基于景观格局的鄱阳湖生态经济区湿地时空变化

鄱阳湖生态经济区湿地是我国重要的淡水湖湿地,也是国际上重要的生态湿地。但近年来该地区湿地呈现出萎缩退化的趋势,生态功能也逐渐下降。因此,对该地区湿地的动态变化及变化驱动力研究就显得尤为重要。本文基于eCognition面向对象的最邻近域法,选取最优特征组合,对鄱阳湖生态经济区1995,2005,2015三期遥感影像进行解译和分类提取。同时采取动态度和景观格局指数等指标对20年间该地区湿地的动态变化特征进行分析,并采用地理探测器研究其变化驱动力,从而为湿地变化预测及保护提供依据。结果表明：(1)从分类结果看,eCognition面向对象的分类方法对湿地影像的提取效果良好,三期影像分类结果总体精度均大于85%,Kappa系数大于0.85,分类结果较好 (2)鄱阳湖生态经济区1995至2015年间湿地总体面积减少,总体变化率为-22.7%。其中,减少最多的是天然湿地,共减少191083.19hm_²。(3)鄱阳湖生态经济区20年间湿地的总体特征表现为各景观层次上总体变化较小,但各类斑块破碎化程度加大。(4)地理探测器结果表明人口密度、年均温及坡向均对湿地变化的空间分异有较强的解释能力,人口密度对湿地变化空间分异的解释能力高于年均温和坡向。本研究可以为鄱阳湖生态经济区湿地保护提供理论依据及数据支撑,也可以为我国及其他地区淡水湿地保护提供经验借鉴。

Temporal and Spatial Dynamics of Wetland Landscape Patterns in the Poyang Lake Eco-economic Zone

The wetland in Poyang Lake Eco-economic zone is an important freshwater lake wetland in China and an important ecological wetland in the world. However, in recent years, the wetlands in this area are shrinking and degenerating, and their ecological functions are gradually declining. Therefore, it is particularly important to study the dynamic changes and driving forces of wetlands in this area. In this paper, based on eCognition object-oriented nearest neighbor method, the best feature combination is selected to interpret and classify the remote sensing images of Poyang Lake Eco-economic zone in 1995, 2005 and 2015. At the same time, dynamic attitude and landscape pattern index were used to analyze the dynamic change characteristics of wetland in this area in the past 20 years, and the driving force of change was studied by using geographic detectors, thus providing a basis for wetland change prediction and protection. The results show that: (1) from the classification results, the eCognition object-oriented classification method is effective in extracting wetland images, and the overall accuracy of the three-phase image classification results is greater than 85%, the Kappa coefficient is greater than 0.85, and the classification results are good. (2) The total wetland area in Poyang Lake Eco-economic zone decreased from 1995 to 2015, with an overall change rate of -22.7%. Among them, natural wetlands decreased the most, with a total decrease of 191083.19hm². (3) The general characteristics of wetlands in Poyang Lake Eco-economic Zone in the past 20 years are that the overall changes at various landscape levels are small, but the fragmentation degree of various patches is increasing. (4) The results of geographic detectors show that population density, average annual temperature and slope direction have strong explanatory power to the spatial differentiation of wetland change, and the explanatory power of population density to the spatial differentiation of wetland change is higher than that of average annual temperature and slope direction. This study can provide theoretical basis and data support for wetland protection in Poyang Lake Eco-economic zone, and also provide experience for freshwater wetland protection in China and other regions.