2003—2016年东洞庭湖自然保护区湿地动态变化特征

Dynamic Characteristics of the Wetland of East Dongting Lake Nature Reserve from 2003 to 2016

基于中分辨率成像光谱仪(MODIS)遥感数据的MOD13Q1系列产品,利用决策树分类法,对东洞庭湖自然保护区2003—2016年共322个时相的16 d合成数据进行分类解译,得到2003—2016年时间序列的东洞庭湖水体湿地、泥滩湿地、草滩湿地、芦苇湿地分类结果,分析了分类精度,以及水体湿地和草滩湿地的年际间及年内变化趋势及其主导因子。结论:1)决策树分类法应用于时间序列的东洞庭湖MODIS遥感影像分类,其分类精度处于可接受范围;2)2003—2016年(三峡工程蓄水运行期)东洞庭湖水体和草滩湿地面积最大最小值未发生年际间的明显变化;3)东洞庭湖水体和草滩湿地面积随着水文节律发生年内周期性波动,二者具有较好的线性回归关系。研究认为:将东洞庭湖水位控制在合理区间是维护生态系统健康的关键。

Based on the product of MOD13Q1 of MODIS(Moderate Resolution Imaging Spectroradiometer),this paper dealt with 322 available images from 2003 to 2016 by using decision tree classification method,and then got a time-based series of classified data about water,mud flats,grassland,and reed of wetland in East Dongting Lake.It analyzed the degree of accuracy of the classification results,and the annual and interannual variation trends of water and grassland of wetland,as well as the key driving factors,summarized that:(1)it is acceptable of the degree of accuracy which was calculated from the classification results by using the decision tree method on the series data of MODIS images from East Dongting Lake.(2)There is no significant interannual variety of the area of water and grassland of wetland from 2003 to 2016,when the construction and operation of the Three Gorges Dam was underway.(3)Area of water and grassland of wetland varies with the hydrological rhythm,and there is an extremely significant negative correlation between them.This paper proposed that,water level is the key factor of the ecosystem of East Dongting Lake,it is crucial to keep it in a reasonable range to maintain the health of ecosystem.