THE CHANGE ANALYSIS OF WETLAND LANDSCAPE BASED ON REMOTE SENSING DATA IN DONGTING LAKE, CHINA

摘要

Wetlands have very important ecological and service functions for human beings. However, the changing hydrological conditions and basins may result in the evolution of a wetland ecosystem. Understanding the knowledge of wetland changes can help us to conserve them. As an increasing abundant data sources, remote sensing data have their specific advantages for large scale analysis for wetland landscape. Dongting Lake is the second largest freshwater lake in China of an international importance for winterbirds and other important values. Here, the changes of wetland landscape were investigated based on optical remote sensing images from 1989 to 2010. The landscape types are classified four types consisting of open water, mudflats, lake grasses and reeds. During the past 20 years, the pattern of wetland landscape has changed rapidly. The area of reeds showed a steady increase with a growth rate of 13.1km2 per year. It increased from 475 km2 in 1989 to 751 km2 in 2010. The distribution area of lake grass kept stable but with slight fluctuation. The distribution area of water and mudflats has significantly reduced in near years. Generally, the evolution of landscape pattern in Dongting Lake shows the tendency of the extrusion of reeds into lake grasses and lake grasses into open water and mudflats.