Effects of Land Use/Cover Change on Wetland Landscape of Honghe Nature Reserve
流域土地利用/覆被变化对 洪河保护区湿地景观的影响

Analysis of land use/cover change in six periods from 1954 to 2005 was conducted with the aid of remote sensing and GIS techniques on the watershed scale.The landscape diversity of wetlands within Honghe Nature Reserve and the surrounding area in the watershed was calculated by using landscape diversity index to reflect landscape diversities and their changes in historical periods.At the same time,the landscape connectivity of the Honghe Nature Reserve with the surrounding area of the watershed was calculated to study the effects of landscape isolation on landscape diversity of the wetlands.Results show that the large-scale land reclamation started in the 1980s resulted in an annual increase of 101 km2 of agricultural land.The direct land use/cover change brought about the decline of wetland landscape diversity in watershed,and also impacted the diversity of wetlands in Honghe Nature Reserve.Decline of landscape connectivity between wetlands within the nature reserve and the surrounding area of the watershed due to land use changes has seriously segmented the original relationship between the nature reserve and its surrounding area,which directly resulted in the decline of wetland landscape diversity within the Honghe Nature Reserve.At present,the decline of landscape diversity of the wetlands in the Honghe Nature Reserve has serious negative effects on wetland structure and its ecological function.So it is necessary not only to conserve the wetlands in the nature reserve,but also to protect the wetlands in the surrounding area.We should restore certain area of the marsh wetlands to keep a high diversity of the landscape and landscape structure of the wetlands within the nature reserve,as well as to restore certain area of the wetlands in the surrounding area of the nature reserve for maintaining a high landscape connectivity in the watershed so that good conservation benefits of the nature reserve in the Sanjiang Plain can be achieved.