近20年广西北部湾滨海湿地时空格局变化研究

Spatial and Temporal Changes in Coastal Wetlands in Guangxi Beibu Gulf in Recent 20 Years

基于面向对象的信息提取方法,利用1990、2000和2010年Landsat TM遥感影像数据,提取北部湾滨海湿地信息,并对其空间分布及其变化进行研究。结果表明:基于面向对象法提取出的研究区3个时期滨海湿地分类总精度分别为91.02%、89.06%和89.84%,kappa系数均达到0.80以上;3个时期自然湿地在湿地类型构成中占绝对优势,其面积占湿地总面积的比例分别为66.96%、65.65%和64.90%;1990-2010年,研究区滨海湿地面积呈平稳增长态势,其面积由3 138.08km2增加到3 165.77 km2;湿地类型中养殖水面增幅最明显,其面积比重由1990年的3.19%增加到2010年的6.15%。1990-2010年,研究区滨海湿地变化明显,湿地之间、湿地与非湿地之间的相互转化频繁,受人为活动影响干扰突出。

The 1990, 2000 and 2010 Landsat TM images of coastal wetlands in Beibu Gulf were used tbr an analysis of spatial distribution and its changes based on object-oriented data-mining. The coastal wetlands were classified into 6 types, including tidal flat, mangrove, water, paddy field, reservoir pond and aquatic farm. Tile distribution and the spatial changes of the coastal wetlands were analyzed and compared using GIS spatial analysis function. The results showed that：The precision of classification for the three periods in the area were 91.02%, 89.06% and 89.84 % respectively based on object-oriented method, and all kappa indices reached 0.80 and above. The natural wetland accounted for an absolute majority for all the 3 periods. The area of natural wetlands during the 3 periods were 66.96%, 65.65% and 64.90% respectively of the total area of all types of wetlands. The total area of coastal wetlands had increased stably from 1990 to 2010, with the area increased fi＇om 3138.08 kin2 to 3165.77 kin2. Among the wetland types, the increase of aquatic farm was most evident, from 3.19 % in 1990 to 6.15% in 2010. During the period of 1990 to 2010, evident changes were found in the coastal wetlands. There were frequent transitions among wetlands and between wetland and non-wetland types, and human disturbance was evident.