Dynamics and influence width of dry valley landscape boundary in upper reaches of Minjiang River
岷江上游干旱河谷景观边界动态及其影响域

Based on RS and GIS techniques,the distribution extent of the dry valley in upper reaches of Minjiang River was determined,with the dynamics and influence width of its landscape boundary analyzed.The results indicated that the dry valley had a gradually expanded distribution,and the total length of its boundary was increased.The boundary complexity increased from 1974 to 1995 but decreased from 1995 to 2000,and the upper boundary of the dry valley ascended rapidly along mountain slope.The uppermost elevation of the dry valley boundary was 3 128 m in 1974,3 167 m in 1995,and 3 181 m in 2000.In the last 26 years,the upper boundary of the dry valley ascended 53 m in total,being about 2 m per year.The influence width of the dry valley boundary was 800 m,which could be regarded as a buffer zone to disturbances.The area between 800-1200 m from the dry valley boundary to exterior was a transition zone intensely influenced by the dry valley and its surrounding landscape,which should be addressed in the restoration of the dry valley.