Nicola Arndt und Matthias Pohl - Neobiota

Subzones reflect the latitudinal change of the vegetation cover within the limits of a zone. The
subzones, in turn, can be further subdivided into latitudinal belts. However, there are not sufficient
data at the present time for the allocation of latitudinal belts in all subzones. Accordingly, regional
map segments are provided only in certain subzones or parts of them. For example, there are two belts
in the subzone of mixed coniferous and coniferous – broad-leaved forests of eastern Europe (B5 1 and
B5 2 ). The northern belt (B5 1 ) is distinguished by the prevalence of spruce forests coupled with broadleaved
trees in the second layer. In the southern section (B5 2 ), stands occur with mixed spruce, oak,
and lime trees in the first layer of the forests.
Fifteen subzones have been classified on the map. In eastern Europe, the main zones contain the
following subzones, respectively: A: high arctic, arctic, typical and arctic shrub tundras; B: forest
tundra, northern, middle, and southern taiga (coniferous forests) and subtaiga (mixed broad-leavedconiferous
forests); C: broad-leaved forests, forest steppes; D: northern (forb-bunchgrass), middle (dry
grass) and southern (desert) steppes; E: northern lowland plain and southern foothill deserts.
In each subzone, regional variation in combinations of plant communities of different formations
exists along a gradient from west to east. This is due to differences in climate, relief, lithology and
flora. These geographic variants are named after certain geographical localities or landscapes, and are
indicated on the map by small letters. Plant species were selected to characterize the main peculiarities
of subunits – subzones and regional combinations of plant formations.
The boreal coniferous forests (B - taiga zone), for example, are characterized by the dominance of
both dark and light coniferous forests: spruce, Siberian fir, Siberian pine, Scots pine, and larch forests.
The zone is divided into five subzones: forest tundra (B.1), northern (B.2), middle (B.3), and southern
(B.4) taiga, and subtaiga or mixed broad-leaved-coniferous forests (B.5). The subzone of southern
taiga (B.4), encompassing dwarf-shrub and herb-moss coniferous forests in combination with mires, is
in turn divided into five geographical variants: The Eastern European variant (B.4a) with spruce
(Picea abies) and pine (Pinus sylvestris) forests with Oxalis acetosella and nemoral herbs
(Galeobdolon luteum, Hepatica nobilis, Stellaria holostea, Pulmonaria obscura); the pre-Ural
variant (B.4b) consisting of spruce and fir-spruce (Picea obovata, Abies sibirica) forests with nemoral
herbs (Pulmonaria obscura, Asarum europaeum, Aegopodium podagraria) and Siberian tall forb
species (Aconitum septentrionale, Crepis sibirica, Cacalia hastata); the Western Siberian variant
(B.4c) with fir-spruce (Picea obovata), Siberian pine-fir (Abies sibirica, Pinus sibirica), and pine
forests (Pinus sylvestris) with an herb (Carex macroura, Circaea alpina)-moss layer; the Central
Siberian variant (B.4d) with larch (Larix sibirica), pine (Pinus sylvestris) and fir - spruce forests with
an herb-dwarf-shrub (Carex macroura, Vaccinium uliginosum)-moss layer; and the East Siberian -
Far East variant (B.4e) with larch (Larix gmelinii), and pine (Pinus sylvestris) forests with a shrub
layer (Rhododendron dauricum, Ledum palustre).
On the map of Russia, 78 geographical variants of the zonal plant formations have been delineated.
They fit into the scheme of FAO Ecological Zoning Levels 1 and 2 (see Table 1).
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