托木尔峰国家级自然保护区土地利用/覆被生态服务价值变化分析

参照中国陆地生态系统服务价值当量,结合研究区不同土地利用∕覆被类型的生物生产量,研究各土地利用/覆被类型的生态服务价值变化。结果表明：① 1989-2014年,冰川面积增长27.63%,草地增长35.69%,水体减少55.43%,荒地减少13.81%,林地减少9.87%;1989-2002年的区域综合动态度为0.72%,2002-2014年的为0.62%。② 保护区的生态服务价值为52.31×10⁸元/a,突出了保护区重要的生态地位。在保护区11项生态服务功能中,水文调节和水资源供给生态服务功能价值最高,食物和原料生产生态服务功能价值较低。③ 1989-2014年生态服务总价值量降低31.49%,其中冰川和草地的总价值量持续增长27.63%和35.70%,水体和荒地的持续减少55.43%和13.81%,林地的先减22.13%,后增15.75%。在价值构成比例上,1989年水体占主要地位,2014年冰川占主要地位。     

Conservation-induced resettlement as a driver of land cover change in India: An object-based trend analysis

Located in the foothills of the Indian Himalaya, Rajaji National Park was established to protect and enhance the habitat of the Asian elephant (Elephas maximus) and tiger (Panthera tigris). In 2002 the Van Gujjars, indigenous forest pastoralists, were voluntarily resettled from the Chilla Range (an administrative unit of Rajaji National Park) to Gaindikhata, a nearby area where they were granted land for agriculture. In this study we used a variety of remote sensing approaches to identify changes in land cover associated with the resettlement. The methods comprise two main approaches. First, we used object-based image analysis (OBIA) to identify the pre-resettlement land cover classes of use areas (representing agricultural expansion and adjacent areas of grazing, and collection of fuelwood and fodder) and recovery areas (representing areas where settlements were removed, and the adjacent areas of resource use). Secondly, we used trend analysis to assess the gradual and abrupt changes in vegetation that took place in use and recovery areas. To conduct the trend analysis we used BFAST (Breaks For Additive Season and Trend), which separates seasonal variation from long-term trends, and identifies breaks that can be linked back to disturbances or land cover changes. We found that the OBIA classification yielded high average class accuracies, and we were able to make class distinctions that would have been difficult to make using a traditional pixel-based approach. Pre-resettlement, the recovery areas were classified as mixed forest and riparian vegetation. In contrast, the use areas were classified primarily as grass dominated, brush dominated, and plantation forest, and were located relatively far away from riparian areas. Following the resettlement, the trend analysis showed a sudden change in the seasonal variation of NDVI in areas converted to agriculture. Areas neighboring the new agricultural land experienced sudden decreases in NDVI, suggestive of disturbances, at a higher rate than the same land cover types elsewhere. At the same time, these neighboring areas experienced a gradual overall increase in NDVI which could be caused by an expansion of leafy invasive shrubs such as Lantana camara in areas heavily used for biomass collection. The recovery areas also experienced a gradual increase in NDVI as well as sudden breaks to this trend, but we lacked evidence to connect these changes to the resettlement. Our findings support the claim that the resettlement has shifted pressure from more ecologically valuable to less ecologically valuable land cover types, and suggest that to some degree resource use pressure has increased outside the park. The study employs a novel synthesis of OBIA and trend analysis that could be applied to land change studies more broadly.     

Three centuries of land cover changes in the largest French Atlantic wetland provide new insights for wetland conservation

Grassland to cropland conversion has been a major land cover change in wetlands during recent decades. Many conservation strategies have therefore focused on the protection or restoration of grasslands considered the remnant fragments of nature in wetlands before agricultural development. Through the example of the largest French Atlantic wetland (the Marais Poitevin) and using high-resolution historical records documenting landscape changes since the beginning of the 18th century, we propose the first long-term analysis of a wetland conversion at a large spatial scale. We demonstrate that, although the last land cover changes corresponded to significant grassland to cropland conversions, the mid-20th century was characterized by an exceptional grassland cover (90% of the area). We also show that current surface areas covered by grasslands are similar to those of the 18th and 19th centuries, and that grassland to cropland conversion followed a massive decline in the most natural habitats of the wetland such as marshes, salt-marshes and other marine habitats. From a long-term perspective, grassland to cropland conversion is rather a recent change and grasslands can be viewed as the result of agricultural development in this wetland rather than pristine habitats. In contrast, marshes, salt-marshes and other marine habitats can be considered the remnant fragments of nature of conservation interest, although they are neglected in current conservation plans. We discuss the problem of the time-span and the reference state to be considered when analyzing land cover changes and assessing wetland conservation issues at large spatial scales.     

A case study of land cover change (1950-2003) and runoff in a Mediterranean catchment

Mediterranean environments have been subject to major land cover change since the end of the second world war. Housing, agricultural activities, forests, green spaces and other land uses have shifted due to urbanisation and tourism. These changes influence runoff, and municipal authorities often cannot estimate the net impact of complex land cover transitions. During this period, elected representatives have become increasingly sensitive to the risks of flooding and have implemented a number of channel management strategies. The main objective of this case study was to analyse the impact of land cover change on total storm runoff between 1950 and 2003 in a Mediterranean catchment near St Tropez, France. A secondary objective was to compare these changes to the impacts of channel management on bankfull discharge. Aerial photographs were used to classify land cover in 3 urban categories, vineyards and bare soil, forests, and green spaces. Stream discharge was estimated using a distributed event based total runoff approach. After validating the model for a large winter event (114 mm) for 1982, runoff was calculated for the same event for 1950 and 2003. Land cover changes occurred mainly in the alluvial plain area. Total gauge catchment urban area increased from 30.1 ha to 393.8 between 1950 and 2003 at the expense mainly of agricultural land, but this was compensated in part by an increase in grassed area. Some of the loss in vineyards was replaced by clearing forested land on the first hills close to the plain. Bank stabilisation and channel maintenance since the 1980’s reduced surface roughness and increased channel area, thereby greatly increasing bankfull discharge. While the impact of urbanisation on runoff was small, channel management effects increased bankfull discharge substantially. Flood damage from extreme events was not studied here.     

Land use/land cover change detection and prediction in the north-western coastal desert of Egypt using Markov-CA

Detecting land-use change has become of concern to environmentalists, conservationists and land use planners due to its impact on natural ecosystems. We studied land use/land cover (LULC) changes in part of the northwestern desert of Egypt and used the Markov-CA integrated approach to predict future changes. We mapped the LULC distribution of the desert landscape for 1988, 1999, and 2011. Landsat Thematic Mapper 5 data and ancillary data were classified using the random forests approach. The technique produced LULC maps with an overall accuracy of more than 90%. Analysis of LULC classes from the three dates revealed that the study area was subjected to three different stages of modification, each dominated by different land uses. The use of a spatially explicit land use change modeling approach, such as Markov-CA approach, provides ways for projecting different future scenarios. Markov-CA was used to predict land use change in 2011 and project changes in 2023 by extrapolating current trends. The technique was successful in predicting LULC distribution in 2011 and the results were comparable to the actual LULC for 2011. The projected LULC for 2023 revealed more urbanization of the landscape with potential expansion in the croplands westward and northward, an increase in quarries, and growth in residential centers. The outcomes can help management activities directed toward protection of wildlife in the area. The study can also be used as a guide to other studies aiming at projecting changes in arid areas experiencing similar land use changes.     

基于多期数据集的中亚五国土地利用/覆盖变化分析

针对目前中亚地区土地利用变化和分布格局方面的信息相对匮乏,现有资料较为陈旧且零散,无法满足中亚生态与环境变化研究需求的现状,利用全球的UMD, DISCover,GLC2000,GlobCover2005和GlobCover2009的5期土地覆被遥感数据集,提取中亚地区长时间序列土地覆被信息。并针对上述4个土地覆被分类系统无法进行直接对比和变化分析的问题,分别将其综合为4类土地覆被类型：耕地、自然植被、水体和其他,以分析近30 a中亚土地利用/土地覆被变化趋势。中亚土地利用类型多样,草地、裸地、农田、灌丛占绝对优势。自前苏联解体以后,20世纪90年代初至2000年期间,耕地面积大幅度减少,至2010年尽管有所恢复,但仍无法达到20世纪90年代初水平。而自然植被表现出了相反的趋势,这说明在此时间段内,由于社会政治制度的变化和市场经济的建立,耕地发生了较大规模的弃耕,弃耕地通常转换为草地、灌丛等自然植被。近10 a由于社会经济条件的变化,前苏联解体后所弃耕的土地又被收复和重新开发为耕地。90年代初至2000年期间,水体呈现先减少后增加的趋势。利用全球基于多期不同信息源获得的中亚土地覆被数据,尽管分类体系不统一,但均可较好地表征当时地表覆被状况。这在一定程度上弥补了中亚地区土地覆被数据不足的现状。通过对耕地、自然植被、水体及其他土地覆被类型进行大类合并,可基本体现中亚土地覆被的宏观特征和变化趋势。     

黄土高原植被覆盖度变化的地形分异及土地利用/覆被变化的影响

基于16 d合成MODIS NDVI数据提取的时间序列植被覆盖度数据,采用一元线性回归趋势分析,对黄土高原2000-2008年植被覆盖度的时空变化及其地形分异、土地利用/覆被变化的影响进行了定量分析。结果表明：（1）研究时段黄土高原植被覆盖度整体呈快速上升趋势,局部下降;（2）黄土高原植被覆盖度变化存在明显的地形分异,陡坡等植被恢复、重建和保育的主要区域植被覆盖度增速显著;（3）土地利用/覆被变化对植被覆盖度的增加影响突出,土地利用/覆被类型变更区植被覆盖度增速显著高于未变化区域,退耕还林还草区增速尤其突出;（4）土地利用/覆被类型未变化区域植被覆盖度总体上也呈增加趋势,但因植被覆盖度水平相对较高,增速明显低于土地利用/覆被类型变化区。上述结果表明,黄土高原植被保育、植被恢复和重建在植被覆盖度提升方面取得了明显成效。     

大青沟国家自然保护区土地利用与覆盖变化研究

通过对"科尔沁草原大青沟自然保护区沙漠化程度图"的数字化处理以及相关社会、经济活动资料的收集整理,建立了大青沟及其附近地区土地利用与覆盖变化的地理信息系统数据库。同时,对1958年到1981年20多年间该地区土地利用与覆盖的变化进行了分析。结果显示大青沟自然保护区内天然植被得到了很大程度的恢复,面积由1958年的446hm²增加到了1981年的6094hm²。人工林面积也有所增加。与此同时,大青沟保护区周边地区由于不合理的土地利用,引起了以沙漠化发生发展为显著特征的土地退化过程。流动沙丘面积和斑块数由1958年的916hm²和70块增加到了1981年的9221hm²和300块,半流动、半固定和固定沙丘的面积逐渐减少。在可识别的16种土地类型中,其余土地类型的变化相对较小。值得注意的是该地区水体数量由1958年的50个减少到了1981年的25个左右,面积减少了71hm²。在科尔沁沙地这样一个生态环境脆弱的地区建立自然保护区,而保护区附近地区的土地则发生严重退化,无论这种现象与保护区的建立有无关系,都是值得引起注意的问题。     

Modeling spatially non-stationary land use/cover change in the lower Connecticut River Basin by combining geographically weighted logistic regression and the CA-Markov model

Simulating land use/cover change (LUCC) and determining its transition rules have been a focus of research for several decades. Previous studies used ordinary logistic regression (OLR) to determine transition rules in cellular automata (CA) modeling of LUCC, which often neglected the spatially non-stationary relationships between driving factors and land use/cover categories. We use an integrated geographically weighted logistic regression (GWLR) CA-Markov method to simulate LUCC from 2001–2011 over 29 towns in the Connecticut River Basin. Results are compared with those obtained from the OLR-CA-Markov method, and the sensitivity of LUCC simulated by the GWLR-CA-Markov method to the spatial non-stationarity-based suitability map is investigated. Analysis of residuals indicates better goodness of fit in model calibration for geographically weighted regression (GWR) than OLR. Coefficients of driving factors indicate that GWLR outperforms OLR in depicting the local suitability of land use/cover categories. Kappa statistics of the simulated maps indicate high agreement with observed land use/cover for both OLR-CA-Markov and GWLR-CA-Markov methods. Similarity in simulation accuracy between the methods suggests that the sensitivity of simulated LUCC to suitability inputs is low with respect to spatial non-stationarity. Therefore, this study provides critical insight on the role of spatial non-stationarity throughout the process of LUCC simulation.     

Land use and land cover change in Greater Dhaka, Bangladesh: Using remote sensing to promote sustainable urbanization

This study evaluates land use/cover changes and urban expansion in Greater Dhaka, Bangladesh, between 1975 and 2003 using satellite images and socio-economic data. Spatial and temporal dynamics of land use/cover changes were quantified using three Landsat images, a supervised classification algorithm and the post-classification change detection technique in GIS. Accuracy of the Landsat-derived land use/cover maps ranged from 85 to 90%. The analysis revealed that substantial growth of built-up areas in Greater Dhaka over the study period resulted significant decrease in the area of water bodies, cultivated land, vegetation and wetlands. Urban land expansion has been largely driven by elevation, population growth and economic development. Rapid urban expansion through infilling of low-lying areas and clearing of vegetation resulted in a wide range of environmental impacts, including habitat quality. As reliable and current data are lacking for Bangladesh, the land use maps produced in this study will contribute to both the development of sustainable urban land use planning decisions and also for forecasting possible future changes in growth patterns.     

山区土地利用/覆被变化对土壤侵蚀的影响

本文以福建省山区为例,在对福建省水土保持实验站、建瓯市牛坑龙水土保持试验站长期观测、实验资料深入分析对比的基础之上,探讨了土地利用/土地覆被变化对土壤侵蚀的影响规律。分析结果表明,土地利用/土地覆被变化对径流的产生和土壤侵蚀有重要影响,植被的覆盖度的变化直接影响着径流系数和土壤侵蚀模数;植被的覆盖度和径流系数呈负线性关系,随着覆盖度的增加径流系数逐渐减小;植被覆盖度和土壤侵蚀模数为负指数关系,随着植被覆盖度的增大,土壤侵蚀模数急剧下降。     

中国可持续发展问题与土地利用/覆被变化研究

土地利用 /覆被变化 (LUCC)研究 ,已成为全球环境变化和可持续发展领域前沿的核心问题。中国是世界上人多地少、生态与环境问题较为突出的发展中国家 ,目前中国可持续发展所面临的许多问题 ,都与土地利用及其变化有着内在的、必然的联系。因此 ,面向可持续发展战略的实施 ,开展土地利用 /覆被变化的系统研究 ,具有重要的科学价值与战略意义。本文重点对土地利用 /覆被变化与可持续发展重点问题的关系 ,以及面向可持续发展问题的LUCC研究目标、主要内容和技术方法等进行了讨论     

The potential of old maps and encyclopaedias for reconstructing historic European land cover/use change

Continental to global reconstructions of historic land cover/use are important inputs for many environmental, ecological and biogeochemical studies. While local to regional reconstructions frequently make use of old topographic maps and land use statistics, continental to global reconstructions are mostly model-based reconstructions. As a result they are subject to large uncertainties. A wealth of historic land cover/use maps and statistics have been produced and these are now more accessible due to the ending of copyrights and secrecy statuses, enthusiastic hobby communities and national cartographic institutes or cadastres that have a strategy towards data sharing with society. In this paper we made use of historic statistics and old topographic maps to demonstrate the added value for model-based reconstructions of historic land cover/use for Central Europe back to 1900. We harmonized these diverse data types and different types of historic land data were incorporated into the land use reconstructions. The added value of using these data was evaluated using historical maps by performing a reconstruction with and without the historic information. The accuracy of the land allocation in the historic reconstruction was improved by 16.5% using historic maps. Additionally, historic maps improved the representation of the spatial structure of landscapes. The historic land cover/use statistics used showed a strong agreement with independent estimates, like historic maps.     

Spatial features of land use/land cover change in the United States

With the classification data covering American land-use/land-cover (LUCC) with 30 m resolution from the project of National Land Cover Data (NLCD), we normalized them and made their resolution changed into 1 km ×1 km, created the data of American land-use grade and analyzed the spatial distribution and features of American LUCC as well as the influence of population and altitude on the land-use grade in light of methods of sampling analysis and correlation study. Based on the analysis, we concluded that forestry and grassland, accounting for 71.24% of the whole country, has taken the main part of American land cover, and besides, construction and arable land has occupied 19.22% of the total land, the rest of land cover types, including water area, wetland and underdeveloped land, is 9.54% of the country's total. The developing potential of American land resources is enormous with less destroyed and disturbed ecological environment. Although, in some sense, the population and altitude influence the spatial variation of American land-use grade respectively, the influence of spatial variation of altitude and population density on that of land-use grade is not significanct.     

美国土地利用/土地覆盖变化的空间特征

1IntroductionInrecentyears,studyonglobalchangehasbecomethefocus,onwhichstresshasbeenlaidbytodayhumansociety.Inordertodealwithseriesofenvironmentalproblemssuchasdegradationoflandresources,globalwarming,destructionofozonosphereandsoon,andassurethestabilizationandsustainabledevelopmentofworldeconomy,IGBPhasestablishedthestudyframeforglobalchange.Withavastrangeofstudy,researchonglobalchangehasbroughtforwardagreatdealofimportantscientificquestionsrelatedtofeasibilityforhumanelivingoftheEarth.Inth…     

巴西土地利用/覆盖变化时空格局及驱动因素

土地利用/覆盖变化(LUCC)是全球变化研究的热点问题之一。本文采用人机交互方法基于2005 年基准年的Landsat TM/ETM遥感影像修正欧空局GlobalCover 2005 年土地利用数据,进而采用逆时相目视解译法从1980年基准年的Landsat MSS/TM遥感影像数据提取1980-2005 年土地利用/覆盖变化信息,分析其变化的时空格局及驱动因素。结果表明:1980-2005年的25年间,巴西土地利用/覆盖变化面积达79.43万km²,占土地总面积的9.33%。其中,单纯耕地像元面积增加了20.18 万km²;耕地/自然植被镶嵌混合像元区面积增加了10.70 万km²;林地面积减少了53.12 万km²;灌丛与草地净增加21.10 万km²;水体面积增加0.46 万km²;城乡建设用地面积增加7573.87 km²。由此导致热带和亚热带湿润阔叶林生态地理区、热带和亚热带干旱阔叶林生态地理区、热带及亚热带草原生态地理区、草原和沼泽湿地生态地理区、沙漠和旱生植物生态地理区以及红树林生态地理区内分别呈现不同的土地利用/覆盖变化特征。近25 年间,地形地貌、气候、植被等自然地理条件深刻影响着土地利用的宏观格局,而土地利用政策调控、经济及对外贸易发展、人口增加及空间迁移、道路修建等是导致巴西土地利用变化的主要原因。     

Monitoring 25 years of land cover change dynamics in Africa: A sample based remote sensing approach

The study examines the changes in sub-Saharan's natural land cover resources for a 25 year period. We assess these changes in four broad land cover classes – forests, natural non-forest vegetation, agriculture and barren – by using high spatial resolution Earth observing satellites. Two sets of sample images, one ‘historical’ targeted at 1975 and a second ‘recent’ targeted at the year 2000, have been selected through a stratified random sampling technique over the study area, targeting a sampling rate of 1% in each of the strata. The results, presented at eco-region level and aggregated at sub-Saharan level, show a 57% increase in agriculture area at the expense of natural vegetation which has itself decreased by 21% over the period, with nearly 5 million hectares forest and non-forest natural vegetation lost per year. The impacts of these changes on the environment on one site and on the socio-economy on the other site are discussed and possible pressures on human well being are highlighted.     

远程耦合视角下的土地利用/覆被变化解释

传统的土地利用覆被/变化驱动力研究在很大程度上并未充分考虑远距离相互作用的影响,对全球化世界中由远距离相互作用驱动的土地利用/覆被变化日益缺乏解释力。鉴于此,本文旨在将远程耦合（Telecoupling）理论框架引入到土地利用/覆被变化的动力机制研究中来。在概述土地利用/覆被变化驱动力研究的基础上,从驱动力背景的变化出发,切入远程耦合框架的介绍,并基于此给出远距离相互作用驱动土地利用/覆被变化的经验证据;认为远程连接、全球化和城市化是远距离相互作用驱动土地利用/覆被变化的3种主要形式;进而提出建立“时—空—事”三位一体的土地利用/覆被变化解析路径、土地利用/覆被变化的近远程驱动力分解和基于网络的跨系统综合研究是土地利用覆被/变化驱动力研究中应用远程耦合框架的重点内容。     

An assessment of land use and other factors affecting sediment loads in the Rio Puerco watershed, New Mexico

Rapid channel erosion in the Rio Puerco watershed of northwest New Mexico has been attributed to land use, climate changes, and internal channel adjustments. The objectives of this study were to assess (1) the impacts of land uses on sediment load, (2) the quantitative relationships between land use and sediment load, and (3) the effectiveness of different erosion control methods. The impacts of land uses on sediment load were assessed via hypotheses that, holding other erosion-related variables constant, sediment load correlates positively with grazing intensity and with density of unpaved roads, and correlates negatively with the number of erosion control treatments. We calculated the average annual sediment load for 17 subbasins of 0.67–17.97 km² by comparing sediment accumulation at two points in time (mid-1960s and 1999) behind intact sediment retention structures. We assessed land use via grazing records and measurements of unpaved roads generated from aerial photographs. Soil characteristics, vegetation, and physical factors were quantified for each subbasin. Using 18 variables for each subbasin, we employed Mallow's C_p as a selection criterion. We used six statistical models, including multiple regression and principal components analysis, to determine inherent mathematical relationships between significant independent variables and sediment load. The results indicate that sediment load does not correlate with grazing intensity except in small, relatively low-relief basins with fewer bedrock exposures. However, this interpretation may be compromised by the low quality of data available to quantify grazing. Sediment load is highly sensitive to the presence of unpaved roads, which serve as high gradient, channelized conduits of water and sediment during storms. Sediment load does not correlate with erosion control except in the subset of small, relatively low-relief subbasins that also proved sensitive to grazing intensity. Overall, the statistical analyses suggest that the impact of land uses on sediment load can be assessed using the data available although physical factors appear more significant than land use in producing high sediment loads in the Rio Puerco subbasins. Historical erosion control techniques, as implemented in the Rio Puerco watershed, prove largely ineffective against accelerated sediment loads because they have not been appropriately implemented or maintained.     

Unplanned urban growth: land use/land cover change in the Guwahati Metropolitan Area,India

Unplanned urban growth, particularly in developing countries has led to changes in land use/land cover (LULC). Numerous Indian cities face problems of unplanned LULC change due to nominal or non-existent planning efforts compounded by rapid urban population growth. The Guwahati Metropolitan Area (GMA) is one such urban centre. The present study assesses the trajectories of LULC change using Landsat imageries acquired in 1976, 1989, 2002 and 2015. Natural and semi natural vegetated area and artificial and natural water bodies decreased while built-up areas, cultivated and managed areas, and natural and semi natural non-vegetated areas increased. The built-up area increased from 23.9 in 1976 to 115.1 km² in 2015 becoming the dominant land cover class accounting for 41.8% of the total geographical area. During this period, natural and semi natural vegetated land were reduced by 88.9 km² at an annual rate of 2.2 km². Over the years there was an increasing trend of built-up land and cultivated and managed areas in the peripheral areas of the city while natural and semi natural vegetated land diminished. Consequently, as in many other developing countries, there is an urgent need for the governmental authorities and other stakeholders to implement effective urban planning policies.