What determines gene flow? Effects of landscape, pollinators, selection by mother tree

人类活动对自然栖息地的破坏和破坏是陆地生态系统中普遍存在的现象，被认为是对生物多样性的主要威胁。随着研究水平的提高，我们对破碎过程及其影响的理解在过去几十年中有了相当大的发展。最近的重要研究进展包括长期碎片化实验的结果，阐明了在碎片和周围改变的边缘之间产生的影响，详细考虑了遗传和人口学后果的碎片化和植物-动物相互作用的交替，特别是在植物繁殖过程中。在这项研究中，我们重点研究了森林碎片化对基因流的影响。首先，我们观察了不同生境中传粉者的区系和密度。窗口捕获物在不同森林类型间诱捕昆虫的丰度和种类组成存在显著差异，表明人为干扰对授粉过程有较大影响。我们的目标是观察到主要鸟类散布植物的种子传播。我们在连续和破碎的森林中设置了种子陷阱，以观察果实的产生和种子的传播规律，并监测了两种森林中的传播密度。我们发现，鸟类的密度在很大程度上取决于森林的果实产量，而不是森林的大小。因此，碎片化本身不太可能引起种子传播的变化，尽管碎片化通过改变植物种类组成从而影响果实生产模式来影响种子传播。这一结果与热带森林的研究不一致，热带森林的研究表明，由于碎片化，残障人士的传粉者服务减少。这种不同可能是因为日本温带森林的主要散布者是候鸟，它们在森林中只停留了很短的一段时间，从来没有强烈依赖森林。

The loss and fragmentation of natural habitats by human activities are pervasive phenomena in terrestrial ecosystems and considered to be major threats to biodiversity With increased levels of research, our understanding of processes involved in fragmentation and their impacts have developed considerablly over last decades. Recent important research advances include results of long-term fragmentation experiments, elucidation of the of influences caused by the creation of edges between fragments and surrounding altered detailed considerations of genetic and demographic consequences fragmentation and alternation of plant-animal interactions especially in plant reproductive processes. In this study we focused on alternation of gene flow by fragmentation of forests. First we observed pollinator fauna and density among different habitats. Window trap catches showed significant differences of abundance and species composition of trapped insects among different forest types, suggesting large changes of pollination processes by human disturbances. We aim observed seed dispersal of major bird-dispersed plants. We set seed traps in continuous and fragmented forests to see fruit production and seed dispersal patterns, and monitor density of disperses in the two forests We found that bird density was largely depended on fruit production of the forests rather than forest size. Thus it is unlikely that fragmentation itself caused changes in seed dispersal, although fragmentation afflicted seed dispersal through changes in plant species composition and thus fruit production patterns. The result is inconsistent with studies from tropical forests, which have indicated maims decline of pollinator service due to fragmentation. The difference may be because major dispersers in temperate forest of Japan are migratory birds, which inhabit a forest for only a short period and never strongly depend on the forest.