Notes on distribution and habitat preferences of Sphagnum inexspectatum and S. mirum in Western Siberia

Abstract

New records of two rare moss species, Sphagnum inexspectatum Flatberg (4) and S. mirum Flatberg & Thingsgaard (9) are reported from Western Siberia, and discuss them in context of their habitat preferences in region as well as general range. Their distribution in Russia is considered and re-assessed. Geobotanical relevés of plant communities with Sphagnum inexspectatum and S. mirum from Western Siberia are presented. It is shown that in the taiga zone S. inexspectatum occurence is closely related to communities of the alliance Stygio-Caricion limosae Nordhagen 1943, class Scheuchzerio-Caricetea nigrae Tx. 1937, and similar Sphagnum carpets in meso-oligotrophic mires, where it grows as single stems among other peat mosses in poor conditions on slightly acidic substrates. In forest tundra and southern tundra this species occurs only in communities of the alliance Caricion stantis Matveyeva 1994. More diverse communities with S. mirum are assigned mainly to the alliance Sphagno-Caricion canescentis Passarge (1964) 1978, which comprises sedge-Sphagnum vegetation located in fens and transitional bogs in a wide variety of habitats from moderately poor to moderately rich in mineral nutrients and with slightly acidic substrate. This species occurs both with low (as single stems) and high abundance (frequently being dominant) in moss layer.