三江源地区土地利用程度的时空变化分析

Analysis of Spatio-spatial Change of Land-use Degree in the Three Rivers Headwaters Region

三江源地区位于我国青海省南部,是黄河、长江和澜沧江的源头区域。本研究利用该区域1995、2005和2015年三个时段的遥感影像,分析了该区域土地类型以及利用程度在时间和空间维度的变化特征。结果表明:1995—2015年研究区建筑用地和耕地的面积明显增加,而林地、草地和水体的面积持续下降;研究区各县土地利用程度在时间和空间维度上的变化差异显著,建筑用地和耕地是研究区各市县变化强度较大类型,主要的土地利用类型草地相对变化率在甘德县最高,久治县最低。20年间三江源地区的土地利用程度一直处于上升趋势,经济驱动土地利用的深度广度不断增大,同时,环境生态保护的力度也在加强,自然生态资源的质量也在逐渐提高。

Located in Qinghai Province of China,the Three Rivers Headwaters Region is the source region of the Yangtze,Yellow and Lantsang Rivers,and plays an important role in biodiversity conservation and regulating water supply. Despite many efforts on land use change in Qinghai,knowledge of the spatial variation of land use change is still lacking. Remote sensing images of 1995,2005 and 2015 were analyzed to derive land use distributions;patterns and structures of the landscape were then quantified with landscape metrics. The results showed: in 1995-2015,farmland and building area increased,and the forest,grassland and water area decreased;the change of land use degree in different counties is distinct. The change rate of grassland was highest in Gande County,Jiuzhi is lowest. Although the land use degree still tended to aggravate,but the quality of the ecological resources are gradually improved.