Negative impacts of dominance on bee communities: Does the influence of invasive honey bees differ from native bees?

Invasive species can reach high abundances and dominate native environments. One of the most impressive examples of ecological invasions is the spread of the African sub-species of the honey bee throughout the Americas, starting from its introduction in a single locality in Brazil. The invasive honey bee is expected to more negatively impact bee community abundance and diversity than native dominant species, but this has not been tested previously. We developed a comprehensive and systematic bee sampling scheme, using a protocol deploying 11,520 pan traps across regions and crops for three years in Brazil. We found that invasive honey bees are now the single most dominant bee species. Such dominance has not only negative consequences for abundance and species richness of native bees but also for overall bee abundance (i.e., strong “numerical” effects of honey bees). Contrary to expectations, honey bees did not have stronger negative impacts than other native bees achieving similar level...外来入侵物种可达到极高的种群丰度，并主导本土生态系统。生态入侵最具代表性的案例之一，便是非洲蜜蜂亚种自巴西单一引入位点开启扩散后，在整个美洲大陆的蔓延传播。此前学界普遍认为，相较于本土优势蜂种，入侵性蜜蜂会对蜂群群落的种群数量与多样性造成更为严重的负面影响，但这一假说尚未得到实证检验。本研究构建了一套全面系统的蜂类采样方案，于巴西境内跨区域、跨作物类型布设11520个诱捕盘（pan traps），并持续三年开展采样工作。研究结果显示，入侵性蜜蜂现已成为当地最具优势的单一蜂种。这种优势地位不仅会对本土蜂类的种群丰度与物种丰富度产生负面影响，同时也会降低整体蜂类群落的种群丰度（即入侵蜜蜂表现出显著的“数量效应”）。但与预期相悖的是，入侵蜜蜂并未对达到相似种群规模的本土蜂类造成更强的负面影响……