Spatio-Temporal Dynamic Study on Landscape Patterns in Lancang River Watershed of Yunnan Province

Based on land use and land cover data,the landscape has been classified into twelve types,transition of landscape components and the changes of landscape patterns have been studied in Lancang river basin from 1985 to 2000 using GIS and Fragstats3.3.According to the results,the transition of the landscape was mainly happened among dry land,forest land,brush land,sparse woods,high-coverage grassland,middle-coverage grassland.At the landscape level,the fragmentation of landscape was decreased with a decrease in patch number from 44 054 to 44 978,the index of area-weighted fractal dimension and landscape shape index was decreased respectively,which leaded to the shape of patches more regular and simple.The other index of landscape was increased respectively,which leaded to the spatial aggregation and connectedness was improved,both the diversity and evenness of landscape were increasing.At patch level,the landscape components had a complex structural change and their pattern had a biggish difference due to man's advantaged and disadvantaged disturbance to landscape,the change trend of landscape pattern for forest land,bush forest and high-coverage grassland was consistent with that of regional landscape,however,the change trend of landscape pattern for sparse woods,middle-coverage grassland,paddy field and construction land was inconsistent with that of regional landscape,the dry land had a more complex structural change.The distribution of landscape components types has evident verticality and the landscape types about 80% distribute in elevation from 1 000 to 25 000 meter.The elevation 2500 meter is the important boundary for human activities and landscape types in this basin.The disturbance coming from human activities are focused on middle and low elevation.