LUCC and landscape pattern variation of wetlands in warm-rainy Southern China over two decades

摘要

This study aims to investigate the Land-Use and Land-Cover Change (LUCC) and landscape variation of lake-type wetlands, Huixian Wetlands, which locates in Guilin City of Guangxi province, southern China. The area of the wetlands significantly reduced from about 65km~2 in 1950s to 7.79 km~2 after 50 years development. By the means of remote sensing retrieval, a series of remote sensing data(TM) in 1987, 1991, 2006 and 2009 were used to extract the information of Huixian Wetlands. The land use transition matrixes showed that, the increase of farmland leaded to the degeneration of the wetlands during 1987-2009. Referring to the natural wetlands in these years, 53.99% changed into farmland and 37.83% turned into artificial wetlands. Consequently, the area proportion of the artificial wetlands, accounting in all kinds of land use types in 1987, increased to 26.82% in 2009. Moreover, the total area of wetlands increased from 7.29 km~2 to 7.79 km~2 during 2005-2009, which showed that measures on the wetlands restoration were taken by local government works. The landscape indices were calculated to further analyze the landscape changes of the Huixian Wetlands. The results show that the mean area of patches increased during 1987-2005, but the edge density decreased. It proved that the wetlands had been developed with a high-intensity level in 1987 which coincides with the practical situation of local economy. Moreover, the temporal distribution of the farmland showed that the wetlands evolution following the degeneration mode: first, the wetlands are reclaimed into many patches; secondly, small pieces of farmland become a big one and the number of wetlands patches decreases; finally, the wetlands turn into other kinds of landscape.