Data from: Allometric scaling of long-distance seed dispersal by migratory birds

Migratory birds are often suggested to be important vectors for long-distance dispersal (LDD) of plant and animal propagules. The scale of such dispersal events (hundreds to thousands of kilometers) can influence landscape-level biological processes and species distributions. However, the few vector species studied and the lack of proper integration of their migratory movement in models of LDD has precluded the study of their potential as long-distance biotic dispersers. By means of a mechanistic model parameterized with empirical data, we first investigated the properties of seed dispersal curves generated by migratory birds and then analyzed the effect of bird size on model parameters and consequent seed dispersal patterns. Seed dispersal curves showed in most cases large and heavy tails, resulting in relatively frequent LDD (up to 3.5% of dispersal distances longer than 100 km). Bird size mediated trade-offs between bird movement and seed retention time that, in turn, determined seed dispersal patterns and the potential of each bird species as an LDD vector. Our modeling framework builds on a mechanistic understanding of seed dispersal by migratory birds and may thus be a useful tool to estimate the scale and frequency of bird-mediated, large-scale transport of native, invasive, and pathogenic organisms.

候鸟常被认为是动植物繁殖体（propagules）长距离扩散（long-distance dispersal, LDD）的重要媒介。这类扩散事件的尺度可达数百至数千公里，可对景观尺度的生物过程及物种分布格局产生影响。然而，当前已研究的媒介物种数量有限，且未能将其迁徙运动合理整合至长距离扩散模型中，这极大阻碍了对其作为长距离生物扩散媒介潜力的探究。本研究借助基于实证数据参数化的机理模型，首先解析了候鸟介导的种子扩散曲线特征，随后分析了鸟类体型对模型参数及后续种子扩散格局的影响。多数情况下，种子扩散曲线呈现宽尾与重尾特征，使得长距离扩散事件发生频率相对较高——最高可达3.5%的扩散距离超过100公里。鸟类体型介导了其运动能力与种子滞留时间之间的权衡关系，而该关系进而决定了种子扩散格局，以及各鸟类物种作为长距离扩散媒介的潜力。本研究的建模框架基于对候鸟介导种子扩散的机理认知，因此可作为有效工具，用于评估鸟类介导的本土、入侵及病原生物的大规模扩散尺度与发生频率。