Mountain-climbing bears protect cherry species from global warming through vertical seed dispersal

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• 作者：Shoji Naoe¹ ; ^{naoeshoji@affrc.go.jp" class="auth_mail" title="E-mail the corresponding author} ; Ichiro Tayasu² ; ³ ; Yoichiro Sakai⁴ ; Takashi Masaki¹ ; Kazuki Kobayashi⁵ ; Akiko Nakajima⁵ ; Yoshikazu Sato⁶ ; Koji Yamazaki⁷ ; Hiroki Kiyokawa⁸ ; Shinsuke Koike⁹
• 刊名：Current Biology
• 出版年：2016
• 出版时间：25 April 2016
• 年：2016
• 卷：26
• 期：8
• 页码：R315-R316
• 全文大小：121 K

文摘

In a warming climate, temperature-sensitive plants must move toward colder areas, that is, higher latitude or altitude, by seed dispersal [1]. Considering that the temperature drop with increasing altitude (-0.65°C per 100 m altitude) is one hundred to a thousand times larger than that of the equivalent latitudinal distance [2], vertical seed dispersal is probably a key process for plant escape from warming temperatures. In fact, plant geographical distributions are tracking global warming altitudinally rather than latitudinally, and the extent of tracking is considered to be large in plants with better-dispersed traits (e.g., lighter seeds in wind-dispersed plants) [1]. However, no study has evaluated vertical seed dispersal itself due to technical difficulty or high cost. Here, we show using a stable oxygen isotope that black bears disperse seeds of wild cherry over several hundred meters vertically, and that the dispersal direction is heavily biased towards the mountain tops. Mountain climbing by bears following spring-to-summer plant phenology is likely the cause of this biased seed dispersal. These results suggest that spring- and summer-fruiting plants dispersed by animals may have high potential to escape global warming. Our results also indicate that the direction of vertical seed dispersal can be unexpectedly biased, and highlight the importance of considering seed dispersal direction to understand plant responses to past and future climate change.