延河流域土地利用变化特征分析

Characteristic Analysis of Land Use Changes in Yan River Basin

研究土地利用时空变化特征对促进区域生态经济协调发展具有重要意义。以延河流域为例,基于不同时期遥感影像,借助RS、GIS和ENVI软件平台技术,获取了1980-2015年延河流域土地利用变化状况,并进行了土地利用转移分析;在此基础上解译了不同时期的土地利用类型,分析了延河流域土地利用时空变化特征和影响因素。结果表明,1980-2000年流域内土地利用结构整体变化较小,耕地、林地、草地3类土地利用面积相互转化频繁但整体面积趋于稳定,建筑用地面积增加了1.25倍;2000-2015年流域内耕地、林地和草地发生了显著变化,其中耕地面积减少了28%,林地面积增加了40%,草地面积增加了15%,建筑用地面积增加了近两倍,但比例很小,未利用地和水体变化幅度不明显;2000年前后流域内土地利用变化空间特征存在明显不同,2000年之前各土地利用类型变化主要发生在延安市区,2000年之后整个流域地区均有不同土地利用类型的转移;2000-2015年国家"退耕还林、草"生态修复政策、产业经济生产总值不断上升、人口数量稳定增长、城镇化发展迅速等均对流域土地利用结构产生了影响。

It is of great significance to study the spatio-temporal characteristics of land use for promoting the coordinated development of regional eco-economy.Taking Yan River basin for example,based on remote sensing images of different periods,we used RS,GIS and ENVI software platform technology to obtain the land use change situation of Yan River basin from 1980 to 2015,and carried out the land use transfer analysis.On the basis of this,we interpreted the land use types in different periods,and analyzed the spatio-temporal change characteristics and influence factors of land use.The results show that the change of land use structure in the basin from 1980 to 2000 is relatively small,and the land use areas of cultivated land,woodland and grassland change frequently,but the whole area tends to be stable,and the area of construction land increases by 1.25 times.From 2000 to 2015,the cultivated land,woodland and grassland change significantly,among which the area of cultivated land decreases by 28%,the woodland increases by 40%,and the grassland increases by 15%,the construction land increases nearly twice,with a very small proportion.The change range of unused land and water body are not obvious.The spatial characteristics of land use change in the basin are obviously different before and after 2000.The change of land use types mainly occurred in Yan’an before 2000,and the whole basin area have different types of land use conversion after 2000.The government’s policy of"Returning Farmland to Forestry and Grassland"ecological restoration has a great influence to land use structure.The growth of economics and population,the urbanization development all have impacts on the land use structure of Yan River basin.