Landscape change and its driving forces of dry valley in upper reaches of Minjiang River
岷江上游干旱河谷景观变化及驱动力分析

The study based on GIS and RS showed that from 1974 to 2000, the area of dry valley in the upper reaches of Minjiang River increased continuously. Shrub land occupied >60% of the total, being the landscape matrix. Among the landscape types, cropland had the greatest change in its proportion. The whole figure of the dry valley was relatively simple, and its fragmentation and heterogeneity increased gradually from 1974 to 1995 but changed in adverse from 1995 to 2000. The connectivity inside the patches increased first and decreased then, being represented in the first increase and subsequent decrease of patch density and diversity, an adverse variation trend of landscape contagion, and the continuous decrease of edge density and fractal dimension. Population increase and government policy were the main driving forces of the dry valley landscape change in the upper reaches of Minjiang River.