Ecological Groups Of Plants Research Articles

Can Environmental Stressors Determine the Condition of Ecological Plant Groups?

There is still a need to investigate the relationships between glycophytes and halophytes and the many biotic and abiotic factors in their natural environments. Therefore, we study the effects of the type of environment on the ecophysiological responses and condition of the glycophyte Elder Sambucus nigra L., the macrophyte Common Reed Phragmites australis (Cav.) Trin. ex Steud., the facultative halophyte Weeping Alkaligrass Puccinellia distans (Jacq.) Parl, and the obligate halophyte Common Glasswort Salicornia europaea L. in a saline-disturbed anthropogenic region of central Poland. We analyzed the effects of salinity, acidity, and soil organic matter on shoot length, lipoperoxidation, and proline in roots and green parts, and evaluated plant responses to environmental disturbance, which allowed for the comparison of adaptation strategies. The studies were carried out in (1) "sodium production" (near sodium factories), (2) "anthropogenic environments" (waste dumps, agroecosystems, calcium deposits, post-production tanks), (3) "wetland environments" (near river channels and riparian areas), and (4) "control" (natural, unpolluted environments). Green parts of plants are better suited to indicate environmental stress than roots. Their higher structural MDA membrane damage is related to the transport of toxic ions to the shoots by a rapid transpiration stream in the xylem. We found high salinity to be the main factor inducing growth and found it to be correlated with the high pH effect on proline increase in glycophytes (Elder, Reed) and Weeping Alkaligrass, in contrast to Common Glasswort. We suggest that proline accumulation allows osmotic adjustment in the green parts of reeds and alkaligrasses, but may have another function (in Elder). Common Glasswort accumulates large amounts of Na+, which is energetically more effective than proline accumulation for osmotic adjustment. Organic matter affects plant growth and proline levels, but soil salinity and pH alter nutrient availability. Plant distribution along the salinity gradient indicates that Elder is the most salt-sensitive species compared to Reed, Alkaligrass, and Glasswort. Salinity and the lack of control of thick reeds, which compete with other plant groups, affect the distribution of halophytes in saline environments.

Uncultivated synantropic flora a forestry park ,,Lunca Gaștei” in the city of Chisinau

This article presents the results of research on the uncultivated synanthropic flora of the „Lunca Gâștei” forest park. The analysis of taxonomic diversity revealed the presence of 298 plant species, which are belonging to 214 genera and 59 families. A new location of growth was discovered for the critically endangered species Orchis purpurea Huds. Bioecological characteristics were analyzed, and the adventive fraction of uncultivated synanthropic flora in the park was emphasized. Species of Euro-Asian origin predominate in the geographical element. The diversity of existing biotopes on the researched territory also determined the diversity of the ecological groups of plants depending on the water regime, mesophytes and xeromesophytes being dominant. In the spectrum of biomorphs, hemicryptophytes are the most representative. 53 adventive species were identified, most of which are of American origin.

Study of Hedysarum theinum (Fabaceae Lindl.) in the flora of Kazakhstan

Analysis of historical data on the distribution of Hedysarum theinum Krasnob. in Kazakhstan presented in this paper is based on herbarium collections kept at the Institute of Botany and Phytointroduction, Almaty and the Digital Herbarium of Moscow State University, Moscow, as well as a list of species of Hedysarum theinum on the Ivanovsky Ridge, Kazakhstani Altai with specimens collected as a result of expedition trips to the study area. The cenoflora includes 176 species from 120 genera and 41 families. The hierarchical order of the leading families is as follows: Asteraceae Dumort, Poaceae Barnhart, Ranunculaceae Juss., Rosaceae Juss. Comparative analysis of life forms shows that short rhizomatous plants prevail – 33%, as taproot plants constitute 24% and tussock plants – 11%. The basis of communities in relation to the temperature, moisture and substrate structure are made of the following ecological groups of plants: mesophytes – 30%, and, in a smaller proportion, of mesohygrophytes – 19%, mesoxerophytes – 20% and mesopsychrophytes – 18%.

Deuterogyny and the Association of Two Vagrant Eriophyoid Mites (Acariformes, Eriophyoidea) with the Host-plant Generative Organs of Two Broad-leaved Trees in North-West Russia.

Phytoparasitic mites of the superfamily Eriophyoidea Nalepa live and feed on mature leaf surfaces, between leaf bud scales, and (though less commonly) on flowers or fruits. In this study, we focused on the seasonal associations of two eriophyoid species, Shevtchenkella serrata (Nalepa 1892) with the Norway maple tree (Acer platanoides L.), and Brevulacus reticulatus Manson 1984 with the common oak (Quercus robur L.). These species have complex life cycles with two morphologically different, seasonal female forms, the protogyne and deutogyne. In B. reticulatus, both forms retain all the major generic characteristics but in S. serrata only the protogynes conform to the diagnosis of Shevtchenkella, whereas the deutogynes have the typical traits of Anthocoptes. We confirmed the conspecificity of the protogynes and deutogynes of both eriophyoid species by sequencing a barcode fragment of the Cox1 gene from which we obtained four pairwise identical sequences: ON920305/ON920306 (S. serrata) and ON920307/ON920308 (B. reticulatus). In addition, taxonomical studies on Shevtchenkella and Brevulacus resulted in new synonymies and combinations: (1) Oxypleurites obtusus Roivainen 1947 is considered a deutogyne of S. serrata and treated as a junior synonym of S. serrata; (2) two rhyncaphytoptine species from North America are transferred from the genus Rhyncaphytoptus to Brevulacus: B. albus (Keifer 1959) comb. nov. and B. atlanticus (Keifer 1959) comb. nov.; and (3) one species, B. salicinus Soika et al. 2017, is excluded from Brevulacus and transferred to Rhyncaphytoptus: Rhyncaphytoptus salicinus (Soika et al. 2017) comb. nov. Apart from distinct morphological deuterogyny in S. serrata and B. reticulatus, we observed the persistent association of S. serrata with the generative organs of the maple tree, A. platanoides, leading to transmission to the next host generation via the seed-containing winged fruits (samaras) and subsequent colonization of seedlings. In B. reticulatus, similar synchronization with host-plant dispersal was not detected; however, in mid-summer, temporary colonization of immature acorns and feeding was observed. Additional studies conducted in various ecosystems and including different ecological groups of plants, especially anemochorous plants, are needed to estimate the frequency of the association of eriophyoids with plant generative organs, seeds and seedlings to better understand what role in mite ecology such associations may play.

ECOLOGICAL ASSESSMENT OF ANTHROPOGENIC IMPACT ON THE STATE OF PHYTOCENOSES OF HOLOSIIV PARK NAMED AFTER MAKSYM RYLSKYI OF THE CITY OF KYIV

Anthropogenic load on natural phytocenoses is manifested by disturbance of plant cover, synanthropization of the floristic composition of groups, destruction of plant distribution areas, reduction of biodiversity, and changes in plant growth and development conditions. The degree of anthropogenic load on natural phytocenoses is a global problem that requires detailed study and monitoring studies, especially in the conditions of urban ecosystems. The natural conditions affecting the state of the phytocenoses of Holosiiv Park named after Maxim Rylskyi city of Kyiv according to physical and geographical, climatic, edaphic, and orographic features. The influence of anthropogenic activity in the experimental plots was determined and the level of anthropogenic pressure on the state of the phytocenoses of Holosiiv Park named after Maxim Rylskyi city of Kyiv was carried out by analyzing available sources of industrial production, transport, etc. It has been established that Holosiiv Park named after Maksym Rylskyi is subjected to constant anthropogenic load, in particular, intensive recreational use, atmospheric air pollution has been established, which leads to the impoverishment of biodiversity in certain areas of the park. The level of atmospheric air pollution in the territory adjacent to the experimental sites was assessed using computational and instrumental methods. It was established that the estimated CO level exceeds the standards by 8 times on Holosiivskyi Avenue and by more than 30 times at the intersection of Maksym Rylskyi Street and Holosiivskyi Avenue. The analysis of the state of the atmospheric air using instrumental research methods did not show an excess of the content of the main pollutants, however, according to the Air Quality Index, it is moderately polluted by the content of dust with a diameter of 2.5 microns. The study of the state of the phytocenoses of Holosiiv Park named after Maksym Rylsky of the city of Kyiv within the experimental plots was carried out by studying their floristic composition and evaluating the ecological groups of plants. Because it is the analysis of ecological groups of plants that makes it possible to assess the ecological conditions of plant groups, the place of growth, and phytocenotypes of plant species that are part of the phytocenosis, that is their role in the formation of the phytocenosis. The ecological assessment of the state of phytocenoses of Holosiiv Park named after Maksym Rylskyi of the city of Kyiv was carried out using the method of bioindication and lichen indication (lichen research). These methods make it possible to determine the level of anthropogenic load acting quickly and relatively easily on phytocenoses within the experimental plots. To determine the state of the trees in the experimental plots, the method of assessing the asymmetry of morphological structures was used (using the example of the hanging hornbeam Carpinus betulus L.). A comparison of the floristic composition and the state of the phytocenoses showed that plot No. 1 has a depressed state, plants do not grow evenly, and drying of trees was observed. Plot No. 2 has the best condition, the plants of the plot are characterized by the best indicators of growth and development, the largest number of species, and the frequency of occurrence of species. Site No. 3 did not record significant degradation of the phytocenosis, but there is a certain mosaic of the phytocenosis, which may be due to atmospheric air pollution and significant recreational pressure, in particular, trampling. Plot No. 2 and Plot No. 3 have the highest coefficient of species composition commonality. Common plant species in the respective areas are: Carpinus betulus L., Anemonoides ranunculoides L., Ficaria verna, Trifolium repens and Corydalis solida.

STRUCTURAL AND SPECIES DIVERSITY ON NORTH AND SOUTH SLOPES IN CONIFEROUS-DECIDUOUS FORESTS OF THE NORTH-WESTERN CAUCASUS

The research was conducted in similar soil-orographic conditions of three widespread coniferous-deciduous forest types in the North-Western Caucasus: aspen-hornbeam, beech-fir-hornbeam, and fir-beech. The methods used included geobotanical, population-ontogenetic, and soil-zoological. It was found that the north and south slopes in all the studied forest types, in comparison with the flat areas, are characterised by significantly higher plant species richness. The efficiency of the renewal of arboral cenopopulations was much higher on the slopes, in comparison with the flat areas: the number of tree species (higher by 20–70%); density of tree species (higher by 50–100%); the number of cenopopulations of tree species with a complete ontogenetic spectrum was larger on the slopes, in comparison with the flat areas. A greater number of ecological groups of plants were described on the north and south slopes, in comparison with the flat areas. The proportion of boreal species was higher on the north slopes, in comparison with the south slopes, whereas the majority of meadow-forest edge species were the south slopes. The north and south slopes were characterised by the full functional diversity of soil invertebrates, whereas endemic and sub-endemic macrofauna also preserved. On the north slopes, we revealed a high biomass of large litter and soil saprophages, including species and groups actively participating in transformation of plant litter and soil formation. The south slopes showed high densities of phytophages and predators (among soil macrofauna), which regulate the diversity of other components of forest communities through biotic interactions. All the studied forest types on the north and south slopes exceeded the flat areas in terms of species diversity of plant communities, regeneration of tree species, ecological plant groups, endemic fauna of soil invertebrates, including soil formers.

Study of Plant Adaptation to the Arid Zone of Uzbekistan based on System Analysis

Studying the ecological and biological features and water regime of plants of the mountainous semidesert of Uzbekistan to determine their stability in these conditions, we concluded to use an integrated approach to solve the problem of adaptation. Functional, structural or other biological features can equally determine the resistance of a species to extreme factors, such as, for example, the rhythm of development. The purpose of the work is to identify a complex of elements of plant adaptation to arid zone to xerothermic conditions and to characterize ecological groups by the generality of adaptation systems. Based on the system analysis, the biological and structural-functional adaptive features of plants were analyzed, and the studied species were classified into ecological groups as adaptive systems and according to the generality of adaptations to the experience of the dry period. The original data obtained, which relate to the characteristics of the elements of biomorphological adaptation and adaptation of the water regime, the remaining adaptive elements were identified based on the analysis of literary data. Along with structural and behavioral signs, we focus on those features of the water regime that ensure a positive water balance among representatives of various environmental groups. Each of the selected ecological groups of plants is characterized by a certain combination of adaptive features of a physiological and biomorphological plan. With a variety of adaptive features in different plant species to drought and the absence of an integral indicator of drought resistance, it is impossible to focus on any one of them, of course, it is necessary to take into account the whole complex of signs. The complex of features will allow determining more accurately the nature of a particular combination of biomorphological and functional features peculiar to a particular ecological group

The invasive herb Lupinus polyphyllus can reduce plant species richness independently of local invasion age

The ecological impacts of invasive species may change or accumulate with time since local invasion, potentially inducing further changes in communities and the abiotic environment. Yet, time since invasion is rarely considered when investigating the ecological impacts of invasive non-native species. To examine the effect of time since invasion on the ecological impacts of Lupinus polyphyllus, a perennial nitrogen-fixing herb, we surveyed vascular plant communities in the presence and absence of L. polyphyllus in young, intermediate, and old semi-natural grassland sites (ca. 5, 10, 15 years representing both time since lupine invasion and plant community age). We analyzed vascular plant community composition, vascular plant species richness, and the cover of various ecological plant groups and L. polyphyllus. In contrast to our hypotheses, we found no change in the mean cover of L. polyphyllus (about 35%) with time since local invasion, and an ordination did not suggest marked changes in plant community composition. L. polyphyllus was associated with lower species richness in invaded plant communities but this effect did not change with time since invasion. Invaded plant communities were also associated with lower occurrence of generalist, oligotrophic (low-nutrient-adapted) and copiotrophic (nutrient-demanding) species but no temporal dynamics were detected. We conclude that even the intermediate cover of L. polyphyllus can reduce plant species richness, but the ecological impact caused by this invader might not dramatically change or accumulate with time since invasion.

Red wood ants in Bulgaria: distribution and density related to habitat characteristics

The only National Inventory of red wood ants in Bulgaria was carried out about 50 years ago (1970–1973). Formica rufa Linnaeus, 1761, F. pratensis Retzius, 1783, F. lugubris Zetterstedt, 1838 and F. polyctena (as F. polyctena x rufa hybrid) were found in a current monitoring programme. This study presents data on their current distribution and nest density, and provides more details about the habitat requirements for conservation purposes. Field studies were carried out by the transect method along the main mountainous areas in Bulgaria. We found 256 nests of red wood ants along 172 transects. The most abundant species was F. lugubris, followed by F. rufa and F. pratensis. Among the environmental variables, the elevation, exposure, ecological groups of plants, stone cover, grass cover, canopy cover and forest age appeared as significantly related to the presence and nest density of red wood ants.

Dynamics of self-regeneration of the vegetation cover of coal deposits of Republic of Tyva (Russia)

The article deals with the characteristic feature of the dynamics of self-restoration of vegetation cover on the dumps of the Chadan coal mine of the Republic of Tyva. The initial zonal vegetation is dry-steppe. Currently, there is a high proportion of weed species in the herbage, the presence of trees, willows and a solid carpet of lower plants (green moss), which is not typical for dry steppes. Even after 40 years of restoration of vegetation on coal dumps, the species composition, dominant structure, and ecological groups of plants have not yet been formed. In general, the long-term dynamics of self-restoration of vegetation cover in the area of the coal mine is characterized by some xerophytization of vegetation.

РОЛЬ ВЫСШИХ СОСУДИСТЫХ РАСТЕНИЙ В БИОЛОГИЧЕСКОЙ ОЧИСТКЕ СТОЧНЫХ ВОД

The article presents the results of a botanical analysis of water systems in the south of Kazakhstan. Hydromacrophytic vegetation of the reservoir reflects its hydrological and thermal regime and can characterize the features of its chemical composition, trophic status, age (as a stage of development). In some cases, phytocenosis and some types of macrophytes can be used as bioindicators, for example, in clean water, as well as to determine the degree and nature of anthropogenic impacts. Metals, metal compounds and toxins cause disturbances in many metabolic processes in plants. As a result, the highly toxic nature of their ions selectively affects the species composition of the phytocenosis. In Shymkent, almost a unique system of treatment facilities has been operating for about 20 years, during this time, resistant species adapted to the environment were selected, and a plant cenosis consisting of dominant species was formed. In this regard, a floristic study was carried out in the canals around the treatment plant, adapted to climatic conditions and pollutants. As a result of the study, the species composition and the number of plant communities decreased due to the toxic concentration of water. It is clearly seen that Cerathophyllum demersum, Lemna minor, L. trisulca, Phragmites australis, Scirpus lacustris, Epilobium adnatum were identified as effective phytomeliorants, significantly reducing the content of the main pollutants in urban wastewater. In addition, algae have been found to be indicators of pollution. Highly effective organic fertilizers can be obtained from the used vascular plants and algae. In general, these data showed that the optimal consortium of wastewater treatment plants at low temperatures should be formed from different ecological groups of plants: coastal, floating and inhabiting the aquatic environment. In addition, among these plants were found sedimentary hornbeam, campfire fish, southern reed, lake reed and a related cypress.

Эколого-таксономический анализ прибрежной флоры Аулиекольского района (Костанайская область)

The study of flora is an important aspect of biodiversity maintenance and monitoring. Kostanay region is not a sufficiently explored region requiring a detailed analysis of coastal vegetation. During research in 2016–2019 the composition of the coastal flora of 6 geographical points was studied: rivers (Ubagan, Karasu) and natural lakes (Teacher, Solyenoe No. 1, Solyenoe No. 2, Kairankol). As a result of studies conducted on the territory of the Auliekol district of the Kostanay region, 106 species of coastal flora from 84 genera and 37 families were found. The taxonomic composition is characterized by dominance among the families Asteraceae, Poaceae and Fabaceae, among the genera — Artemisia, Plantago, Astragalus. In the Auliekol region, plants of the steppe cenotic group prevail, which is explained by the location of the study area within the Turgai lodge. In the surveyed territory, 7 ecological groups of plants were identified, with the maximum number of species being xero-mesophytes (33 taxa), the minimum — xerophytes (1 species). Among life forms, only 4 groups were noted, of which the maximum falls on perennial herbaceous plants (78 species). Uneven distribution of plants in the surveyed reservoirs was revealed. The maximum amounts falls on the floodplain of the river Ubagan, the minimum — on the lake Teacher.

Investigation of the influence of distribution of heavy metals from construction waste disposal on plant associations of adjacent ecosystems

The question of influence of distribution of pollution of soils by heavy metals from the landfill on the soil-plant complex of natural ecosystems in the zone of influence of object is investigated. The presence of increased bioaccumulation of heavy metals of certain specialized ecological groups of plants – submerged macrophytes and weed–ruderal plants was revealed. Specificity of accumulation of heavy metals is not a property of plant life forms. However, within plants of one life form there are species with an increased ability to selective accumulation of individual heavy metals, which is especially pronounced in mosses. The results obtained can be used to improve the efficiency of bioengineering protection of the natural environment through environmental planning of landscapes in the areas contaminated with heavy metals around landfills and other industrial facilities.

Жизненные формы и экологические группы растений в некоторых типах леса на территории Уссурийского заповедника (Приморский край, Россия)

Жизненные формы и экологические группы растений в некоторых типах леса на территории Уссурийского заповедника (Приморский край, Россия)

ВОДНЫЙ РЕЖИМ НЕКОТОРЫХ ПРЕДСТАВИТЕЛЕЙ РОДА IRIS ПРИ ИНТРОДУКЦИИ НА ЮЖНОМ УРАЛЕ

The article presents the results of a study of the parameters of the water regime of irises of the subgenus Xyridion introduced in the Southern Urals (Iris graminea, I. halophila, I. halophila var. sogdiana, I. notha, I. orientalis, I. spuria, I. spuria subsp. carthaliniae, I. spuria subsp. musulmanica) in comparison with local species (I. sibirica, I. pseudacorus, I. pumila). The experiments were carried out on the basis of the laboratory of introduction and selection of flower plants of the South-Ural Botanical Garden-Institute of Ufa Federal Research Centre of Russian Academy of Sciences. The objects of the study were different ecological groups of plants in relation to water ‒ hydrophytes, mesophytes and xeromesophytes. The water deficit of leaves and accompanying characteristics (relative turgescence) were determined by saturation of plant samples according to methodological guidelines; water retention capacity, tissue hydration and the level of daily water loss were determined by artificial wilting. The obtained results characterize the peculiarities of the water regime of irises and indicate significant interspecific differences. It was revealed that the flora of the Republic of Bashkortostan contains plants both with a wide range of variability of water retention capacity (I. pumila) and with a fairly conservative one (I. pseudacorus, I. sibirica). Both strategies are successful in the continental climate of the Southern Urals. Introduced taxa of the subgenus Xyridion also keep to a particular strategy and it can be considered an indicator of successful introduction. It is shown that local species of irises do not form a water deficit in conditions of excessive moisture, while 6 taxa of the subgenus Xyridion have an average level of water deficit. According to the sum of indicators, the studied taxa belong to the groups with medium and high stability of the water regime due to low water deficit, high water retention capacity and hydration. These parameters are found in various combinations and sustain the stability of the water regime of cultivars. The studied physiological indicators can be used to assess the success of introduction in comparison with local control species.

ОСОБЛИВОСТІ РОСЛИННОЇ СУКЦЕСІЇ У КАР'ЄРІ ЦЕГЕЛЬНОГО ЗАВОДУ В С. НОВИЙ ТІК (РІВНЕНСЬКА ОБЛАСТЬ)

Termination of quarries is the reason for the settlement of pioneer plants, which exploit "free" areas of soil in a certain sequence, called successions. The theoretical foundations of restorative plant successions in the quarries are still relatively poorly developed, although there is much empirical research on the subject. The object of our study is the quarry of a brick factory located in the eastern outskirts of the village. Novy Tik (Demydiv district, Rivne region) in the central part of Volyn height, 27 km south of Lutsk. Since 2008, when the brick factory ceased to function in the quarry, there has been a primary plant succession, which is now at a youth stage and is characterized by an increase in biodiversity. As of autumn 2019, 72 plants spices have been identified in the quarry, including 6 species of trees, 1 species of shrubs and 65 species of grasses. According to the results of the systematic analyze, the Asteraceae and Fabaceae families predominate. The prevailing ecological groups of plants in the quarry are determined: in relation to lighting prevail heliophytes; in relation to the thermal regime, the largestproportion is made up of temperate-warm climate species; in the vegetation cover at the present stage of succession, Central European species prevail. Based on the analysis of the population of plant associations and the appearance of interspecific and intraspecific competition, it is established that plant succession in the studied quarry is at a youth stage. Also, heterochrony and microzonal differentiation of succession processes in different parts of the quarry are found. The difference in the passage of succession stages depending on the features of the relief is taken as the basis for the quarry microzoning. It has been established that at the present stage of vegetation succession, the determining factor in the qualitative and quantitative composition of plant communities is abiotic quarry factors, especially morphology and relief dynamics and lithological-stratigraphic structure of deposits. The initial stage of soil succession was revealed, which became possible due to the accumulation of a significant amount of mortmass in recent years.

Influence of Phosphogypsum Dump on the Soil Ecosystem in the Sumy region (Ukraine)

This paper investigates the influence of a phosphogypsum dump on the surrounding environment (soil ecosystem) in the Sumy region (Ukraine). Analysis of the surrounding soils was performed to study the possible presence of compounds leaching from the dump. For physical chemical analysis of samples, X-ray fluorescence (XRF) analysis, X-ray diffraction (XRD) analysis, and Fourier transform infrared spectrophotometry (FTIR) were used. XRF analysis did not confirm the contamination of soils around the phosphogypsum dump, and the soil fluoride levels measured in this study were comparable to the average soil fluoride concentration of soils globally. The colonization of the surface of the phosphogypsum dump by living organisms after the reclamation process was also analyzed. Field research was carried out on the routes, which specify the boundaries of the contours of plant communities, for description of phytocenoses in the territory of the dump, where the pH value ranged from 2.5 to 5.3, depending on the age of phosphogypsum terraces. Annual and perennial herbaceous plants are dominant on the reclaimed dump slopes. On the third and fourth phosphogypsum terraces (20 and 25 years old, respectively), tree forms have begun to settle, represented mainly by Populus tgemula, Populus alba, Betula pendula, and Robinia pseudoacacia. The studied patterns of ecological groups of plants growing under natural change of species can be used for the complete reclamation of the dump.

Restoration of agroecosystems in the Republic of Tyva

Until 1995, a special study of the flora and vegetation of Tuva agroecosystems was not carried out. This work is devoted to the research of features of overgrowth of abandoned arable land, species composition of vegetation, productivity, stages of healing and their duration, prospects of their use as forage lands. Purpose. To determine the main trends of fallow ecosystems in the course of succession: changes in the species composition of phytocenoses, a set of dominant species, ecological groups of plants, the structure of plant matter and primary products in different edaphic conditions, but in the same climatic zone. Methods. For the study of each succession, key sites on the initial (control) and successional ecosystems were selected, where changes in the species composition of communities, the composition of dominants, phytomass stocks and its structure were studied. The studies were conducted in the period 1997-2018. Results. In the sharply continental climate of Tuva, the development of agriculture without irrigation has not justified itself. In the 50-60 years of the last century there were periods of mass development of virgin lands. In the early 1990s, the area of land cultivated for cultivation began to decline sharply. It is shown that the fallow succession proceeds naturally and synchronously. Summary. In arid conditions of Tuva, the initial stage of succession (0-4 years) is weeds. The first intermediate stage (4-7 years) is marked on all deposits by the absolute dominance of wheatgrass and the appearance of dominants characteristic of a certain type of steppes. The second intermediate stage (7-11 years) is characterized in that all deposits are dominated by species of the original indigenous steppes. The late stage (11-20 years) is the phase of formation of terminal communities with characteristic sets of species for each steppe, including the dominant ones.

Sustainable management of natural pastures in Buryatia

The article deals with the issues of sustainable pasture resources management on the example of the Tunkinsky district of the Republic of Buryatia. Sustainable pasture management contributes not only to the preservation of forests, but also to the promotion of adaptation to climate change, the preservation of biodiversity, and the improvement of the living standards of the local population. The use of pasture resources provides a long-term balance between livestock numbers, fodder production and pasture productivity, while maintaining the functionality and structure of the entire ecosystem. Pasture ecosystems are dominated by plants from the families Poaceae, Asteraceae, Fabaceae, Brassicaceae, Chenopodiaceae, Asteraceae. Lack of grazing leads to the decreasing share of forage species to 47% (on average), as it not used in the ecosystem. For sustainable pasture exploitation, the experimentally established structure of ecological groups is recommended: 70% for forage grass, 15% for medicinal, 7% for ruderal, 5% for poisonous, 1% for others. Unsystematic grazing of animals on pastures leads to a 2.5-3 fold reduction in species of biodiversity (27-30 species), and the family representation becomes 2 times lower. In relation to animal grazing, a total of 5 ecological groups of plants were identified. More than that, their structure, ecosystem, and economic role in stabilizing the ecological situation of pastures were established. In the course of the research conducted in the study area in environmental, economic, financial, and institutional aspects, three scenarios for the management of pasture resources are highlighted: unstable, extensive, and balanced.

The Influence of Agricultural Land Use on the Dynamics of Biological Cycling and Soil Properties in the Course of Postagrogenic Succession (Kostroma Oblast)

The postagrogenic dynamics of biological cycling and soil properties have been studied in three soil successions characterizing postagrogenic overgrowing of: (i) former cropland on a loamy sandy soil underlain by loam (Retic Albic Podzol (Anoarenic, Endoloamic, Ochric)), (ii) well-fertilized garden loamy sandy soil underlain by loam (Plaggic Podzol (Anoarenic, Endoloamic, Humic)), and (iii) loamy soil of a hayfield developed from the former arable land (Albic Retisol (Loamic, Ochric)). The dynamics of acidity and organic carbon content are determined by the rate of the succession depending on soil fertility during the agrogenic stage in the past. In case of overgrowing of poor sandy agrosoddy-podzols, the changes in soil acidity and organic carbon content are adequately reflected by the proportion between different ecological groups of plants in the herb–dwarf-shrub layer. In the case of reforestation of former croplands, the organic carbon stock in biogeocenoses increases from 30–40 to 120 t/ha after 35–40 years. The restoration of forest vegetation on well-manured soils of private vegetable gardens with the initial carbon stock of 100–120 t/ha is retarded for a long time, and the organic carbon stock remains unchanged for at least 35 years.