三峡库区腹地草堂溪小流域土地功能格局变化

探讨三峡库区腹地土地功能格局动态特征是促进库区土地功能优化、土地利用可持续发展的重要途径之一。以草堂溪小流域为研究区,基于1990~2015年4期遥感影像和1∶5万DEM数据,借助ArcGIS 10.2与Fragstats 4.2软件,依据土地提供主要服务的差异性将土地功能划分为3个大类5个亚类,并分析研究区土地功能格局时空演变特征。结果表明:近25 a,研究区生态功能用地占绝对优势,面积增长1 541.96 hm~2,生产功能用地面积缩减1 844.19 hm~2,生活功能用地面积扩展302.24 hm~2;生物质生产功能用地和人工/天然生态功能用地间的转移关系是研究区土地功能转移网络的关键关系,决定着研究区土地功能变化特征;土地功能变化空间集聚特征时空差异性显著,生物质生产功能用地和人工/天然生态功能用地附近为土地功能变化热点区域,1990~2015年土地功能变化热点区向研究区西部推移;生物质生产功能用地、交通功能用地和住宅功能用地优势区间为中低地形位,中高地形位是非生物生产功能用地优势区间,人工/天然生态功能用地在高地形位占优势;较低地形位上景观异质性高、形状复杂,较高地形位上景观类型单一、聚集程度高。

LAND USE FUNCTIONS DYNAMICS PATTERN OF CAOTANGXI WATERSHED IN THE THREE GORGES RESERVOIR AREA

The center of the Three Gorges Reservoir is a sensitive ecological environmental area,and red zone of reservoir water environment protection.The process of the Three Gorges Project,water impoundment operations and urbanization is always accompanied by land use changes in the center of Three Gorges Reservoir,including land use structure,land use function structure and ecological,economic,social attributes.Therefore,to explore the dynamics of land use functions in the center of Three Gorges Reservoir is one of the important approaches to promote the optimization of land use functions and sustainable land use development.Attempts have been made in Caotangxi watershed which has been selected as the study area.According to the difference of providing services by the land,the land use functions is divided into three classes and five second-class in this paper.Based on four period data and the 1:50 000 DEM,this paper analyzed the spatial and temporal dynamics of land use functions pattern of study area,by some means of the theory of GIS and landscape ecology,such as ArcGIS 10.2,Fragstats 4.2.The results showed that:In recent 25 years,ecological land which occupied the largest proportion of the whole area increased 1 541.96 hm2,while industrial land decreased 1 844.19 hm2 and living land increased 302.24 hm2.The land use functions change and relationships of biomass production function land and artificial/natural ecological function land played key roles in the whole network of land use functions change,and thus determined the characteristics of land use functions change in the study area.The spatial features of land use functions varied at different scales.From the perspective of spatial analysis,the regions near biomass production function land and artificial/natural ecological function land were hot spots of land use functions change.From 1990s to 2015s,the hot spot of land use functions change gradually transferred from east to west region.Biomass production function land,traffic function land and residential function land were mainly distributed in the area with low-medium terrain niche index,non-biological production land were mainly distributed in the area with medium-high terrain niche index,while artificial/natural ecological function land in high terrain niche index area.At a 25-year scale,landscape shape was complicated and landscape diversity was relatively high in the lower terrain niche index area.Conversely,the higher terrain niche index area has the characters of simplex,larger patches and less fragmentation.