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.大型鱼类往往是最高效的种子传播者，同时也是渔业捕捞的首选目标。我们近期才逐渐认识到大型食果鱼类（frugivorous fish）物种的局地灭绝对天然森林更新的不利影响，但对于种内体型选择性捕捞（intraspecific size-selective harvest）如何影响鱼果互利共生（fish–fruit mutualism），仍缺乏系统性的认知。我们的文献综述表明，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，从取食更多样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厘米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）中的种子传播过程，填补了这一研究空白。即便在小体型物种中，大型个体也能吞食更多完整种子，但未必能提升完整种子的摄取比例。总体而言，我们的研究结果证实，在泛滥生境中，大体型个体作为核心种子传播者发挥着不成比例的关键作用。因此，无论对大体型还是小体型鱼类物种开展的体型选择性捕捞，都会对遭受过度捕捞的湿地的种子传播及天然更新产生负面影响。