Data from: Fishing-down within populations harms seed dispersal mutualism

Large fish are often the most effective seed dispersers, but they are also the preferred target for fisheries. We recently started to comprehend the detrimental impacts of the extirpation of large frugivorous fish species on natural forest regeneration, but we lack a general understanding of how intraspecific size-selective harvest affects fish–fruit mutualism. Our literature review demonstrated that large individuals within populations positively affect diverse aspects of seed dispersal, from consuming a higher diversity of seeds to enhancing germination. Furthermore, we filled a research gap by studying how individual size variations within two small frugivorous fish species (<16 cm) affect seed dispersal in flooded savannas. Even within small-bodied species, large individuals swallow a higher number of intact seeds, but not necessarily a higher proportion. Overall, our results demonstrate the disproportional role of large-bodied individuals as key seed dispersers in flooded habitats. Consequently, fishing-down within both large- and small-bodied species can negatively affect seed dispersal and natural regeneration in overfished wetlands.大型鱼类往往是最为高效的种子传播者，同时也是渔业捕捞的首选目标。尽管我们近来已开始认识到大型食果鱼类（frugivorous fish）的局部消亡对天然森林更新所产生的不利影响，但我们仍缺乏对种内体型选择性捕捞（intraspecific size-selective harvest）如何影响鱼果互利共生关系（fish–fruit mutualism）的全面认知。本研究的文献综述表明，种群内的大型个体对种子传播的多个维度均产生积极影响——从取食更高多样性的种子，到提升种子萌发率。此外，我们通过研究两种体长小于16 cm的小型食果鱼类的个体体型差异如何影响泛滥稀树草原（flooded savannas）中的种子传播，填补了相关研究空白。即便在小型鱼类类群中，体型较大的个体所吞食的完整种子数量也更多，但这未必意味着其吞食的完整种子占比更高。综合来看，本研究结果表明，在泛滥生境中，体型较大的个体作为核心种子传播者发挥着不成比例的重要作用。由此可见，无论大型还是小型鱼类类群，针对其开展的捕捞下行效应（fishing-down）均会对过度捕捞湿地中的种子传播与天然更新造成不利影响。