Spatiotemporal characteristics and driving mechanisms of land use/land cover(LULC)changes in the Jinghe River Basin,China

Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB.

Land Cover Changes and Drivers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China from 2000 to 2015

The Middle Route of the South-to-North Water Diversion Project(MR-SNWDP)in China,with construction beginning in 2003,diverts water from Danjiangkou Reservoir to North China for residential,agriculture and industrial use.The water source area of the MR-SNWDP is the region that is most sensitive to and most affected by the construction of this water diversion project.In this study,we used Landsat Thematic Mapper(TM)and HJ-1 A/B images from 2000 to 2015 by an object-based approach with a hierarchical classification method for mapping land cover in the water source area.The changes in land cover were illuminated by transfer matrixes,single dynamic degree,slope zones and fractional vegetation cover(FVC).The results indicated that the area of cropland decreased by 31%and was replaced mainly by shrub over the past 15 years,whereas forest and settlements showed continuous increases of 29.2% and 77.7%,respectively.The changes in cropland were obvious in all slope zones and decreased most remarkably(–43.8%)in the slope zone above 25°.Compared to the FVC of forest and shrub,significant improvement was exhibited in the FVC of grassland,with a growth rate of 16.6%.We concluded that local policies,including economic development,water conservation and immigration resulting from the construction of the MR-SNWDP,were the main drivers of land cover changes;notably,they stimulated the substantial and rapid expansion of settlements,doubled the wetlands and drove the transformation from cropland to settlements in immigration areas.

Impact of large-scale vegetation restoration project on summer land surface temperature on the Loess Plateau, China

A large-scale afforestation project has been carried out since 1999 in the Loess Plateau of China. However, vegetation-induced changes in land surface temperature (LST) through the changing land surface energy balance have not been well documented. Using satellite measurements, this study quantified the contribution of vegetation restoration to the changes in summer LST and analyzed the effects of different vegetation restoration patterns on LST during both daytime and nighttime. The results show that the average daytime LST decreased by 4.3°C in the vegetation restoration area while the average nighttime LST increased by 1.4°C. The contributions of the vegetation restoration project to the changes in daytime LST and nighttime LST are 58% and 60%, respectively, which are far greater than the impact of climate change. The vegetation restoration pattern of cropland (CR) converting into artificial forest (AF) has a cooling effect during daytime and a warming effect at nighttime, while the conversion of CR to grassland has an opposite effect compared with the conversion of CR to AF. Our results indicate that increasing evapotranspiration caused by the vegetation restoration on the Loess Plateau is the controlling factor of daytime LST change, while the nighttime LST change is affected by soil humidity and air humidity.

LAND USE CHANGE AND ITS SOCIO-ECONOMIC DRIVING FORCES UNDER STRESS OF PROJECT IN OLD RESERVOIR AREA——Case Study of Linshui Reservoir Area of Dahonghe Reservoir in Sichuan Province

The old reservoir areas built in 1950s- 1970s left behind many socio-economic problems, because of the administrative backward migration and little migration fund, and all these problems would be tied to land. Based on interviewing with peasant households, combining land use survey and socio-economic statistical index, this paper analyzed land use change and its corresponding driving forces in Linshui reservoir area of Dahonghe Reservoir. Results showed that land use change in the reservoir area was mainly embodied on low-lying land submergence and migration requisition land. The former changed the land use patterns, and the latter mainly reconstructed original land property and made land over-fragmented. Cultivated land per capita was 0.041ha in this area, below the cordon of cultivated land per capita enacted by FAO. Currently, there were still 30.25% of peasant households being short of grain in trimester of one year, and there were 35.27% of people living under the poverty line. The conditions of eco-environmerit in Linshui Reservoir Area were worse, and healthy and sub-healthy eco-environment accounted for less proportion, composed of green belt around the reservoir area and paddy field ecosystem, and economic forest and orchard ecosystem, respectively. The stress of the reservoir project was macroscopic background to analyze the driving factors of land use change, and real underlying diving factor of the land use change in the area was the change of cultural landscape under the stress of reservoir project. The rapid increase of population was the key factor to induce the change of man-land relationship in the reservoir area, the low level of rural economy was the crucial factor to decide how migrants input for production, and the belief of migrants, influencing the land use patterns in a certain extent, was the inducing factor to keep land use stable. The low-lying submergence and infrastructure construction accompanied the reservoir project were leading factors driving land use change in the area, while changes in land use patterns, after the reservoir being built, were the responses of peasant households＇ behaviors to land use change.

Study on the After-evaluation Index System and Evaluation Model of Industrial Estate Land Development Project

According to the modem management theories and the characters of industrial estate land development project, this paper studies the after-evaluation＇s content and method of industrial estate land development project and puts forward the index system of course after-evaluation, finance after-evaluation and society after-evaluation. Moreover, this paper also brings forward the method and model of synthetic after-evaluation.

Compensation for Land Loss in Reservoir Resettlement: A Case Study of The Three Gorges Project, China

This paper studies current policies in compensation for land lost due to construction of the Three Gorges project (TGP), China. In the case study of Kaixian County, the value of land in the peri-urban areas is underestimated. Some losses in land are tangible and thus measurable, but some losses are intangible and thus immeasurable. The land available in the resettlement areas is scarce and rarely of equivalent quality. This study suggests that the loss of agricultural land be compensated with alternative land and/or non-land-based livelihood strategies, including part compensation in monetary terms and preferential policies.

REMOTE SESING INVESTIGATION AND APPRAISAL OF LAND USE AND CAPACITY IN THE REGION OF THE YANGTZE RIVER GORGES’PROJECT

The region around the Three Gorges project on the Yangtze River has an area of 62552 square kilometres and population of 20.14 million. It limits a range hetween the sorth-north watersheds and from Yichang of Hubei Province to Jiangjin of Sichuan, including 24 cities and counties-Chongjing, Yichang and Wanxian etc. In this region, relief are mainly hills and middle-low mountains. Remote censing investigation and appraisal of land use and capacity which are two of the major restrict factors for the Three Gorges project have provided related scientific bases for macro-dicision-making of the project.

E-mail and the "Golden Bridge Project" in China

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2023年积石山Ms6.2级地震同震地质灾害初步分析

2023年12月18日,甘肃省临夏回族自治州积石山县发生Ms6.2级地震,触发了大量同震地质灾害,亟需查明同震地质灾害的基本特征、发育分布规律和成因机制,为震后恢复重建与地质灾害防治提供支撑。本文基于多源高分辨率遥感解译和已有研究成果对比分析,初步揭示了此次地震地质灾害的基本特征和发育分布规律,并探讨了草滩村液化滑坡—泥流的成因机制。结果表明:此次地震Ⅶ度及以上烈度区内共发育1 535处同震地质灾害,主要为中小规模黄土滑坡和浅表层岩质崩塌,集中分布于黄土梁和黄土塬内冲沟两侧、单薄黄土梁两侧以及大型历史滑坡后壁等局部地形较陡峭的部位。地震因素控制了同震地质灾害的区域分布规律,而地形因素控制了同震地质灾害的局部分布规律。同震地质灾害在0.1~0.3 g震峰值加速度区域、发震断层下盘区域、南东坡向、30~60 m坡高范围、斜坡中部以上20~40 m范围分布数量最多。受广泛关注的草滩村“砂涌”灾害本质是饱水黄土在地震作用下发生的液化滑坡。2016年完成的填沟造地工程改变了滑源区地表和地下水流通条件,地下水通道被堵塞,导致地下水位抬升和下部土体饱和可能是该处发生液化滑坡的重要原因。

基于LANDSAT的辽宁省朝阳市1985—2020年退耕还林工程动态监测

[目的]分析辽宁省朝阳市退耕还林工程作用下的土地覆被情况,跟踪监测年际间地类变动趋势,探讨退耕还林工程对朝阳市荒山、耕地、林地和草地的影响,为朝阳市土地资源合理规划利用提供科学支撑。[方法]基于1985—2020年逐期Landsat影像,利用C5.0算法提取该地区地表覆被时空分布信息,借助土地利用动态度、土地利用转移矩阵等分析36 a间山田林草的动态变化及其驱动因素。[结果]①36 a间朝阳市荒山绿化面积达2745.5 km^(2),退耕还绿的面积约933 km^(2),工程成效较为显著。②退耕区和还林区主要分布在坡度>25°和海拔超过500 m的地区,二者变化主要表现在内部结构的转换,即增加海拔低于500 m和坡度<25°的耕地比例,基本符合退耕还林政策要求。[结论]5个阶段内朝阳市的山田林草在年际间都存在相互转换的情况,相比前3个阶段,后两个阶段在政策实施的加持下“逆过程”现象减少,工程实施方面仍需加强监督,精确理解国家政策和项目技术规程,因地制宜地贯彻有关政策。

太湖流域水环境治理工程土地节约集约利用评价研究

土地节约集约利用评价及其障碍因子诊断对固守耕地红线、保障国家粮食安全具有重要意义,以太湖流域为例,从建设过程和建设结果两方面构建水环境治理工程土地节约集约利用评价体系,选择信息熵改进TOPSIS模型研究太湖治理工程土地节约集约利用现状及变化趋势,并通过障碍度模型进行障碍因子诊断。研究结果表明:太湖治理工程土地节约集约综合利用水平整体随着时间的推移呈平稳上升趋势,太湖治理工程土地集约利用水平排序依次为新孟河工程(0.564 4)、新沟河工程(0.480 5)、走马塘工程(0.431 6),均处于适度利用等级(Ⅲ级),存在较大提升空间;影响太湖治理工程土地节约集约利用的障碍因子存在差异,障碍度变化各不相同,但总体呈现障碍因子集中、重要障碍因子具有较为明显共性的特点。

金课背景下融入课程思政元素的教学设计探索——以高等数学课程中“距离问题”为例

以高等数学课程中“距离问题”为例,对如何融入课程思政元素以及如何满足“两性一度”的金课要求进行了教学设计与实践探索,为金课建设与课程思政建设等教学改革提供参考.

基于ESG理念的重大工程弃渣造地项目选址价值评价

为了强化弃渣造地项目选址的可持续性,本文引入了ESG理念作为决策依据,构建了集成ESG理念的重大工程弃渣造地项目选址价值工程框架,并提出了适用于评价西部复杂艰险地区重大工程弃渣选址造地的ESG功能评价指标体系。在此基础上,结合AHP方法给出了确定ESG项下各分量指标的权重及价值工程实施的具体操作步骤,并通过一个具体案例进行操作说明。ESG理念的引入及所构建的功能评价指标体系和弃渣选址造地的价值工程分析方法,有助于提升我国重大工程弃渣处置的可持续能力,助推重大工程弃渣选址造地的科学化和重大工程ESG理念的实现。

大数据税收征管有助于抑制关联交易吗?--来自“金税三期”工程的准自然实验证据

近年来,上市公司的关联交易不断增长,严重损害了中小股东的利益。文章以“金税三期”工程作为准自然实验,探究大数据税收征管对公司关联交易的治理作用及其影响机制。基于2011—2018年我国非金融上市公司发生的商品与劳务类关联交易数据,通过构造多期双重差分模型,文章研究发现以“金税三期”工程为代表的大数据税收征管模式显著降低了企业的关联交易水平。异质性分析发现,当公司内部治理水平较低,外部市场制度不完善时,“金税三期”工程对关联交易的治理作用更为显著。关于机制的研究显示,大数据税收征管通过征税效应、治理效应和信息效应降低委托代理成本、提高会计稳健性和提升会计信息透明度,从而减少企业关联交易水平。文章的研究不仅从理论上丰富了大数据税收征管的经济效应,而且对我国在数字经济时代深化监管方式改革提供了政策启示。

供水工程影响下中国北方地区耕地后备资源开发潜力

灌溉水源是北方地区耕地后备资源能否有效开发的关键。当前,中国正在推动国家水网工程规划建设,为北方地区耕地后备资源开发提供了新的机遇。在以往研究基础上,该研究考虑北方地区已建、在建及规划的供水工程,基于自然适宜、利用高效、发展稳定三方面评价准则,结合三维魔方空间分类方法,开展了雨养情景和供水灌溉情景下耕地后备资源开发潜力分析。结果表明:雨养农业情景下,北方地区勉强适宜(Ⅱ级)、中度(Ⅲ级)和高度(Ⅳ级)适宜的耕地后备资源面积分别为2.9万、1.0万和0.6万km^(2)。灌溉农业情景下,耕地后备资源面积明显增加,勉强适宜(Ⅱ级)、中度(Ⅲ级)和高度(Ⅳ级)适宜的耕地后备资源面积将分别达到5.4万、7.6万和6.5万km^(2),主要集中于新疆、内蒙古和甘肃3省(自治区)。该研究结果可为中国耕地后备资源开发利用及国家水网工程效益发挥提供参考。

土地发展权视角下全域土地综合整治工具探索——以佛山市南海区“三券”为例

全域土地综合整治是稳妥推进农村土地制度改革的关键抓手。在全域土地综合整治中,不同的整治模式会造成土地发展权的非均衡配置,使得被赋予土地发展权的项目容易实施、被削减或终止土地发展权的项目难以实施。本文从土地发展权视角出发,探究了南海区“三券”政策的三个典型案例,分析了“三券”政策的实施机制,指出“三券”政策实质上是通过土地发展权的补偿和转移来保护村集体利益、助力实施全域土地综合整治的有效工具和重要路径。建立和完善土地发展权转移和补偿机制,有利于推进实施全域土地综合整治、解决因土地性质变化而产生的土地收益“暴损”问题,有利于以全域土地综合整治为牵引深化农村土地制度改革,促进乡村振兴和城乡融合发展。

基于RS和GIS的陕西省洛川县土地利用类型和植被覆盖变化特征

明确土地利用类型转变和植被覆盖度变化的范围、幅度和归因是评估生态工程环境效应的前提。然而,在黄土高原塬区县域尺度类似的研究鲜有报道。基于长时间序列NDVI数据和Landsat系列卫星数据,探究黄土高原洛川县土地利用和植被覆盖度的变化状况。结果表明:退耕还林(草)工程实施以来,洛川县植被覆盖度从0.6(2000年)增至0.9(2020年),耕地面积减少了481.8 km2,其中231.3 km2为坡度≤15°的适耕区转为苹果园。由于坡耕地还林草的面积在洛川县土地变化总面积中仅占1.5%,远小于其他地类改种苹果的面积(占20.0%),因此,洛川县植被覆盖度的提升主要是政府大力推广苹果树种植的结果。研究结果可为黄土高原经济林建设提供基础数据和科学参考。

玛曲县退牧还草工程实施效果评估

为了综合评价甘肃省玛曲县在第二轮退牧还草工程(2005~2020年)实施中取得的成效,本文构建经济效益、生态效益、社会效益、工程的可持续性、工程的自身特性5个准则层、17个指标层的综合评价体系。采取随机抽样的方法展开问卷调查,结合相关部门意见构建层次分析-模糊综合评价模型,对实施成效进行评估。评估结果表明,自退牧还草工程实施以来,当地生态效益(0.4274)上升最为显著,其次是经济效益(0.2658)、社会效益(0.1693)、工程的可持续性(0.0838)和工程的自身特性(0.0564)。虽然退牧还草工程取得了显著的生态成效,但如何使成果持续有效地延续下去至关重要。通过项目实施前后指标层的权重分析,建议政府需加大与科研院所的合作力度,采取近自然修复技术,选择适合高寒环境的乡土草种补播,提高草场的生物多样性和稳定性;引领牧民构建畜产品产业链,促进第二、三产业发展,向以非传统牧业为主的经济收入模式迈进;加大对牧民文化教育事业的投入,提高牧民保护草原的生态意识;构建以草定畜、草畜同步发展的自然-人文耦合系统下的放牧模式和“减畜不减产、减畜不减收”的草地农业模式,促进草场可持续发展。以上研究结果有助于政府对退牧还草工程制定科学的规划和宏观的管理措施。

陆海交通连接工程对海岛区域景观格局时空演变的影响研究——以平潭综合试验区为例

陆岛联通工程是沟通陆域与岛屿地域的重要纽带,探明陆岛连接交通工程对海岛地区景观格局时空演变的影响,对维护海岛地区生态环境质量,实现可持续发展具有重要意义。以福建省平潭综合试验区作为研究区域,利用2017-2022年10 m分辨率土地数据,借助面板回归模型,探究大陆-海岛交通连接工程对海岛区域景观格局时空演变的影响。结果表明:(1)2017-2022年,平潭综合试验区景观格局整体呈现斑块间连通性趋好、景观集聚性越来越高,破碎化程度、景观多样性和异质性程度在不断减弱;(2)在空间方面,平潭岛内与海岛边缘景观格局指数变化差异显著,集聚度及破碎化趋势岛内高于边缘地带;(3)面板回归模型显示,公铁大桥建设对景观蔓延度存在显著负面影响,说明公铁大桥开通在短时间内导致海岛整体景观格局趋向于破碎化。

税收征管信息化与企业风险承担水平--基于“金税三期”工程的准自然实验

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