海南羊山湿地的传粉网络及其季节动态

Pollination network and seasonal dynamics of Yangshan Wetland in Hainan Island, China

传粉网络是植物和传粉者之间形成的网状相互作用关系,为理解群落物种多样性形成与维持机制提供了全新的视角。湿地是典型的群落交错区,环境异质性与物种多样性都很高,传粉网络可能比草地和森林等生态系统具有更复杂的结构。该研究针对海南岛海口市南郊的羊山湿地,比较4个样地在旱季(5月)与雨季(8月)的传粉网络及其动态变化,揭示湿地生态系统的传粉网络结构特征以及在干湿季的变化规律。结果表明,羊山湿地传粉网络共有71种开花的植物, 131种传粉者,传粉网络呈现低连接度、高嵌套度、中等网络特化程度的结构特征。在季节动态方面, 4个样地旱季的植物与传粉者种类高于雨季;而传粉网络的连接度、嵌套度与网络特化程度没有明显的季节差异。白花鬼针草和水角等多个物种可同时在雨季和旱季开花,使得植物-传粉者的种间关系虽然存在季节变化,但传粉网络在旱季与雨季间的动态变化不大。总体而言,羊山湿地物种多样性较高,边缘效应较明显,传粉网络结构较稳定。

Aims Wetland is a typical ecotone between terrestrial and aquatic ecosystems, with very high levels of habitat heterogeneity and biodiversity. The complex community structure and species interactions may have unusual pollination networks as compared to other ecosystems such as meadows and forests, which will affect species coexistence and community assembly. Our objective was to determine the pollination network and its seasonal dynamics in a tropical wetland.Methods In this research, we studied pollination networks in four plots of Yangshan Wetland on Hainan Island,in dry seasons(May) and rainy seasons(August) respectively. Two 10-m-long walked line transects were set in each plot to sample pollination events. Both pollinators and their visitation times on each flower(plant) were recorded to determine the pollination networks.Important findings The results showed that the species of plants and pollinators in the dry season were richer than that in the rainy season. The pollination network structure was not different between two seasons, and the visitation relationship between plant and pollinator species was relatively stable in the two seasons. There was no seasonal difference in connectance, nestedness and network specialization(H′2) on pollination network. The nestedness and H′2 of Plot 4 with higher species diversity fluctuated less in seasonal dynamic, and species relationships was stable in the community of 4 plots.