Data from: Disentangling the interplay of generative and vegetative propagation among different functional groups during gap colonization in meadows

Meadow plant communities are commonly driven by strong competition, and the colonization of gaps plays an important role in the maintenance of their species diversity. Despite this, species-specific information about the dynamics of vegetative and generative propagation, and on the role of seed bank and seed rain, is rather scarce. In a 3-year manipulative experiment, we aimed to disentangle the effects of seed bank, seed rain and vegetative propagation in vegetation and during colonization of artificial gaps in a mesotrophic meadow. Vegetative propagation was manipulated by felting and the presence of the seed bank by soil sterilization using gamma radiation. We focused on the dynamics of four main species groups with different regeneration strategies: dicots, Cyperaceae, Juncaceae and Poaceae. The shift from seedling dominance in early stages towards vegetative resprouts dominating at a later stage in the gap colonization process differed considerably among the four species groups. Dicots and Juncaceae, regenerating frequently from the seed bank, acted as pioneer species, and determined species composition of newly disturbed sites. Seed rain became crucial later in the season and resulted in shifting dominance to the more competitive Poaceae. Stress-tolerating Cyperaceae were colonizing the gaps vegetatively mainly towards the end of the experiment. While graminoids showed preference for growing into gaps clonally, dicots propagated vegetatively mostly within intact vegetation. Although seed rain soon equalized seedling numbers in plots with and without a seed bank, the presence of a seed bank proved to be crucial for certain species, and its effect on species diversity remained positive in all functional groups for the duration of the experiment, demonstrating the importance of a seed bank for the maintenance of species diversity. Nevertheless, seedling assembly converged to a similar functional composition in all gap types after 3 years. We have not detected any competitive effect of vegetative resprouts on seedlings or seedlings on vegetative resprouts throughout the experiment. Each of the three means of regeneration has its unique role in the maintenance of species diversity during gap colonization, and the importance of these roles differs in different functional groups.

草甸植物群落通常受强烈的种间竞争调控，裸地空隙的拓殖在维持其物种多样性中发挥着关键作用。尽管如此，关于植物营养繁殖（vegetative propagation）与有性繁殖（generative propagation）的动态特征，以及种子库（seed bank）和种子雨（seed rain）所扮演的生态角色的物种特异性信息仍相当匮乏。在一项为期3年的野外操控实验中，我们旨在厘清中营养草甸（mesotrophic meadow）的植被动态，以及人工创建的裸地空隙拓殖过程中，种子库、种子雨与营养繁殖三者的影响效应。本实验通过毡布覆盖操控营养繁殖过程，利用伽马辐射（gamma radiation）进行土壤灭菌以去除种子库。我们重点关注4类具有不同更新策略的主要功能群：双子叶植物、莎草科（Cyperaceae）、灯心草科（Juncaceae）与禾本科（Poaceae）。在裸地空隙拓殖过程中，4个功能群的优势类群从早期的实生苗（seedling）向后期的营养萌株转变的模式存在显著差异。常通过种子库完成更新的双子叶植物与灯心草科充当了先锋物种，决定了新生干扰生境的物种组成。种子雨则在生长季后期发挥关键作用，促使优势类群转向竞争力更强的禾本科。耐胁迫的莎草科主要在实验后期通过营养繁殖途径拓殖空隙。尽管禾草类（graminoids）更倾向于通过克隆生长占据空隙，双子叶植物的营养繁殖则多发生在未受干扰的原生植被中。尽管种子雨很快使得有种子库与无种子库样地的实生苗数量趋于一致，但种子库的存在对部分物种而言仍至关重要；且在实验全程，种子库对所有功能群的物种多样性均存在正向调控效应，证实了种子库在维持物种多样性中的重要性。不过，3年后所有空隙类型样地的实生苗群落均收敛至相似的功能群组成。本实验全程未检测到营养萌株对实生苗，或实生苗对营养萌株的竞争性互作效应。三种更新途径在裸地空隙拓殖过程中对物种多样性的维持各自具有独特作用，且这些作用的重要性因功能群的不同而存在差异。