基于贝叶斯网络的生态系统服务权衡协同关系及其驱动因子分析——以陕北黄土高原为例

了解生态系统服务的权衡协同关系及其驱动因子效应是实现生态系统有效管理和改善人类福祉的基础。以陕北黄土高原为例,定量评估其2018年土壤保持、产水服务、粮食供给和固碳服务,在构建贝叶斯网络生态系统服务模型的基础上,通过节点的重要性分析识别影响生态系统服务的关键节点,利用联合概率分布、概率推理和情景模拟探讨生态系统服务权衡协同关系及其驱动因子效应。结果表明：（1）陕北黄土高原各类生态系统服务空间异质性较强。其中,土壤保持、产水服务和固碳服务的空间分布情况较为一致,高值区集中在东南部,低值区在西北部,呈"南高北低"的分布特征;粮食供给呈"中部高、南北低"的分布特征。（2）土壤保持、产水服务和固碳服务之间互为协同关系,粮食供给分别与土壤保持、产水服务、固碳服务为权衡关系。其中,产水服务与固碳服务的协同关系、产水服务与粮食供给的权衡关系较强。（3）土地利用、降水和NPP （Net primary production）是影响生态系统服务权衡协同关系的主要驱动因子,其中土地利用主要影响生态系统服务的协同关系,而降水和NPP在影响协同关系的同时对权衡关系也有一定的制约作用。研究发现：不同驱动因子在不同状态下产生相同的协同（或权衡）方式,相同驱动因子在不同状态则会造成协同（或权衡）方式的差异。研究对于认识多种生态系统服务间的复杂关系及其驱动因子差异,为后续提出改善生态系统管理和提高人类福祉的对策与措施,具有重要的理论和实践价值。

Ecosystem service trade-off and synergy relationship and its driving factor analysis based on Bayesian belief network: a case study of the Loess Plateau in northern Shaanxi Province

Understanding the trade-offs and synergies among various ecosystem services and the differences in their driving factors, which is the foundation for effective ecosystem management and improved human well-being. Taking the Loess Plateau in Northern Shaanxi Province as the study area. Firstly, the soil conservation, water production services, grain supply and carbon sequestration services were quantitatively assessed in the the study area in 2018. Secondly, based on the Bayesian network ecosystem service model, key nodes affecting ecosystem services were identified by node importance analysis. Finally, joint probability distribution, probabilistic reasoning and scenario simulation were used to explore the synergistic relationship of ecosystem service trade-offs and their driving factors. The results showed that:(1) The spatial heterogeneity of various ecosystem services was strong in the Loess Plateau of Northern Shaanxi Province. In terms of soil conservation, water production and carbon sequestration services, the spatial distribution of these three services was relatively consistent, that was, the high value area was concentrated in the southeast, and the low value area was in the northwest, showing the distribution characteristics of high in the south and low in the north. But for grain supply, it showed a distribution pattern of high in the middle and low in the north and south. (2) There was a synergistic relationship among soil conservation services, water production services and carbon sequestration services. However, soil conservation, water production and carbon sequestration services had trade-offs with grain supply, respectively. Among them, the synergistic relationship between water production service and carbon sequestration service, and the trade-off relationship between water production service and grain supply were relatively strong. (3) Anthropogenic and natural factors such as land use, precipitation and NPP (Net primary production) were the main driving factors affecting the trade-offs and synergies of ecosystem services in the study area. Among them, land use factors mainly affected the synergetic relationship between the ecosystem services, while precipitation and NPP factors not only affected the synergetic relationship but also restricted the trade-offs relationship to a certain extent. Further research showed that, land use, precipitation and NPP drivers produced the same synergy or trade-off in different states. Conversely, the same drivers in different states would lead to differences in the way of synergy or trade-off. This study had important theoretical and practical value for understanding the complex relationships among various ecosystem services and their driving factors, and for proposing countermeasures and measures to improve ecosystem management and human well-being.