Home – Home – Jornals – Contemporary Problems of Ecology 2020 number 1

The peculiarity of the paleogeographic situation in the south of the Vitim plateau of the Transbaikalia led to the formation of landscapes with numerous heaving mounds and thermokarst depressions. The cryolithozone responded to the climate warming by reducing the area, increasing the temperature and depth of seasonal thawing of permafrost. The differentiation of the soil profile in the helix mounds and thermokarst depressions, which led to changes in the morphological, physicochemical properties, which in turn caused the response of the biota, was revealed.

In the Baikal region, warming under conditions of climate continentality is accompanied by increasing of the area of forest fires and the risk of post-pyrogenic ecosystems not turning back into the forest cover. The study of pine forests on sand sediments in the South-Eastern Baikal region showed that ecosystems, located on the territory damaged by fire, develop in different directions depending on the type of a fire and local conditions. After a ground fire, the adult forest stand is preserved and stable signs of pyrogenesis in the soil are developed in the form of charred epipedons. Under these conditions, sparse-grass and dead-cover open stands are formed with almost no signs of renewed young growth and shrubs. The coal influence causes a decrease in soil acidity, an increase in the content of calcium exchange, the formation of humus of humate composition and the base unsaturation. It is proposed to identify the soils with coal epipedons at the level of subtype: psammosoils humus post-perogenic. After a top fire, the plant cover and the soil cover are completely destroyed, the ecosystem begins its development from the 0-moment. Forest renewal in lowlands and on the slopes of shadow and leeward expositions occurs actively in a natural way, as well as against the background of the performed reforestation works. During the post-fire period the soil of Underdeveloped section, psammosoil humus, was formed under the young forest. On the slopes of solar, upwind expositions, despite the actions taken to restore the forest stand, deflation zones, not covered with forest and with no signs of soil formation, are formed. Remote sensing methods made it possible to ascertain that for fifteen years of post-fire development, despite the performed reforestation, the area of uncovered deflation zones has increased in eleven times compared to the pre-fire period. It is recommended to include forest stand restoration in the form of loosening the charred soil on the territories damaged by ground fires, as well as repeated execution of forest planting works in the deflated areas considering protection of the forest edges from wind, into a set of measures to restore forest ecosystems after wildfires.

The article described a variety of psammophyte grass vegetation, in which communities occurs or potentially can recover Pinus sylvestris in Southern Nechernozemye of Russia and identified trends of forming of composition and structure of communities under the influence of leading environmental and coenotical factors. Research realized on the territory of Bryansk, Kaluga and Smolensk regions in 2010-2018; were collected more than 150 relevés of psammophyte grass vegetation. The vegetation belongs to the class of Koelerio-Corynephoretea Klika 1931, which combines dry grasslands on sandy soils and on rocky outcrops of the temperate to boreal zones of Europe, the North Atlantic islands and Greenland. Differences in environmental regimes of habitats of psammophyte communities identified. In most cases, the ecological amplitude of syntaxonomical units in three leading edaphic factors (moisture, reaction, and a soil richness in mineral nitrogen) vary significantly and form a fairly compact environmental space: within syntaxa values of factors vary normally in narrow limits. By method of regression analysis found that species richness of communities shows dependence on significant statistical level only from the richness in mineral nitrogen and soil moisture. Based on the results of the statistical analysis, the number of plants of Pinus sylvestris at any age does not depend on the species richness of the communities, general cover of grasses, separately calculated the cover of mosses and lichens, as well as from environmental factors by H. Ellenberg. The only factor on which the dependence of the number of pine trees at venues, is the distance from the source of the diasporas, which determines the possibility of invasion. The data of phytocoenotic and floristic diversity of psammophyte grass vegetation will be incorporated into a single database for the Southern Nechernozemye of Russia, with the aim of identifying of environmental and botanico-geographical features of this type of plant communities in the region.

The primary successions of vegetation have been investigated in the continental conditions of the North-Chuya center of present-day glaciation (the Central Altai) from the colonization of deglaciated terrains by the first plants and the formation of simple plant groups to the primary plant communities. The observations were carried out for 15 years on the young moraines of the valley glaciers of Maly Aktru (2200-2250 m) and Bolshoi Left Aktru (2370-2500 m above sea level), in chrono-sequences from the ends of glaciers to the moraines of the mid-19th century. Three stages and four sub-stages of the primary succession of vegetation were identified, the species composition of vascular plants, mosses and ground lichens was identified, the dominant species, the peculiarities of primary vegetation were characterized. The ideas about the course of successions and their peculiarities at different altitudes in the upper part of the forest and sub-chalet belts are obtained. It was identified that in the 150 period a young forest community is formed on new moraines in the upper part of the forest belt, and a combination of microcenoses similar to tundra communities are formed in the alpine belt. Primary succession of vegetation on both glacier forelands has some similarities, especially in early stages of ecosystems development (pioneer species composition, three-stage structure of successions); the strong differences appear during the late stages of succession. The primary succession of vegetation on the foreland of the Malyi Aktru glacier involves 146 species of vascular plants, 44 species of mosses and 6 species of lichens; on the foreland of Bolshoi-Levyi Actru 128 species of vascular plants, 26 species of mosses and 8 ground lichens were recorded.

The structure of flora and fauna, which is a standard of the state and dynamics of the taiga forests in humid climatic facies of the Altai-Sayan mountain region is analyzed on the example of the undisturbed mountain Siberian Pine taiga (Eastern Sayan mountains). Ecological-phytocenotic features, floristic and faunistic composition of late succession stage were studied. The dominance of the green moss group of forest types is revealed across the topographic profiles. The forest stands have a different-age structure with Pinus sibirica (Du Tour.) dominance, low productivity (IV-V quality classes prevail), high class of normality (from 0.5 to 1.0) and sufficient regeneration. The floristic, ecological-coenotic analysis of the herb-dwarf-shrub layer, the elements of undergrowth and the moss cover indicates dominance of the humid taiga flora. The species of the taiga ecological-coenotic group (ECG) ( Vaccinium myrtillus , Carex iljinii , Calamagrostis obtusata , Gymnocarpium dryopteris , Phegopteris connectilis , Oxalis acetosella , Aegopodium alpestre , Trientalis europaea , Linnaea borealis , Maianthemum bifolium , Stellaria bungeana et al.), moss-bog ECG ( Ledum palustre , Vaccinium uliginosum , Carex globularis et al.) and bor-taiga ECG ( Vaccinium vitis-idaea , Pyrola rotundifolia , Lycopodium annotinum et al.) form the herb-dwarf-shrub layer in the prevailing forest types. Green mosses ( Hylocomium splendens , Pleurozium schreberi with a mixture of Ptilium crista-castrensis and Rhytidiadelphus triquetrus ) dominate in the moss layer.Polytrichum commune , P. strictum , Dicranum scoparium , D. polysetum and Sphagnum sp. mosses are found in some sites. The increased role of higher spore plants characterized the flora as well-preserved archaic features flora. The Siberian Pine forests coenoflora consists of 224 species and belongs to the Cyperaceae -type. In the structure of the geographical elements of the flora, the leading role belongs to the Palaearctic, European and Siberian elements with an increased role of endemics. The species of typical for the Siberia taiga complex consist the core of the fauna. The most diverse avifauna is represented by 102 species ( Tarsiger cyanurus , Parus montanus , Parus ater , Luscinia calliope , Sitta europaea , Loxia curvirostra , Coccothraustes coccothraustes , Tetrastes bonasia , Phylloscopus proregulus et al.).

The study of the horizontal and vertical distribution of phytoplankton of Lake Sevan was conducted in mid-July 2018, during its maximum blooms of Cyanoprokaryota. The summer biomass of algae in the pelagic zone of the lake were compatible with values of mesotrophic waters. Cyanoprokaryota biomass in Lake Sevan had horizontal and vertical heterogeneity and was related to the depth, morphometry of the lake parts, distribution of currents, transparency, temperature and biomass of Cladocera. In areas where there was water blooms, there was a decrease in the specific number of phytoplankton species and water transparency. The following factors contributed to the increase the average phytoplankton biomass compared to 2013-2017: 1) increased water temperature, 2) weakening of zooplankton press due to the disappearance of Daphnia magna, 3) increased phosphorus load due to increased contribution of D. longispina and Diaphanosoma lacustris in the zooplankton biomass .

Conifer decline ( Abies sibirica Ledeb. stands) as a result of complex biotic effects on the territory of the Krasnoyarsk region by 2018 reached an area of 541,4 thousand hectares; the potential area of further death of A. sibirica is up to 10 million hectares. The main reason is the phytopathogenic fungi Armillaria mellea s. l. and Heterobasidion annosum s. l. when combined with bark beetle Polygraphus proximus . Trees affected by root pathogens are centers of forest dieback, from which pathological outbreaks spread, including due to the effects of P. proximus and its phytopathogenic mycoassociates. Neonectria fuckeliana (C. Booth) Castl & Rossman is among the concomitant pathogens in the scale of the lesion, which causes a resin flow that is similar to the effects of P. proximus attack. The phytopathogenicity of pure cultures of the dominant root pathogens of Armillaria borealis Marxm. & Korhonen and Heterobasidion annosum (Fr.) Bref . , as well as the stem pathogen of N. fuckeliana , has been confirmed by a series of experiments in vitro . Promising natural agents for the regulation of P. proximus abundance are highly virulent aboriginal strains of Beauveria bassiana (Bals.-Criv.) Vuill., resulting in maximum insect death (up to 100 %) for 7-11 days and retaining activity in the temperature range of (16-24) ± 1 °C.

The structure of Thymus petraeus individuals was studied using the architectural approach. It is established that in the South of Siberia the species occurs in similar habitats: in the present, meadow, sandy steppes and their petrophytic variants on the slopes and low rocky peaks of hills. Classification I. G. Serebryakov [1964], T. petraeus - vegetatively-semimobile dwarf shrub with persistent throughout the life system of the main root and with rooting runners. In the structure of individuals T. petraeus identified 3 architectural units that differ in the position of the compound skeletal axis in space (orthotropic-plagiotropic, plagiotropic, orthotropic). Each architectural unit consists of the main compound skeletal axis, the compound skeletal axes of 1st order, formation shoots, branching and enrichment shoots. It is shown that the structure of individuals can be formed by repeating only two architectural units. It is established that in the present steppes and their petrophytic variants the structure of individuals is built at the expense of repetition of orthotropic-plagiotropic and plagiotropic architectural unit; in sandy steppes - at the expense of repetition of plagiotropic and orthotropic architectural unit. The features of T. petraeus development in specific ecological and cenotic conditions are shown. In this regard, characterized by: 1) morphological polyvariance, which is based on changes in the structure of shoots (shortened, elongated) and the composition of architectural units (no compound skeletal axes of the 1st order or enrichment shoots); 2) dimensional polyvariance, manifested in the change in the length and number of compound skeletal axes; 3) dynamic polyvariance, associated with fluctuations in the duration of monopodial growth of shoots formation (from 2 to 5 years) and the architectural unit as a whole (from 6 to 20 years). The revealed modifications of architecture do not lead to a change in the life form of the dwarf shrub, but reflect the mechanisms of its adaptation.

The results of the study of the dynamics of elements of seed productivity amfilikt Hierochloё repens (Host) Beauv. (2 n = 28) and the optional apomict Hierochloё odorata (L.) Beauv. (2 n = 42) (Poaceae) are presented. The plants were grown in the absence of competition and in single-species artificial cenoses with low (5 plants/m²) and high (20 plants/m²) starting density. It was found that plants according to the classification of ecological strategies belong to K-species, the expenses of reproduction was 1.8-5.8 % of the biomass of an individual. The reproductive capacity of two-year cenoses depended on the starting density of plants. In low-density cenoses, plants had 2.4-2.7 times fewer generative shoots compared to high-density cenoses. The influence of species features (F₁) on fruiting abundance varied with age. At two-year coenosis proportion of influence of this factor on the number of generative shoots per unit area was 43,11 % (F₁ = 16,12 %), from three-year - 60,04 % (F₁ = 31,26 %) have a four-year - of 29.19 % (F₁ = 7,24 %; F₀₅ = 4,49; F₀₁ = 8,53). Intrapopulation correlation of indicators of reproduction of the dimension indicators individuals clarified, expressed through the mass and proportion of organ weight from the biomass of individuals. The real seed productivity of H. repens plants was 2.2 times higher in individuals and 1.4 times higher in cenoses compared to H. odorata . Reproductive imbalance in H. odorata is associated with polyploidy and the possibility of apomixis.

In this work, we consider the dynamics of vegetation indices and surface temperature of post-fire areas of different ages in the larch forests of the permafrost zone of Siberia, obtained using long-term Terra/MODIS satellite imagery. Preliminary classification of Landsat/ETM, OLI satellite images was performed to analyze the degree of pyrogenic disturbance in the sample of post-fire sites. An increase of the average temperature of the underlying surface of the post-pyrogenic areas by 3.9-4.6 °C was recorded depending on the degree of disturbance of the litter, which is 15-30 % of the average background values. The deviation (decrease) for the NDVI comparing to background values in the next post-fire year was 22 %, for the NBR index - 72 %. Recovery of the NDVI to background values required 7-10 years after the fire. The recovery period for the surface temperature and the NBR index are significantly higher - 15 years or more. Moreover, for 15-20 years after the fire, the observed temperature anomalies of the underlying surface remain significant.