Data from: ENSO and frost co-determine decade-long temporal variation in flower and seed production in a subtropical rain forest

Flower and seed production of plants can be greatly influenced by both natural climatic oscillations and local weather extremes. However, owing to the rarity of long-term monitoring studies conducted at a sufficient temporal scale to capture climatic oscillations and the unpredictability of extreme weather events, evidence that demonstrates how these two external forcings act in concert to drive plant reproduction remains scarce. In addition, considerable variation in species’ phenological responses to the external climatic forcings was often observed. Phylogenetic relationships may mediate this inter-specific variation, but previous studies yielded inconsistent results when testing this hypothesis. We monitored the flower and seed production in a subtropical rainforest, Fushan, Taiwan (24°45'N, 121°35'E), for over ten years (since September 2002). In March 2005, a record low temperature (-1.3°C) occurred at Fushan and caused great frost damage to plants. We used weekly phenological records and long-term meteorological data to assess the effects of climatic fluctuations and extreme weather event on plant reproductive output. We show that the El Niño Southern Oscillation (ENSO) indices, which integrated local climatic variables at Fushan over several months, were strongly associated with flower and seed production. The 2005 spring frost also had long-lasting effects on the flower and seed production of several species. In particular, we detected phylogenetic signals in the relationships between phenological responses of flowering production and several climatic variables (maximum temperature, irradiance, and ENSO34 index). By contrast, the relationships between seed production and climatic variables, as well as phenological responses to the frost event, did not exhibit a phylogenetic signal. Synthesis: Our findings add to the growing evidence that together the natural climatic oscillation (ENSO) and the extreme weather event (frost) determined the temporal variation in flower and seed production. In addition, phylogenetically closely related species resembled each other in their flowering responses to abiotic variation in this subtropical rainforest. Improved understanding of these abiotic and biotic interactions may help predicting population- and community-level phenological responses under future climate changes.植物的开花与种子生产极易受到自然气候振荡和局地极端天气的双重影响。然而，由于开展足够长时间尺度以捕捉气候振荡的长期监测研究较为稀缺，且极端天气事件本身具有不可预测性，目前尚缺乏足够证据阐明这两种外部驱动因子如何共同作用调控植物繁殖过程。此外，不同物种对外界气候驱动因子的物候响应往往存在显著差异。系统发育关系可能介导这种种间差异，但过往检验该假说的研究结果并不一致。 本研究于中国台湾福山亚热带雨林（24°45'N，121°35'E）开展了长达十余年的监测（自2002年9月起），记录了植物的开花与种子生产情况。2005年3月，福山地区出现有记录以来的最低温（-1.3℃），对当地植物造成了严重的霜冻危害。本研究结合每周物候观测记录与长期气象数据，评估了气候波动与极端天气事件对植物繁殖产出的影响。 研究结果显示，整合了福山地区数月局地气候变量的厄尔尼诺南方涛动（El Niño Southern Oscillation, ENSO）指数，与植物的开花和种子生产存在显著关联。2005年春季霜冻事件还对多个物种类群的开花与种子生产产生了长期影响。尤为重要的是，我们在开花生产的物候响应与部分气候变量（最高温、辐照度及ENSO34指数）之间的关系中检测到了系统发育信号。与之形成对比的是，种子生产与气候变量之间的关联，以及物种对霜冻事件的物候响应，均未表现出系统发育信号。 综合分析结果表明：本研究结果进一步补充了现有证据，证实自然气候振荡（ENSO）与极端天气事件（霜冻）共同决定了植物开花与种子生产的时间动态。此外，在该亚热带雨林中，系统发育亲缘关系较近的物种对非生物因子变化的开花响应模式更为相似。深入理解这些非生物与生物交互作用，将有助于预测未来气候变化背景下种群和群落水平的物候响应。