Data from: Diverse pollinator communities enhance plant reproductive success

Understanding the functional consequences of biodiversity loss is a major goal of ecology. Animal-mediated pollination is an essential ecosystem function and service provided to mankind. However, little is known how pollinator diversity could affect pollination services. Using a substitutive design, we experimentally manipulated functional group (FG) and species richness of pollinator communities to investigate their consequences on the reproductive success of an obligate out-crossing model plant species, Raphanus sativus. Both fruit and seed set increased with pollinator FG richness. Furthermore, seed set increased with species richness in pollinator communities composed of a single FG. However, in multiple-FG communities, highest species richness resulted in slightly reduced pollination services compared with intermediate species richness. Our analysis indicates that the presence of social bees, which showed roughly four times higher visitation rates than solitary bees or hoverflies, was an important factor contributing to the positive pollinator diversity–pollination service relationship, in particular, for fruit set. Visitation rate at different daytimes, and less so among flower heights, varied among social bees, solitary bees and hoverflies, indicating a niche complementarity among these pollinator groups. Our study demonstrates enhanced pollination services of diverse pollinator communities at the plant population level and suggests that both the niche complementarity and the presence of specific taxa in a pollinator community drive this positive relationship.

解析生物多样性丧失的功能效应，是生态学研究的核心目标之一。动物介导的传粉作用是人类赖以存续的关键生态系统功能与服务。然而，当前学界对传粉者多样性如何影响传粉服务的认知仍较为有限。本研究采用替代实验设计，通过人工操控传粉者群落的功能群（functional group, FG）与物种丰富度，探究其对专性异交模式植物萝卜（Raphanus sativus）生殖成功的影响。传粉者功能群丰富度的提升，可同时提高植物的坐果率与结籽率。此外，当传粉者群落仅包含单一功能群时，结籽率会随物种丰富度的提升而升高。但在多功能群传粉者群落中，当物种丰富度达到最高水平时，其传粉服务反而略低于中等物种丰富度的群落。分析结果显示，社会性蜜蜂的存在是推动传粉者多样性与传粉服务间正相关关系的关键因素，尤其是对坐果率而言；社会性蜜蜂的访花频率约为独居蜂或食蚜蝇的四倍。社会性蜜蜂、独居蜂与食蚜蝇的访花频率随日间时段发生显著变化，而花层高度对其访花行为的影响相对较弱，这表明三类传粉者类群间存在生态位互补效应。本研究证实，在植物种群水平上，多样化的传粉者群落可提升传粉服务能力；研究同时表明，生态位互补效应与传粉者群落中特定类群的存在，共同驱动了这一正相关关系。