基于土地利用/覆被的滇池流域生境质量时空演变

Spatial and temporal variations of habitat quality in Dianchi Lake basin based on land use/cover change

滇池是我国西南地区最大的高原淡水湖泊,也是云南省面积最大的淡水湖。研究滇池流域土地利用/覆被类型与生境质量的时空演变特征,对流域生态环境保护具有重要意义。本文基于1988—2018年土地利用/覆被数据,将InVEST模型与GIS空间分析工具相结合,分析滇池流域生境时空变化,并利用莫兰指数和热点分析量化生境质量的空间集聚及演化特征。结果表明:(1)1988—2018年滇池流域土地利用/覆被类型变化剧烈,由1988年的农田占优势转变为2018年城镇用地占优势;(2)流域生境质量总体呈下降趋势,环滇池的城市区域生境质量较低,流域周边山地与丘陵质量较高但分布分散;(3)生境“冷热点”呈集聚分布,“热点”地区主要位于周边林地,随时间变化其范围逐渐缩小,而“冷点”地区位于环滇池城市区域,随时间变化而大幅增加。本研究表明,城市化过程中土地利用/覆被的剧烈变化是引起城市生境发生变化的主要原因,研究结果可为滇池流域土地利用类型优化以及提升或维持生物多样性提供参考依据。

Dianchi Lake is the largest high-altitude freshwater lake in southwest China and the largest freshwater lake in Yunnan Province.Understanding the spatiotemporal variations of land use/cover types and habitat quality in the Dianchi Lake basin is of great significance for the protection of the ecological environment in the basin.Based on land use/cover data from 1988 to 2018,we analyzed the spatiotemporal variations in habitat in the Dianchi Lake basin using InVEST model and the spatial analysis tool of GIS,and quantified the spatial aggregation and evolution characteristics of habitat quality using Moran’s I index and hot spot analysis.The results showed that:(1)Land use/cover types in the Dianchi Lake basin changed dramatically,from the dominance of farmland in 1988 to the dominance of urban land in 2018.(2)The overall habitat quality in the basin declined,with lower habitat quality in the urban areas surrounding Dianchi Lake and higher quality in the surrounding mountains and hills,but distributed sparsely.(3)The cold and hot spots of habitat followed aggregated distribution.Hot spots were mainly located in the surrounding forests,and their range gradually shrunk with time.The cold spots were located in the urban areas surrounding Dianchi Lake,and their number increased greatly over time.Our results indicate that the drastic change of land use/cover during urbanization is a main reason for the changes of urban habitat,providing reference for optimizing land use types and improving or maintaining biodiversity in Dianchi Lake Basin.