Nicola Arndt und Matthias Pohl - Neobiota

The deserts of the eastern Transcaucasus Region differ from those of the northern Caspian Region by a
set of formations (see Table 1). They include the communities of two wormwood species (Artemisia
fragrans and A. szowitsiana) and of three perennial saltworts (Salsola nodulosa, S. ericoides and
S. dendroides). Ephemeroid grasses (Poa bulbosa and Catabrosella humilis) constantly occur in these
communities.
On solonchaks in the eastern Transcaucasus, communities of several formations (Halostachys
belangeriana, Suaeda microphylla, Gamanthus pilosus, Zeidlitzia florida) are characteristic in
addition to the communities of the same formations as in the northern Caspian Region (Halocnemum
strobilaceum, Atriplex verrucifera and annual saltworts) (Table 2).
The vegetation of the northern Caspian Region is species-poor and represented by a small number of
ecotypes correlated with the low diversity of environmental conditions in the area. The Vegetation
Map of Europe shows exactly the peculiarities of their distribution.
To the west of the Volga River, extensive plains with sandy-loamy soils are occupied by
hemipsammophytic deserts of the Artemisia lerchiana-Poa bulbosa type which is locally combined
with psammophytic types on sand: Artemisia lerchiana-Calligonum aphyllum and Artemisia arenaria-
Calligonum aphyllum with Krascheninnikovia ceratoides. The pelitophytic desert complex is
distributed along the steppe boundary as a narrow strip. Depending on salt concentration, the
communities of Artemisia lerchiana (on soils with lower salt concentrations) and those of Artemisia
pauciflora (on soils with higher salt concentrations) predominate alternately in complexes.
Table 2: Formations on solonchak.
Formation
Northern deserts in
the Caspian Lowland
Atriplex cana +
Kalidium foliatum +
Southern foothill deserts
in eastern Trans-caucasus
Halocnemum strobilaceum + +
Atriplex verrucifera + +
Annual saltworts + +
Kalidium сaspicum +
Halostachys belangeriana +
Suaeda microphylla +
Gamanthus pilosus +
Zeidlitzia florida +
On the Volga-Ural interfluve psammophytic deserts predominate. In terms of the area covered, the
dominant communities are those of Artemisia lerchiana with grasses (Stipa sareptana, S. lessingiana)
or psammophytic shrubs and semishrubs (Calligonum aphyllum, Krascheninnikovia ceratoides) on flat
sands, stabilized dunes and plains with sandy soils. Communities of Artemisia arenaria are widely
distributed, with constant participation of Calligonum aphyllum restricted to semi-moving sands on
hills and ridges. Locally, shrub deserts (Calligonum aphyllum, Tamarix ramosissima, T. laxa) are
found on the weakly stabilized sands of barkhans.
The hemipsammophytic Artemisia lerchiana-Poa bulbosa communities are characteristic of areas on
both sides of the Volga River, but their ranges are smaller than those of psammophytic types. Complex
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