Data from: Influence of niche similarity on hybridisation between Myriophyllum sibiricum and M. spicatum

The impact of ecological factors on natural hybridization is of widespread interest. Here, we asked whether climate niche influences hybridization between the two closely related plant species Myriophyllum sibiricum and M. spicatum. Eight microsatellite loci and two chloroplast fragments were used to investigate the occurrence of hybridization between these two species in two co-occurring regions: north-east China (NEC) and the Qinghai-Tibetan Plateau (QTP). The climate niches of the species were quantified by principal component analysis with bioclimatic data, and niche comparisons were performed between the two species in each region. Reciprocal hybridization was observed, and M. sibiricum was favoured as the maternal species. Furthermore, hybrids were rare in NEC but common in the QTP. Accordingly, in NEC, the two species were climatically distinct, and hybrids only occurred in the narrow geographical or ecological transition zone, whereas in the QTP, obvious niche overlaps were found for the two species, and hybrids occurred in multiple contact zones. This association between hybridization pattern and climate niche similarity suggests that the level of hybridization was promoted by niche overlap. Compared with the parental species, similar climate niches were found for the hybrid populations in the QTP, indicating that other environmental factors rather than climate were important for hybrid persistence. Our findings highlight the significance of climate niche with respect to hybridization patterns in plants.

生态因子对自然杂交的影响一直是学界广泛关注的研究议题。本研究旨在探究气候生态位是否会影响两种近缘植物物种——西伯利亚狐尾藻（Myriophyllum sibiricum）与穗状狐尾藻（M. spicatum）之间的杂交现象。研究选取8个微卫星位点与2个叶绿体片段，对中国东北（NEC）及青藏高原（QTP）两个同域分布区域内的两物种杂交发生情况展开了调查。研究人员借助生物气候数据，通过主成分分析量化了两物种的气候生态位，并针对每个区域内的两个物种开展了生态位比较分析。结果显示二者存在双向杂交，且西伯利亚狐尾藻更倾向于充当母本。此外，杂交子代在中国东北区域较为罕见，但在青藏高原区域则分布普遍。据此可知，在中国东北区域，两物种的气候生态位分化显著，杂交子代仅出现在狭窄的地理或生态过渡带中；而在青藏高原区域，两物种的生态位存在明显重叠，杂交子代在多个接触带均有分布。这种杂交模式与气候生态位相似性之间的关联表明，生态位重叠能够提升杂交发生的水平。与亲本物种相比，青藏高原区域的杂交种群具有相似的气候生态位，这说明维持杂交种群存续的关键并非气候，而是其他环境因子。本研究结果凸显了气候生态位对植物杂交模式的重要意义。