The oligotrophic peatlands of Western Siberia-the largest peino-helobiome in the world

Summary

The paper summarizes the vegetation pattern of the largest swamp (peat bog) area in the world. The core area covers about 800×1800 km (NS x EW) in West Siberia between the Ural mountains and the river Yenisey. The core area is one gigantic oligotrophic swamp (Peino-Helobiome acc), the new classification suggested in Walter 1976, see also summary in Vegetatio 32, 1976, pp. 75–81. A map of the entire area is presented.

Intensive recent field studies were executed by the geobotanical-soil science faculty of the University of Moscow and the first five publication under the editorship of A. I. Popov (1971–1975) are the basis for this paper. The original papers are in Russian, still unavailable for most western scientists.

The bog genetics was stratigraphically analyzed. The analysis revealed that the majority of the Northern bogs started in taiga forests. The peat in these areas is now 4–7 m deep. About 60% of the peat consists of the mixed “(Sphagnum) fuscum type” deposit. Peat type profiles are shown in Figure 4. The figure illustrates the different peat deposits in relation to depth as well as to surface pattern of strings and hollows.

The surface vegetation shows the pattern typical for many northern peat bogs on very slightly inclined land¹: parallel strings of peat moss and Pinus trees alternating with hollows filled with rain water and hydrophytic Sphagna (Sph. dusenii, Sph. balticum). A cross section through this vegetation pattern is given in Figure 5. Details of the pattern: strings and hollows are given in Chapter 4 of the paper.

The second chapter of this paper deals with regression phenomena in the vegetation development due to excessive water logging caused by the development of the strings. Under such conditions black water lakes are formed which grow in size through the erosive action of wind and waves on the expense of the peat moss surface.

Bog development in the middle and northern Taiga zone of the biome are discussed in Section 3. The hydrology of this area is ruled by the seasonal fluctuation of water level. The amplitude of the Ob river amounts to 12 m with the amplitude of the tributaries ranging around 4–6 m. The annual flood is aggravated in spring by huge ice packages. The entire area is for extended periods one great lake which dissects into hundreds of thousands of little lakes during the low water season.

In some parts of this area local drainage is responsible for the development of small forest patches. The crown cover in this forest is reported up to 50%; the species composition changes from Pinus sibirica, P. sylvestris, Picea spec. near the drainage creeks to Pinus sylvestris f. willkommii and Betula in the drained upland portions.

In this area the general peat bog is eutrophic because of the high influence of the flood. The local development of oligotrophic raised bogs is frequent, however. These bogs are obviously a successional stage in series that leads eventually to a boreal forest.

Section 5 deals with the vegetation typology of the entire area. Three different subdivisions of the Helobiome are distinguished, with several regional subdivisions in each. The principle for the biome division is the environmental change from oligotrophic water on the northern lower end of the watershed to the eutrophic water condition further south in the forest steppe zone. In the area of the southern eutrophic biome are forest islands “Ryami” and even the first salt soil patches noticeable especially in the northern steppe zone. This indicates the regional transition to the Halo-Helobiome. Some vegetational and floristic details for the subdivisions are summarized in this chapter.