Effects of Land Use Changes on Ecological Sensitivity of Nyang River Basin in Tibet

Abstract

[Objective] The ecological sensitivity of the the Nyang River basin in Tibet (a typical ecologically fragile plateau area) under land use changes during 1995—2020 was studied in order to provide theoretical references for land use planning and ecological environment protection in the watershed. [Methods] We calculated the watershed land use intensity index and the ecosystem service value to construct the land use change. The ecological sensitivity index was based on the temporal and spatial changes of the land use intensity index and the ecosystem service value in each sub-basin. The spatial distribution of ecological sensitivity in the Nyang River basin was obtained using GIS spatial analysis technology. [Results] The areas of woodland and construction land in the Nyang River basin increased from 1995 to 2020, while the unused land area and water area declined. The land use intensity index increased from 1.725 5 to 1.725 9, and the ecosystem service value of land use decreased about 30 million yuan. The areas exhibiting increasing intensity index were located in the downstream basin. The ecological sensitivity index of the basin increased from 0.3 to 9.4. The middle and high sensitive areas of the basin were mainly located in the middle and lower reaches. The extent of the high sensitive areas was increasing. [Conclusion] The change in regional ecological sensitivity for the watershed was determined by the direction of transfer and flow between land use types. Overall, the ecological sensitivity of the basin has responded more significantly to land use changes in the ecosystem over the last 25 years, with a deteriorating trend in the middle and lower reaches.

Keywords

• land use changes
• ecological sensitivity
• ecosystem service value
• nyang river