Understanding how tropical tree phenology (i.e., the timing and amount of seed and leaf production) responds to climate is vital for predicting how climate change may alter ecological functioning of tropical forests. We examined the effects of temperature, rainfall, and photosynthetically active radiation (PAR) on seed phenology of four dominant species and community‐level leaf phenology in a montane wet forest on the island of Hawaiʻi using monthly data collected over ~ 6 years. We expected that species phenologies would be better explained by variation in temperature and PAR than rainfall because rainfall at this site is not limiting. The best‐fit model for all four species included temperature, rainfall, and PAR. For three species, including two foundational species of Hawaiian forests (Acacia koa and Metrosideros polymorpha), seed production declined with increasing maximum temperatures and increased with rainfall. Relationships with PAR were the most variable across all four species. Community‐level leaf litterfall decreased with minimum temperatures, increased with rainfall, and showed a peak at PAR of ~ 400 μmol/m2s−1. There was considerable variation in monthly seed and leaf production not explained by climatic factors, and there was some evidence for a mediating effect of daylength. Thus, the impact of future climate change on this forest will depend on how climate change interacts with other factors such as daylength, biotic, and/or evolutionary constraints. Our results nonetheless provide insight into how climate change may affect different species in unique ways with potential consequences for shifts in species distributions and community composition.

中文翻译：

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夏威夷山地湿林中物种营养和繁殖物候的气候敏感性

了解热带树木物候（即种子和叶子生产的时间和数量）如何对气候做出反应对于预测气候变化如何改变热带森林的生态功能至关重要。我们使用大约 6 年收集的月度数据，研究了温度、降雨量和光合有效辐射 (PAR) 对夏威夷岛山地湿林中四种优势物种的种子物候和群落级叶物候的影响。我们预计温度和 PAR 的变化比降雨量能更好地解释物种物候，因为该地点的降雨量不受限制。所有四种物种的最佳拟合模型包括温度、降雨量和 PAR。对于三个物种，包括夏威夷森林的两个基本物种（金合欢树和 Metrosideros polymorpha），种子产量随着最高温度的升高而下降，随着降雨的增加而增加。与 PAR 的关系在所有四个物种中变化最大。社区水平的落叶量随最低温度而减少，随降雨而增加，并在 PAR 处达到峰值，约为 400 μmol/m2s−1。不能用气候因素解释的每月种子和叶片产量有相当大的变化，并且有一些证据表明日长的中介作用。因此，未来气候变化对这片森林的影响将取决于气候变化如何与其他因素相互作用，如日长、生物和/或进化限制。尽管如此，我们的结果提供了对气候变化如何以独特的方式影响不同物种的见解，并对物种分布和群落组成的变化产生潜在影响。