Tang Yue, Xie Yong-Hong, Li Feng, Chen Xin-Sheng
Dongting Lake Station for Wetland Ecosystem Observation and Research/Key Laboratory of Agroecological Processes in Subtropical Region/Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
Ying Yong Sheng Tai Xue Bao. 2013 Nov;24(11):3229-36.
Based on multi-temporal Landsat MSS/TM/ETM+ images, and by using decision tree method, this paper extracted the areas of emergent herbaceous wetlands with different water levels in 1989-2011 in the East Dongting Lake, China. The change characteristics and change trends of the emergent herbaceous wetlands areas were investigated based on the DEM data and the daily water level data from the Chenglingji Hydrological Station. The area of the emergent herbaceous wetlands was significantly affected by water level (R2 = 0.875, P < 0.001), presenting a significant linear relationship between the two. Moreover, the emergent herbaceous wetlands area decreased with increasing water level. The higher the water level, the smaller the effects of the water level on the emergent area were. The emergent area changed regularly with water level. In January-July, water level increased, and the emergent area decreased; in July-December, it was opposite. In 1989-2011, the areas of emergent herbaceous wetlands had a continual increase. The newly emergent herbaceous wetlands area was mainly transformed from mudflat. The emergent herbaceous wetlands expansion was the co-effects of the increase of the emergent herbaceous wetlands areas at different elevations, and the rapid expansion of the emergent herbaceous wetlands in low bottomland (22-25 m of Yellow Sea elevation) played the most important role in the expansion. The change of water level at different elevations was the dominant cause for the changes of emergent herbaceous wetlands areas in the East Dongting Lake in the past 20 years.
基于多时相陆地卫星MSS/TM/ETM+影像，运用决策树方法，提取了1989—2011年中国东洞庭湖不同水位下的挺水草本湿地面积。基于DEM数据和城陵矶水文站的日水位数据，研究了挺水草本湿地面积的变化特征和变化趋势。挺水草本湿地面积受水位影响显著（R2 = 0.875，P < 0.001），二者呈显著线性关系。此外，挺水草本湿地面积随水位升高而减小，水位越高，其对挺水面积的影响越小，挺水面积随水位呈规律性变化。1—7月水位上升，挺水面积减小；7—12月则相反。1989—2011年，挺水草本湿地面积持续增加，新增挺水草本湿地面积主要由泥滩转化而来。挺水草本湿地扩张是不同高程挺水草本湿地面积增加共同作用的结果，其中低滩地（黄海高程22—25米）挺水草本湿地的快速扩张在扩张过程中起了最重要作用。不同高程水位变化是近20年来东洞庭湖挺水草本湿地面积变化的主导因素。
