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Activity indices of plant species in altitudinal zonal elements of the flora were analyzed. As a result, displacement of forest-steppe species by true steppe species in Cleistogenetea squarrosae communities was revealed. Comparison of these tendencies with those in forest vegetation in Baikal Region suggests that ridge slopes are characterized by increasing of humidity. On the contrary, aridization process is observed in basins. Both alternatively oriented trends are inspired by general climate warming. Due to temperature increase, the permafrost existing on the forested slopes is gradually melting and provides additional soil moisturing. At the same time, the steppe ecosystems suffer a loss of the soil water supply as well as air moisture affected by climate warming.

Accurate reconstruction of past vegetation based on pollen data needs understanding of the relationships between pollen and vegetation. For this aim we placed traps and collected surface samples in typical communities in Hulun Buir steppe. A (association index), O (over-representation index), and U (under-representation index), which measure pollen representation to vegetation, were calculated when combining pollen data with vegetation data. The results suggest that the pollen produced by dominant plants, such as Artemisia, Poaceae, Rosaceae, Asteraceae, Cyperaceae and Ranunculaceae, Chenopodium is well represented and indicates the plant species growing around. It seems there is no significant correlation between the pollen productivity and pollen dispersal. Although pollen assemblages can reflect plant communities in Hulun Buir steppe, the coefficient of similarity was only 0.6, which revealed a high effect of background pollen components on the accuracy of pollen representation to vegetation in this study area.

The small patches of relict Chinese pine forests in the Ortindag Sand Land in North China are at their northern
distribution limits. Herein we summarized achievements of the recent study of cambial activity as well as tree growth and regeneration dynamics of Chinese pine populations, climate reconstructions from tree rings up to
ecosystem dynamics in the Ortindag Sand Land and their implications for ecosystem management.

The carbon flux in grassland ecosystems of different bioclimatic zones within the Transbaikal region has been studied. The extra-arid steppe (Selenginskoye middle mountain area: sedge-grass-herbage community on meadow-chestnut soil), moderately arid forest-steppe (the Selenga River delta: herbage-grassy community on meadow-subsaline soil), cryoarid forest-steppe (Vitimskoye plateau: grass-herbage community on meadowchernozem cryosoils) were among them. NPP values in all ecosystems were low: 2404 g/m² per year in the forest-steppe zone, 1407 in the arid steppe zone, and 1540 in the cryoarid ecosystem. Prevalence of the below-ground part in the total biomass structure was revealed for all communities of continental territories. On account of short warm period the total CO₂ emission is low. It is maximal from the meadow-subsaline soil in moderately arid forest-steppe and evaluated as equal 1163 g C/m². The CO₂ emission from the meadow-chestnut soil is much lower (633 g C/m²), and falls to the minimal value (353 g C/m²) in the meadow-chernozem cryosoils. The soils appear as the significant depositary of the carbon.

Soil respiration (SR) is the primary pathway by which plant-fixed CO₂ is released back to the atmosphere. Recent studies suggested that aboveground photosynthesis activity may affect as strongly as or more strongly on SR than soil temperature. We conducted a preliminary study to explore the effect of short-term assimilate supply on SR and to estimate the contribution of root-derived respiration to SR across 6 ecosystems in a foreststeppe ecotone, north China.

Description of the ecotone strip between the forest and high-mountain belts is given in the article. The main
structural ecotone elements as synusia and community are singled out. Different types of ecotone strips are described, their indicative significance is substantiated.

Floristic and geographical distinctions between meadow steppes of the order Festucetalia valesiacae and true
steppes of the order Helictotricho-Stipetalia in the South Urals were studied. The geographical differentiation of
the communities of the orders is difficult due to the complexity of the relief and strong fragmentation of the steppes. The
floristic differentiation is possible in the absence in Helictotricho-Stipetalia communities of a diagnostic combination
of meadow steppe species represented by the alliance Festucion valesiacae.

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.

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.