The classification of forest vegetation of the Tuul river basin within the green belt of the Ulaanbaatar city has been carried out. Two associations (Linnaeo borealis–Pinetum sibiricae and Vaccinio vitis-idaeae–Laricetum sibiricae) relating to Vaccinio–Piceetea are described. Diagnostic signs and characteristics of the ecological and geographical peculiarities of the units are presented, and anthropogenic transformation is assessed. To determine the models of succession processes, the series of permanent sample plots (PSPs) are established in the communities of the Linnaeo borealis-Pinetum sibiricae association, located at different distances from the city, in taxation units with unequal intensity of recreational load. Recreational forest assessment is calculated according to the approach by V.S. Romanov and L.N. Rozhkov (1974). In the Linnaeo borealis-Pinetum sibiricae association, large areas are occupied by moderately transformed communities. The Vaccinio vitis-idaeae–Laricetum sibiricae association is characterized by being weakly transformed forests. Different stages of anthropogenic pressure lead to the formation of serial communities unequal in structure and species diversity. Serial plant communities of allogeneic succession develop according to two models of geitogenesis: tolerance (Linnaeo borealis-Pinetum sibiricae ↔ Rhytidium rugosum; Linnaeo borealis-Pinetum sibiricae ↔ Chamaenerion angustifolium) and inhibition (Linnaeo borealis-Pinetum sibiricae → Betula rotundifolia). The comprehensive assessment of the recreational potential is based on three indicators: natural conditions, air hygiene, and landscaping. All activities aimed at increasing the recreational potential should contribute to the improvement of these indicators. A prerequisite for increasing the recreational forest assessment should be functional zoning of the territory with the allocation of infrastructure, walking, and sanitary protective zones. Forest management is of great importance in increasing the recreational assessment of forests. The forest management project for the organization of recreational forests should be aimed at the formation of sustainable and aesthetically attractive forest plantations.

The technogenic vegetation of overburden dumps of the Kholboldzhinsky coal mine is considered, represented by one association, three communities, which belong to four 4 unions and orders of the classes Stellarietea mediae, Artemisietea vulgaris, Thero-Salicornietea. An indirect ordination analysis was performed using the principal component method, which made it possible to determine the leading environmental factors of differentiation of syntaxa: moisture and salinity richness.

The plant communities of the sandy massifs of the Northern Gobi Desert on the territory of the Bulgan Omnogovi aimag are considered. The classification of vegetation by the Braun–Blanquet method, first carried out for vegetation of the flat part of the Bulgan soum, revealed six vegetation associations belonging to three unions of three orders of the class Stipetea glareosae-gobicae Hilbig 2000. The flora of sandy massifs includes 108 species from 73 genera and 28 families. The species structure of genera and families reflects the specifics of the flora of this desert–steppe region within the Bulgan soum. In the spectrum of life forms of plants in sandy communities, perennial and annual and biennial grasses predominate, although in terms of participation in the structure of plant communities, the dominant phytocenotic role belongs most of all to woody plants. Dominant types of vegetation of the sandy massifs (Krascheninnikovia ceratoides, Caragana korshinskii, Haloxylon ammodendron, Psammochloa villosa, Nitraria sibirica, Brachanthemum gobicum, etc.) are natural sand fixers. At the same time, these species are for the most part well-eaten food for livestock. Consequently, grazing in such habitats must be strictly regulated.

The study of the state and economic value of pasture ecosystems in Mongolia in the context of their progressive degradation continues to be very relevant. The existing methods of forage assessment of pastures are either laborious (the zootechnical method) or do not reflect the real situation (assessment of overall productivity) in the formation of low-species or monodominant degraded communities. To determine the nutritional value and productivity of pasture ecosystems in Mongolia, the palatability coefficient (PC) is proposed, which is determined on the basis of data on the nutritional usefulness of plant species that make up the community, as well as the diversity of eaten species. The PC was calculated as the ratio of the phytomass eaten to the total aboveground phytomass, multiplied by the number of eaten species included in the composition of dominants and codominants. The PC was determined for 158 communities of meadow and steppe pasture ecosystems. These were ranked in four categories. It has been established that a significant part of the studied communities have a high PC. Although these communities are characterized by varying degrees of anthropogenic disturbance, including severe ones, the high PC is due to the fact that some of the digressively active species have satisfactory or good palatability. This fact probably supports the potential for an increase in the number of livestock in Mongolia, which have a wide range of food preferences. At the same time, there is a high proportion of pastures with low and very low PCs. To a greater extent, such pastures are formed by communities of real and dry steppes, which experience the greatest pasture load in Mongolia.

A database, including a map layer of ecosystems of the Lake Baikal basin, has been compiled at a scale of 1 : 500 000. The area is divided into 71 types of mesocombinations of plant communities and their anthropogenically transformed variants, which reflect natural units, corresponding to the level of urochishche/suburochishche of landscapes. A digital map layer of morphogenetic relief types (31 were specified) was elaborated to reflect the spatial variability of the distinguished geobotanical units. The map layer of the soil cover of the basin was based on interpolation of various published thematic data and supplemented by archived and long-term data of terrain survey of the soil cover performed by the Joint Russian–Mongolian Complex Biological Expedition of the Russian Academy of Sciences and of the Mongolian Academy of Sciences. The prepared database includes spatial data on ecosystems and their anthropogenic disturbance for nine model polygons (at a scale larger than 1 : 200 000) and eight test plots (at a scale of 1 : 5000–1 : 10 000), as well as 1757 geobotanical descriptions made by the authors earlier. The 5.1 GB spatial database is a cartographic web service located at https://mon-exp.nextgis.com/resource/ . It is intended for open use on any personal computer, workstation, notebook, tablet, and smartphone with Windows and Android OS, including mobile ones with Internet access.

Трансформация наземных экосистем бассейна Байкала: основные риски и экологические последствияБажа С.Н. 1 (monexp

The article outlines the main causes and effects of the destabilization of ecosystems in the Lake Baikal basin. They were identified via long-term monitoring based on large-scale mapping and landscape and soil-geobotanical studies on a network of model polygons and key sites established in areas with increased ecological tension. The degree of disturbance of the natural environment of the region is assessed, the main factors of degradation are revealed, and the pattern of degradation processes is determined in different types of terrestrial ecosystems in the Baikal basin.

The features of the distribution of the Siberian apricot (Prunus sibirica L.) in the southern (Mongolian) part of the Selenga river basin is discussed. It was found that there is a clear trend in the successional change of pine forests to shrubby vegetation represented by Siberian apricot communities. This trend is facilitated by the reduction in forest area after fires, felling, and grazing, which, in turn, leads to the change in the landscape and ecological conditions in forest ecotopes. In addition, the coenotic positions of Prunus sibirica are strengthened because of its physiological and biochemical adaptation to the pyrogenic factor, its consumption by livestock, and the variability of the functional parameters of the species.

The current state of the dry-steppe, desert-steppe, mountain-steppe, and desert ecosystems of the Gobi Desert (Mongolia) has been studied. In the dry steppes and steppe deserts, not only is there a decrease in the phytocenotic indicators of plant communities and deterioration of the state of dominants, but also a change in their composition has been revealed. Thus, there was a replacement of typical grass species of dry steppes (Stipa krylovii, Agropyron cristatum, etc.) with desert-steppe species (Allium polyrrhizum). In steppe deserts, the role of herbal species (Stipa glareosa and Cleistogenes songorica) in the community structure significantly decreased, and the proportion of desert shrubs (Anabasis brevifolia and Salsola passerina) increased. The vegetation of true and extremely arid deserts turned to be the most resistant to aridization and increased pasture loads. The changes were revealed only in the Sympegma community, where a significant decrease in the abundance of Sympegma regelii was observed. A mismatch has been found between the values of the NDVI index obtained remotely from Landsat 8 images and the phytocoenotic indices determined in field studies. The data from field spectrometry of the dominant species and the surface of soils and plant communities showed that the soil background plays a significant role in formation of spectral images of plant communities, especially with low projective cover.

Рассматриваются основные пути процесса обезлесения на южной границе бореальных лесов в Монголии, обусловленные иссушением либо, напротив, переувлажнением корнеобитаемого слоя почвогрунтов лесных экотопов, а также различными вариантами конкурентных отношений с кустарниковой растительностью.Нередко указанные факторы действуют совместно.Данные были получены в ходе многолетних наблюдений на нескольких исследовательских полигонах в лесах разных типов.Для определения характера и направленности сукцессионных смен использовались стандартные лесоводственные и геоботанические методы, а также осуществлялись исследования почвенного покрова.Показано, что для разных регионов Северной и Центральной Монголии характерны свои пути обезлесения, ведущие, как правило, к смене коренных лесных сообществ на заросли кустарников тех или иных видов.Кустарники не только замещают распадающиеся леса, но и служат индикаторами экотопов, потенциально пригодных для искусственного лесоразведения, как в случае с Dasiphora fruticosa, или не пригодных для лесоразведения при сукцессии Armeniaca sibirica.Результатом работ явилась общая схема постлесных

The study was carried out within the framework of the scientific program of the Joint Russian–Mongolian Complex Biological Expedition of RAS and MAS, and with the financial support of the grant RFBR 17-29-05019

The degradation of landscapes related to their deforestation is the most widespread process in the world at the present time, and its control is considered especially important for preservation of the ecological stability of forest regions. Thus, the elaboration of measures for reforestation of previously forested lands is a high-priority task. This is the case for the forest-steppe landscapes of the Lake Baikal basin. The results of the use of a combination of indicators to reveal those ecotopes that still have regeneration potential for coniferous and coniferous–small-leaved forests at the southern boundary of the boreal belt in Asia are given in this article.

Changes in the state of Mongolian arid ecosystems revealed in long-term field studies have been analyzed in accordance with the developed concept of island-type desertification. Trends have been revealed in the development of climate aridity, drought frequency, and the anthropogenic load on pastures. Indicators of area moistening, anthropogenic desertification islands, and the overgrazing degree of arid pastures have been developed on the basis of satellite MODIS data. It has been shown that the effects of a sharp reduction in the number of livestock because of natural hazards (dzut, drought) are reliably manifested by a decrease in the surface albedo and an increase in the vegetation index. The dynamics of the islands of anthropogenic desertification has been analyzed. The degree of degradation of dry-steppe, desert-steppe, and desert ecosystems has been estimated snowstorms.

The studies of the steppe ecosystems in Central Mongolia have showed that the simplification of steppe communities has taken place over recent decades. This occurred by reduction of species diversity and abundance of indigenous dominants—tussock grasses—as a result of sharp rise in pasture loads and a long dry period. We have identified two types of introduction of invasive species from different landscapes: (a) extraand intrazonal and (b) zonal. The first type of succession is characterized by focal distribution of Ephedra sinica from ecosystems of low mountains to the surrounding mountain plains. The second type of succession in dry steppes is associated with the expansion of Allium polyrrhizum, whose distribution has largely a frontal character and is caused by weakening of the competitiveness of indigenous species of grass communities because of their significant digression. A further factor in ensuring the conditions for invasion is the aeolian alkalization of the upper horizons of zonal chestnut soils. The ecological and biological features of these two species, widespread in the desert-steppe and desert landscapes and penetrating into the steppe ecosystems, make it possible to speak about biological desertification. The wide area of Ephedra sinica and Allium polyrrhizum indicates a progressive character of the studied types of succession, and as a result of this, the borders of these areas have reached at present the southern periphery of the Baikal Lake basin. The paper describes the processes which lead to the reduction of the fodder value of pastures and jeopardize the maintenance of cattle breeding in Central Mongolia.