Home – Home – Jornals – Contemporary Problems of Ecology 2009 number 4

The notion of species diversity includes two components: species richness and uniformity. Species diversity is the number of species per unit area (geobotanical description). Uniformity is the distribution of species over their abundance in a community. There is a positive correlation between these indices; however, high species richness is not necessarily accompanied by high uniformity. It is impossible to compare the species richness of the communities formed by the plants of different size (rain tropical forest and meadow steppe). High species diversity is peculiar to the plant communities with a medium level of productivity, medium degree of disturbance and is not connected with their stability.

For Euphorbia genus of Northern Asia as an example, some aspects of the investigation of phylogenetic links of rare and endemic species are considered as the scientific foundation of the conservation of biological diversity. Results of the investigation of specific processes of evolutionаl morphological transformations, ecological and geographic differentiation in different groups of species including rare and endemic taxons are presented.

For the representatives of cereals (Poaceae) characteristic of the flora of the Asiatic part of Russia, a comparative anаlysis of the ecological ranges of plant species confined to the coastal regions and the species for which the major part of the range is situated within the continental regions (interior Asia) was carried out. The anаlysis was carried out according to the ecological phytocoenotic groups: coniferous and mixed forests, broad-leaved forests, meadows, communities of spray zones, rocks and stony rubbly outcrops and talus. The trends in the changes of the whole set of indices of the ecological ranges of species, accompanying the transition from the continental climatic conditions of Interior Asia to the Pacific coast with its monsoon climate were revealed.

Biodiversity patterns of the woodland-steppe ecotone in southeastern Inner Mongolia were investigated. Controlled by climatic factors, the plant species diversity of the woodland-steppe ecotone is medium in comparison to the adjacent woodland zone and steppe zone. From woodland zone, through the woodland-grassland zone and woodland-steppe zone, to the steppe zone, about 2/3 species were replaced at each boundary, only 7 herb species were detected to be distributed in all the four vegetation zones. Landscape classification based on landform, climate and vegetation shows that landform condition is most critical to landscape diversity in the studied area. The most fragmented landform in the woodland zone does not necessarily lead to low plant species diversity. However, similar understory species in different woodland types lead to a continuous woodland vegetation and hence a high species richness. High fragmentation in the woodland-steppe zone and discontinuous distribution of woodlands might be a driving factor for lower species richness in it. Reconstruction of the Holocene climatic changes and vegetation development demonstrates that the highest plant species diversity occurred in the ecotone before 4500 to 2500 ¹⁴C yr B. P. at different sites, while the woodland zone moved much further northwestward. When woodlands retreated from the current ecotone with climatic drying, the fragmentation of woodlands in the current ecotone led to plant species loss.

The diversity of the West-Siberian lichen biota and its distribution within the boundaries of its two components - the West-Siberian plain and the south West-Siberian mountains - were studies. At present, the level of the diversity of West Siberia achieves 1845 species from 325 genera and 95 families, of the West-Siberian plain - 1421 species from 271 genera and 86 families, of the south West-Siberian mountains - 1682 species from 312 genera and 94 families.

Data on nemoral lichens in the Dzherginski state nаtural reserve (Northern Pribaikalia) are reported. The distribution of the lichens of the nemoral element is anаlyzed, a conclusion concerning their most preferable habitats is made. Nemoral lichens prefer dark coniferous forests, exposed slopes and nearby thermal springs in middle elevation.