Landscape evolution in the middle Heihe River Basin of north-west China during the last decade

摘要

Landscape evolution in the middle Heihe River Basin during the last decade was investigated by two methods: (a) the changes of various landscape metrics were analysed using the landscape structure analysis program FRAGSTATS; (b) the transition matrix of landscape patch types was calculated with the help of the GIS software, IDRISI. The results showed that from early 1980s to late 1990s, the landscape within the study area has undertaken a complicated evolution in landscape structure and composition, but as a whole it still displayed a pattern of sharp contrast between oasis and desert landscapes. The human activities have significantly changed the distribution and allocation of limited water resource in the basin, leading to a contradiction between desertification and expansion of oases. The decrease of Shannon's diversity index and evenness index manifested intensive management and reconstruction of landscape by human beings. While this improved the socio economic benefits of the region, it reduced landscape heterogeneity and landscape diversity, leading to the decrease of environmental benefits of some areas in the basin.