基于Landsat8卫星影像土地利用景观破碎化研究——以陕西省延安麻塔流域为例

A study of the landscape fragmentations of land cover structure based on Landsat8 remote sensing image:A case study of Mata watershed in Yan’an,Shaanxi Province

景观破碎化的过程将伴随着景观的功能衰退,因此对景观破碎化的研究对于及时监控生态安全与土地优化调整具有重要意义。以陕西省延安麻塔流域为研究对象,通过对Landsat8卫星影像的解译,获取土地利用图;利用6个景观指数评估麻塔流域在斑块、景观要素、景观3个层次的景观破碎化程度。研究结果表明:Landsat8卫星能够准确地刻画该区的土地利用现状,监督分类精确度为74%,Kappa值为0.68;麻塔流域土地利用可以分成6个类型:森林、灌木、草地、果园、农田和其他(道路和房屋),其中果园在所有土地利用类型中占据的面积最大;森林、果园和其他3类土地利用类型的景观破碎化程度低,它们在生态防护和农业生产服务方面发挥重要的景观功能;灌木、草地和农田的景观破碎化严重,它们在生态防护和农业生产方面的景观功能已经被削弱;将灌木、草地和农田的小斑块改造成相邻大斑块的土地类型将提高麻塔流域景观整体化水平,有利于麻塔流域整体景观功能的提升。

The process of landscape fragmentation is accompanied by the decline of landscape function.Therefore,the study of landscape fragmentation is of great significance for timely monitoring of ecological security and adjustment of land cover structure.This research was designed to map the current status of land cover structure of Mata watershed using supervised classification algorithms in south of Yan’an City based on Landsat 8 satellite data and to describe its landscape fragmentation using six fragmentation indices at three organization levels:patch,class,and landscape.The results are as follows:①The status of land cover in this area can be characterized accurately based on Landsat8 satellite image and the accuracy of supervised classification is 74%together with the kappa value of 0.68;②Mata watershed can be classified into 6 land cover classes,i.e.,forest land,shrub land,grass land,orchards land,farm land,and others land(road and village).The orchard land occupies the largest area in all land cover types;③The extent of landscape fragmentation for shrub,grass and farm lands is relatively more serious than that of forest,orchard and others lands,indicating that landscape functions of shrub,grass and farm lands have been weakened in capability of ecological protection and agricultural production;④Transforming small patches of shrub,grass and farm lands into adjacent land type with large patches should improve the integration level of landscape in the Mata watershed,which is conducive to the improvement of landscape function in Mata watershed.