2000~2010年汉江流域湿地动态变化及其空间趋向性

基于面向对象分类方法建立汉江流域2000年、2005年和2010年湿地景观数据库。运用湿地景观动态变化指数、强度指数及多度指数等方法分析近10a来汉江流域湿地景观变化的时空分异特征及空间趋向性。结果表明：2000年以来，汉江流域湖泊、河流、水田湿地面积大幅度减少，其中前5a（2000~2005年）湿地变化强度明显高于后5a（2005~2010年）。空间趋向性以湿地景观内部转变和湿地向其他用地转移为主要特征，内部转变以水田与水库坑塘间的转变为主，在空间上呈现3种趋向特征：湖泊周围0-12]km两者之间转化强度随距离拉大而增大；河流周围两者转变趋势明显，在4-6] km变化尤为突出；交通用地附近0-4] km水田与水库坑塘间转变强度高。水田、湖泊和水库坑塘湿地向建设用地的转变是引起区域湿地面积萎缩的重要原因，10a间湿地向建设用地转变总量约为470.43 km²，占湿地变化总量的22.55%。

DYNAMIC CHANGE ANALYSIS OF WETLAND AND ITS SPATIAL-TEMPORAL TREND IN HANJIANG BASIN FROM 2000 TO 2010

Remote sensing and geographical information system were integrated to monitor wetland changes in the Hanjiang basin. By combining the landscape dynamic model (K) and dynamic intensity index (DⅡ), we analyzed the wetland data of 2000, 2005, and 2010 of the Hanjiang Basin to reveal the general pattern. Buffer analysis and index of abundance were adopted to identify the spatial heterogeneity of wetland in the Hanjiang Basin. Results showed that, area of lakes, rivers, and paddy fields decreased greatly, wherein the values of K and DⅡ in the first 5 years were evidently higher than those after 5 years. Spatial heterogeneity of wetland in the Hanjiang Basin was apparent, the most drastic change occurred downstream, followed by the middle reaches of the basin. The external and internal changes together contributed to wetland shrinkage. There are three main characteristics of transformation between paddy fields and reservoirs/ponds:(1) the intensity of change increased with a distance from 8 km to 12 km around the lakes, (2) the trend of change was evident from 4 km to 6 km near the rivers, and (3) a significant change occurs near land utilized for traffic. Paddy fields, lakes, reservoirs, and ponds were easily transformed into construction land, which accounted for 22.55% of the total variation during 2000 to 2010.