[Identification of critical ecological management zones and conservation strategies in the Nyangchu River Basin, Tibetan Plateau, China].

The Qinghai-Tibet Plateau region is a global ecological security barrier and a nationally important ecologically fragile zone. Research on ecological zoning and conservation strategies at the watershed scale is essential for formulating precise systematic management measures, which are crucial for the scientific ecosystem management and the harmonious development of humans and nature. We proposed a composite analytical framework of "comprehensive zoning of ecological services/sensitivity-identification of key ecological conservation areas-strategic research on key type areas via cluster analysis". Taking the Nyangchu River Basin, an area with prominent human-land conflict, as the research object, we systematically analyzed the quantitative structure and spatial pattern of key areas for ecological management. For key conservation areas, we used cluster analysis to analyze the structural types of dominant factors and research management strategies. The results showed that areas of comprehensive ecological service importance and critical in the study area accounted for approximately two-thirds and 13.7% of the basin, respectively, with the critical areas concentrated in the lower-altitude river valleys, mountains, and along both sides of the river channels. The comprehensive ecological sensitivity was relatively high, with sensitive and extremely sensitive areas accounting for 88.3% and 11.5%, respectively. The extremely sensitive areas were distributed contiguously in the high-altitude alpine regions of the upper reaches and linearly in the relatively lower-altitude valley areas of the middle and lower reaches. The degree of importance for ecological conservation was high, with critical and important areas accounting for 99.9%. The critical areas of ecological conservation accounted for 23.7%, concentrating in the upper reaches to form two independent network structures with large patches and good connectivity, and distributed as small patches or strips along the mainstream in the middle and lower reaches. The freeze-thaw erosion, windbreak and sand fixation, land desertification, and water conservation were the key factors driving the spatial differentiation of critical ecological conservation areas. Ecological management work in the Nyangchu River Basin could be divided into the following three scenarios. The Bailang Land Desertification Management Area should focus on controlling land desertification issues, implementing a coordinated governance strategy of "closure for conservation-engineering sand fixation-vegetation restoration". The ecological management area along the mainstream in the middle and lower reaches needed to focus on maintaining windbreak and sand fixation functions and biodiversity conservation, adopting a strategy coordinated between land use efficiency improvement and "Three Zones and Three Lines" spatial control. The high-altitude ecological management area in the upper reaches should prevent freeze-thaw erosion risk and maintain water conservation functions, adopting a linkage strategy combining monitoring, protection, and natural restoration. The basin should be suitable for developing characteristic valley agriculture and low-interference ecotourism, establishing an ecological compensation mechanism based on water conservation capa-city and carbon sink increment.