滇西北高原湖泊剑湖流域景观时空演变特征

为深入了解流域景观演变规律并有效保护高原湖泊，以滇西北剑湖流域为研究对象，基于1990-2015年6期剑湖流域以及1974-2015年8期剑湖湖泊Landsat影像数据，在Arc GIS平台下采用Fragstats计算景观指数，并运用SPSS分析流域景观格局与剑湖景观形状的相关性。结果表明:①25 a间剑湖流域的建设用地和耕地呈增加趋势，分别增加了1 269.27和1 038.42 hm2，水域和未利用地显著减少，分别减少了93.51和2 664.99 hm2，林地面积变化幅度不大，增加了450.81 hm2；②景观水平斑块个数、斑块密度和蔓延度指数增加，分别增加了193个、0.09和0.60，景观多样性指数降低了0.05；③剑湖湖泊面积整体呈递减趋势，从1974年的504.47 hm2减少到2015年的451.72 hm2；剑湖景观形状指数越来越复杂，金龙河入湖口形状变化尤其剧烈；剑湖湖泊质心向西南偏移，1974-2015年偏移了113.92 m。表明:剑湖流域25 a间景观破碎化程度和景观蔓延度不断增加，泥沙淤积、围湖造田等人类活动对剑湖景观的演变起主要作用，流域景观格局的演变影响湖泊形状及质心的变化。

Temporal and spatial evolution of landscapes in Jianhu Lake Basin of northwestern Yunnan Province

To better understand the evolution of basin landscapes and to protect plateau lakes effectively, Jianhu Lake Basin in northwestern Yunnan Province was chosen as a study area. Based on data from six Landsat images for Jianhu Basin from 1990 to 2015 and data from eight Landsat images for Jianhu Lake from 1974 to 2015, several landscape indices with Fragstats using Arc GIS operational platforms were calculated and SPSS software was used to analyze the relationship between landscape patterns and landscape shapes of Jianhu Lake. Results showed that (1) in the 25 years from 1990 to 2015, significant increases in building and arable land areas, and significant decreases in water areas and unused land areas occurred; whereas, changes in forest land areas were small. Among these changes, water areas decreased 93.51 hm2 and unused land areas decreased 2 664.99 hm2. Arable land areas increased 1 038.42 hm2, forest land areas increased 450.81 hm2, and residential lands increased 1 269.27 hm2. (2) Also, in the 25 years from 1990 to 2015, landscape indices, such as number of patches, patch density, and contagion index, increased separately 193, 0.09 and 0.60, but Shannon's Diversity Index decreased 0.05. (3) Overall, the water bodies of Jianhu Lake Basin from 504.47 hm2 in 1974 to 451.72 hm2 in 2015. Landscape shapes in the Jianhu Lake Basin have become more complex, in particular, the river mouth shape of the Jinlong River has drastically changed. From 1974 to 2015 the centroid of Jianhu Lake Basin has also shifted to the southwest by 113.92 m. This work showing degree of landscape fragmentation and contagion levels as well as the effect of human activities, such as land reclamation from the lake and acquiring building land around the lake, could provide a theoretical basis for basin landscape optimization and scientific protection of the Jianhu Lake Basin.