Dark coniferous forests of West Siberian plain on their southern limit

West Siberian subtaiga is a climatically and partly edaphically determined latitudinal subzone with deciduous forests dominated by birch and aspen trees as climax vegetation (Shumilova, 1962). Dark coni­ferous forests have here their southern limit of distribution and they are presented by the relatively small “islands” embedded into the “matrix” of deciduous forests mixed with meadows and arable lands. Main limited factor for the coniferous trees distribution is low humidity during vegetation period. Therefore the dark coniferous forests in subtaiga occupy the habitats with high and constant moisture. They are mainly the big rivers terraces or small river valleys. The total area of this habitat type is quite small. There are no special articles or monographs devoted to this vegetation. At the same time these dark coniferous forests are rich in species and they are a shelter of many rare and protected plants.

The main goal of this article is to describe the composition, structure, distribution and syntaxonomical position of West Siberian dark coniferous forests on their southern limit.

The article is based on 103 relevés collected through the West Siberia from Kemerovskaya region at the east to Omskaya region at the west from 1998 till 2014. All relevés were stored in a data base and developed by syntaxonomical analysis with IBIS 6.2 (Zverev, 2007), ordination and cluster analysis with PAST 2.14 (Hammer et al., 2001) and using the Ramensky ecological scales (Korolyuk, 2006).

Usually one “spot” of coniferous forest consists of few (up to four) microbelts of communities depending on their geomorphologic position and drainage rate. In smallest spots on the valley bottom they are all covered by one community type. In all cases a main dominant tree is spruce (Picea obovata). In well-drained habitats sufficient part of tree layer consists of Siberian fir (Abies sibirica). Other trees are in minor amount. Coniferous forests often alternate with mires.

It terms of the Braun-Blanquet classification we described four new syntaxa:

•  Ass. Caragano arborescentis–Piceetum obova­tae ass. nov. hoc. loco.

•  Ass. Scutellario galericulatae–Piceetum obova­tae ass. nov. hoc. loco.

•  Ass. Mnio stellari–Pinetum sibiricae Lapshina 2010

Subass. caricetosum albae subass. nov. hoc. loco.

•  Ass. Cacalio hastatae–Piceetum obovatae ass. nov. hoc. loco

In fact these four syntaxa represent a syntaxonomical continuum between the order Carici macrourae–Abietetalia sibiricae (class Asaro europaei–Abietetea sibiricae) — zonal dark coniferous forests of West Siberian plain and the  order Calamagrostio purpuraea–Piceetalia obovatae (class Alnetea glutinosae) — ­forested mires of continental parts of Eastern Europe and Siberia (Lapshina, 2010).

The most drained habitats are occupied by Caragano arborescentis–Piceetum obovatae association. From previously described associations of the same order it differs by dominance of spruce in tree layer and a presence of diagnostic species of Brachypodio pinnati–Betuletea pendulae Ermakov, Korolyuk et Lashchinsky 1991 class in herbs layer. In addition it is characterized by well-developed shrub layer.

Next association of the same order — Scutellario galericulatae–Piceetum obovatae — occurs on mi­neral soil with weak drainage and high moisture. It has many diagnostic and affine species of Alnetea glutinosae class but with clear predominance of Asaro europaei–Abietetea sibiricae species.

Swampy spruce forests on wet soils with thin peat layer belong to Cacalio hastatae–Piceetum obovatae association. In herb layer still high presence of Asaro europaei–Abietetea sibiricae species but Alnetea glutinosae species play the main role.

The most wet forest type spread on valley bottoms belongs to subassociation Mnio stellari–Pinetum sibiricae caricetosum albae. Species of Alnetea glutinosae class dominate absolutely in herbs layer; another typical feature is well-developed microrelief formed by sedge tussocks and big thick horizontal spruce roots. Dead-water can be seen between tussocks.

Ecological ordination made by DCA-analysis and independently by using the Ramensky ecological scales has shown that all newly described syntaxa ­ordinate in a line which was interpreted as gradient of moisture. At the same time each syntaxon has its own ecological amplitude slightly overlapped with others. So, ecological ordination has proved an independence of new syntaxa in ecological space.

To compare the new syntaxa with previously described ones we used cluster analysis with Ward ­coefficient. In comparison following syntaxa were included: forested mires with spruce stands from West Siberian southern taiga (Lapshina, 2010), green mossy spruce forests from Ufa plateau (Martynenko, Zhigunova, 2004) and swampy spruce forests from Salair ridge (Lashchinsky, 2009). Obtained dendrogram shows a large difference between Siberian and European syntaxa. There is a big set of species in European forests which are absent or rare in Siberia. In addition all European forests were described from well-drained habitats without mire species but with some meso­xerophilous species. Among Siberian syntaxa newly ­described associations are closely related with associations from Salair ridge but the distance between them all is comparable or even bigger than the distance ­between other associations. So, new syntaxa have rank at least at association level.

Specific feature of subtaiga spruce forests is their species richness and heterogeneity. Coenoflora of these forests based on 103 relevés is 322 higher vascular plants. Species richness is determined by combination of different microhabitats inside of one community.

Stabile microclimatic conditions, constantly high humidity and relatively good temperature conditions in combination with microhabitat diversity helped to conserve groups of species from different times of the Quaternary period. Such complexes as boreal, southern taiga, nemoral and even hypoarctic are well-presented in these forests. Many of them are considered as relics from different phases of Pleistocene.

About 30 species of higher vascular plants from subtaiga spruce forests are listed in federal and regional Red Books.

High species diversity is typical for other groups of plants too. In these forests were found 112 species of mosses what is more than one third of forest bryoflora of the West Siberia.

Key words: forest vegetation, spruce forest, subtaiga, syntaxonomy, West Siberian plain, forested mires, Picea obovata, Asaro europaei–Abietetea sibiricae, Alnetea glutinosae

Section: Articles

How to cite

Lashchinsky N. N., Pisarenko O. Yu. 2016. Dark coniferous forests of West Siberian plain on their southern limit // Vegetation of Russia. N 28. P. 89–107. https://doi.org/10.31111/vegrus/2016.28.89

Received July 27 2015

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