Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, UNSW, Sydney, NSW, Australia.
The Australian PlantBank, Australian Institute of Botanical Science, Australian Botanic Garden, Mount Annan NSW, Australia.
Ann Bot. 2021 Apr 17;127(5):613-620. doi: 10.1093/aob/mcaa203.
Different seed dormancy classes control the timing of germination via different cues. The ecological dissimilarities between classes therefore suggest that they are likely to be subject to different selective pressures, and that species within each class will have diverse functional responses. We aimed to investigate this by assessing how variation in the distribution of dormancy classes is correlated with regional environmental factors, in particular rainfall seasonality and temperature. Additionally, we compare the relative proportions of species with physiological (PD) or physical (PY) dormancy to assess whether dormancy class influences their ability to persist under different rainfall seasonality regimes.
Dormancy class was assigned for 3990 species from 281 genera occurring across two climate regions, with either winter or aseasonal rainfall, across temperate fire-prone Australia. All regions have similar vegetation and fire regimes. Using a Bayesian framework, we compared the distribution of dormancy classes across temperature and rainfall climate gradients, for threatened and common species.
A high dormant:non-dormant species ratio highlighted the critical role of dormancy across our study regions. Critically, species showing PD were more likely to be threatened in aseasonal rainfall climate regions.
Our results support the assumption that dormancy is favoured in environments with stochastic disturbance.
不同的种子休眠类群通过不同的线索控制萌发的时间。因此，类群之间的生态差异表明它们可能受到不同的选择压力的影响，并且每个类群内的物种将具有不同的功能响应。我们旨在通过评估休眠类群的分布变化与区域环境因素（特别是降雨季节性和温度）的相关性来研究这一点。此外，我们比较具有生理休眠（PD）或物理休眠（PY）的物种的相对比例，以评估休眠类群是否影响它们在不同降雨季节性制度下的生存能力。
为来自 281 个属的 3990 种物种分配休眠类群，这些物种分布在澳大利亚温带火灾多发地区的两个气候区，分别具有冬季或无季节性降雨。所有地区都具有相似的植被和火灾制度。使用贝叶斯框架，我们比较了休眠类群在温度和降雨气候梯度上的分布，包括受威胁和常见的物种。
高休眠：非休眠物种比例突出了休眠在我们研究区域中的关键作用。至关重要的是，在无季节性降雨气候区，表现出 PD 的物种更有可能受到威胁。
我们的结果支持休眠在具有随机干扰的环境中受到青睐的假设。
