Biodiversity, University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany.
Institute for Biology and Environmental Science (IBU), Plants Biodiversity and Evolution, Carl Von Ossietzky University, Carl-von-Ossietzky-Str. 9-11, 26129, Oldenburg, Germany.
Sci Rep. 2020 Sep 2;10(1):14431. doi: 10.1038/s41598-020-71332-z.
Here, we analyzed patterns of taxon richness and endemism of freshwater protists in Europe. Even though the significance of physicochemical parameters but also of geographic constraints for protist distribution is documented, it remains unclear where regional areas of high protist diversity are located and whether areas of high taxon richness harbor a high proportion of endemics. Further, patterns may be universal for protists or deviate between taxonomic groups. Based on amplicon sequencing campaigns targeting the SSU and ITS region of the rDNA we address these patterns at two different levels of phylogenetic resolution. Our analyses demonstrate that protists have restricted geographical distribution areas. For many taxonomic groups the regions of high taxon richness deviate from those having a high proportion of putative endemics. In particular, the diversity of high mountain lakes as azonal habitats deviated from surrounding lowlands, i.e. many taxa were found exclusively in high mountain lakes and several putatively endemic taxa occurred in mountain regions like the Alps, the Pyrenees or the Massif Central. Beyond that, taxonomic groups showed a pronounced accumulation of putative endemics in distinct regions, e.g. Dinophyceae along the Baltic Sea coastline, and Chrysophyceae in Scandinavia. Many other groups did not have pronounced areas of increased endemism but geographically restricted taxa were found across Europe.
在这里，我们分析了欧洲淡水原生生物分类群丰富度和特有性的模式。尽管已经有文献记录了理化参数的重要性，以及地理限制对原生生物分布的影响，但仍不清楚高原生生物多样性的区域位于何处，以及高分类群丰富度的区域是否拥有高比例的特有种。此外，这些模式可能是原生生物的普遍模式，也可能在分类群之间存在差异。基于针对 rDNA 的 SSU 和 ITS 区域的扩增子测序活动，我们在两个不同的系统发育分辨率水平上解决了这些模式。我们的分析表明，原生生物具有有限的地理分布区域。对于许多分类群，高分类群丰富度的区域与具有高比例假定特有种的区域不同。特别是，作为非地带性生境的高山湖泊的多样性与周围低地不同，即许多类群仅在高山湖泊中发现，而几个假定的特有类群则出现在阿尔卑斯山、比利牛斯山脉或中央高原等山区。除此之外，分类群在特定区域表现出明显的假定特有种积累，例如鞭毛藻类在波罗的海沿岸，金藻在斯堪的纳维亚。许多其他类群没有明显的特有种增加区域，但在整个欧洲都发现了地理上受限的类群。
