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

点击翻译按钮获取中文摘要

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.