三峡库区生态敏感区土地利用变化及其生态效应研究——以奉节、巫山县为例

Land Use Change and its Ecological Effects in Ecologically Sensitive Area of the Three Gorges Reservoir Area: A Case Study of Fengjie and Wushan

土地利用变化及其生态效应的研究对区域社会经济发展和生态环境建设具有重要的指导意义.以三峡库区腹地奉节县和巫山县作为研究区,选取1986—2015年4期遥感、土地利用等数据,在GIS和RS技术的支持下,运用土地利用综合程度指数及土地利用转移信息图谱分析研究区土地利用空间格局演变,从湿度、绿度、干度和热度4方面构建遥感生态指数,反映研究区生态效应时空演变,探讨土地利用变化及其与生态效应的关系.结果表明:1)就土地利用而言,在空间上,耕地和建设用地多分布于低海拔平坝河谷区,林、灌、草地多分布于高海拔中低山区,交通建设用地多分布于各类用地之间起连通的作用;在土地利用强度和转换方式上,以林、灌、草地和耕地变化最为显著.2)就RSEI而言,长江及其支流沿岸低地,受土地开发及城镇扩张的影响,生境退化严重;研究区其余范围,受退耕影响,生境趋好.研究区土地利用变化最大的地区也是生态效应变化最为剧烈的地区,若人类活动合理,生态状况好转.

The study of land use change and its ecological effects are greatly significant to the regional social,economic,and ecological development.Based on the data of GIS and RS,this writer selects data of remote sensing and land use in the four sections from 1986 to 2015 of the Three Gorges Reservoir area in Fengjie and Wushan counties as the study area,using the land use comprehensive degree index and the land use transfer information map to analyze the evolution of spatial pattern of land use.The remote sensing ecological index(RSEI)is constructed from four aspects of humidity(WET),greenness(NDVI),dryness(NDSI)and heat(LST)to reflect the temporal and spatial evolution of ecological effects in Fengjie,Wushan.Finally,the relationship between land use change and ecological effects is discussed.The result shows:(1)In terms of land use,in the space,cultivated land and construction land are mostly distributed in the low-lying flat valley area.The forest,irrigation and grassland are mostly distributed in the middle-low mountains with high elevation,and the traffic construction land is connected with all kinds of land and the changes of land use intensity and conversion mode are most significant with forest,irrigation,grassland and cultivated land.(2)As far as RSEI is concerned,the Yangtze River and its tributaries are affected by land development and urban expansion.The ecological environment is degraded greatly.The ecological environment of other areas has been improved because of the influence of returning farmland.The largest land use change area in the study area is also the region where the ecological effect is most severe.