Vertical seed dispersal toward higher or lower altitudes has been recognized as one of the critical processes for plants to escape from climate change. Studies exploring vertical seed dispersal are scarce, preventing the prediction of future vegetation dynamics. In the present study, we show that the timing of fruiting, rather than topography, determines the direction of vertical seed dispersal by mammals and birds across mountains in central Japan. We found strong uphill seed dispersal of summer fruiting cherry and weak downhill seed dispersal of summer-to-autumn fruiting cherry, irrespective of mountains and animals. The ascent or descent of animals, following the altitudinal gradients in food plant phenology in the temperate zone, was considered to be a driver of the biased seed dispersal. We found that megafauna (i.e., bears) intensively dispersed seeds vertically. The results suggest that the timing of fruiting and megafauna strongly affect whether animal-dispersed temperate plants can maintain their populations under climate change.

中文翻译：

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结果的时间而不是地形的时间决定了哺乳动物和鸟类垂直传播种子的方向

垂直向较高或较低高度扩散种子已被认为是植物逃避气候变化的关键过程之一。缺乏探索垂直种子扩散的研究，这妨碍了对未来植被动态的预测。在本研究中，我们表明结果的时间而不是地形决定了哺乳动物和鸟类在日本中部山区的垂直种子传播方向。我们发现夏季果樱桃的上坡种子散布性强，夏至秋季果樱桃的下坡种子散布性强，而与山地和动物无关。在温带地区，根据食品植物物候学的海拔梯度变化，动物的上升或下降被认为是造成种子扩散的原因。我们发现巨型动物（即 熊）垂直密集地散布种子。结果表明，结实时间和大型动物区系的时间强烈影响动物分散的温带植物能否在气候变化下维持其种群。