The changes of the main urban land-use and its ecological risk assessment in Guangzhou

Based on the information of land-use which was achieved by the satellite remote sensing TM image in 1990 and 2006, this paper took the main urban area of Guangzhou as a study area to analyze its structure and dynamics of land-use changes, as well as the spatial-temporal variation of ecological risk degree of the land-use by dynamic degree of land-use, land-use composite index, and the ecological risk index of land-use in line with the land-use structure features. The results showed that land-use composite indexes of the main urban area in Guangzhou were in an increased trend, particularly in construction land-use. A large number of farmland, woodland, gardens and waters turned into construction land-uses, so construction land-use areas made a significant growth. The results also showed that a clear regional inhomogeneity represented from the ecological risk of this study area. This area was divided into two ecological high-risk areas - the old main urban area (Yuexiu District, Liwan District, and Haizhu District) and the emerging urban area (Panyu District and Nansha District). In addition, the comprehensive ecological risk index of land-use in the main urban area of Guangzhou which was in an upward trend and reached a high-risk stage could be learned from the results, too.