Wetlands shrinkage, fragmentation and their links to agriculture in the Muleng-Xingkai Plain, China
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- 作者：Kaishan Song ; Zongming Wang ; Lin Li ; Lenore Tedesco ; Fang Li ; Cui Jin ; Jia Du
- 关键词：Wetlands shrinkage ; Fragmentation ; Land use/cover change ; Remote sensing
- 刊名：Journal of Environmental Management
- 出版年：2012
- 出版时间：30 November, 2012
- 年：2012
- 卷：111
- 期：Complete
- 页码：120-132
- 全文大小：1986 K
文摘
In the past five decades, the wetlands in the Muleng-Xingkai Plain, Northeast China, have experienced rapid shrinkage and fragmentation. In this study, wetlands cover change and agricultural cultivation were investigated through a time series of thematic maps from 1954, and Landsat satellite images representing the last five decades (1976, 1986, 1995, 2000, and 2005). Wetlands shrinkage and fragmentation were studied based on landscape metrics and the land use changes transition matrix. Furthermore, the driving forces were explored according to socioeconomic development and major natural environmental factors. The results indicate a significant decrease in the wetlands area in the past five decades, with an average annual decrease rate of 9004?ha/yr. Of the 625,268?ha of native wetlands in 1954, approximately 64 % has been converted to other land use types by 2005, of which conversion to cropland accounts for the largest share (83 % ). The number of patches decreased from 1272 (1954) to 197 (1986) and subsequently increased to 326 (2005). The mean patch size changed from 480?ha (1954) to 1521?ha (1976), and then steadily decreased to 574?ha (2005). The largest patch index (total core area index) indicates wetlands shrinkage with decreased values from 31.73 (177,935?ha) to 3.45 (39,421?ha) respectively. Climatic changes occurred over the study period, providing a potentially favorable environment for agricultural development. At the same time population, groundwater harvesting, and fertilizer application increased significantly, resulting in wetlands degradation. According to the results, the shrinkage and fragmentation of wetlands could be explained by socioeconomic development and secondarily aided by changing climatic conditions.