SUPPORTING INFORMATION 5.12

1. The Qinling Mountains are rich in vegetation and diverse in pollinating insects. In the past few decades, both the population and diversity of bees in the Qinling Mountains and surrounding areas are decreasing dramaticallydue to the effects of Apis mellifera, with cascading impacts on community structure and ecosystem stability in the region.2. In order to improve the protection of native bees in the natural and agricultural landscape of the Qinling Mountains and its surrounding areas, we investigated 33 sampling sites in 3 habitats (forest, forest-agriculture ecotones and farmland).3. We used a generalized linear mixing model, t-test and other data analysis methods to explore the impact mechanisms of Apis mellifera on local pollinator bee diversity, abundance, and the pollination network in different habitats in these region areas.4. The results show that ① Apis mellifera has a significant negative effect on the abundance and richness of wild bees, while the Apis cerana abundance is also affected by beekeeping conditions; ② There arealso significant negative effectsof Apis melliferaon the community structure of pollinatorbees in the Qinling Mountains and its surrounding areas: the ShannonWiener diversity index, Pielou evenness index and Margalef richness index of bee communities at sites with Apis mellifera influence were significantly lower than those at sites without Apis mellifera influence.③the driver of this effect is the competition between Apis melliferaand native bees for floral resources: Apis melliferatend to visit flowering plants with large nectar sources that make up a large proportion of the local community, and maintain a central role in the pollinator bee-plant pollination network, competitively replacing native pollinator bee access to floral resources, which ultimately resulted in a decrease in the local bee-plant interaction, resulting in a decrease in the complexity and stability of the bee-plant interaction network and the overall ecological structure.

1. 秦岭植被资源丰富，传粉昆虫类群多样。近数十年来，受西方蜜蜂（Apis mellifera）的影响，秦岭及周边区域的蜜蜂种群数量与多样性均出现大幅下降，进而对区域群落结构与生态系统稳定性产生连锁效应。
2. 为强化秦岭及周边自然与农业景观中本土蜂类的保护工作，本研究在森林、林农交错带、农田三类生境中布设了33个采样样地。
3. 本研究采用广义线性混合模型（generalized linear mixing model）、t检验（t-test）等数据分析方法，探究了西方蜜蜂对该区域不同生境下本土传粉蜂类多样性、种群丰度以及传粉网络的影响机制。
4. 研究结果显示：① 西方蜜蜂对野生蜂类的种群丰度与物种丰富度存在显著负向影响，同时东方蜜蜂（Apis cerana）的种群丰度亦受养蜂条件的制约；② 西方蜜蜂对秦岭及周边区域传粉蜂类的群落结构同样存在显著负向效应：受西方蜜蜂影响的样地中，蜂类群落的香农-威纳多样性指数（Shannon-Wiener diversity index）、皮卢均匀度指数（Pielou evenness index）与玛格列夫丰富度指数（Margalef richness index），均显著低于未受其影响的样地；③ 该效应的驱动机制为西方蜜蜂与本土蜂类间的花蜜资源竞争：西方蜜蜂偏好造访在本地植物群落中占比较高的大蜜源开花植物，并在传粉蜂-植物传粉网络中占据核心地位，通过竞争挤占本土传粉蜂类的花蜜资源获取途径，最终导致本地蜂-植物交互作用减少，进而降低了蜂-植物交互网络的复杂度与稳定性，以及整体生态结构的稳定性。