Aquatic flora of the high-mountain lakes in the southeastern part of the Chersky Ridge within the basin of the upper Kolyma River

Abstract

We investigated several intermountain depressions in lakes with diverse flora of aquatic vascular plants in the southeastern part of the Chersky Range. The study area was located between 63–64° N and 147–148.5° E, at approximately 800–1200 m a.s.l. We identified 48 species and three hybrids.Among them, the families Potamogetonaceae (13 species and 1 hybrid) and Ranunculaceae (7 species) were characterized by the greatest diversity. For the first time, Stuckenia subretusa was found in the Magadan Region, which is the southernmost locality for this species. In an ultracontinental climate with an average annual air temperature of –13.1 °С, Arctophila fulva, Eleocharis acicularis, Hippuris vulgaris, Potamogeton alpinus, Ranunculus gmelinii, R. reptans and Sparganium hyperboreum are widespread. The species composition of aquatic plants is most diverse in small lakes at altitudes of 750–850 m a.s.l. in the plain interfluve, where the rarest species in the Kolyma River Basin are found. At altitudes above 850 m a.s.l. the most diverse species were found in the smallest lakes located near the large lakes. Obligate aquatic plants (80 %; 41 taxa; 30 hydrophytes and 11 hydrohygrophytes) dominated the flora of the mountain lakes. Only 20 % (10 species) of the flora were represented by plants of excessively moist coastal habitats. Among the 30 hydrophyte taxa 11 species grew up to 1050 m a.s.l. and 19 species grew at 950 m a.s.l. We identified four species that were protected at the regional level. Stuckenia pectinata is included in the Red Book of the Magadan Region, and Isoёtes asiatica, Nuphar pumila and Subularia aquatica are included in the Red Books of the Magadan Region and the Republic of Sakha (Yakutia).