Home – Home – Jornals – Advanced Search

The need for separating such terms as «fluctuations» and «successions» for assessing consequences of climatically induced vegetation changes is emphasized. Despite significance, the ambiguity of these terms meaning is noted. The ambiguity is connected with existing different mechanisms of vegetation dynamics, which, in general, are described by two concepts — holistic and individualistic. Attempting to analyze some of terms (e.g., fluctuations, successions, chronosequences, successional step, successional threshold) commonly applied to vegetation dynamics performance, we assume that they are relevant to a holistic concept. In case of vegetation dynamics going as described by an individualistic concept, the phenomenological immanence of the above mentioned terms disappears. They turn into «just terms» and should be only implicated for pragmatic reasons. Besides, we could conclude that chronosequence analysis gives opportunity to reveal a dynamic process as a succession properly. From the other side, in order to determine the direction of dynamic processes, analysis of ecological groups and functional plant types is appropriate.

Flora of halophytic vegetation within Western Zabaikaliye is overviewed. Three hundred thirty six species and subspecies of vascular plants from 163 genera and 52 families have been registered. The distinct specificity of flora is a high rank of Chenopod family in the families’ spectra, and Chenopodium, Suaeda, as well as Plantago, Puccinellia — in the genera’ spectra. Enrichment of the saline habitat flora is achieved mostly due to numerous glycophytes tolerant to substrate salinity. Despite it, plant communities in saline habitats are always predominating by halophytes. The preliminary classification of halophytic plant communities in accordance with Braun-Blanquet approach is proposed. As a result 3 orders, 4 alliances, 14 associations, 4 subassociations, and 11 variants, belonging to the classes Scorzonero-Juncetea gerardii and Thero-Salicornietea, are distinguished. The first class contains the majority of recognized syntaxa. Such features as great variability of synmorphology, widely fluctuating physiognomic aspects, and mostly low species richness have been noted as typical of halophytic plant communities.

The results of study of bryophytes in the moderately dry oak-woods (all. Lathyro-Quercion roboris), pine forests (all. Caragano fruticis-Pinion sylvestris) and larch-birch forests (all. Veronico teucrii-Pinion sylvestris) of the South Urals are discussed. Eighty moss species and 8 liverworts have been revealed. Forty nine percent of bryophyte species have low constancy. The lowest diversity of bryophytes is characteristic of larch-birch forests (23 species) and oak-woods (32 species), the highest — of pine forests (83 species). Species that grow on the bases of tree trunks and on the rotten wood (Pylaisia polyantha, Pseudoleskeella nervosa, Stereodon pallescens, Sciuro-hypnum reflexum, Brachytheciastrum velutinum, Plagiomnium cuspidatum, Platygyrium repens) have high constancy. In the forest communities which are developed on the slopes, epilythic bryophytes of carbonate rocks (Tortella tortuosa, Schistidium apocarpum s.l., Pseudoleskeella tectorum) and ground light-loving species (Abietinella abietina, Ceratodon purpureus, Rhytidium rugosum, Syntrichia ruralis) are abundant. In comparison with moderately dry forests of the Russian Plain, communities from the South Urals are distinguished by almost complete absence of ruderal moss species. This indicates low disturbance and natural character of the Urals communities and emphasizes their high conservation value.

Populations of East-Asian species (Sсutellaria baicalensis, Sophora flavescens, and Astragalus membranaceus) in the territory of Zabaikaliye, the Russian Far-East and Inner Mongolia were studied. A total of 363 relevees were processed using the ecological scales, and ranges of environmental conditions were evaluated. To assess population optimum, the individual and cenopopulation features were taken into account. As the most appropriate, the ecological scales method proposed by I.A. Tsatsenkin et al. (1978) for analyzing forest-steppe communities was used. By integrating data on plant communities and populations the optimal conditions for each species were revealed. Generally, habitats of South and South-Eastern part of Zabaikaliye and the Russian Far-East are the most favorable for the species under study. We conclude that moisture might be the key factor for functioning of populations of East-Asian species.

Indices of temperature, precipitation and relative evapotranspiration (RET) for the last 51 years in the borderland
between Shaanxi and Gansu Provinces, and Ningxia Hui Autonomous Region (BSGNAR) were calculated
to analyze the climate change in this area. During the past 50 years, the average temperature increased
significantly, while precipitation decreased slightly with regional differences. RET change was not so distinct
in general, but had a minor increase at the late stage of the study period. Under such circumstances, climate
change had clear effects on distribution of potential vegetation in the area, with a tendency to transit to warming
and drying vegetation types.

A comprehensive study of the critical taxon Leymus buriaticus Peschkova was carried out in comparison with natural and cultivated populations of L. littoralis and L. chinensis from various localities in Buryatia. The factorial analysis performed by 15 morphological characters showed that L. buriaticus occupied an intermediate position between L. chinensis and L. littoralis. SDS-electrophoresis of individual seeds showed presence of similarity of relations between samples identified as L. buriaticus and selected samples of L. littoralis and L. chinensis in mixed population from a classical locality. The analysis of subfractional composition of histon Н1 also revealed presence of common subfractions of L. littoralis, L. chinensis and L. buriaticus. It was concluded that the endemic L. buriaticus was of a hybrid origin.

Typification of 20 Primula L. (Primulaceae) taxa from Siberia and the Russian Far East kept in the Herbarium of V. L. Komarov Institute of Botany was carried out. The citation of the place of valid publication, categories of type specimens, label, protologue, currently accepted name or synonym, and locality are presented for the taxa. Holotypes for 5 taxa, lectotypes for 15 taxa, 28 syntypes and 1 paratype are given. A photography of the lectotype is published for P. patens.

Data on distribution of anthropophilous species of the genus Calystegia in Siberia were summarized. Their status in region flora was considered and maps of areas of these species were made for the first time.

Polyporus choseniae (Vassilkov) Parmasto and P. pseudobetulinus (Murashk. ex Pilat) Thorn, Kotir. et Niemela were found in the mountain riverside woods of the Altai Krai and the Altai Republic for the first time. New
localities were indicated for 8 Polyporus species known earlier.