure agriculture tourism is the combination of agriculture and tourism,which is an important part of the new rural construction.The area around Poyang Lake is rich in flora and fauna,landscape,agricultural and fishing products,folk and other natural and cultural resources,so it has good infrastructure of leisure agriculture tourism.Under the background of the formal approval of "Planning of eco-economical region in the area of Poyang Lake in Jiangxi Province" by the State Council,which aims to escalate the constructing of Poyang Lake from eco-economical region to national strategic policy,leisure agriculture tourism in the area around Poyang Lake has broad development prospects.This paper discussed the advantages,and disadvantages of the development and management of leisure agriculture tourism in the area around Poyang Lake,and also put forward some suggestions and countermeasures.

Rapid Extraction of Water Area in Poyang Lake Based on Sentinel-1 Satellite Images

Based on the images taken by Sentinel-1A before and after rainstorm in Poyang Lake in June 2017,the expansion range of water area in the lake area was extracted quickly and effectively using the threshold method and vector superposition method.It is proved that the method is simple and feasible,which can provide reference for the research and utilization of Sentinel-1 satellite data in the assessment of flood disaster.

近40年鄱阳湖区“三生空间”格局转型与空间异质机制

洞察快速城市化进程下三生空间的转型规律和空间异质驱动机制,是湖域地区生产生活方式“绿色化”转变和国土空间规划高质量发展的重要基础,对于地区国土资源优化配置和生态系统韧性建设具有重要意义。以鄱阳湖区为研究对象,基于1980—2020年土地覆被遥感影像数据,从“空间结构-分布格局-空间功能”演变视角分析鄱阳湖区三生空间格局转型规律,并定量识别环湖区、近湖区和远湖区格局转型的空间异质机制。结果表明:(1)近40年鄱阳湖区三生空间格局转型具有显著的空间动态异质性,生产空间持续聚焦于湖滨及河流沿岸平原区,生活空间向各城市建成区蔓延集聚,生态空间存续于湖域及边缘山区丘陵地带。县域尺度格局转型同样呈显著的差异化演进格局,其中生态空间的收缩趋势呈现出由环湖向远湖逐渐衰减的态势;(2)尽管以生态空间为主导的结构基本面未改变,但生态空间在生产和生活空间侵占下持续减损,突出表现为大规模水域和林地生态空间被农业生产、工矿和城镇建设空间侵占;(3)功能指数转型中持续呈现出由环湖区向远湖区的梯度变化过程,证实了三生空间功能转型“湖泊效应”现象的存在;(4)城市化和工业化是环湖区和近湖区三生空间格局转型的关键驱动因子,而城市化和农业现代化主导了远湖区的三生空间格局转型,而城市人口集聚、经济增长、产业经济规模增长和农机使用水平等二级细分因素通过不同情景组合塑造了鄱阳湖区不同地域差异化的三生空间格局转型机制。研究结果为认识湖域地区独特的国土空间演进规律和因地而异的演化机制提供了新的视角,也为构建面向现代化的国土空间规划体系和“生产-生活-生态”协同的生态文明新格局提供了新的见解。

鄱阳湖地区级配不良偏细砂砾石料力学特性

基于大型三轴试验数据,研究了级配和相对密度D_(r)对鄱阳湖地区级配不良偏细砂砾石料强度和变形特性的影响。结果表明:随着小于5 mm粒径颗粒质量分数的增加,砂砾石料压实性能降低;随着大于5 mm粒径颗粒质量分数P_(5)和D_(r)的增大,强度指标、初始切线弹性模量与体积模量增大;本文研究范围内,随P_(5)和D_(r)的增大,强度指标c、φ、φ_(0)、Δφ线性增大,且P^(5)和D_(r)对强度指标的作用效应几乎不存在相互影响;随P 5和D_(r)的增大,邓肯E-B模型参数K、K_(b)增大,且P_(5)越高D_(r)对K、K_(b)的影响越显著,D_(r)越大时P_(5)对K、K_(b)的影响越强烈,存在相互影响效应;提出了考虑级配与D_(r)双重影响的强度指标和变形参数经验计算公式,该公式能高精度预测鄱阳湖地区级配不良偏细砂砾石覆盖层料的力学指标。

基于最佳景观尺度的鄱阳湖区土地利用冲突时空演变及多情景模拟

[目的]科学评估区域土地利用冲突水平的时空演化特征,可为区域土地资源的合理配置发挥重要作用。[方法]基于景观生态风险视角构建土地利用冲突测算模型,借鉴最佳景观尺度设定方法确定了适宜的分析尺度,分析了鄱阳湖区1990—2020年土地利用冲突的时空演变特征,并借助PLUS模型多情景模拟了2035年土地利用冲突空间格局。[结果]鄱阳湖区土地利用冲突的总体空间格局是滨湖区显著高于外围地区,南部地区总体高于北部地区,平原地区高于山地和丘陵地区,河流两侧的冲突值也显著偏高。1990—2005年城镇地区的冲突变化并不显著,乡村地域及县域交界区域冲突水平较高,2005—2020年冲突水平进一步加剧;2035年不同情景下冲突的总体空间格局将延续2020年的状态,但可持续发展情景能有效缓和冲突水平,实现生态保护和经济发展的平衡发展。[结论]1990—2020年鄱阳湖区土地利用冲突重心由乡村及县域交界区域向城镇地区转移,且冲突水平呈不断上升趋势,未来应坚持可持续发展方式,有序进行国土空间开发,注重生态保护和经济发展间的平衡。

鄱阳湖双退区受损湿地土壤氮素空间分布特征及影响因素

【目的】土壤氮素是湿地营养水平的重要指标,研究鄱阳湖双退区受损湿地土壤氮素空间分布特征及其影响因素,为开展鄱阳湖受损湿地植被生态恢复与重建提供科学依据。【方法】在鄱阳湖退田还湖区中的双退区选择位于江西省都昌县多宝乡的马影湖湿地4类受损湿地土壤,分别为沼泽土、草甸土、草甸沼泽土和次生草甸沼泽土,研究0~20 cm(表层土)、20~40 cm(中层土)和40~60 cm(深层土)3个土壤剖面的全氮(TN)、硝态氮(NO_(3)^(-)-N)和氨态氮(NH_(4)^(+)-N)的空间分布特征,利用聚类推进树算法量化环境因子对氮素的相对贡献,利用Pearson相关性分析氮素与环境因子的关系、利用结构方程模型分析了环境因子对氮素的影响路径。【结果】除沼泽土NH_(4)^(+)-N以中层土最高及次生草甸沼泽土土壤TN、NO_(3)^(-)-N、NH_(4)^(+)-N分别以中层土和深层土最高外,其余土壤类型皆以表层(0~20 cm)土壤氮素含量最高,分别为TN(0.35±0.03)g/kg、NH_(4)^(+)-N(4.02±0.38)mg/kg和NO_(3)^(-)-N(4.84±0.53)mg/kg。土层深度、有效磷(AP)对氮素分布和积累具有重要影响,pH通过影响土壤有机碳(SOC)、AP、有效钾(AK)间接影响到氮素,阳离子交换量(CEC)通过影响SOC间接影响到氮素。【结论】与鄱阳湖天然湿地相比,区内4类受损湿地土壤氮素含量均处于极低水平,各氮素最高值多集中在土壤表层,其中TN以草甸土含量最高也最易淋失,其次为草甸沼泽土、次生草甸沼泽土,沼泽土最少且最易被流水冲洗,氮素的积累和分布受土层深度、AP、pH、CEC等影响较大。

鄱阳湖区堤防险情影响因素敏感性

为解决堤防险情的预测预报以及防汛对策的制定问题,基于2020年鄱阳湖区堤防险情数据,结合确定性系数法,定量分析堤防险情影响因素(警戒水位持续天数、堤内外水位差相对值、水位涨落幅度、防洪标准、迎水坡坡比、背水坡坡比)对堤防险情数量的影响规律。结果表明:各影响因素对堤防险情的作用具有非线性特征,不同区间的影响因素对堤防险情的作用存在明显差异,警戒水位持续时间6~10 d、堤内外水位差相对值>0.80、水位涨落幅度>0.63 m、防洪标准10年一遇、迎水坡坡比1:2.0、背水坡坡比1:2.0为各影响因素的显著敏感区间;警戒水位持续时间、堤内外水位差相对值、水位涨落幅度是鄱阳湖区堤防险情的主要控制因素,防洪标准、迎水坡坡比、背水坡坡比对堤防险情具有较低的敏感性。

基于Landsat影像的鄱阳湖面积监测及其与水位关系研究

湖泊是陆地生态系统的一个重要的组成部分,湖泊水域的变化对环境和人类的生产活动都有着重大的影响。鄱阳湖作为中国第一大淡水湖,近年来多次出现洪旱灾害现象,因此对鄱阳湖进行动态监测意义重大。文章以2000—2021年鄱阳湖175期Landsat影像作为数据源,对比分析了归一化差异水体指数(normalized difference water index,NDWI)、改进的归一化差异水体指数(modified normalized difference water index,MNDWI)、自动水体提取指数(automated water extraction index,AWEI)、谱间关系法(spectrum photometric method,SPM)这4种水体提取方法,优选最适宜鄱阳湖的水体提取模型;利用175期面积数据分析了鄱阳湖2000—2021年面积的年际变化趋势,分析年内季节变化特征,同时结合2009—2013年和2017—2018年同时期的50组水位数据,建立面积-水位关系模型。结果表明:①AWEI模型提取水体精度优于其他3种,该文最终选用AWEI进行鄱阳湖水体提取;②鄱阳湖面积存在明显的季节性变化,且丰水季面积年际波动大,枯水季较平缓;③棠荫水位站湖泊面积-水位分段线性模型为最佳模型,从而可以根据鄱阳湖区域的实时水位观测值对水体覆盖面积进行预测,以弥补云雨天气时利用可见光遥感手段难以监测到湖泊水体淹没情况的不足。

近20年间鄱阳湖湿地春秋季植被生物量时空动态

湿地生态系统是碳密度最大的生态系统之一,摸清湿地植被生物量及其动态变化对于实现“双碳”目标具有重要意义。基于Landsat遥感影像对鄱阳湖湿地2000—2020年间春秋季的植被地上生物量进行了反演和估算,分析了植被生物量随时间的变化趋势以及空间热点区域。结果表明:①近20年间鄱阳湖湿地春季和秋季植被地上生物量分别为0.85×10^(9)~4.20×10^(9) g和0.68×10^(9)~6.69×10^(9) g,春季植被地上生物量随时间变化不明显,秋季植被地上生物量随时间呈上升趋势。②鄱阳湖湿地春季植被地上生物量分布热点区域面积为754.15 km^(2),秋季为1085.49 km^(2),分别占鄱阳湖湿地总面积的21.58%和30.66%。③鄱阳湖湿地春季和秋季植被地上生物量与月均温度呈显著正相关关系。鄱阳湖湿地植被碳汇功能较强,且呈平稳甚至上升趋势,有利于碳中和目标的实现。

近40年鄱阳湖面积变化及其归因分析

鄱阳湖是中国最大的淡水湖泊,其面积变化对区域生态环境具有重要的影响。基于Landsat遥感影像,提取了1984—2021年鄱阳湖部分日期的水面面积,运用多元回归模型构建了水面面积与湖区水文站实测水位之间的关系,并对连续长序列面积进行了估算,获得了1980—2021年鄱阳湖连续的日尺度面积数据;其次,采用Mann-Kendall检验对面积变化情况进行了详细分析,并基于双累积曲线法定量分离了气候变化和人类活动对鄱阳湖面积变化的贡献。结果表明:(1)过去40年间,鄱阳湖面积显著减少,面积变化的突变点为2003年,突变点前的基准期(1980—2002年)的多年平均面积为2585.4 km^(2),突变点后的变化期(2003—2021年)的多年平均面积为2198.7 km^(2);相比基准期,变化期的面积减少了386.7 km^(2),减少了约15.0%;(2)不同季节鄱阳湖面积的减少程度不同,其中秋季面积减少得最多,减少了约22.8%,其次是冬季、春季和夏季的面积,分别减少了约13.6%、13.1%和11.8%;(3)气候变化和人类活动对鄱阳湖面积减少的贡献分别为24.7%和75.3%,人类活动是造成鄱阳湖面积减少的主要原因。

生态文明视野下鄱阳湖区水文化建设的路径

鄱阳湖区水文化是湖区生态文明的重要组成部分,主要包括渔文化、水利文化和水神信仰等,这一文化在历史上对湖区生态保护起到了积极作用。随着生产方式改变、科技发展以及教育普及,鄱阳湖区水文化发生了重大变化,与其他地区相比,鄱阳湖区水文化建设存在较大不足。应尝试进一步加大水文化遗产保护力度,重视加强湖区水文化宣传教育,建立水文化研究的专门队伍与平台,加强国际国内合作与交流等路径,解决当前湖区生态环境问题,实现湖区可持续发展,助力湖区生态文明建设。

鄱阳湖影响过湖对流强度的数值模拟及机理分析

湖陆下垫面的非均匀性对强对流天气的发展演变有很大的影响。鄱阳湖是我国最大的淡水湖,湖面积具有明显的月变化和季节变化,而模式中的下边界一般默认湖面积不变,这与实际情况的差异较大,必然带来模式预报误差。利用WRF模式对夏季夜间发生在鄱阳湖地区的一次强对流天气过程进行数值模拟,并通过湖面积变化的敏感性试验,深入研究鄱阳湖对强对流天气发展演变的影响及其机理,结果表明:夏季夜间湖面上空2 m温度明显高于陆面,向湖陆风在湖面上空辐合上升,岸边则存在下沉辐散气流。这导致降水在湖西岸减弱、湖上空增强。随后用去湖敏感性试验印证了鄱阳湖的暖湖效应,湖泊的存在能够通过激发陆风次级环流对湖西岸(湖面)上空降水起抑制(促进)作用。去湖试验的降水在湖西岸增强20%,在湖面上空减弱16%,体现出湖泊对降水强度的重要影响。此外,还发现湖面积扩大1.5、2.5、3.5、4.0倍的扩湖敏感性试验的降水在湖面上空分别增幅7%、16%、30%、43%,进一步证实了强对流强度对鄱阳湖面积变化较为敏感。这指示我们在预报夏季夜间穿湖而过的强对流天气时,应重点关注其可能存在的入湖前减弱、入湖后增强的变化趋势。同时,在利用数值模式模拟湖区强对流天气过程时,如果湖面积与模式中默认的湖面积相差较大,则应考虑将实际湖面积引入模式下边界,以期提升模式对于湖区对流的预报能力。

鄱阳湖越冬雁类时空分布特征及热点区域识别

鄱阳湖是东亚—澳大利西亚迁徙路线上重要的水鸟越冬栖息地,雁类是迁徙路线上的优势种群。然而,近年来迁徙路线上的雁类种群数量有所下降,识别越冬地雁类时空分布特征,确定分布热点区域是科学、精准保护的前提。本研究利用2018—2021年越冬期在鄱阳湖区域开展的共58次水鸟调查数据,提取了基于时间序列的白额雁(Anser albifrons)、豆雁(Anserfabalis)、鸿雁(Anser cygnoid)的分布数据,分析了3种雁类在越冬地的种群动态、时间和空间分布动态,评估了鄱阳湖各子湖的重要性,确定了雁类分布热点区域。研究结果表明,3种雁类在越冬地的种群数量表现出一定的年际波动,雁类种群总数量维持在27.9万~44.8万只;不同雁类迁徙的时间节律存在差异,本次地面调查数据显示白额雁、豆雁、鸿雁分别是在10月初至11月初、11月中旬、12月中旬到达鄱阳湖,其中鸿雁到达最晚;高峰期集中在11月底至次年2月初,持续时间约为100天;3种雁类分别在2月中旬、2月底和3月中旬开始迁离鄱阳湖。3种雁类空间分布范围有所差异,豆雁分布范围最广,白额雁分布相对集中,高峰期雁类的分布范围最大,对子湖的利用强度也最大。从空间分布特征来看,大湖池和大汊湖重要性最高,鄱阳湖保护区是雁类利用强度最高的区域,其次是都昌保护区。此外,雁类,特别是鸿雁,对保护区以外的子湖利用强度也较高。本研究对精准刻画鄱阳湖越冬雁类时空分布范围、针对性地开展栖息地保护和修复、加强子湖保护和管理具有重要意义。