J Plant Ecol ›› 2020, Vol. 13 ›› Issue (5): 657-666.DOI: 10.1093/jpe/rtaa054

• Research Articles • Previous Articles    

Seasonal dynamic variation of pollination network is associated with the number of species in flower in an oceanic island community

Xiangping Wang , Tong Zeng, Mingsong Wu and Dianxiang Zhang*   

  1. Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, China

    *Corresponding author. E-mail: dx-zhang@scbg.ac.cn
  • Received:2020-03-10 Revised:2020-07-14 Accepted:2020-08-04 Online:2020-08-11 Published:2020-10-01

Abstract:

Aims

Plant–pollinator interaction networks are dynamic entities, and seasonal variation in plant phenology can reshape their structure on both short and long timescales. However, such seasonal dynamics are rarely considered, especially for oceanic island pollination networks. Here, we assess changes in the temporal dynamics of plant–pollinator interactions in response to seasonal variation in floral resource richness in oceanic island communities.

Methods

We evaluated seasonal variations of pollination networks in the Yongxing Island community. Four temporal qualitative pollination networks were analyzed using plant–pollinator interaction data of the four seasons. We collected data on plant–pollinator interactions during two consecutive months in each of the four seasons. Four network-level indices were calculated to characterize the overall structure of the networks. Statistical analyses of community dissimilarity were used to compare this community across four seasons to explore the underlying factors driving these patterns. We also evaluated the temporal variation in two species-level indices of plant and pollinator functional groups.

Important Findings

Both network-level specialization and modularity showed a significantly opposite trend compared with plant species richness across four seasons. Increased numbers of plant species might promote greater competition among pollinators, leading to increased niche overlap and causing decreased specialization and modularity and vice versa. Further analyses suggested that the season-to-season turnover of interactions was dominated by interaction rewiring. Thus, the seasonal changes in niche overlap among pollinators lead to interaction rewiring, which drives interaction turnover in this community. Hawkmoths had higher values of specialization and Apidae had higher values of species strength compared with other pollinator functional groups. These findings should be considered when exploring plant–pollinator interactions in ecosystems of isolated oceanic islands and in other ecosystems.

Key words: interaction rewiring, modularity, oceanic island, pollination networks, seasonality, specialization, species strength

摘要:

植物与传粉者相互作用的传粉网络是一个动态的实体,植物开花物候的季节性变化可以在短时间和长时间内重塑其结构。然而,很少有研究考虑到这种季节性动态变化,特别是海洋岛屿群落的传粉网络。本研究探讨了海洋岛屿群落的植物与传粉者间传粉网络的结构是如何随群落内花资源丰富度的季节性变化而动态变化的。利用春夏秋冬四个季节的植物与传粉者间相互作用的数据,分析了四个季节定性的传粉网络结构的动态变化,研究了中国南海西沙群岛的永兴岛群落传粉网络的季节性动态变化。在这四个季节中,分别收集了连续两个月的植物与传粉者相互作用的数据,并计算了四个网络水平的指标来表征传粉网络的总体结构。采用群落差异性统计分析方法,对群落四个季节的网络结构参数进行比较分析,探讨影响这种动态变化格局的潜在因素。同时计算并比较了植物和传粉功能群在物种水平的网络指标的季节动态变化。研究结果表明,永兴岛群落网络水平的特化性和模块化在四个季节的变化均与植物物种丰富度的变化呈明显相反的变化趋势。开花植物种类的增加可能促进了传粉者之间更激烈的竞争,从而导致生态位重叠的增加,引起传粉网络特化性和模块化的下降,反之亦然。进一步分析表明,传粉网络的季节动态变化的内在驱动力是植物与传粉者间连接的重新组合。因此,传粉者之间生态位重叠的季节性变化导致了植物与传粉者间相互作用的重组,从而推动了该群落内植物与传粉者间相互作用的更替变化。在物种水平上,与其它传粉功能群相比,天蛾类传粉者最特化,而蜜蜂科传粉者的物种作用强度最大。因此,在探索孤立的海洋岛屿生态系统以及其它生态系统中的植物与传粉者间相互作用时,应适当考虑到这些新的发现。

关键词: 相互作用重组, 模块化, 海洋岛屿, 传粉网络, 季节性, 特化性, 物种作用强度