Impacts of Land Cover Changes on Ecosystem Carbon Stocks Over the Transboundary Tumen River Basin in Northeast Asia

Understanding the effects of land cover changes on ecosystem carbon stocks is essential for ecosystem management and envi- ronmental protection, particularly in the transboundary region that has undergone marked changes. This study aimed to examine the impacts of land cover changes on ecosystem carbon stocks in the transboundary Tureen River Basin （TTRB）. We extracted the spatial information from Landsat Thematic Imager （TM） and Operational Land Imager （OLI） images for the years 1990 and 2015 and obtained convincing estimates of terrestrial biomass and soil carbon stocks with the INVEST model. The results showed that forestland, cropland and built-up land increased by 57.5, 429.7 and 128.9 km2, respectively, while grassland, wetland and barren land declined by 24.9, 548.0 and 43.0 km2, respectively in the TTRB from 1990 to 2015. The total carbon stocks encompassing aboveground, belowground, soil and litter layer carbon storage pools have declined from 831.48 Tg C in 1990 to 831.42 Tg C in 2015 due to land cover changes. In detail, the carbon stocks de- creased by 3.13 Tg C and 0.44 Tg C in Democratic People＇s Republic of Korea （North Korea） and Russia, respectively, while increased by 3.51 Tg C in China. Furthermore, economic development, and national policy accounted for most land cover changes in the TTRB. Our results imply that effective wetland and forestland protection policies among China, North Korea, and Russia are much needed for protecting the natural resources, promoting local ecosystem services and regional sustainable development in the transnational area.

POLLUTION TREND IN THE TUMEN RIVER AND ITS INFLUENCE ON REGIONAL DEVELOPMENT

The Tumen River had failed to meet Grade Ⅲ and Ⅳ levels in the environmental quality standard for surface water, and had exceeded Grade Ⅴ level. Surface water pollution is serious. The major excessive standard pollutants were COD Mn and SS. After taking effective treatment steps, the worsening trend of water pollution will be basically under control. But the change of runoff in the Tumen River is large in a year, especially during as long as five month freezing period, smaller flow and lower temperature of river waters led to weak dilution and self purification capacity. The water quality of the Tumen River will not reach the appoint functional water quality standards, even if sewage meets discharge standard, which will influence water resources utilization in the lower reaches of the Tumen River and regional economic development. Therefore water pollution has become the major restrictive factor of the development of the Tumen River area.

UNITED INTERNATIONAL CENTRAL CITY: A NEW SPATIAL ORGANIZATION MODEL IN TUMEN RIVER ECONOMY DEVELOPMENT ZONE

This paper puts forward a new conceptual idea on constructing an international central city in the Tumen River Economy Development Zone (TREDZ) on the basis of analysis of the superiorities and problems in developing city, and from the view point of present social, economic and natural conditions in this area and the background of Northeast Asia. The united international central city is the best distribution model not only in its polycentric spatial structure but also in organizing form. Its feasibility and practicability are thoroughly proved from various aspects including urban planning principles, comparison of port cities, special characteristics of cooperation in TREDZ, and natural, social, cultural factors etc.

Spatial Patterns of LULC and Driving Forces in the Transnational Area of Tumen River:A Comparative Analysis of the Sub-regions of China,the DPRK,and Russia

Understanding the spatial patterns of land-use and land-cover(LULC)and their driving forces in transnational areas is important for the sustainable development of these regions.However,the spatial patterns of LULC and their driving forces across multiple scales are poorly understood in transnational areas.In this study,we analyzed the spatial patterns of LULC and driving forces in the transnational area of Tumen River(TATR)in 2016 across two scales:the entire region and the sub-regions of China,the Democratic People’s Republic of Korea(DPRK),and Russia.Results showed that the LULC was dominated by broadleaf forest and dry farmland in the TATR in 2016,which accounted for 66.86%and 13.60%of the entire region,respectively.Meanwhile,the LULC in the three sub-regions exhibited noticeable differences.In the Chinese and the DPRK’s sub-regions,the area of broadleaf forest was greater than those for the other LULC types,while the Russian sub-region was dominated by broadleaf forest and grassland.The spatial patterns of LULC were mainly influenced by topography,climate,soil properties,and human activities.In addition,the driving forces of the spatial patterns of LULC in the TATR had an obvious scaling effect.Therefore,we suggest that effective policies and regulations with cooperation among China,the DPRK,and Russia are needed to plan the spatial patterns of LULC and improve the sustainable development of the TATR.

Spatio-temporal Changes in Water Conservation Ecosystem Service During 1990–2019 in the Tumen River Basin, Northeast China

The water conservation(WC) function of ecosystems is related to regional ecological security and the sustainable development of water resources, and the assessment of WC and its influencing factors is crucial for ecological and water resource management.The Tumen River Basin(TRB) is located in the core of the Northeast Asian ecological network and has been experiencing severe ecological crises and water shortages in recent years due to climate change and human activities. However, these crises have not been fully revealed to the extent that corresponding scientific measures are lacking. This study analyzed the spatial and temporal evolution characteristics and drivers of WC in the TRB from 1990 to 2019 based on the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model. The results showed that: 1) under the combined effect of nature and socioeconomics, the WC depth of the TRB has slowly increased at a rate of 0.11 mm/yr in the past 30 years, with an average WC depth of 36.14 mm. 2) The main driving factor of the spatial variation in WC is precipitation, there is a significant interaction between precipitation and velocity, the interaction between each factor is higher than the contribution of a single factor, and the interactions between factors all have nonlinear enhancement and two-factor enhancement. 3) Among the seven counties and municipalities in the study area, the southern part of Helong City and the southeastern part of Longjing City are extremely important areas for WC(> 75 mm), and they should be regarded as regional water resources and ecological priority protection areas. It is foreseen that under extreme climate conditions in the future, the WC of the watershed is under great potential threat, and protection measures such as afforestation and forestation should begin immediately. Furthermore, the great interannual fluctuations in WC depth may place more stringent requirements on the choice of time scales in the ecosystem service assessment process.

URBANIZATION AND ITS IMPACTS ON WATER ENVIRONMENT IN TUMEN RIVER BASIN

The trans-boundary scope of the Tume n River Basin(TRB)going through China,Russia and DPRK has been defined,and on the basis of this,status of urbanization and its impacts on water environment in recent 20years in TRB have been analyzed.Urbanizatio n in TRB can be characterized as:1)There is medium level of overall urbanization in TRB.Certain distance still exists compared with developed countries.And it is lower than the average urbanization level of Russia and higher than that o f China.2)There is unbalanced distribution of urbanization development in TRB.Urbanization in China part owns the c haracter of low starting point and hi gh-speed development.In Russia part,charac-ter of urbanization can be described as high starting point and stable development.In DPRK part,urbanizatio n level is low,and motive power lacks.3)Due to large population,in China part there is broader region urbanized,larger radius and higher frequency of human activities,which lead to heavier pressure on environment.Meanwhile,the paper has point-ed that impacts of urbanization on wa ter environment are as follows:1)Urban population growth and industr y develop-ment increase the demand for freshwa ter,and also exacerbate the contrad iction between limited water supply and increas-ing freshwater demand.2)Urban infrastructure doesn’t match with urban productive function especially treatment facili-ties,which results in the pollution of the Tumen River.3)The pollution situation in the Tumen River got peak point in1995,and presently,such situation has been improved in great scale,due to effective interventions adopted.However,there still exist 2enterprises that are urgent to be harnessed.Moreover,pollution of municipal sewage will become more and more apparent.4)The influence of urbanization on soil is mainly caused by industrial effl uent and slag,and pollut-ed water irrigation.Soil and water l oss has also been a serious problem caused by urbanization.5)Urbanization results in the decrease of wetlands area.Fur thermore,the paper has given a brief account of the perspective and recom menda-tions on urbanization and environme ntal impacts.

Application of Grain Size Analysis to Study Sedimentary Environment of Sand Dune in the Vicinity of Tumen River

The average size of the sand of dune in the vicinity of Tumen River is 0.12～0.30 mm, its standard deviation is 0.45～0.99 φ and the frequency cumulative distribution curve is divided into the single peak and the double peak. The Ski of the single peak is negative and the double peak is positive. There are two different areas in the plot of the Ski versus σi* It is shown that the sedimentary environment of the dunes is neritic deposit by the expressions of the grain-size parameters. All of the characters show that the sand dunes in Estuary of Tumen River may be the dunes of sea facies which were changed again by weathering and fluvialaction.

THE FLUX OF LAND-BASED SOURCE POLLUTANTS FROM TUMEN RIVER SYSTEM ENTERING THE SEA OF JAPAN

The influence of land based source pollutants to marine ecological environment is principally in coastal or enclosed sea waters. Flux of land based source pollutants into the sea will be effected due to social and economic development in the Tumen River basin. Pollutant type and primary pollution factor of the Tumen River in Northeast China is described by weighted coefficient method in this paper. The results indicate that the river is organic pollution type and primary pollution factor is COD. Fresh water fraction proves that the estuary is not affected by tide cycle. COD annual flux entering the Sea of Japan calculated by zero dimension model in 1993 was 90.50 ×10 3 tons. It is estimated with emission coefficient method that the COD will be 176.4 ×10 3 and 458.6 ×10 3 tons for the years of 2000 and 2010 respectively.

A STUDY ON QUALITY OF AQUATIC ENVIRONMENT IN TUMEN RIVER AREA

ＡＳＴＵＤＹＯＮＱＵＡＬＩＴＹＯＦＡＱＵＡＴＩＣＥＮＶＩＲＯＮＭＥＮＴＩＮＴＵＭＥＮＲＩＶＥＲＡＲＥＡ①ＺｈｕＹａｎｍｉｎｇ（朱颜明）ＣｈａｎｇｃｈｕｎＩｎｓｔｉｔｕｔｅｏｆＧｅｏｇｒａｐｈｙ，ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，...

THE DEVELOPMENT OF THE TUMEN RIVER AND THE ECONOMIC GEOGRAPHICAL BACKGROUND OF ITS HINTERLAND

ＴＨＥ ＤＥＶＥＬＯＰＭＥＮＴ ＯＦ ＴＨＥ ＴＵＭＥＮ ＲＩＶＥＲＡＮＤ ＴＨＥ ＥＣＯＮＯＭＩＣ ＧＥＯＧＲＡＰＨＩＣＡＬ ＢＡＣＫＧＲＯＵＮＤ ＯＦ ＩＴＳ ＨＩＮＴＥＲＬＡＮＤ ＷａｎｇＲｏｎｇｆｅｎ（王荣芬）；ＬｉＷｅｉ（李为）（Ｃｈａｎｇ...

Eco-environmental problems and protectionin Tumen River development

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GEOFEATURES AND RESOURCE ELEMENT COMBINATION OF TUMEN RIVER ECONOMIC GROWTH TRIANGLE

The development of world economy has been heading for globalization and regionalization. In recent years, this tendency has born great impact on the rapid economic development of the Asian and Pacific countries, which assumes the form of economic growth triangle as their major way for regional cooperation involving multiple nations. Among these, the Tumen River Triangle consisting of six countries' cooperation may have attracted great attention. Since 1991 when UNDP began to draw up plans for such a mammoth project which is called the Tumen River Area Development Project (or TRADP), the international economic cooperation in this area has been developing energetically. It is now necessary to assess the characteristics of geographical conditions and various economic resources from the viewpoints of economic geography and expound the mammoth benefits both in economy and to society. The demonstration would undoubtedly absorb more international capital to this area and enhance its economic and social development.

Spatial patterns of net primary productivity and its driving forces:a multi-scale analysis in the transnational area of the Tumen River

Analyzing the spatial patterns of net primary productivity(NPP)and its driving forces in transnational areas provides a solid basis for understanding regional ecological processes and ecosystem services.However,the spatial patterns of NPP and its driving forces have been poorly understood on multiple scales in transnational areas.In this study,the spatial patterns of NPP in the transnational area of the Tumen River(TATR)in 2016 were simulated using the Carnegie Ames Stanford Approach(CASA)model,and its driving forces were analyzed using a stepwise multiple linear regression model.We found that the total amount of NPP in the TATR in 2016 was approximately 14.53 TgC.The amount of NPP on the Chinese side(6.23 TgC)was larger than those on the other two sides,accounting for 42.88%of the total volume of the entire region.Among different land-use and land-cover(LULC)types,the amount of NPP of the broadleaf forest was the largest(11.22 TgC),while the amount of NPP of the bare land was the smallest.The NPP per unit area was about 603.21 gC/(m2 yr)across the entire region,while the NPP per unit area on the Chinese side was the largest,followed by the Russian side and the DPRK's side.The spatial patterns of NPP were influenced by climate,topography,soil texture,and human activities.In addition,the driving forces of the spatial patterns of NPP in the TATR had an obvious scaling effect,which was mainly caused by the spatial heterogeneity of climate,topography,soil texture,and human activities.We suggest that effective land management policies with cooperation among China,the DPRK,and Russia are needed to maintain NPP and improve environmental sustainability in the TATR.

冰上丝绸之路与图们江大通道建设共同推进“一带一路”向北经济发展研究

冰上丝绸之路与图们大通道建设紧密相连,彼此相辅相成,是“一带一路”向北经济发展的重要构成部分,对于深化向北地区区域合作、打通“一带一路”向北开放的新通道、深化“双循环”新发展格局、推进向北经济绿色发展具有重大战略意义。从研究视角看,将冰上丝绸之路、图们江大通道建设、“一带一路”向北经济发展纳入统一分析框架,深入剖析二者建设共同推进“一带一路”向北经济发展的重要性及理论逻辑,为相关学者研究提供了新的视角。从研究内容看,基于重要性及理论逻辑分析,审视和剖析了二者建设共同推进向北经济发展的有利条件和制约因素,提出了二者建设共同推进向北经济发展的布局思路及实现路径,丰富了“一带一路”相关研究内容。研究认为,冰上丝绸之路与图们江大通道共同建设能够通过向北地区现代农业合作、数字经济合作、能源产业合作、绿色经济合作实现北极国家(地区)与东北亚国家(地区)区域合作,进而推进“一带一路”向北经济发展。

长吉图地区土壤保持服务功能时空变化与供需匹配

[目的]依据长吉图地区土壤保持服务功能时空变化及其供需匹配特征,辨别区域内不同土壤修复治理需求,为推进区域土壤生态环境保护有效落实提供科学依据。[方法]利用InVEST模型,定量评估2000,2010,2020年3期长吉图地区各地市、县区的土壤保持服务功能,分析土壤保持服务供需及其时空变化匹配状态关系,以识别亟需采取针对性管理的优先区域并制定土壤整治策略。[结果]2000—2020年长吉图土壤保持强度为0.00~2590.42t/km^(2),减少侵蚀服务功能为0.00~1544.23t/km^(2),泥沙持留服务功能为0.00~2452.20t/km^(2),区域间土壤保持服务水平差异显著,具有明显的时空分异特征;研究区供需匹配情况较平衡,未出现低供给高需求匹配类型;区域土壤保持服务供需变化匹配关系包括供需同增/供增需减可持续,供需同减/供减需增不可持续4种类型。亟需治理的不可持续区域比例逐年扩大,截至2020年分别为68.15%(减少侵蚀),72.57%(泥沙持留),集中于研究区东侧以及西侧的中间部分,土壤保持服务弱化显著。[结论]长吉图地区土壤保持服务功能空间差异明显。确定长吉图地区中东部、东部尾端与西部区域为土壤敏感区、土壤脆弱区、土壤修复区,其土壤生态管理工作应分别以土壤整治、土壤保育、土壤修复为主。

近60 a图们江流域极端气候变化及未来趋势预测

【目的】气候变化背景下,洪涝灾害、高温干旱等极端气候事件的发生频率与强度不断增加。图们江位于中国、朝鲜、俄罗斯三国边境,是我国重要的国际河流之一,研究流域内极端气候变化及未来趋势对流域内人民生产生活有重要意义。【方法】以图们江流域为对象,基于流域内和流域附近的11个气象站点1960—2021年的气象数据,采用27个极端气候指数,利用Mann-Kendall趋势检验、Morlet小波分析等方法分析了流域极端气温和降水的时空变化特征,并预测了在SSP1-2.6、SSP2-4.5、SSP5-8.5三种情景下未来极端气候事件的演变特征。【结果】结果显示:(1)近60 a极端气温指数中极端冷指数均呈显著下降趋势,极端暖指数和极值指数均呈显著上升趋势。大部分极端气温指数突变年份集中在1980年以后,且多以35~37 a为第一主周期。极端降水指数中除CWD(持续湿润日数)外,其他指数均呈不显著上升趋势,多以45 a为第一主周期。(2)极端气温指数中极端暖指数和极值指数在汪清北部、和龙南部、安图区域呈现显著下降趋势,珲春南部和延吉-龙井区域则呈显著上升趋势,极端冷指数则相反。与降水强度有关的极端降水指数高值均位于珲春南部区域。(3)从未来不同情景来看,除极端冷指数中的ID0(结冰日数)较于基准期呈下降趋势外,其他气候指数均呈上升趋势,且排放情景越大,增幅越大。【结论】结果表明:图们江流域气温呈变暖趋势,降水呈增多趋势。极端气温指数突变年份集中在1980年以后,极端降水指数无明显突变时期。极端气候指数在流域空间上呈现不同变化特征,珲春南部和延吉-龙井地区发生极端高温事件的概率高于其他地区,珲春南部发生极端降水事件的概率高于其他地区。流域未来极端降水和极端高温事件发生的概率将显著增大,且随着排放情景的增加概率也逐渐增大。

图们江下游湿地生态系统健康评价

湿地是世界上具有独特结构与功能的生态系统,图们江流域湿地生态系统的健康对该区乃至东北亚地区综合生态系统网络的建设具有重要意义。选择图们江流域下游为研究区,基于压力-状态-响应(PSR)模型,在压力系统、状态系统、响应系统三个层面选取30个指标构建了图们江下游湿地生态系统健康评价指标体系,运用层次分析法和多级模糊综合评判法对研究区湿地生态健康状况进行综合评价,其结果为0.5878,处于亚健康状态。其中,压力系统的健康指数为0.5292,响应系统的健康指数为0.6866,状态系统的健康指数为0.5116,各等级隶属度S=(16.83%,25.37%,16.76%,16.97%,24.07%)。主要表现在研究区域湿地的补水水质差,导致湿地水质污染加重,富营养化现象严重;并且由于人为因素,湿地大面积退化,景观破碎化加剧,功能逐渐丧失,生产力水平下降;急需对本区域湿地进行保护与管理。

图们江流域河流生态系统健康评价

河流是重要的自然生态系统,也是重要的生态廊道之一,图们江流域河流生态系统的健康状况,对维护跨国界流域的水环境的管理和可持续发展有着重要的意义。基于河流水文、河流形态、河岸带状况、水体理化参数以及河流生物5个层面选取22个指标构建了图们江流域河流生态系统健康评价指标体系,运用层次分析法和加权平均法对其进行了健康评价。评价结果表明,虽然该地区处于"健康"级别,但也有28%的地区处于"亚健康"状态。河流健康综合指数(RHI`)与河流生物指标、水体理化指标、河流形态指标、河岸带指标等4项呈显著相关(P<0.05),相关系数依次为0.847、0,757、0.740、0.547。研究结果表明图们江流域水生生物的生存环境遭到严重破坏、水体污染严重,河岸带生态退化、城市化影响严重等一系列影响河流健康的问题。

基于3S技术的图们江流域湿地生态安全评价与预警研究

图们江是我国重要的国际性河流之一,随着我国经济的迅速崛起,图们江地区进入到多国合作联合开发阶段,该区环境也因此受到了不同程度的干扰和破坏,对该区域进行湿地生态安全评价与预警研究,可为图们江流域生态环境的可持续发展提供依据。以图们江流域湿地生态安全为出发点,基于PSR模型构建了适合该区域生态环境的生态安全评价指标体系,在3S技术支持下,通过解译1976年、1990年、2000年、2010年4个年份的TM/MSS影像,获取了这4个时期的景观格局指标数据,并运用层次分析法确定指标权重;在使用逻辑斯蒂增长曲线模型对各个指标进行单指标评价的基础上,使用综合评价法对各个时期的图们江流域湿地生态安全进行评价,最终得到1976年、1990年生态安全值分别为0.650、0.620,湿地生态系统比较安全,2000年、2010年生态安全值分别为0.536、0.454,湿地生态系统处于预警状态,应及时对该区域湿地生态系统进行保护。基于灰色预测模型构建湿地生态安全预测模型,经检验,模型精度较高,可以进行图们江流域湿地生态安全的预测研究。做出了图们江流域未来40a的湿地生态安全预测,分别为0.3903、0.3345、0.2866、0.2456,湿地生态系统处于中度预警状态,并有向重度预警发展的趋势,生态安全面临的威胁越来越严重,急需对本区域湿地生态系统进行保护与管理。