González-Varo Juan P, Carvalho Carolina S, Arroyo Juan M, Jordano Pedro
Integrative Ecology Group, Estación Biológica de Doñana, EBD-CSIC, Sevilla, Spain.
Department of Zoology, Conservation Science Group, University of Cambridge, Cambridge, UK.
Mol Ecol. 2017 Aug;26(16):4309-4321. doi: 10.1111/mec.14181. Epub 2017 Jun 9.
Seed dispersal constitutes a pivotal process in an increasingly fragmented world, promoting population connectivity, colonization and range shifts in plants. Unveiling how multiple frugivore species disperse seeds through fragmented landscapes, operating as mobile links, has remained elusive owing to methodological constraints for monitoring seed dispersal events. We combine for the first time DNA barcoding and DNA microsatellites to identify, respectively, the frugivore species and the source trees of animal-dispersed seeds in forest and matrix of a fragmented landscape. We found a high functional complementarity among frugivores in terms of seed deposition at different habitats (forest vs. matrix), perches (isolated trees vs. electricity pylons) and matrix sectors (close vs. far from the forest edge), cross-habitat seed fluxes, dispersal distances and canopy-cover dependency. Seed rain at the landscape-scale, from forest to distant matrix sectors, was characterized by turnovers in the contribution of frugivores and source-tree habitats: open-habitat frugivores replaced forest-dependent frugivores, whereas matrix trees replaced forest trees. As a result of such turnovers, the magnitude of seed rain was evenly distributed between habitats and landscape sectors. We thus uncover key mechanisms behind "biodiversity-ecosystem function" relationships, in this case, the relationship between frugivore diversity and landscape-scale seed dispersal. Our results reveal the importance of open-habitat frugivores, isolated fruiting trees and anthropogenic perching sites (infrastructures) in generating seed dispersal events far from the remnant forest, highlighting their potential to drive regeneration dynamics through the matrix. This study helps to broaden the "mobile-link" concept in seed dispersal studies by providing a comprehensive and integrative view of the way in which multiple frugivore species disseminate seeds through real-world landscapes.
在一个日益碎片化的世界中，种子传播是一个关键过程，它促进了植物种群的连通性、定殖和分布范围的变化。由于监测种子传播事件存在方法上的限制，揭示多种食果动物物种如何作为移动连接体在碎片化景观中传播种子一直难以实现。我们首次将DNA条形码和DNA微卫星相结合，分别识别碎片化景观中森林和基质中动物传播种子的食果动物物种和源树。我们发现，在不同栖息地（森林与基质）、栖息处（孤立树木与电线杆）和基质区域（靠近与远离森林边缘）的种子沉积、跨栖息地种子通量、传播距离和树冠覆盖依赖性方面，食果动物之间存在高度的功能互补性。从森林到遥远基质区域的景观尺度种子雨的特点是，食果动物和源树栖息地的贡献发生了转变：开阔栖息地的食果动物取代了依赖森林的食果动物，而基质树木取代了森林树木。由于这种转变，种子雨的规模在栖息地和景观区域之间均匀分布。因此，我们揭示了“生物多样性-生态系统功能”关系背后的关键机制，在这种情况下，即食果动物多样性与景观尺度种子传播之间的关系。我们的结果揭示了开阔栖息地食果动物、孤立的结果树和人为栖息处（基础设施）在产生远离残留森林的种子传播事件中的重要性，突出了它们通过基质推动再生动态的潜力。这项研究通过提供一个全面综合的视角，展示了多种食果动物物种如何在现实世界景观中传播种子，有助于拓宽种子传播研究中的“移动连接体”概念。
