Extensive sympatry and frequent hybridization of ecologically divergent aquatic plants on the Qinghai-Tibetan Plateau

Hybridization has fascinated biologists in recent centuries for its evolutionary importance, especially in plants. Hybrid zones are commonly located in regions across environmental gradients due to more opportunities to contact and ecological heterogeneity. For aquatic taxa, intrazonal character makes broad overlapping regions in intermediate environments between related species. However, we have limited information on the hybridization pattern of aquatic taxa in alpines, especially submerged macrophytes. In this study, we aimed to test the hypotheses that niche overlap and hybridization might be extensive in related aquatic plants across an altitudinal gradient. We evaluated the niche overlap in three related species pairs on the Qinghai-Tibetan Plateau and assessed the spatial pattern of hybrid populations. Obvious niche overlap and common hybridization were revealed in all three pairs of related aquatic plants. The plateau edge and river basins were broad areas for the sympatry of di...

近几个世纪以来，杂交现象（hybridization）因其在进化过程中的重要意义，一直备受生物学家关注，在植物类群中该现象的研究价值尤为突出。杂交带通常分布于环境梯度跨度较大的区域，这是因为相关类群在此类区域的接触机会更多，且生态异质性（ecological heterogeneity）更强。对于水生类群（aquatic taxa）而言，隐域性特征（intrazonal character）使得近缘物种在过渡性中间环境中形成广泛的重叠分布区。然而，我们对高山生境下水生类群的杂交模式却知之甚少，尤其是沉水大型植物（submerged macrophytes）类群。本研究旨在验证下述假说：沿海拔梯度（altitudinal gradient）分布的近缘水生植物类群中，生态位重叠（niche overlap）与杂交现象可能广泛存在。我们以青藏高原（Qinghai-Tibetan Plateau）的3组近缘物种类群为研究对象，评估了其生态位重叠情况，并分析了杂交种群的空间分布格局。研究结果显示，3组近缘水生植物类群均表现出显著的生态位重叠与普遍的杂交现象。高原边缘与河流流域是近缘类群同域分布（sympatry）的广阔区域，[原文后续内容未完整给出]