Landuse/landcover changes in Zhangye oasis of Hexi Corridor

Taking two f alse color composite Landsat 5 TM (Thematic Mapper) images of band 4,3,2 taken in 1995 and 2000 as data resources, this paper carried out study on LUCC of Zhan gye oasis in recent five years by interpretation according to land reso urces classification system of 1:100,000 Resources and Environmental Data base of the Chinese Academy of Sciences. The results show that great changes have taken place in landuse/landcover in Zhangye oasis since 1 995: (1) Changes of landuse structure show that cropland and land for urban c onstruction and built-up area increased, on the contrary, water area an d grassland decreased. These changes reflect the deterioration of eco-e nvironment and the acceleration of urbanization, and also indicate the problems existing in the arrangement of water and land resources betw een the upper and lower reaches of the Heihe River. (2) Regional diff erences of landuse/landcover are evident, characterized by following asp ects: in Sunan County located in Qilian Mountain area, unused land an d grassland decreased, but cropland and land for urban construction an d built-up area increased. In Minle and Shandan counties located in f oothills, unused land, water area and cropland decreased, but grassland and land for urban construction and built-up area increased. In Zhan gye City, Linze County and Gaotai County located in plain area of th e middle reaches of the Heihe River, unused land, water area and gra ssland decreased, while woodland, cropland and land for urban construction and built-up area increased.

Assessment of Stakeholders’ Perceptions of Landuse/Landcover Change Drivers in Abuja, Nigeria

Landuse/Landcover(LULC)changes are recognised as some of the major causes of environmental problems like land degradation and climate change.To achieve sustainability,we need to properly understand such changes in order to have adequate information that will enable us to design and implementing measures to mitigate their negative impacts.Doing this particularly requires a proper understanding of how stakeholders perceive the changes in general and their drivers in particular.Unfortunately,not much is known for many areas about the perspective of landuse stakeholders on drivers of LULC changes.This paper reports the results of a study conducted to examine the perceptions of different landuse stakeholders on drivers of LULC changes in Abuja Federal Capital Territory,Nigeria.Questionnaire survey was utilised,involving 514 households across four settlements,2 rural(Karshi and Orozo)and 2 urban(Nyanya and Karu)towns in the territory,which were complimented with Focus Group Discussions were conducted.The results obtained showed that urban dwellers are largely aware of drivers of changes in socio-economic drivers(physical development on lands,more commercial complex development and more institutional development).Rural dwellers are largely aware of environmental drivers of LULC changes(bush burning,livestock overgrazing,collections of wood and medicinal plants,and agricultural expansion).It was concluded that there is the need to bring about a harmonisation of the perceptions of LULC change drivers by the rural and urban dwellers so as to bring about a common front understanding and responding to LULC changes in the study area.

利用遥感技术进行全球测图项目中的中国土地利用覆盖和植被分类图的制作ProduceLanduse&La

全球测图是联合国为推动“全球空间数据基础设施”建设而开展的一项国际性合作计划项目 ,是在全球测图国际指导委员会 (ISCGM)指导下各参加成员国、地区共同合作旨在开发出一组包括全球范围的高程、植被、土地利用、土地覆盖、交通网、居民地、水系和行政边界 8个专题图层的 1∶ 10 0万的数字地理数据集。就开发全球测图中中国数据集的植被、土地利用。

Watershed Characteristics and Landuse Analysis of Govindsagar Catchment, Lalitpur (UP) India Using Remote Sensing and GIS Techniques

Watershed characteristics and land use/land cover study is necessary, for improved decision-making and for the resource management strategies. The methodology necessitates the provision of the base map from SOI toposheet, delineation of drainage, preparation of slope and flow direction map using ASTER data and for the land use/land cover change detection, visual interpretation has been carried out using IRSP6-LISS-III data of 2005 and 2015. The land use/land cover analysis discloses several categories of land cover as well as land use present in Govindsagar variation from 2005 to 2015. The study area is mainly cramped to cultivated land and uncultivated land which show changes since last decade, there is an increase in cultivated land of about 4.86% of the geographical area where as uncultivated land (fallow land) shows a decline of 1.61% of the total geographical area, morphometric analysis reveals that area has impermeable subsurface materials and mountainous relief with dendritic drainage pattern with low surface runoff.

Establishing landuse/cover change patterns over the last two decades and associated factors for change in semi arid and sub humid zones of Tanzania

This study investigated landuse cover change patterns and established potential environmental and social factors that have contributed to changes in two zones namely sub humid and semi-arid found in southern highland and central parts of Tanzania respectively. The overall objective was to understand change patterns;the process evolves and clearly isolates various factors that have contributed to the changesover the last 20 years. A total of four villages,two in each zone were involved whereby historical land use cover changes were analysed using remote sensing techniques. To do so satellite imageries for1991 and 2011 and those of1986 and 2009 for sub humid and semi-arid zones respectively. Factors for changes were established through focus group discussions (FDGs) with a total of 80 participants (20 per village) and household (HH) interviews subjected to 10% of the total number of HH per village. Both woodlands and bush lands decreased in the expense of mixed farming in both sub humid and semi- arid zones to a maximum of 121% and 146.8% respectively. Wetland farming also increased particular in sub humid zone. In general, both environmental and social factors were found to have contributed to LUCC in various magnitudes in both zones. Such observed change on landuse will continue and it is recommended that there is a need to have in place and implement proper landuse plan also have capacity building programs on climate and land management issues for both livelihood and ecosystem sustainability need to in place.

Monitoring and Evaluation of Soil Changes Under Landuse of Different Patterns at a Small Regional Level in South China

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Land Capability Index Mapping for Waste Disposal Landuse Option Using Geographic Information System (GIS) in Enugu Area, South Eastern Nigeria

The projected 300% growth rate in the population of Enugu area and its environs by the year 2020 and the expected increase in waste generation necessitated the need to map out areas for waste disposal for future utilization and as a protective strategy for the environment in Enugu area. Land capability index mapping using Geographic Information System (GIS) is one of the appropriate tools required for solving this problem. A total of 12 landuse determinants were selected as thematic data layers, and as basic factors influencing the choice of waste disposal landuse option in the area. The themes (thematic maps) generated from field/laboratory measurements and from literature, include slope, water table, surface and subsurface water conditions, elevation, geology, soil, drainage and geo-structural stability (fault, erosion, landslide and flooding) maps. The maps were scanned, digitized, georeferenced, and polygonized using autocard drawing capabilities to convert them into vector format and later exported to arc view software for analysis. The final processing using overlay model builder yields layers that display areas of preferred waste disposal sites in a map form, which generally shows areas of varying suitability (suitable, moderately (low) suitable and unsuitable). The waste disposal map of Enugu area shows that blocks1 (Obeagu area) and 3 (Ebe/Nsude areas) represent suitable and unsuitable areas, respectively, while block 2 (Ngwo area) has low suitability for waste disposal.

Analysis of the Relationship between Landuse and Non-point Source Pollution in Ashi River Basin

Landuse is one of the most influential factors of non-point source pollution. Based on the three-year landuse data( 2000,2005 and 2008),Arc GIS and Fragstat were used to analyze the landuse type and the change of landscape pattern. The relationships between landuse and non-point source-total nitrogen( NPS-TN) and nonpoint source-total phosphorus( NPS-TP) were discussed with the methods of spatially statistical analysis,landscape pattern analysis and principal component analysis. The study results conveyed that agricultural land and forestland,which accounted for over 92% of the study area,were the major landuse type of Ashi River Basin.Meanwhile,the NPS pollution had close connections with landuse type and landscape pattern. When it comes to landuse type,the export risks of NPS-TN and NPS-TP were agricultural land > urban land > grassland > forestland. As for landscape pattern,NPS-TN and NPS-TP were positively related to SHDI and SHEI, while negatively connected with LPI,AI and COHESION. Therefore,the study could reach the conclusion that the more fragmented and complicated the landscape patterns were,the more serious the NPS pollution was.

Quantifying Spatiotemporal Change in Landuse and Land Cover and Accessing Water Quality: A Case Study of Missouri Watershed James Sub-Region, North Dakota

Spatial causal effects on water quality are essential in identification of vulnerable watersheds. Modelling landuse variables is an effective method of projecting localized impairment. This study presents an integrated index, designed to gauge the ability of an 8-digit Hydrologic Unit Code watershed in its ability to produce clean water. This index, IAPCW, can be successfully applied on a geospatial platform. In this study we utilized IAPCW to address forest cover dynamics of an impaired watershed, that is, Missouri Watershed James Sub-region in North Dakota. Specific parametric functions were analysed and combined within a customized GIS interface to provide a multi-faceted structured technique to derive IAPCW. These included ambient forest cover, housing density, agricultural land, soil erodibility and road density;it can be lucidly ascertained that where a prevailing forest cover undergoes conversion processes, the secondary effect may spur an exponential increase in water treatment costs. These parameters when projected statistically validated temporal and spatial relations of landuse/land cover dynamics to nutrient concentrations especially those that would be noted at the mouth of the watershed. In this study, we found that the levels of Total Dissolved Solids (TDS) were much higher for the years 2014 to 2016 with a discernible increased alkalizing effect within the watershed. When IAPCW was compared to Annualized Agricultural Nonpoint Source (AnnAGNPS), the spatial distribution generated by the AnnAGNPS study showed that fallow areas produced significant amounts of sediment loads from the sub-watershed. These same locations in this study generated a low IAPCW.

The non-point output of different agriculture landuse types in Zhexi hydraulic region of Taihu Basin

This paper takes Zhexi hydraulic region in Taihu Basin as a study area. On the basis of hydraulic analysis function of Arcgis8.3, the drainages were delineated by selecting the monitoring points and discharge stations as outlets. The landuse map were finished by denoting the TM/ETM image. The precipitation map was finished by spatial interpolation according to the rainfall monitoring records. Overlaying the drainage boundary, landuse map and precipitation map, the rainfall, different landuse type area, and runoff pollution concentration and runoff were calculated. Based on these data in different sub-watersheds, by Origin7.0 regression tool, an equation is established to predict runoff using the relationships between runoff, precipitation depth and land use patterns in each of the sub-watersheds. Selecting the sub-watershed which is mainly composed of forest landuse type, the mean runoff concentration (MRC) from sub-watershed has been estimated. The mean runoff concentration of farmland has been estimated by the same methods after the contribution of forest landuse type was removed. The results are: for the forest landuse type, the mean runoff concentrations of COD, BOD, Total N and Total P are 2.95 mg/l, 1.080 mg/l, 0.715 mg/l, and 0.039 mg/l, respectively; for the farmland, the mean runoff concentrations of COD, BOD, Total N and Total P are 5.721 mg/l, 3.097 mg/l, 2.092 mg/l, and 0.166 mg/l, respectively. By using these results, the agriculture non-point pollution loads have been assessed. The loads of COD, BOD, Total N and Total P in Zhexi region are 14,631.69 t/a, 6401.93 t/a, 4281.753 t/a and 287.67 t/a, respectively.

THE LAND RESOURCE AND LANDUSE OF HONG KONG

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A STUDY ON REGIONAL DIFFERENCE OF CHINA＇S PAID URBAN LANDUSE SYSTEM AND GRADING

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An Integrated Remote Sensing and GIS in Monitoring Landuse and Land Cover Change in Egbeda Local Government Area, Oyo State, Nigeria

Effective planning relies on accurate and up-to-date information on existing land use and land cover. The timely detection of trends in land use and land cover change and a quantification of such trends are of specific interest to planners and decision makers. The aim of this research is to use remote sensing and GIS to monitor landuse and land cover change in Egbeda Local Government Area, Oyo State with a view to determining how useful such information can be to planners and decision makers for effective urban management. The research was conducted using remote sensing and Geographical information System at determining the trend and extent of land use and land cover change and its driving force in Egbeda Local Government Area, Oyo State. The methods used include: digitization, digital image processing and spatial analysis using an inverse distance weighted (IDW) technique, Maximum likelihood supervised classification and post classification change detection techniques were applied to Landsat imageries acquired in 1984, 2006 and 2018. Imageries were classified into built-up area, vegetation, bare surface, cultivation and water body. The results of the analysis obtained showed drastic change in built-up area which rose to 32.8% from 25.4% between 1984 and 2018 periods. To reduce the effect of land use expansion in the study areas, policy measures were recommended which include proper inventory of land use and land cover, regular monitoring of urban areas spread of development and regional development programs. These will enable the government, stakeholders, policy makers and planners to make informed decisions provided by these technologies to attain and sustain future urban development.

Study on the Landcover Changes Based on GIS and RS Technologies: A Case Study of the Sanjiangyuan National Nature Reserve in the Hinterland Tibet Plateau, China

With global warming and increased human activity, more and more ground surface areas have been affected, which leads to the creation of many problems. To understand the ecological environment changes in a typical alpine region, information on landcovers changes in the study area from 2000 to 2020 was obtained by combining remote sensing, geographic information system, and traditional statistical analysis for the Sanjiangyuan National Nature Reserve on the Qinghai-Tibet Plateau, China. The results show that the changes of surface cover in Sanjiangyuan National Nature Reserve are relatively concentrated, mainly distributed in the sections of south, northwest, central, and northeast, with the area of the changed regions and the unchanged regions being 31,127.45 km2 and 271,941.37 km2, respectively. The transformation between the various types of ground landcover is mainly characterized by a shift from other types to grassland and from grassland to bare land. And the regions of change are mostly concentrated between 3500 - 4600 m in elevation.

基于支持向量机的蓄水工程土地利用分类与动态变化

为进一步恢复和重建蓄水工程建成前后土地利用变化的历史过程,更好掌握和预报土地利用转移方向,本文利用支持向量机理论开展了土地利用类型解译的适应性研究,通过梳理土地利用动态变化,剖析了蓄水工程建成前后土地利用结构的自适应调节能力和演变方向。结果表明:(1)依靠自学习和自适应等优势能力,支持向量机解译土地利用分类的总体精度高达91.7%、Kappa系数为0.90;除耕地生产者精度相对较低外,水体、林地等其他土地类型具有较高的分类识别能力。(2)利用谷歌地球引擎(GEE)平台梳理土地利用类型演变过程发现,受“三北防护林”工程二阶段(2001—2020年)等项目实施影响,建设用地、林地面积出现较大增幅,其中,林地面积较2000年实施初期增加了近5倍。(3)工程建设运行后林地和建设用地近2/3面积保持了原貌,水体和未利用土地受水利和城建工程影响,原貌类型超过65%以上面积变成了其他类型;“三北防护林”工程加快了林地面积的增加和草地植被覆盖度的提高,低覆盖度草地转移到中、高覆盖度草地的面积净增幅达48.0%、50.2%。

山江海耦合关键带生态系统服务价值时空变化及其权衡研究

[目的]量化和分析山江海耦合关键带生态系统服务价值及时空变化,有助于深入了解其生态系统服务现状,进而阐明山江海耦合关键带生态服务之间的权衡/协同关系,对提高生态系统服务之间相互作用的认识,促进区域全面可持续发展和生态环境保护与修复具有重要意义。[方法]基于1990—2020年7期土地利用数据及结合修订后的当量因子表,运用网格法、地理加权回归等方法分析了山江海耦合关键带1990—2020年ESV时空变化和各项生态系统服务相互关系及其空间分异特征。[结果]1990—2020年山江海耦合关键带总ESV从788.55亿元增加至792.30亿元,增幅为0.48%,林地、耕地、水域地类ESV较高,为区内总ESV主要贡献因子,建设用地ESV较低,ESV在空间上呈现从西北向东南降低的趋势;1990—2020年各项生态系统服务相互关系以协同关系为主,约占85.45%,其中权衡高值区主要分布在山江海耦合关键带中部及南部地区,低值区主要分布在百色市喀斯特山区;协同低值区主要分布在人口密集、人类活动频繁、经济较为发达的市县级城区及沿海地区。[结论]1990—2020年山江海耦合关键带生态系统服务整体协调且保持动态平衡,食物生产活动会影响其他生态服务的能力,未来地方应严格把控生产活动开发边界,注重对生产地区的环境保护与修复。

土地利用对流域水源涵养及水质净化的影响——以乌江流域为例

乌江流域是长江上游重要的水源涵养区和生态屏障,基于InVEST模型中水源涵养和水质净化模块,利用2000-2020年3期土地利用为数据源,对乌江流域水源涵养、水质净化服务时空变化及其土地利用变化响应进行了分析。结果表明:(1)乌江流域平均水源涵养总量达到449.13×10^(9)m^(3),在时间上呈现先减少后增加的趋势,空间上呈现由西到东逐渐递增特征。不同土地利用类型中水源涵养能力大小依次为草地>林地>耕地;(2)水质净化方面,2000-2020年总氮(TN)年均输出总量均在3.2×10^(4)t以上;总磷(TP)年均输出总量均在3.0×10^(2)t以上,高强度输出区域主要分布在耕地覆盖区域,低强度输出区域主要分布在林地、草地覆盖区域;(3)流域土地利用变化对水源涵养、水质净化的响应主要体现在作用强度、面积变化、转化类型等方面,草地、林地与水源涵养和水质净化呈明显的正相关关系,耕地与水质净化呈负相关关系。研究有助于山区生态服务研究的发展,结果可为乌江流域土地利用格局优化调整和水质保护、水污染控制、水资源配置提供科学依据。

西辽河上游生境质量时空演变特征与影响机制

西辽河上游是我国辽河流域的重要水源地,其生境质量的好坏关系到下游流域生态安全和人类福祉。然而针对西辽河上游生境质量及其影响机制的研究还有待深入。基于ArcGIS软件、InVEST模型,定量分析了西辽河上游1980—2018年土地利用和生境质量的时空演变特征;并进一步探究了西辽河上游生境质量变化的主要驱动因子。结果表明:(1)1980—2018年,西辽河上游草地面积较1980年下降了21.93%,其中大部分转化为林地(7719.09 km^(2))、耕地(6014.90 km^(2))和裸地等(3025.71 km^(2))等,各斑块的空间分布异质性增加;尽管研究期内,林地面积较基期大幅度提升了48.67%,但全区域平均生境质量指数由0.74下降到0.72。(2)该地区无论在区域本底环境和区域社会经济发展水平上,均对于西辽河上游的生境质量改善产生了积极作用,年均气温(0.218)、降水(0.229)、地区生产总值(0.850)和受教育程度(0.132)与生境质量指数呈现较为明显的正相关关系;然而,本地区城镇化速率(-1.137)、景观分离度指数(-0.532)和道路的扩张(-0.394)与生境质量指数呈现较为明显的负相关,可见快速的城镇化所引起的人类活动加剧是导致区域生境质量的下降的重要诱因。本研究旨在为平衡区域发展和生态保护,为以半干旱农牧交错带地区为代表的生态脆弱区可持续发展提供科技支撑。

粤北鹿颈水库小流域土壤有机碳分布特征及其影响因素

土壤有机碳是土壤养分和质量评估的重要指标之一,在小流域尺度上,研究土壤有机碳(SOC)含量水平和垂向的分布特征及其主要影响因素对土地利用的科学管理具有重要意义。以粤北英德市鹿颈水库小流域为研究对象,通过采集流域内茶园(英红12号和英红9号)、桉树林、马尾松林和次生林等4种主要土地利用类型的土壤,测定土壤的粒度组成、土壤容重(BD)、pH、电导率(EC)、SOC、颗粒有机碳(POC)、全氮(TN)、碳氮比(C/N),以及土壤的δ13C和δ15N,结合采样点的坡度、坡向以及凋落物的质量和厚度,采用冗余分析研究SOC和POC含量的主要影响因素。结果表明:1)鹿颈水库流域土壤pH在4.2~5.8之间,出现土壤酸化现象,土壤质地均为粉壤土,不同土地利用类型之间土壤pH、EC、TN含量、C/N及δ13C、δ15N差异显著(P<0.05);2)在0~40 cm的土壤深度,SOC和POC含量均随深度的增加而降低,变化范围分别为0.5%~1.3%和1.2~3.9 g/kg,表现出明显的表聚性,但不同土地利用类型之间SOC和POC含量没有明显差异;3)本研究所选取的土壤因子、地形因子和环境因子可以解释SOC和POC含量78.1%的变异,其中土壤因子中的C/N、TN含量、pH、土层深度和BD是影响水库流域SOC和POC含量变化的主要因素,SOC和POC含量与C/N、TN含量呈显著正相关,而与土壤pH、土层深度和BD呈显著负相关。