Stability and generalization in seed dispersal networks: a case study of frugivorous fish in Neotropical wetlands

When species within guilds perform similar ecological roles, functional redundancy can buffer ecosystems against species loss. Using data on the frequency of interactions between fish and fruit, we assessed whether co-occurring frugivores provide redundant seed dispersal services in three species-rich Neotropical wetlands. Our study revealed that frugivorous fishes have generalized diets; however, large-bodied fishes had greater seed dispersal breadth than small species, in some cases, providing seed dispersal services not achieved by smaller fish species. As overfishing disproportionately affects big fishes, the extirpation of these species could cause larger secondary extinctions of plant species than the loss of small specialist frugivores. To evaluate the consequences of frugivore specialization for network stability, we extracted data from 39 published seed dispersal networks of frugivorous birds, mammals and fish (our networks) across ecosystems. Our analysis of interaction freque...当功能群（guild）内的物种行使相似的生态功能时，功能冗余（functional redundancy）可缓冲生态系统，使其免受物种丧失的冲击。本研究依托鱼类与果实间的交互频率数据集，评估了在3个物种丰富的新热带湿地中，共存的食果动物是否能够提供冗余的种子传播服务。本研究结果显示，食果鱼类多为广食性物种；但体型较大的鱼类相较小型鱼类拥有更广的种子传播广度，在部分场景下可提供小型鱼类无法实现的种子传播服务。由于过度捕捞对大型鱼类的影响具有非对称性，相较于小型特化食果动物的丧失，这些大型鱼类的局部灭绝可能会引发更为严重的植物次生灭绝事件。为评估食果动物特化对网络稳定性的影响，我们从跨生态系统的39篇已发表文献中提取了食果鸟类、哺乳类及鱼类的种子传播网络数据（即本研究的网络数据集）。本研究对交互频率的分析……