关中-天水经济区土地利用/覆被变化与景观格局

以1980年和2005年的TM影像为数据源,应用ArcGIS,Erdas软件对影像解译,把关中-天水经济区(简称“关天经济区”)的土地利用景观分为6大类景观类型.基于ArcGIS分析模块,分析了关天经济区土地利用/覆被变化过程,并使用景观软件Fragstats分别从景观级别和景观类型级别上计算了相应的景观指数,得出以下结论:(1) 25 a间耕地和未利用地面积减少,林地、草地、水体和建筑用地面积增加,大量的耕地转变为林地、草地、建筑用地.同时较多草地开垦为耕地,但小于耕地向其转化的量.而建设用地属于转入型用地,转出量几乎为0.(2)关天经济区土地利用景观的蔓延度、优势度指数减少,香农多样性指数、香农均匀度指数增加.(3)耕地是关天经济区的优势景观类型,建设用地景观斑块正在向规模化扩张.研究结果为合理制定该区域可持续发展的土地利用政策及规划提供科学的参考及依据.

Land Use/Cover Change and Ecological Landscape Pattern in Guanzhong-Tianshui Economic Zone

Using 1980and 2005TM image data and applying ArcGIS and Erdas to interpret the images,theland use landscape in Guanzhong-Tianshui economic zone is divided into six types.Land use/cover changein the zone is analyzed based on ArcGIS analysis module and the corresponding landscape indexes are calculated by the landscape levels and types using and the landscape software named Fragstats.Results are as follows:(1)In the past 25years,the areas of cultivated land and unused land were decreased,while the areasof forest,grassland,water and construction land were increased.A large amount of cultivated land wastransformed to forestland,grassland and construction land.At the same time,some of grassland was reclaimed for cultivated land,but the reclaimed proportion was less than the cultivated land transformed fromgrassland.Construction land was the transformed-in land type and the quantity of transformed-out construction land was nearly negligible.(2)The landscape contagion index and dominance index were decreased,while Shannon diversity index and Shannon evenness index were increased in the study area.(3)Cultivatedland occupied a major position in Guanzhong-Tianshui District,but the landscape patch of construction land expanded to a large scale.Land use/cover change and landscape pattern in the district are discussed and landscape pattern and change characteristics in the whole district are revealed quantitatively.The study may provide scientificreference for formulating sustainable land use policies and making reasonable planning in the district.