摘要
大型水生植物对湖泊的生物地球化学循环具有重要影响。一方面,大型水生植物在生长过程吸收营养;另一方面,其通过向水体释放氧气而影响磷元素以及其他相关因子,进而影响磷元素的生物地球化学循环。为了从宏观上了解骆马湖生态系统变化,以1990年9月20日、2000年5月2日和2008年10月15日Landsat TM/ETM+影像为主要数据源,以大型水生植物的归一化植被指数(NDVI)为测试变量,运用分类回归树(classification and regression tree,CART)方法确定分割阈值,通过构建知识决策树的方法识别骆马湖大型水生植物动态变化特征。3个时期的遥感分类的总体精度与kappa系数分别为92.28%和0.87、91.73%和0.86、93.38%和0.88,因此,该方法的分类精度完全满足骆马湖水生植物分布及变化的研究。研究结果表明,骆马湖大型水生植物分布面积由1990年的55.461 6 km2,减少到2000年的41.801 4 km2,2008年又增加到79.065 km2;大型水生植物主要分布在骆马湖北部河湖交汇区;人类活动干扰是造成骆马湖大型水生植物分布面积发生变化的主要原因。
Macrophyte plays a vital role in the biogeochemical cycle of lake. On the one hand, macrophyte takes up nutrients during growth process. On the other hand, it affects phosphorus biogeochemical cycle through releasing oxygen to water. In order to understand change of Luoma lake ecosystem, the study identi- fied the macrophyte distribution of Luoma Lake applying method of knowledge decision tree. Landsat TM da- ta in 1990, 2000 and 2008 were used as the main data sources of study. The values of normalized difference vegetation index are regarded as test variables, and segmentation threshold was determined by classification and regression tree algorithm. After the statistics, it could be found that the precision accuracy of classification and kappa coefficients all exceeded 85% in 1990, 2000 and 2008; they were 92.28% and 0.87, 91.73% and 0.86, 93.38% and 0.88, respectively. It fully satisfied the requirements of research. The result showed macro- phytes mainly distributed in esturay area of the north Luoma Lake. The disturbance of human activities was the main reason for macrophyte change. The area of macrophytes reduced from 55.461 6 km2 in 1990 to 41.801 4 km2 in 2000, then increasing to 79.065 km2 in 2008.
出处
《湿地科学》
CSCD
北大核心
2013年第3期320-325,共6页
Wetland Science
基金
江苏省住房与城乡建设厅科技计划项目(200906170001)
住房与城市建设部研究开发项目(2011-K6-27)资助
