BIODIVERSITY AND LAND‐USE CHANGE IN THE AMERICAN MOUNTAIN WEST

ABSTRACT. Rural private lands in the Mountain West of the United States are undergoing a profound land‐use conversion, from agriculture to low‐density residential or exurban development, though little scientific study documents the ecological consequences of this change. Nongovernmental conservation organizations are working with ranchers to keep rangeland out of development and in ranching, ostensibly because these organizations believe that biodiversity is better protected on ranches than on exurban developments. We compared plant and wildlife communities across the principal rural land uses in the Mountain West: protection, livestock ranching, and exurban development. Native plant and faunal biodiversity was better maintained on ranches and protected areas than on exurban developments. Exurban developments favored species that were nonnative or adapted to human‐altered environments. The continued conversion of ranches to exurban development suggests a long‐term alteration of the region's natural heritage.     

Topographic thresholds in gully development on the hillslopes of communal areas in Ngqushwa Local Municipality, Eastern Cape, South Africa

The relationships between the spatial distribution of gully erosion and topographic thresholds in the form of slope angle, position and configuration, as well as land use change in the form of abandoned lands were examined in several affected catchments of the Eastern Cape Province, South Africa. Land use and permanent gullies were mapped, digitized from orthophoto maps in Arc/info 3.5.2 GIS and converted to shapefiles using ArcView 3.2 GIS. Relationships between the mapped phenomena and topographic variables were sought using a Digital Elevation Model (DEM) in Idrisi Kilimanjaro GIS. A comparison between areas with a high potential for gullying and actual gully erosion was made using the Stream Power Index (SPI) as a surrogate for critical flow shear stress. Field surveys were also conducted to assess the present condition of the gullied sites as well as to validate DEM derivations.Seventy five percent of the gullied area was noted to lie on abandoned lands. A predominance of gullying in concave bottom lands was also identified. The SPI values highlighted a distinct preferential topographic zone for gully location. A conceptual model depicting the interaction between land use and topographic parameters to induce gully erosion was developed. This should assist local authorities to develop a policy regarding management of abandoned lands.     

元阳县土地利用空间格局及其变化的图谱方法研究

信息图谱为区域土地利用空间格局及变化提供了一种谱系化、定量化与定位化相结合的研究方法.以云南省元阳县为例,在遥感、GIS空间分析和统计分析模型的支持下,从土地利用时空演变模式、空间扩展过程、斑块的空间分布特征三方面建立土地利用空间格局及变化信息图谱,并对其图谱特征进行分析.结果表明:土地利用时空演变征兆图谱更直观形象地揭示了区域土地利用变化的基本模式,提供了时空复合的表达方式;土地利用斑块形态与空间扩展图谱的建立应用空间格局研究中的相关概念和方法,将微观、宏观层次的图形信息与变化过程相结合;利用等步长变距离缓冲区分析法建立的VCM曲线可直观地描述不同土地利用类型斑块的空间分布特征及不同研究时段内其空间分布特征的变化情况.     

深圳土地利用时空变化与地形因子的关系研究

引入GIS空间分析和数字地形模型(DEM)技术,利用土地利用数据和地形数据,定量分析土地利用时空变化与地形因子的关系,从土地利用空间分布、土地利用转移和土地利用变化速度3方面总结地形因子对深圳土地利用时空变化的影响特征及规律。结果表明:在深圳土地利用时空变化过程中,地形因子对土地利用变化的影响作用明显,在不同地形级别上土地利用分布、土地利用转移和土地利用变化速度等均表现出不同的时空变化特征。     

利用PRA方法研究小尺度区域土地利用变化--以科尔沁沙地尧勒甸子村为例

土地利用变化研究可涉及多个时空尺度,目前正由全球性研究不断转向针对性的区域性研究。典型区域的小尺度研究是其研究的一个重要方面。参与性农村评估(PRA)是一种通过与研究地区居民进行非正式访谈来对地方的实际情况有所了解的方法。文章借助PRA结合实地测量,以科尔沁沙地东南部尧勒甸子村为例对小尺度区域的土地利用变化进行初步研究。绘制一系列尧勒甸子村建国以来各个时代的土地利用图,重建和恢复了其50年来的土地利用过程,并运用GIS对其土地利用变化进行了研究。     

哈尼梯田土地利用空间格局及其变化的信息图谱研究

以云南省元阳县为例,建立土地利用空间格局及变化信息图谱,对其图谱特征进行分析。结果表明:土地利用时空演变征兆图谱更直观形象的揭示区域土地利用变化的基本模式,提供时空复合的表达方式;土地利用斑块形态与空间扩展图谱的建立应用空间格局研究中的相关概念和方法,将微观、宏观层次图形信息与变化过程结合;土地利用变化景观特征图谱建立以度量空间格局变化为目标的景观指数体系。     

发展时态GIS的可操作性时空数据模型

当前GIS广泛采用的空间数据模型不足以满足时态GIS发展的需要。该文探讨时态GIS所需的、可操作性时空数据模型,并且以土地利用和交通发展的时空相互作用为例,说明如何设计和实施相关的时空数据模型,用于支持发展时态GIS。     

Spatiotemporal analysis of rural–urban land conversion

Understanding the complexity of urban expansion requires an analysis of the factors influencing the spatial and temporal processes of rural–urban land conversion. This study aims at building a statistical land conversion model to assist in understanding land use change patterns. Specifically, GIS coupled with a logistic regression model and exponential smoothing techniques is used for exploring the effects of various factors on land use change. These factors include population density, slope, proximity to roads, and surrounding land use, and their influence on land use change is studied for generating a predictive model. Methods to reduce spatial autocorrelation in a logistic regression framework are also discussed. Primarily, an optimal sampling scheme that can eliminate spatial autocorrelation while maintaining adequate samples to allow the model to achieve the comparable accuracy as the spatial autoregressive model is developed. Since many of the previous studies on modeling the spatial complexity of urban growth ignored temporal complexity, a modified exponential smoothing technique is employed to produce a smoothed model from a series of bi‐temporal models obtained from different time periods. The proposed model is validated using the multi‐temporal land use data in New Castle County, DE, USA. It is demonstrated that our approach provides an effective option for multi‐temporal land use change modeling and the modeling results help interpret the land use change patterns.     

中国耕地和农村宅基地利用转型耦合特征与机制(英文)

Land use transition refers to the changes in land use morphology (both dominant morphology and recessive morphology) of a certain region over a certain period of time driven by socio-economic change and innovation, and it usually corresponds to the transition of socio-economic development phase. In China, farmland and rural housing land are the two major sources of land use transition. This paper analyzes the spatio-temporal coupling characteristics of farmland and rural housing land transition in China, using high-resolution Landsat TM (Thematic Mapper) data in 2000 and 2008, and the data from the Ministry of Land and Resources of China. The outcomes indicated that: (1) during 2000-2008, the cor-relation coefficient of farmland vs. rural housing land change is -0.921, and it shows that the change pattern of farmland and rural housing land is uncoordinated; (2) the result of Spear-man rank correlation analysis shows that rural housing land change has played a major role in the mutual transformation of farmland and rural housing land; and (3) it shows a high-degree spatial coupling between farmland and rural housing land change in southeast China during 2000-2008. In general, farmland and rural housing land transition in China is driven by socio-economic, bio-physical and managerial three-dimensional driving factors through the interactions among rural population, farmland and rural housing land. However, the spatio-temporal coupling phenomenon and mechanism of farmland and rural housing land transition in China are largely due to the "dual-track" structure of rural-urban develop-ment.     

中国耕地和农村宅基地利用转型耦合分析

土地利用转型,即在社会经济变化和革新的驱动下,某一区域在一段时期内由一种土地利用形态转变为另一种土地利用形态的过程。在中国,耕地和农村宅基地乃土地利用转型的重要源头。本文综合利用2000 年和2008 年两期Landsat TM 影像解译土地利用数据及2000-2008 年国土资源部土地利用年度变更调查数据,分析了中国耕地和农村宅基地利用转型的时空耦合特征。研究表明：① 2000-2008 年期间,中国耕地面积与农村宅基地面积变化的相关系数为-0.921,呈现出明显的增减逆协同演进格局;② 耕地—宅基地变化相关系数与农村宅基地利用变化率的Spearman 等级相关分析结果表明,在耕地和农村宅基地利用的相互转化过程中,农村宅基地利用的变化起主导作用;③ 通过计算全国各省2000-2008 年间的耕地—宅基地变化耦合系数,发现期间耕地和农村宅基地利用变化耦合程度高的省份主要分布在胡焕庸线的东南部。社会经济—生物自然—土地管理三维驱动因素通过“农村人口—耕地—农村宅基地”三者之间的相互联系与相互作用驱动着耕地和农村宅基地利用的转型。然而,耕地和农村宅基地利用转型的时空耦合现象及其发生机制在很大程度上要归因于中国特殊的城乡二元结构社会体制。     

深圳市地形对土地利用动态的影响

基于RS和GIS的技术支持,以深圳市为案例,利用多时段土地利用数据和地形数据,分析土地利用变化的时空分异,研究城市地域地形对土地利用动态的影响。分析表明,土地利用在空间上的变化引起其垂直重心的变化,耕地重心降低,林地和建设用地重心上升。深圳市地形对土地利用动态有明显的制约作用,主要表现为:随着高程和坡度的升高,土地利用动态度大致呈降低趋势。随着城市化的加深,同一高程带和坡度带上土地利用动态度呈加大趋势。土地利用动态度的情景分析指出,在自然景观时期、农业景观成熟期和后城市化时期,土地利用在高程带和坡度带上都比较稳定,动态度低;在这三个时期之间是农业化时期和快速城市化时期,土地利用动态度高。     

Sustainable land-use patterns for arid lands:A case study in the northern slope areas of the Tianshan Mountains

Sustainable land use patterns are ecological and economic prerequisites of regional sustainable development. This is especially true for arid lands, where the environment is wholly fragile thanks to extremely limited precipitation, and where human activities have greatly transformed natural desert system by clearing natural vegetation, expanding oases and even building dams on inland rivers. However, the current studies on land use patterns are still characterized by field investigations and case studies, with almost no solid scientific basis. This paper holds that land types and their combination patterns are the principal basis for designing sustainable land use patterns, and that GIS and RS-based large-scale land type mapping and the study of their spatial combination structures should be coordinated with the demand of social development. The existing environmental problems induced by irrational land use mostly result from their deviation from the natural properties of land types. Taking the northern slope of the Tianshan Mountains (NSTM) as an example and considering land type patterns as the basis of land use patterns, this paper improves the vertical oasis- and-mid-mountain two-belts development model and the sustainable mountain land use model for arid lands put forward in recent years; and in terms of oases patterns, it outlines oasis development models, including intensive land use pattern in alluvial-diluvial fans, moderate agricultural development pattern in alluvial plains, and ecological land use pattern in river-end oases.     

地形因子对京西门头沟区土地利用/覆盖变化的影响

以土地利用数据和数字高程模型(DEM)为基础,运用GIS对空间数据和属性数据的管理和分析功能,用高程、坡度、坡向3个地形因子分析了1990年与2005年北京门头沟地区的土地覆盖现状以及土地利用动态变化度。结果表明,地形因子对土地利用类型的分布规律有明显的影响,研究区在最近的15 a农业用地减少,城镇建设用地大幅度增加,社会经济和政治因素对土地利用/覆盖动态变化的驱动作用显著。     

土地利用变化研究中的GIS空间分析方法及其应用

土地利用变化研究尤其是空间变化研究 ,离不开 GIS的空间分析方法。该方法的数据基础主要是矢量格式的土地利用图件和遥感解译制图成果 ;模型基础包括 GIS的时空数据模型、属性数据模型和提取土地利用变化特征的原理模型 ;而数据处理过程则涉及GIS系统的数据转换功能、编辑功能、空间分析功能、数据库操作功能、空间统计分析功能以及图形显示功能等。本文结合北京市土地利用变化的实例分析 ,从上述三方面详细阐述了 GIS的空间分析方法及其在土地利用变化研究中的应用。     

1960-2010 年贵州省喀斯特山区陡坡土地利用变化

基于GIS 与RS技术, 以贵州省喀斯特山区坡度大于25°的区域为研究对象, 利用1960 年1:50000 地形图、1990 年Landsat TM遥感影像以及2010 年的环境减灾卫星(HJ-1A/1B)影像, 解译获取1960、1990、2010 年3 个时间点的土地利用数据, 并结合贵州省水文地质图、坡度图进行陡坡土地利用变化分析。结果表明:①1960-1990 年的30 年间, 有林地、灌木林、水体呈减少趋势, 其中灌木林减少的最多, 其次是有林地;而草地、建设用地、裸岩和耕地呈持续增长趋势, 其中草地增加的最多, 其次是耕地。②1990-2010 年的20 年间, 灌木林、裸岩、耕地呈减少趋势, 其中耕地减少的最多;而有林地、疏林地、草地、水体呈增长趋势, 其中疏林地增加的最多。③随坡度增加覆盖比例呈降低趋势的土地利用类型为有林地、疏林地、水体、建设用地和耕地;随坡度增加覆盖比例呈增加趋势的土地利用为灌木林、草地和裸岩。     

黄土丘陵沟壑区典型村域土地利用变化及对区域乡村转型发展的启示

深入开展乡村地域土地利用变化和聚落发展规律的研究对于探究乡村地域系统优化、推进城乡融合与乡村可持续发展具有重要意义。论文以延安市碾庄流域为例,基于ENVI和GIS等软件技术,结合Landsat卫星影像、马尔科夫链模型和实地调查,从土地利用转移与交换变化、建筑用地空间转移、社会响应等角度探讨了黄土丘陵沟壑区典型村域土地利用变化特征以及对区域乡村发展转型的影响。研究表明：① 在一系列生态工程措施作用下,碾庄流域生态覆被发生明显改观,主要表现为大量的坡耕地及稀疏生态用地转化为林地,其中,林地面积占比由32.34%(2009年)增加至50.88%(2018年);② 在社会经济发展和延安新城“边缘效应”的影响下,碾庄建设用地呈现向流域的东南和西南方向拓展的趋势,10 a间建设用地面积增加了近75%;③ 在人类活动的主导作用下,黄土丘陵沟壑区的乡村正在朝着生态化和集约化的方向转型发展。研究结果有望为深入理解黄土丘陵沟壑区乡村地域系统结构和优化提供新参考。     

Vertical differentiation of land cover in the central Himalayas

Characterized by obvious altitudinal variation, habitat complexity, and diversity in land cover, the Mt. Qomolangma region within the central Himalayas is one of the most sensitive areas to climate change in the world. At the same time, because the Mt. Qomolangma region possesses the most complete natural vertical spectrum in the world, it is also an ideal place to study the vertical structure of alpine land cover. In this study, land cover data for 2010 along with digital elevation model data were used to define three methods for dividing the northern and southern slopes in the Mt. Qomolangma region, i.e., the ridgeline method, the sample transect method, and the sector method. The altitudinal distributions of different land cover types were then investigated for both the northern and southern slopes of the Mt. Qomolangma region by using the above three division methods along with Arc GIS and MATLAB tools. The results indicate that the land cover in the study region was characterized by obviously vertical zonation with the south-six and north-four pattern of vertical spectrum that reflected both the natural vertical structure of vegetation and the effects of human activities. From low to high elevation, the main land cover types were forests, grasslands, sparse vegetation, bare land, and glacier/snow cover. The compositions and distributions of land cover types differed significantly between the northern and southern slopes; the southern slope exhibited more complex land cover distributions with wider elevation ranges than the northern slope. The area proportion of each land cover type also varied with elevation. Accordingly, the vertical distribution patterns of different land cover types on the southern and northern slopes could be divided into four categories, with glaciers/snow cover, sparse vegetation, and grasslands conforming to unimodal distributions. The distribution of bare land followed a unimodal pattern on the southern slope but a bimodal pattern on the northern slope. Finally, the use of different slope division methods produced similar vertical belt structures on the southern slope but different ones on the northern slope. Among the three division methods, the sector method was better to reflect the natural distribution pattern of land cover.     

苏锡常地区土地利用变化时空分异及其生态环境响应

以苏州、无锡和常州所辖市(区)为分析单元,揭示土地利用变化的时空分异特征,结合对该区域生态环境状况的评价,重点分析土地利用变化时空分异的生态环境响应。结果表明:1980~2000年苏锡常地区土地利用变化的主导类型是城乡建设用地大量扩张和耕地资源急剧减少,土地利用变化类型趋于多样化;土地利用结构存在不同程度的空间差异性,土地利用有序性和综合变化速度也具有明显的空间分异特征,土地利用系统趋向于复杂无序和加速演化;区域多数单元的生态环境状况不断变差,且对土地利用变化时空分异具有明显的响应特征;生态环境状况对土地利用有序性和综合变化速度的响应程度具有明显的区域差异性,而且这种响应和差异性程度都有所加强。     

土地利用动态变化的空间测算模型研究

The spatial calculating analysis model is based on GIS overlay. It will compartmentalize the land in research district into three spatial types: unchanged parts, converted parts and increased parts.By this method we can evaluate the numerical model and dynamic degree model for calculating land-use change rates. Furthermore, the paper raises the possibility of revising the calculating analysis model of spatial information in order to predicate more precisely the dynamic changing level of all types of land uses. In the most concrete terms, the model is used mainly to understand changed area and changed rates (increasing or decreasing) of different land types from microcosmic angle and establish spatial distribution and spatio-temporal principles of the changing urban lands. And we will try to find out why the situation can take place by combining social and economic situations. The result indicates the calculating analysis model of spatial information can derive more accurate procedure of spatial transference and increase of all kinds of land from microcosmic angle. By this model and technology we can conduct the research of land-use spatio-temporal structure evolution more systematically and more deeply, and can obtain a satisfactory result. The result will benefit the rational planning and management of urban land use of developed coastal areas in China in the future.     

中国西南山区稻作梯田的时空演化——以苗岭西江镇和加榜乡为例

稻作梯田是中国南方山区重要的土地利用方式,分析其时空变化规律,对区域土地资源利用、生态环境保护以及农村农业可持续发展具有重要意义。本文基于多源数据获取苗岭山区西江镇（1977—2020年）和加榜乡（1962—2020年）的土地利用分类图,运用景观指数、空间分析和样带分析等方法,研究稻作梯田时空格局与功能的演化特征,以揭示稻田利用与人地关系演变过程及其特殊性变化。结果表明：① 研究区稻田规模长期稳定发展,但近年整体规模有所缩小,斑块破碎化趋势逐渐凸显。在2000年前稻田分布表现出同时向高、低海拔及微坡至急陡坡扩展,2000年后呈反向收缩趋势,种植强度呈相同的变化规律。② 研究区稻田核密度的空间分布,表现出小规模高密度集聚与大规模中低密度分布并存的格局。自2000年以来,两地稻田核密度以小幅变化为主,有明显的“东北-西南”向分布特性。③ 在生产用地导向阶段,大面积林地转为稻田;在生态-经济复合用地导向阶段,稻田规模保持稳定。④ 聚田比指数显示研究区“人多田少型”占比不断上升,这表明部分地区人地矛盾日渐凸显,以西江镇的变化最为强烈。⑤ 依据“林-田-村-河”四素同构的样带分析,稻田功能经历了“生产-生态、经济”的演变过程,与旅游业发展关系密切。研究结果较全面反映了研究区稻作梯田的时空演化特征,有助于促进山区传统稻田资源优化利用和保护传承,在一定程度上为乡村振兴发展提供借鉴。