2026-03-24 総合地球環境学研究所
図1. 哺乳類によるカスミザクラ（上）とウワミズザクラ（下）の標高方向の種子散布
※図は、シュプリンガーネイチャー社から許可を得て、論文中の図を基に作成しました。
＜関連情報＞
- https://www.chikyu.ac.jp/rihn/news/detail/767/
- https://link.springer.com/article/10.1007/s00442-025-05663-x
結実の季節性は、山脈を越えた哺乳類や鳥類による種子の垂直散布の方向に影響を与える Fruiting phenology affects the direction of vertical seed dispersal by mammals and birds across mountain ranges
Yoshihiro Tsunamoto,Shinsuke Koike,Ichiro Tayasu,Takashi Masaki,Shuri Kato,Satoshi Kikuchi,Teruyoshi Nagamitsu,Takashi F. Haraguchi,Tomoko Naganuma & Shoji Naoe
Oecologia Published:24 January 2025
DOI:https://doi.org/10.1007/s00442-025-05663-x
Abstract
Vertical seed dispersal towards higher or lower altitudes is an important process for plants’ adaptation to climate change. Although many plants depend on animals for seed dispersal, studies on vertical seed dispersal by animals, determined by complex animal behaviours, are scarce. Previous studies hypothesised that animals inhabiting temperate regions disperse seeds uphill in spring/summer and downhill in autumn/winter due to their seasonal movement following the altitudinal gradients in food phenology. However, this hypothesis has only been tested in seed dispersal by mammals on one mountain range. Vertical seed dispersal by birds might differ from that by mammals, and frugivorous megafauna extinction and mountain topography may affect seed dispersal patterns. Here we assessed the vertical seed dispersal of summer and summer-to-autumn fruiting cherries by mammals and birds across three Japanese mountain ranges, two of them with presence of a megafauna, the Asian black bear. We found strong uphill seed dispersal of summer fruiting cherry species and weak downhill seed dispersal of summer-to-autumn fruiting cherry species, irrespective of the frugivore community and mountain topography. These indicate that the fruiting phenology affects the direction of vertical seed dispersal by mammals and birds across mountains. Mammals and birds dispersed seeds over a similar vertical profile, although birds are likely to be low-quantity seed dispersers. The absence of bears, which dispersed the majority of the seeds, was not compensated by the remaining mammal species. The results suggest that the fruiting phenology and megafauna presence affect whether animal-dispersed temperate plants can migrate efficiently under climate change.
