Abstract:

Taking Landsat images in 2000, 2010, and 2020 as data sources, we examined the dynamic changes of ecosystem types in the Ali prefecture in Tibet autonomous region over the past two decades by using ecosystem dynamics degree and transfer matrix model. Within the “Sensitivity-Pressure-Resilience” assessment framework, we selected 14 indicators to establish a sensitivity evaluation index system to delineate ecological sensitive zones, aiming to maintain ecosystem stability and scientifically build ecological security barriers. The findings demonstrate that 1) All eight ecosystem types experienced varying degrees of changes.The degree of dynamics for urban ecosystem and agricultural ecosystem displayed the most significant changes. 2) Deserts and grasslands served as crucial “sources” and “sinks” during the ecosystem evolution in the Ali prefecture. 3) The ecological sensitive areas mainly consisted of medium- and high-sensitivity zones, covering an area of 168 800 km², which accounted for nearly 50% of the total. Spatially, the northwest part of Ali prefecture exhibited high sensitivity, while the southeast part low sensitivity, with low-sensitivity areas encircling high-sensitivity areas.

Key words: ecosystem, ecological sensitivity, S-R-P model, Ali prefecture