西昌市1989—2018年林地草地湿地动态变化特征分析

Analysis of the dynamic change characteristics of forest land,grassland and wetland in Xichang City from 1989 to 2018

遥感技术已被广泛应用于生态环境调查与研究。为获取西昌市近30 a生态环境演化趋势,利用1989年、2000年、2010年的专题绘图仪(Thematic Mapper,TM)遥感影像和2018年的陆地成像仪(Operational Land Imager,OLI)遥感影像,通过图像处理、目视解译和野外验证等方法,获得了西昌市1989—2018年的土地利用/覆盖数据,并对林地、草地和湿地的动态变化特征进行了研究。结果表明1989—2018年,西昌市林地、湿地和草地面积持续增加,生态环境持续向好;林地主要分布于安宁河谷和邛海盆地四周山地,在牦牛山、螺髻山一带形成主要林区;草地主要呈星岛状分布于牦牛山、螺髻山一带林地之间;湿地以河流湿地与湖泊湿地为主,主要沿安宁河及邛海分布。但仍存在一些问题森林存在针叶化现象较普遍、树种单一等问题,需要重点加强林区火灾防范;草地多数呈零星片状分布,不具有完整的系统结构和良好的功能,多数草地承载力和生产力较低,不宜大规模开发利用,应通过封山育林促使其向森林转化;湿地分布也比较局限,需要着力予以保护。研究成果可为西昌市生态保护修复措施的制定及经济社会可持续发展提供科学依据。

Remote sensing technology has been widely used in ecological environment investigation and research.In order to obtain the evolution trend of ecological environment in Xichang City in recent 30 years,the authors in this research used TM(Thermal Mapper)remote sensing images in 1989,2000 and 2010 and OLI(Operational Land Imager)remote sensing images in 2018 to acquire the landuse/cover data of Xichang City from 1989 to 2018 and investigate the dynamic change characteristics of forest land,grassland and wetland,through image processing,visual interpretation and field verification.The results show that the area of forest land,wetland and grassland in Xichang City continued to increase from 1989 to 2018,which indicated the improved ecological environment.The forest land is mainly distributed in Anning River Valley and the mountains around Qionghai Lake Basin,and the main forest areas are formed in the areas of Maoniu Mountain and Luoji Mountain.The grassland is mainly distributed in the area of Maoniu Mountain and Luoji Mountain in the forest area,and the wetland is mainly river wetland and lake wetland,mainly distributed along Anning River and Qionghai Lake.However,there still exist some unsolved problems.The coniferous phenomenon is widespread in the forest and the tree species aren’t rich,and the fire prevention should be strengthened in forest area.The grassland is distributed sporadically,without comprehensive system structure and geod quality function.Most of the grassland with low productivity is not suitable for extensive construction and should be converted to forest by closing hillsides for afforestation.The wetland has limited distribution,which need excessive protection.The research results of this paper can provide a scientific basis for the formulation of ecological protection and restoration measures and the sustainable development of economy and society in Xichang City.