Between-year changes in community composition shape species' roles in an Arctic plant-pollinator network

Inter-annual turnover in community composition can affect the richness and functioning of ecological communities. If incoming and outgoing species do not interact with the same partners, ecological functions such as pollination may be disrupted. Here, we explore the extent to which turnover affects species' roles --as defined based on their participation in different motifs positions-- in a series of temporally replicated plant-pollinator networks from high-Arctic Zackenberg, Greenland. We observed substantial turnover in the plant and pollinator assemblages, combined with significant variation in species' roles between networks. Variation in the roles of plants and pollinators tended to increase with the amount of community turnover, although a negative interaction between turnover in the plant and pollinator assemblages complicated this trend for the roles of pollinators. This suggests that increasing turnover in the future will result in changes to the roles of plants and likely those of pollinators. These changing roles may in turn affect the functioning or stability of this pollination network.

群落组成的年际更替可影响生态群落的物种丰富度与生态功能。若迁入物种与迁出物种的交互伙伴并不一致，则传粉作用等生态功能可能受到干扰。本研究以格陵兰高北极地区扎科彭（Zackenberg）的一系列时间重复采样的植物-传粉者交互网络为研究对象，基于物种在不同交互模体中的参与位置定义的物种角色，探究群落组成更替对物种角色的影响程度。本研究观测到植物与传粉者类群存在显著的群落更替，且不同交互网络间的物种角色存在显著差异。植物与传粉者的角色变异程度往往随群落更替强度的增加而升高，不过植物类群与传粉者类群的群落更替之间存在负向交互作用，这使得传粉者角色的变化趋势更为复杂。这意味着未来群落更替程度的加剧，将引发植物角色的改变，传粉者的角色也大概率会随之变化。而这些发生改变的物种角色，又可能反过来影响该传粉交互网络的生态功能与稳定性。