Data from: The role of frugivory in plant diversity maintenance- a simulation approach

Frugivores may play a key role in plant species coexistence by equalizing the species’ representation in the seed rain. Rare species may benefit from enhanced dispersal if frugivores prefer locally scarce fruits, or if rare plants are found in neighborhoods of high fruit density. Using a simulation model of frugivorous birds foraging on landscapes we tested if increased diversity in the seed rain could emerge from rare-biased fruit selection, from the spatial configuration of plants, or both. In the absence of rare-biased fruit selection, frugivores were not able to increase the diversity of the seed rain in any of our simulated landscapes. In contrast, when frugivores were attracted to locally scarce fruits, we found increased diversity in the seed rain whenever frugivore mobility across the landscape was high and plant species were well-mixed in the fruiting neighborhoods. Irrespectively of the behavioral mechanism involved, landscape fragmentation lead to losses in diversity and species richness of simulated communities. In all simulations, density-dependent mortality of dispersed seeds increased diversity in the community of seedlings. However, landscape homogenization at the scale of frugivores movements decreased the magnitude of this diversification effect. In summary, our study shows that frugivory has the potential to increase diversity in the seed rain when frugivores display rare-biased fruit choices, provided that rare and common plants form heterogeneous neighborhoods. They also show that fragmentation is a major threat for diversity maintenance in the early-regenerating community. Finally, they show that rarity confers advantages during regeneration only if it occurs at the scale of frugivores’ foraging decisions.

食果动物（Frugivore）可通过平衡种子雨（seed rain）中的物种占比，在植物物种共存过程中发挥关键作用。若食果动物偏好当地稀缺的果实，或是稀有植物生长在果实密度较高的植株邻域中，稀有物种可从更高效的种子扩散中获益。本研究基于取食景观的食果鸟类模拟模型，检验了种子雨多样性提升是否可源于偏倚稀有果实的取食选择、植物空间配置，或是二者的共同作用。在未设置偏倚稀有果实取食选择的情境下，所有模拟景观中的食果动物均无法提升种子雨的多样性。与之相反，当食果动物偏好当地稀缺果实的取食策略时，只要食果动物在景观中的移动能力较强，且植物物种在结实邻域中均匀混合，种子雨的多样性便会显著提升。无论涉及何种行为机制，景观破碎化（landscape fragmentation）都会导致模拟群落的多样性与物种丰富度（species richness）下降。在所有模拟场景中，扩散后种子的密度制约死亡率（density-dependent mortality）均可提升实生苗群落（seedling community）的多样性。不过，食果动物移动尺度下的景观均质化（landscape homogenization）会削弱这一多样性提升效应的强度。综上，本研究表明：当食果动物表现出偏倚稀有果实的取食选择，且稀有与常见植物形成异质邻域时，食果作用有望提升种子雨的多样性。研究同时证实，景观破碎化是早期更新群落（early-regenerating community）维持多样性的主要威胁。最后，研究发现仅当稀有性发生在食果动物取食决策的尺度内时，才能在植物更新过程中为稀有物种带来竞争优势。