西安市LUCC预测生态系统服务价值损失

人类活动作用于土地资源,使LUCC（土地利用／土地覆被变化）在全球环境变化过程中起主导作用,随着国际LUCC研究计划的进展,各国依据本国的实际情况开展研究。对西安市以往五年（2000-2004年）的土地利用基础数据开展调查统计分析,建立灰色系统动态GM（1,1）模型,预测2005—2010年西安市土地利用结构变化状况,尝试计算西安市土地生态系统服务价值损失（简称生态损失）,用一种直观经济指标-货币来反映这种生态损失。预测2010年西安市生态损失为331、84×10^6元。     

鞍山市铁矿景观格局变化的遥感调查

采用1997和2007年2个时相的卫星遥感数据,对鞍山市城区周边铁矿典型景观类型的面积及其10年来的变化进行了遥感调查和分析。结果表明,国有矿山采矿场的面积相对稳定,边界无明显变化,民营矿山采矿场面积增加明显。采矿场面积变化与开采方式有关,国有矿山采用深凹露天开采,对地表破坏较轻,民营矿山采用山坡露天开采,对地表破坏较严重。排岩场的总面积有所增加,个别矿区增加明显。复垦绿地有大幅度增加,但仍低于排岩场扩张的速度。     

Effect of soil crust on evaporation and dew deposition in Mu Us sandy land, China

The development of soil crust on sandy land may affect the surface hydrological process. This paper investigates the process of evaporation and dew deposition influenced by different soil surface types which were dominated by sand, primitive biotic crust, and advanced biotic crust, respectively, in the south fringe of Mu Us sandy land in Northwest China from July to September of 2006. The experimental results indicate that the advanced biotic crust could increase evaporation and dew deposition compared to the primitive biotic crust and bare sand although the differences between them were not significant. The average evaporation from advanced biotic crust, primitive biotic crust and sand was 6.8, 6.6, and 6.5 mm/d, respectively, and water content is around 16.2 % in the condition of initially identical soil. The average dew amount on advanced biotic crust was 0.116 mm/d with extreme 0.05 and 0.24 mm/d. The average values on primitive biotic crust and sand were 0.105 and 0.101 mm/d, respectively, with extreme 0.04 and 0.21 mm/d for both treatments. Also, the dew deposition on advanced biotic crust seemed stable and might rest for a longer time than that on primitive biotic crust and sand. The results suggest that the advanced biotic crust possibly facilitates evaporation and dew deposition. Therefore, the development of biotic crust may potentially enhance the hydrological circulation in the upper sand layer in sandy land.     

湖北省土地利用结构变化及其驱动机制分析

采用1996～2004年的统计资料,分析了湖北省土地利用结构变化,研究发现全省耕地大幅度减少,其次是未利用地和牧草地;林地则迅速增加,其次为居民点及独立工矿、园地、其他农用地、交通用地和水利设施用地。随后运用典型相关分析法,以湖北省76个县级行政单位为研究单元,进一步对湖北省土地利用结构变化的驱动因子进行了统计分析,定量诊断出各驱动因子对湖北省土地利用结构变化贡献作用的大小。结果显示,湖北省土地利用结构与社会经济因素之间关系可以用4对典型相关变量表示,耕地、居民点及工矿用地、林地、交通用地、水利设施用地的发展变化分别对应于不同的社会经济驱动因子。     

旅游景区周边环境及范围界定

随着旅游业的快速发展和城镇现代化的推进,旅游景区周边涌现出了许多与景区不协调的问题。同时,随着社会的进步,旅游者对景区所处背景环境的要求和标准却在逐步提高,旅游者对景区的观赏已不仅仅局限于景区内将景区作为一个孤立点对待,因此将旅游资源圈起来进行封闭式开发而忽视周边环境与景区完整性的做法已不能适应游客越来越挑剔的目光。提出了旅游景区周边环境的概念,指出周边环境与旅游景区有密切的关系,是旅游景区的组成部分。论述了周边环境的特征,在此基础上进行了周边环境分类,同时基于规划和评价的实际需要,建议在今后旅游规划中应专门对周边环境进行保护整治规划。认为周边环境应有较确切的地理空间范围,据此提出了确定旅游景区周边环境范围的方法。〖     

四川水土资源可持续利用与生态保护

保护好四川水土资源和生态环境,对保障全国粮食安全,对全国的生态保护与建设和长江中下游地区的经济发展均有十分重要的意义。系统分析研究了四川水土资源与生态保护现状,针对水土流失面广强度大、土地沙化、退化和荒漠化严重、人地矛盾日益尖锐、粮食安全保障问题日益凸显、水资源利用率低、旱灾严重等问题,提出了切实保护耕地资源,确保基本农田保护面积总量不减少、质量不降低;合理确定退耕还林规模,稳定和保护现有耕地面积;加大中低产田土改造力度,节约集约利用有限的土地资源;节约用水,加强水利工程建设,提高水资源利用率和供水能力;加强对水土流失的综合治理等5条水土资源可持续利用与生态环境保护的相应对策与措施。     

基于GIS和分形理论的城市蔓延度研究——以马鞍山市为例

在快速城市化过程中,城市不断扩张而产生的蔓延现象与土地可持续发展紧密相关,合理控制城市蔓延度可以节约资源,促进城市内涵式发展。根据蔓延度内部机理和分形理论构建蔓延测度指标体系,采用GIS方法,通过分维数、空间稳定性等指数,以马鞍山市为例分析研究区城市蔓延度特征和时空差异。研究表明:(1)分形理论适用于城市蔓延度的定量研究;(2)从时间维度看,研究区内部不同区域间的蔓延趋势总体相似,但蔓延程度有所差异;(3)从空间维度看,蔓延度与分维数、建设用地破碎度呈正相关,与空间稳定性指数呈负相关。马鞍山市城市蔓延的机制是土地导向,经济发展是抑制过度蔓延的动力。     

A Methodology Framework for Regional Land-use Change Studies based on Landsat TM images: A Case Study in Northeast China

Abstract

Land-use change is an important aspect of global environment change. It is, in a sense, the direct result of human activities influencing our physical environment. This paper analyzed the land- use change in Northeast China during 1985–2000 based on Landsat TM images. It divides Northeast China into five land-use zones based on the dynamic degree model of land-use: woodland/grassland-arable land conversion zone, dry land-paddy field conversion zone; urban expansion zone, interlocked zone of farming and pasturing and reclamation and abandon zone. The findings include the obvious increase of cropland area, paddy field and dry land increased by 75 and 276 thousand hm² respectively; urban areas expanded rapidly, areas of town and rural residence increased by 76.8 thousand hm²; areas of forests and grassland decreased sharply with the amounts of 1399 and 1521 thousand hm² respectively; areas of water body and unused land increased by 148 and 514 thousand hm² respectively. This paper also discusses the driving forces in each land-use dynamic zone and finds that some key biophysical factors affect conspicuously the conversion of different land-use types. The relation between land-use conversion and DEM, accumulated temperature (≤10°C) and precipitation was analyzed and represented. The land-use changes In Northeast China resulted from the changing macro social and economic factors and local physical elements. Rapid population growth and management changes can explain the shaping of woodland/grassland-cropland conversion zone. The conversion from dry land to paddy field in the dry land-paddy field conversion zone, apart from the change of physical elements promoting the expansion of paddy field, results from two reasons: one is that the implementation of market economy in China has given farmers the right to decide what and how they plant their crops, the other factor is originated partially from the change of the dietary habit along with the social and economic development. The conversion from paddy field to dry land is caused primarily by the shortfall of irrigation water, which in turn is caused by poor water allocation managed by local governments. The shaping of the reclamation and abandon zone is partially due to the lack of environment protection consciousness among pioneer settlers. The reason for the conversion from grassland to cropland is the relatively higher profits of farming than that of pasturing in the interlocked zone of farming and pasturing. In Northeast China, the rapid expansion of built-up areas results from two factors: the existence of a small number of towns and the huge potential for expansion of the existing towns and cities. The urban land expanded mainly in areas with a gentle topographic relief and low population density.     

经济增长、市场化改革与土地违法

在当前中国经济快速增长和市场化改革逐步推进的过程中,始终面临着较为严重的土地违法问题;土地违法行为的主体不仅包括企事业单位和令人,更涉及各级地方政府以及农村集体组织.为深入了解经济增长与市场化改革对不同主体土地违法行为的影响,本文进行了初步的理论探讨,并运用全国层面的统计数据开展了相应的实证分析.结果表明,随着经济增长速度的加快,政府和企业的土地违法面积均显著增加;而土地市场化水平的提高则能有效减少土地违法的案件数.进一步地,经济增长和市场化改革对各级政府以及企事业单位、个人和农村集体组织土地违法行为的影响也存在一定的差异.本文的研究也指出,为有效控制土地违法行为的扩大,中国政府仍需采取转变经济增长方式、稳步推进市场化改革、引导企事业单位有序用地和不断完善土地督察制度等措施.     

土地非农化生态价值损失估算

随着城镇化、工业化的快速推进,我国城乡建设用地快速扩展使农用地保护面临巨大挑战,从经济机制上防止土地过度非农化尤为重要.该文对土地非农化生态价值损失过程机制进行了理论探索,建立了价值损失估算方法,并以江汉平原为例进行案例分析.研究表明:单纯的市场机制没有考虑土地非农化造成的生态价值损失,无法实现土地资源最佳配置,非农化规模偏大;土地非农化生态价值损失巨大,1987-2010年江汉平原因此累计损失73 692.11万元,人均承担49.25元;不同类型土地的生态价值损失强度有所差异,每公顷的自然保留地、水域、林地、草地、耕地非农化价值损失分别为2.459 8万元/a,2.036 7万元/a,1.262 9万元/a,0.524 1万元/a,0.354 8万元/a.文章认为,发展与保护始终是土地资源优化配置必然要面对的难题,土地非农化是社会经济发展过程中的必然现象,也是一个土地生态服务功能不断减少和消亡的过程.土地非农化虽然在一定程度上提高了土地的经济效益和社会效益,但生态效益损失巨大,可能会导致总效益净减.土地过度非农化在很大程度上是由于传统市场体系仅部分考虑了土地的经济、社会功能,而几乎完全没有考虑其生态价值导致的.作为一类负外部性,土地非农化过程中的生态价值损失如果不能得到及时遏制,快速增长的城乡建设用地需求将使农地保护面临巨大威胁,这需要将生态价值纳入土地价值体系,计入征地成本,并在一定程度上提高现行土地价格体系的合理性,防止建设用地的过度扩张,减少生态价值损失.