Data from: Extremely long-distance seed dispersal by an overfished Amazonian frugivore

Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the largebodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, little is known about seed dispersal effectiveness of fishes. Extensive mobility of frugivorous fish could result in extremely effective, multi-directional, long-distance seed dispersal. Over three annual flood seasons, we tracked fine-scale movement patterns and habitat use of wild Colossoma, and seed retention in the digestive tracts of captive individuals. Our mechanistic model predicts that Colossoma disperses seeds extremely long distances to favourable habitats. Modelled mean dispersal distances of 337–552 m and maximum of 5495 m are among the longest ever reported. At least 5 per cent of seeds are predicted to disperse 1700–2110 m, farther than dispersal by almost all other frugivores reported in the literature. Additionally, seed dispersal distances increased with fish size, but overfishing has biased Colossoma populations to smaller individuals. Thus, overexploitation probably disrupts an ancient coevolutionary relationship between Colossoma and Amazonian plants.亚马逊流域全境的过度捕捞已导致食果鱼类种群锐减，尤以大型脂鲤科物种巨脂鲤（Colossoma macropomum）为甚。在漫长的年度洪水期内，食果鱼类会进入广袤的亚马逊泛滥平原，吞食大量坠落的果实并排出具有活力的种子。诸多乔木与藤本物种显然特化依赖鱼媒传播（icthyochory），而鱼类介导的种子传播或许对亚马逊湿地森林的存续至关重要。与食果哺乳类和鸟类不同，学界对鱼类的种子传播效能所知甚少。食果鱼类极强的移动能力，可能使其具备极高效率、多方向的长距离种子传播能力。在三个年度洪水季中，我们追踪了野生巨脂鲤的精细移动模式与栖息地利用情况，并监测了圈养个体消化道内的种子留存时长。我们的机理模型预测，巨脂鲤可将种子传播至适宜栖息地，且传播距离极长。模型预测的平均传播距离为337–552米，最大传播距离达5495米，属于迄今已报道的最长传播距离之列。据模型预测，至少5%的种子传播距离可达1700–2110米，远超文献中报道的绝大多数其他食果动物的种子传播距离。此外，种子传播距离随鱼类体型增大而增加，但过度捕捞已使巨脂鲤种群偏向小型个体。因此，过度捕捞可能已破坏了巨脂鲤与亚马逊植物之间源远流长的协同进化关系。