昭通市土地利用时空变化和景观格局演变特征研究

Study on spatial and temporal changes of land use and landscape pattern evolution in Zhaotong city

明晰山区土地利用时空变化及景观格局特征,对提高山区生态系统健康,推进山区可持续发展,最终实现高质量发展具有重要意义。本研究以西南山区的昭通市为例,以2000—2020年土地利用数据集为数据源,基于GIS技术,利用土地利用转移矩阵、标准差椭圆和重心迁移模型三个方法探究昭通市土地利用变化特征,再利用景观格局指数从景观层级水平和景观类型水平分析景观格局演变。结果表明:昭通市的主要用地类型为林地、耕地和草地,建设用地增长幅度最大,其中草地的标准差椭圆方向性最不明显,耕地、林地和草地重心分布较为稳定;从景观层级水平上说,呈现出斑块数目增加,相连度减小,最大斑块分布优势减弱,破碎化程度增加,连通性降低,凝聚度降低和复杂度上升的特征;从景观类型水平上说,斑块数目、斑块密度和边缘密度最大的景观类型均为耕地,最大斑块指数、聚集度最大的景观类型均为林地,平均斑块分维数最大的景观类型为建设用地,散步与并列指数最大的景观类型为水域。

Using the land use data set from 2000 to 2020 as the data source,GIS technology was used to explore the characteristics of land use change in Zhaotong city from three aspects:land use transfer matrix,standard deviation ellipse and center of gravity transfer model,and landscape pattern index was used to analyze the landscape pattern evolution from the landscape level and landscape type level.The results show that:(1) The main land types in Zhaotong are forest land,cultivated land and grassland,the growth rate of construction land is the largest,the standard deviation ellipse of grassland is the least obvious,and the distribution of center of gravity of cultivated land,forest land and grassland is relatively stable.(2) From the landscape level,the number of patches increased,the degree of connectivity decreased,the largest patch distribution dominance weakened,the degree of fragmentation increased,the connectivity decreased,the cohesion decreased and the complexity increased.(3) From the landscape type level,the landscape type with the largest patch number,patch density and edge density is cultivated land,the landscape type with the largest patch index and aggregation index is woodland,the landscape type with the largest mean patch fractal dimension is construction land,and the landscape type with the largest interspersion & juxtaposition index is water.