高山草甸群落传粉网络的动态结构及构建机制

The interactions between different coexisted species at community level could be represented in many different ways. The studies of plant-pollinator interactions at community level had indicated that many plant species shared same pollinator, while pollinators may also visited many plant species. The interactions between plants and pollinators constructed pollination network. However, previous studies mostly focused on visit observations between plants and pollinators, which paid little attentions on other events during pollination, such as quality and quantity of received and donated pollen grains, and their effects on seed production. On another hand, little is studied on how species diversity and composition affected these pollination network assemblages. In this proposal, we prepared to carry a three years study in alpine meadows in Hengduan mountain. Firstly, by investigating the species diversity and composition in fixed communities during flowering seasons, and observing the pollinator visitations and frequencies, we aim to construct the dynamical visitation networks between plants and pollinators. Meanwhile, by investigating the pollen qualities and quantities on pollinators and stigmas of each plant species, we aim to construct dynamical heterospecific pollen transfer networks. Finally, we will study how species diversities and compositions shape the structures and dynamical features of both visitation networks and heterospecific pollen transfer networks, also the potential effects on seed productions of plant species at community level, thus improve pollination network studies into the plant reproduction, which may also provide more details for maintaining mechanism of biodiversity.

群落中共存的生物之间，可能有彼此影响的多种互作模式。群落水平的植物与传粉者互作研究表明，多种植物使用相同传粉者，传粉者也会访问不同植物，从而构成泛化的传粉网络。然而，已有的群落水平上传粉研究大多都是基于植物与传粉者之间的访花观察，缺乏对植物整个传粉过程的研究，比如植物输入和输出的花粉数量和构成，异种花粉落置对结实的影响等。另一方面，群落的物种多样性和构成等因素，都可能塑造网络结构，进而影响群落内物种的授粉情况和结实。本课题拟在前期工作基础上，计划在高山草甸群落，定点调查开花植物的多样性和构成，通过定量分析传粉者种类和访问频率，以及传粉者携带和柱头落置的花粉种类和数目，构建动态的访问和种间花粉流网络。探讨群落物种多样性和构成，对访问网络和花粉流网络动态结构的影响，探索生态网络的塑造机制，以及对群落植物结实的潜在作用，将生态网络的研究深入到植物间对繁殖的相互影响，为生物多样性的维持提供依据。

同域分布的物种之间存在着多种相互作用，构成了复杂的生态网络。群落水平上植物与传粉者之间的网络调查表明，泛化的传粉系统占主导，即多种植物共用相同的传粉者。传粉者在不同开花植物之间混访可能在柱头上落置异种花粉，从而降低花粉供体和受体物种的有性生殖成功。本项目通过在香格里拉高山草甸群落的连续多年研究，构建了定量的多年动态网络，说明尽管传粉网络的物种和连接在年际之间变化较大，部分物种仍旧能够构建起稳定的连接。而且这些连接维持了传粉网络的稳定结构，满足了群落的传粉需求。另外，通过定点调查传粉者种类与混访行为、定量分析同域植物柱头落置的花粉组成，构建传粉者混访和植物种间花粉传递网络，说明了传粉者在群落内的混访行为与植物的异种花粉落置的关系。拥有相同传粉者的共同开花植物，即便传粉者在植物间大量混访，仍旧能保持物种之间较少的异种花粉干扰。项目结果说明了高山草甸的传粉网络动态变化过程，并且深入到群落的传粉过程中，为动物-植物相互作用提供了新的视野。