Classification of aquatic vegetation (Potametea) in Baikal Siberia, Russia, and its diversity in a northern Eurasian context.

摘要

We studied the aquatic vegetation of bottom-rooted plants, i.e. the class Potametea, in Baikal Siberia, a region in the south of Eastern Siberia. Forty associations were found based on 623 original releves and 65 releves from the literature. Six associations (Lemno trisulcae-Sparganietum graminei, Myriophyllo spicati-Potametum compressi, Potametum bottnici, Potametum maackiani, Potametum salicifolii, Potametum vaginati) are described here for the first time. The names of five syntaxa have been typified. Nine new community-types were recorded for Baikal Siberia. Each association is outlined by its diagnostic, constant and dominant species, structure, ecology and distribution. The regional distribution of each association is shown by grid maps. Large-scale phytogeographical comparison of sets of diagnostic species of Potametea across Northern Eurasia revealed that Baikal Siberia harbours two thirds of the diversity of macrophyte vegetation of Northern Asia and 40% of that of Northern Eurasia. Our study showed that Baikal Siberia's Euro-Siberian aquatic vegetation gradually declines in species and community richness towards east. The aquatic vegetation was found to be rich in thermophilous plants in the Russian Far East along the lower course of the Amur River.