Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030, Vienna, Austria.
Department of Systematics, Biodiversity and Evolution of Plants (with herbarium), University of Goettingen, Untere Karspüle 2, 37073, Göttingen.
Ecol Lett. 2018 Mar;21(3):392-401. doi: 10.1111/ele.12908. Epub 2018 Jan 19.
Asexual taxa often have larger ranges than their sexual progenitors, particularly in areas affected by Pleistocene glaciations. The reasons given for this 'geographical parthenogenesis' are contentious, with expansion of the ecological niche or colonisation advantages of uniparental reproduction assumed most important in case of plants. Here, we parameterized a spread model for the alpine buttercup Ranunculus kuepferi and reconstructed the joint Holocene range expansion of its sexual and apomictic cytotype across the European Alps under different simulation settings. We found that, rather than niche broadening or a higher migration rate, a shift of the apomict's niche towards colder conditions per se was crucial as it facilitated overcoming of topographical barriers, a factor likely relevant for many alpine apomicts. More generally, our simulations suggest potentially strong interacting effects of niche differentiation and reproductive modes on range formation of related sexual and asexual taxa arising from their differential sensitivity to minority cytotype disadvantage.
无性类群的分布范围通常比其有性祖先更大，尤其是在受更新世冰川作用影响的地区。对于这种“地理孤雌生殖”，人们给出了有争议的解释，认为生态位的扩展或单亲生殖的殖民优势在植物中最为重要。在这里，我们为高山毛茛 Ranunculus kuepferi 制定了一个扩散模型，并根据不同的模拟设置，重建了其有性和无融合生殖细胞型在整个欧洲阿尔卑斯山的共同全新世分布范围扩张。我们发现，与其说是生态位的拓宽或更高的迁移率，不如说是无融合生殖的生态位本身向更冷的条件的转移更为关键，因为这有助于克服地形障碍，这一因素可能与许多高山无融合生殖有关。更普遍地说，我们的模拟表明，生殖模式和生态位的分化可能对相关有性和无性类群的形成范围产生强烈的相互作用影响，这是由于它们对少数细胞型劣势的敏感性不同所致。
