Algae and epilitic mosses associations of the Hedwigia P. Beauv. genus in mountain taiga of the Khentey Uplands (Zabaykalskiy Krai, Russia)

Abstract

For the first time, information is provided about algobryophytic associations common in mountain taiga regions. The environment-forming organisms these associations are representatives of the genus Hedwigia P. Beauv. (Bryophyta). The research was conducted in the Sokhondinskiy state biosphere reserve (Zabaykalskiy Krai, Russia). We selected algobryophyte communities in the mountain taiga, these associations are function on stones in the forest, stony placers, remnant rocks, rock outcrops, and pebbles. Precipitation is the only source of moisture here. It was found that in moss-carpet of the Hedwigia at higher humidity, the average temperature was 0.6 °C lower than at the same time on the exposed surface of the substrate. In the sod of moss formed on rocks under the forest canopy, compared with open spaces of stony placers, it was warmer by 1–4 °C, and the relative humidity is 4–8 % higher. Representatives of Hedwigia growing on acidic mountain breed are characterized by an acidic reaction of the pH. In all investigated samples of bryophytes discovered epiphytic algae. A total of 68 species from the Chlorophyta (40 species), Cyanoprokaryota (13 species), Streptophyta (8 species), Ochrophyta (4 species), Bacillariophyta (3 species) departments have been registered. Most registered of algae species are typical inhabitants of various terrestrial biotopes. A number of algae genera found are known as lichen symbionts. In the associations were dominated by cyanoprokaryotes-diazotrophs from the Nostoc Vauch. ex Bornet et Flahault and Stigonema C. Agardh ex Bornet et Flahault genera. Significant fluctuations in their numbers in time and space were found. Diazotrophs associated with Hedwigia can serve as a source of nitrogen for this moss. It has been shown, that Hedwigia accumulates 0.7–1.5 (2.2) % of mineral nitrogen. The amount of nitrogen comparable to Hedwigia accumulates one of the dominant moss cover in taiga ecosystems of southern Siberia Rhytidium rugosum (Hedw.) Kindb. This species also forms associations with dominance of the Nostoc и Stigonema. The content of mineral nitrogen in the free-living epigenic and epilitic cyanoprokaryotes of the Nostoc and Stigonema genera can be up to 2–3 times higher than that in the studied mosses.

Keywords

• association of bryophytes and algae
• hedwigia
• cyanoprokaryota
• epilithes
• south of siberia