Abstract:

The Lancang-Mekong River (LMR) is the longest river in Southeast Asia. A broad variety of ecosystems is present in the river basin, including alpine grasslands, meadows, lakes, tropical rainforests, and mangroves, which provide local people with food, wood, and other important services. In recent years, in the context of jointly promoting high-quality development of the Belt and Road initiated by China, practical cooperation between China and the Association of Southeast Asian Nations (Asean) has been expanding. One of the important achievements was the implementation of the Lancang-Mekong Cooperation Action Plan (2023‒2027), which emphasized the cooperation of ecological protection and forestry. Under these circumstances, scientifically evaluating the ecosystem service value (ESV) of the river basin, revealing its temporal and spatial response patterns to land use changes, and identifying the key driving factors affecting the spatial heterogeneity of ESV have become of great significance for formulating reasonable development and protection strategies and promoting sustainable development in the region. This study focuses on the LMR Basin. First, a CV-Markov model was constructed to simulate future land-use changes in the basin under different development scenarios, and a modified equivalent factor method was introduced to evaluate the ESV of the basin. Second, the special-temporal patterns of ESV under different land-use scenarios were analyzed and revealed based on spatial analysis and statistical technologies. Finally, a geo-detector model was adopted to identify the key driving factors that determine the spatial heterogeneity of ESV. The results showed that: 1) From 1995 to 2020, the total ESV and its spatial distribution pattern differed as land use changed in the LMR basin, and the value of total ESV showed non-monotonic variation characteristics, which decreased from 1995 to 2015 and increased in 2020. There are significant differences and spatial heterogeneity in the three development scenarios in 2040, with the lowest ESV in the agricultural development scenario (ADS) and the highest ESV in the ecological protection scenario (EPS). 2) There are significant spatial positive correlations and spatial agglomeration effects of ESV in different scenarios in 2040, and the scale and spatial pattern of ESV cold/hotspots in each scenario are considerably different. 3) The spatial heterogeneity of ESV of the LMR is driven by both natural factors and human activities, in which the human footprint is the dominant driving factor of the ESV spatial pattern among the seven factors, and three factors including average annual temperature, elevation, and slope, are also the key driving factors of ESV spatial heterogeneity in the LMR. In addition, any combination of the two factors has stronger explanatory power for ESV spatial heterogeneity than a single factor. The two factors with the highest explanatory power were the interaction between the human footprint and average annual temperature.

Key words: land use change, ecological service value, CV-Markov model, Geo-detector, Lancang-Mekong River

摘要：

科学评估流域生态系统服务价值（ESV），揭示其随土地利用变化的时空响应规律，识别影响ESV空间异质性的关键驱动因子，对于制定合理开发和保护策略，促进区域可持续发展具有重要意义。以澜沧江-湄公河流域为研究对象，采用CV-Markov模型模拟流域未来不同发展情景下土地利用变化，采用修正的当量因子法评估ESV，基于空间统计分析方法分析揭示土地利用变化影响下的ESV时空演变规律，并利用地理探测器模型识别ESV空间分异的关键驱动因子。结果表明，1）1995－2020年间，流域ESV总量、空间分布发生相应变化，总体呈先减小、后增大的趋势；2040年3种发展情景下流域ESV存在显著的差异性和空间异质性，其中农业发展情景ESV值最低、生态保护情境ESV最高。2）未来不同情景下流域ESV均存在显著空间正相关性和空间集聚效应，但不同情景下的ESV冷点/热点区域规模及其空间格局存在显著差异。3）流域ESV的空间异质性受到自然-人类活动的双重影响，其中人类足迹是ESV空间格局的主导驱动因子，年均气温、高程、坡度3个因子也是ESV空间异质性的关键驱动因子，且任意双因子组合对ESV空间异质性的解释力均强于单一因子，其中解释力最高的双因子为人类足迹与年均气温的组合。

关键词: 土地利用变化, 生态服务价值, CV-Markov模型, 地理探测器, 澜沧江-湄公河