For most terrestrial plants, regeneration depends on the ability of seeds to germinate in the most favourable climatic conditions. Understanding seed germination phenology is thus crucial for predicting plant responses to environmental changes. However, a substantial gap persists regarding how microclimatic conditions influence germination in seasonal ecosystems. Here, we investigate the germination phenology of alpine plants in snow‐related microclimates as a tool for predicting the resilience of plant communities to climate change. We conducted a continuous seasonal experiment with fresh seeds to investigate germination phenology in 54 co‐occurring species from temperate and Mediterranean alpine communities. Using long‐term field microclimatic data series, we precisely mimicked two contrasting microclimatic regimes in growth chambers: (1) windy exposed edges with a snow‐free period in winter and warmer temperatures in summer (‘fellfield’) and (2) sheltered areas with lengthy snow cover and cooler temperatures (‘snowbed’). We validated the laboratory results with field sowing experiments to provide a complete picture of germination phenology. The analysis of phenology traits demonstrated that both communities displayed similar responses to microclimatic variation. Small microclimatic differences of 2–3°C a week, accumulated across a whole year in the laboratory, resulted in a quantifiable germination phenology delay in snowbed regime, with an average of 60 and 45 days for temperate and Mediterranean alpine respectively. The results from climatic chambers under realistic microclimatic regimes were consistent with the germination phenology registered from field experiments. We also observed macroclimatic effects manifested as reduced dormancy and increased autumn germination in Mediterranean alpine species. Synthesis. This study combines novel laboratory and field experimentation to tackle the understudied topic of germination phenology in habitats with sharp microclimatic gradients. Specifically, our findings suggest a predictable phenological shift in the germination of alpine plants along microclimatic gradients. In warmer conditions with reduced snow cover, alpine species are expected to advance germination 52 days on average, with potential disrupting effects on cold‐adapted species with strict germination requirements. This highlights the role of germination phenology to determine plant‐environmental relationships in mid‐latitude ecosystems, with strong impact on plant establishment and extinction risks under local microclimatic gradients.

中文翻译：

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小气候变化调节高山植物群落种子发芽物候


对于大多数陆生植物来说，再生取决于种子在最有利的气候条件下发芽的能力。因此，了解种子发芽物候对于预测植物对环境变化的反应至关重要。然而，关于小气候条件如何影响季节性生态系统的发芽，仍然存在巨大差距。在这里，我们研究了高山植物在与雪相关的小气候中的发芽物候，作为预测植物群落对气候变化的适应力的工具。我们用新鲜种子进行了一项连续的季节性实验，以调查来自温带和地中海高山群落的 54 种共存物种的发芽物候。使用长期的田间微气候数据系列，我们精确模拟了生长室中两种截然不同的微气候状况：（1） 冬季无雪期和夏季温暖温度的多风裸露边缘（“fellfield”）和 （2） 积雪较长且温度较低的遮蔽区域（“雪床”）。我们通过田间播种实验验证了实验室结果，以提供发芽物候的完整图片。物候性状分析表明，两个群落对微气候变化表现出相似的反应。在实验室中一整年累积的每周 2-3°C 的小微气候差异导致雪床状态的发芽物候延迟，温带和地中海高山平均分别为 60 天和 45 天。在现实的小气候条件下，气候室的结果与田间实验记录的发芽物候一致。 我们还观察到宏观气候效应表现为地中海高山物种休眠减少和秋季发芽增加。合成。本研究结合了新颖的实验室和田间实验，以解决在小气候梯度陡峭的栖息地中发芽物候学这一研究不足的话题。具体来说，我们的研究结果表明，高山植物沿小气候梯度发芽的物候变化是可预测的。在积雪减少的温暖条件下，预计高山物种平均将发芽提前 52 天，这对具有严格发芽要求的寒冷适应物种具有潜在的干扰影响。这突出了发芽物候学在确定中纬度生态系统中植物与环境关系的作用，对当地小气候梯度下的植物建立和灭绝风险有很大影响。