Overseas seed dispersal by migratory birds
Overseas seed dispersal by migratory birds
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DOI：
10.1098/rspb.2015.2406
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发表时间：
2016-01
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影响因子：
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通讯作者：
Duarte S. Viana;L. Gangoso;W. Bouten;J. Figuerola
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文献类型：
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作者：
Duarte S. Viana;L. Gangoso;W. Bouten;J. Figuerola
长距离扩散（LDD）促进了对孤立和偏远栖息地的殖民化，因此它被认为是解释许多物种分布的一种机制。鸟类是许多无根生物（如植物）的主要LDD媒介，但从未直接观察到或量化局地和区域尺度以外的LDD。通过对由gps追踪的野生猎鹰在迁徙飞行中捕获的鸟类进行采样，我们发现候鸟将种子运输了数百公里，并介导了从大陆到海洋岛屿的传播。在从欧洲迁徙到撒哈拉以南非洲的途中，到达加那利群岛（Alegranza）小岛的鸟类中，有1.2%的鸟类在肠道中携带了种子。每年进行季节性迁徙的数十亿只鸟可能会携带数百万颗种子。鸟类所携带的植物种类没有一种出现在阿莱格兰萨，大多数也没有出现在附近的加那利群岛，这直接说明了环境过滤器在阻碍移民物种成功定居方面的重要性。然而，这些LDD事件产生的持续传播压力可能解释了一些岛屿的殖民化。因此，候鸟可以调节许多植物类群的范围迅速扩大或转移，并决定它们的分布。
Long-distance dispersal (LDD) promotes the colonization of isolated and remote habitats, and thus it has been proposed as a mechanism for explaining the distributions of many species. Birds are key LDD vectors for many sessile organisms such as plants, yet LDD beyond local and regional scales has never been directly observed nor quantified. By sampling birds caught while in migratory flight by GPS-tracked wild falcons, we show that migratory birds transport seeds over hundreds of kilometres and mediate dispersal from mainland to oceanic islands. Up to 1.2% of birds that reached a small island of the Canary Archipelago (Alegranza) during their migration from Europe to Sub-Saharan Africa carried seeds in their guts. The billions of birds making seasonal migrations each year may then transport millions of seeds. None of the plant species transported by the birds occurs in Alegranza and most do not occur on nearby Canary Islands, providing a direct example of the importance of environmental filters in hampering successful colonization by immigrant species. The constant propagule pressure generated by these LDD events might, nevertheless, explain the colonization of some islands. Hence, migratory birds can mediate rapid range expansion or shifts of many plant taxa and determine their distribution.