Vázquez-Ramírez Jerónimo, Venn Susanna E
School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Melbourne, Victoria, Australia 3125.
Ann Bot. 2025 Jun 23. doi: 10.1093/aob/mcaf132.
The early life-history stages of alpine plants are strongly influenced by climatic factors. Predicted changes in alpine climate could significantly impact the ability of plants to regenerate from seed and thus on the long-term survival of these species. However, our knowledge on this topic has predominantly focused on the effects of warming on germination. Other early life-history stages or other changing environmental factors have been overlooked. Here, we determine the effects of a future warmer and drier climate and post-fire conditions on (i) seed development, (ii) germination and (iii) seedling establishment of thirteen alpine species.
For two years, we conducted a factorial field-based manipulative experiment in the Australian Alps where we created a warmer and drier microclimate using modified open-top chambers and post-fire conditions by controlled burning of selected plots. We (i) collected seeds that had developed under experimental conditions and determined their mass, size, germinability and the characteristics of emerging cotyledons; (ii) buried seeds in experimental plots and monitored germination throughout the snow-free season; and (iii) grown and planted seedlings and determined their survival over a year.
Overall, we found negative responses to the experimental treatments. Warmer and drier conditions during (i) seed development reduced seed mass, seed size and cotyledon area. (ii) Seed germination decreased in response to warmer and drier and post-fire conditions. Importantly, the timing of germination shifted under warmer and drier conditions. (iii) Seedling establishment was negatively affected by post-fire conditions and, to a lesser extent, by warmer and drier conditions. The timing of seedling mortality shifted relative to the control conditions.
Predicted future climate will have a negative impact on the ability of plants to regenerate from seed. Furthermore, species-specific responses are likely to contribute to changes in the composition and diversity of alpine communities.
高山植物的早期生活史阶段受气候因素的强烈影响。预计高山气候的变化可能会显著影响植物从种子再生的能力，进而影响这些物种的长期生存。然而，我们在这个主题上的认知主要集中在变暖对种子萌发的影响。其他早期生活史阶段或其他变化的环境因素被忽视了。在这里，我们确定未来更温暖、更干燥的气候以及火灾后的条件对13种高山植物的（i）种子发育、（ii）种子萌发和（iii）幼苗建立的影响。
两年来，我们在澳大利亚阿尔卑斯山进行了一项基于因子设计的田间操纵实验，通过使用改良的开顶式生长室创造更温暖、更干燥的微气候，并通过对选定地块进行控制性焚烧来模拟火灾后的条件。我们（i）收集在实验条件下发育的种子，并测定其质量、大小、发芽能力和出土子叶的特征；（ii）将种子埋在实验地块中，并在无雪季节监测种子萌发情况；（iii）种植幼苗并测定其一年后的存活率。
总体而言，我们发现实验处理产生了负面反应。（i）种子发育期间更温暖、更干燥的条件降低了种子质量、种子大小和子叶面积。（ii）种子萌发因更温暖、更干燥以及火灾后的条件而减少。重要的是，在更温暖、更干燥的条件下，种子萌发的时间发生了变化。（iii）幼苗建立受到火灾后条件的负面影响，在较小程度上也受到更温暖、更干燥条件的影响。幼苗死亡时间相对于对照条件发生了变化。
预计未来气候将对植物从种子再生的能力产生负面影响。此外，物种特异性反应可能会导致高山群落的组成和多样性发生变化。
