The paper analyzes the features of the demographic development of cities-centers of urban agglomerations of the European part of Russia for the period 2012–2019; 54 cities with populations of at least 250 thousand people were considered. The only exception was the city-centers of the polycentric Kavminvodskaya urban agglomeration, the total population of which is more than 450 thousand people. The analysis was carried out on the basis of open data from the official statistics of Rosstat using traditional methods of summarizing and grouping. Cities with the corresponding parameters were entered into the developed three-tier typological table, which made it possible to consider the resulting groupings as a dynamic typology of core cities by the nature of demographic development. As a criterion for identifying types, we used the rate of increase/decrease in the population size; the selection of groups and subgroups within the types was made taking into account the ratio of the coefficients of natural or migration increase/decrease, the prevalence of international, interregional, intraregional migrations or their combinations. Six types of cities with a predominance of population increase or decrease were identified. Migration is the dominant source of population increase, and natural increase is declining everywhere. Stable indicators of demographic development are typical for a limited number of cities and are manifested in those that have vivid competitive advantages – a favorable geographic location, economic growth, a higher quality of the urban environment, image attractiveness. About a quarter of cities do not have the ability to overcome negative trends and transition to demographic growth. The cities close to the Russian capital are losing a competition for the labor resources. Unfavorable manifestations in the demographic situation of the largest cities, including some million plus cities, are found. A comparative analysis of the dynamics of the population size at the beginning and end of the study period revealed the tendencies of the growth of negative symptoms in the demographic development, practically in all the cities under study.

The purpose of the article is conducting a comprehensive urban−rural typology of the southern Russian Far East. The typology was made having regard to foreign approaches in which the countryside and small towns are grouped into types depending on the distance from the main urban centers. In addition to the remoteness, the administrative status of the territory and the population size were taken into account. Municipalities were the spatial units in the study. Nine types of urban−rural areas were identified in the studied region: large urban areas, other urban areas, accessible small towns, remote small towns, very remote small towns, accessible rural areas, remote rural areas, very remote rural areas, sparsely populated areas. The spatial differences of the settlement patterns for the studied region have been revealed. There is the predicted decrease in population and settlements density, as well as the increase in the area of terrain types with the distance from urban areas. In contrast to the “traditional” south of the Russian Far East, the Transbaikal Region is characterized by the accessible, remote and very remote rural areas development as the belts surrounding urban territories. Furthermore, the absence of some urban−rural area types was identified in the eastern part of the south of the Far Eastern Region. This difference is due to the duration of the development processes of Transbaikalia, Priamurye and Primorye. Sparsely populated areas occupy more than half of the studied region area because of poor development of the Russian Far East. There are significant differences in the population and settlements distribution between accessible and remote types of urban−rural areas. This fact might be used to lineate potential group forms of settlement pattern in the region.

Political-geographic processes in the former Yugoslavia region have led to the creation of new political-territorial communities. The nationalities of Yugoslavia who have lived in the same country nowadays are living in Diaspora. Thus Montenegrins, Macedonians, and Slovenians in the Republic of Srpska (Bosnia and Herzegovina) from constituents have become new national minorities. The subject of the research is the position of the new minorities in the Republic of Srpska after the dissolution of the former Yugoslavia. Data on their number and territorial distribution are obtained by analyzing the last census of the population in the Republic of Srpska in 2013. It is also necessary to point to the relationship between the Republic of Srpska and the new minorities, as well as to the relations of the new minorities with their parent states. It is necessary to explore how these minority groups in the Republic of Srpska seek to preserve their ethnic identity and cultural heritage. Studying the Montenegrin, Macedonian and Slovenian associations, the history of their presence, and their association’s programs would reveal ways of preserving ethnic identity and elements of cultural heritage. There is a social, political, and scientific need to address this issue critically, to point to the status of new minorities in the Republic of Srpska, the possibility of their existence as well as the preservation of ethnic identity and elements of cultural heritage.

The changes in the total mineralization, the content of organic matter and nutrients in the water of the largest Iriklinskii reservoir on the Ural River in 2010–2019 are shown. An analysis of the dynamics of surface air temperature and precipitation on the territory of the Orenburg oblast was carried out. The increase in winter temperatures contributed to the redistribution of the intra-annual water inflow to the artificial reservoir. Over the past decade, its share in the winter period has significantly increased by almost 2 times (from 6 to 15%), and during the flood, on the contrary, a slight downward trend was observed. Changes in the components of the water balance led to an increase in mineralization due to an increase in the content of sulfates, hydrocarbonates and the amount of alkaline elements. The decrease in the amount of precipitation in the region at the beginning of the 21st century was the likely reason for the decrease in the volume of spring floods and, as a result, the decrease in the concentrations of allochthonous organic matter, ammonium nitrogen, and silicon. The dynamics of mineral nitrogen largely depended on water content, and the dominant source in the genesis of phosphates was, obviously, intra-water processes. The iron concentration was determined by the magnitude of the flood inflow. The spatial dynamics of the ingredients is due to the morphometric features of the reservoir. The highest concentrations are noted in the upper reaches. The decrease in the content of the main hydrochemical components in the deep-water lower reaches as a result of intra-water processes indicates a high self-cleaning capacity of the reservoir. The results obtained can supplement the already known data on the functioning of aquatic ecosystems in different geographic zones under current conditions of climate change.

The results of the isotopic composition studies (δ13С / δ15N) of phototrophic communities in the karst caves are presented. The caves were rangier by different physical-geographical regions: mountain taiga (Kungurskaya Ledyanaya cave) and mountain humid-subtropical forest (Akhshtyrskaya or Bolshaya Kazchebrodskaya cave and Novoafonskaya cave named after G.Sh. Smyr). The fractionation of carbon and nitrogen stable isotopes were studied in the communities of phototrophic organisms of subterranean landscapes (lampenflora), as well as the influencing of one’s to the soil-like bodies (soloids) under these communities. That is discussed the difference of lampenflora phytomass isotopic composition in compare with terrestrial similar systematic and ecological groups of phototrophs towards enrichment with isotopes 12C and 14N. An increase of interests of light carbon and nitrogen isotopes was also noted for cave soloids in comparison with soils on the day surface. The ratio of carbon stable isotopes varies from –47.3 to –32.4‰ for subterranean ecosystems and from –35.5 to –26.8‰ for control samples (daylight surface). The isotopic composition of nitrogen shows a smaller variation from –8 to –1.8‰—in underground habitats, and from –3.5 to +2.0‰—on the surface. The hypothesis regarding the specifics of gas exchange in subterranean space and biological circulation of carbon dioxide in a semi-closed atmosphere was created. This hypothesis is confirmed by the trend of accumulation of the 12C isotope in lampenflora and soloids with distance from the cave entrance, which is due to the reduction of air circulation. The data of carbon and nitrogen isotope composition for the lampenflora and soloids from karst caves in the different physico-geographical zone are also generalized and systematized in this work, there is a geographical trend, but it is necessary to increase the number of studied objects from different natural zones to confirm this conclusion.

Numerical substantiation of the conceptual position of the native geographical ecology on the genetic unity of the natural zone and geographical landscape is presented. Quantitative assessments of the landscape organization of the boreal ecotone, an ensemble of zonal transitions from the boreal belt to the sub-boreal belt in the East European subcontinent, were carried out on the basis of well-known methodological approaches to the poly-system analysis of the geographical environment. The problem was solved using empirical-statistical models of landscape-zonal connections. The cybernetic model of natural complexes developed by the author as a hierarchical system of their organization was used as a working tool for analysis. Three methodological approaches to poly-system analysis have been implemented: (1) functional, with the allocation of the structures of ecological niches of landscape units in their factorial space; (2) typological, with the differentiation of the territory by groups of landscapes and the analysis of their interaction; (3) hierarchical, using cluster (taxonomic) landscape classification models. Measures of the tightness of connections between various geocomponents in a set of landscape units are obtained, and based on these measures, geo-synergic kernels of parametric homogeneity of zonal geo-spaces are obtained. Specific partial landscape structures are established, formed by the most closely related geo-components and determining the face of landscape-zonal systems. With the help of information modeling, a differentiated assessment of the landscape organization of natural zones (sub-zones) was carried out by operations with equivalence matrices of geo-component blocks. The territorial space of the boreal ecotone and its zonal parts is described by the set-theoretical and cluster models of geo-complex connections. On the basis of quantitative criteria, the contribution of various factors to the landscape organization of the zonal geo-space is estimated. This makes it possible to determine the degree of sensitivity of the landscape structure of a given territory to changes in zonal-climatic conditions, which is directly related to assessments of the stability of landscape-zonal systems in a changing climate.

We calculated the morphometric features of the debris flow basins of the key mountain massifs of the Russian Subarctic’s European sector (the Monchetundra, the Chunatundra, the Volchyi Tundry, the Khibiny, the Lovozerskiye Tundry on the Kola Peninsula and the Ochenyrd Ridge, the Lyadkhe mountain massif, the Nyarmynkhoi Ridge, the Enganepe Ridge, the Malyi Paypudinskii Ridge, the Bolshoi Paypudinskii Ridge and the Kharbeyskii Ridge on the Polar Ural) by means of GIS. We obtained a data on (a) the different order basins watershed area, height, and mean surface slope, (b) talwegs’ length, altitude position and slope, (c) young and ancient accumulation zones area and range of removal of debris flow deposits beyond the limits of mountain massifs. Comparison of basins of different orders in key areas allowed to identify the most typical conditions for debris flow formation in the mountains of the European sector of the Russian Subarctic. Debris flow form in watersheds of the first order (according to Straller–Filosofov) with an area of 0.6 to 3.2 km² and of the second order with an area of 10 to 12 km². The most typical slope values of mudflow thalwegs of the first order are from 90 to 330‰, of the second order from 45 to 100‰. The most typical altitude level of debris flow formation is from 400 to 800 m. In the basins of the first order, the areas of young debris flow accumulation as a rule, are up to 0.08–0.15 km², the areas of ancient debris flow accumulation are up to 0.2– 0.4 km². In the basins of the second order, the areas of young debris flow accumulation are up to 0.1–0.3 km²; of ancient—up to 0.2–1.0 km². The range of removal of both young and ancient debris flow deposits beyond the boundaries of mountain massifs is up to 0.8–1.3 km.

The features of the spatial and temporal distribution of industrial and household waste and return (after irrigation) waters in the European part of the country are considered. The study is based on the data of water management statistics for the constituent entities of Russia and federal districts. Shown is their contribution to the total volume of waste and return water in the European part of the country. The specific indicators of waste and return waters are calculated—the ratio of their volume to the value of river runoff, the area of the region, and the population. The structure of water use is shown taking into account five federal districts, which revealed the predominance of water use for industrial needs in comparison with irrigation and household and drinking needs. The share of polluted wastewater in the total amount of wastewater in the context of federal districts and subjects has been calculated. The predominance in most cases of polluted waste and return water in their total amount compared with the normatively treated is shown. The multiplicity of dilution of wastewater by the resources of the total river runoff was calculated, which may reflect the degree of pollution of water bodies. The features of spatial differentiation are determined, for example, an increase in the load on water resources in the direction from north to south. A decrease in the overall water intake and the volume of waste and return waters in recent decades has been revealed, which, judging by the frequency of their dilution by the general resources of river flow (local and transit), did not contribute to a radical improvement in the quality of water in rivers and reservoirs.

Agro-landscape and ecological zoning of natural forage lands of Eastern Siberia and the Far East was carried out. Based on its results, the spatial distribution of biological and ecological patterns in the Baikalia mountain province of Eastern Siberia and the Far East is characterized for the forecast and planning of agricultural natural resource use and environmental protection in the region. The province covers the northern part of Republic of Buryatia and Zabaykalsky krai, including the North Baikal, Patom, Stanovoe Highlands and the Vitim Plateau. The area of the province is 48271.1 thousand ha. The province has 9 mountain districts, of which 2 are inland basins, where the main arable land and forage land are located. The area of agricultural land is less than 2% of the total area of the province (arable land 0.3%, hayfields 0.4%, pastures 1%). They are located mainly in the southern part of the province. The area of deposits in some basins significantly (sometimes 10 times or more) exceeds the area of arable land. Deer pastures, covering 2708.9 thousand hectares (or 5.6% of the territory), are concentrated in the mountain ecosystems of the northern half of the province. The richest reproducible natural soil and plant resources of the province, including fodder, are promising for the sustainable development of animal husbandry.

An invasive species of Sosnowsky’s Hogweed (Hheraculum sosnowskyi Manden.) currently poses a serious threat to the health, livelihoods of the population and the economy of most regions of Russia. Not fully realized potential of this species is likely to lead to an even larger distribution of Sosnowsky’s Hogweed in dozens of Russian regions. In order to study the features of the current distribution of Sosnowsky’s Hogweed and the trends in expanding its range in the future, an ecological and geographical analysis of the current abundance, distribution potential, and degree of danger of the studied invasive species in Russia was carried out. The distribution potential is determined by the hypothetically possible areas that the species is able to populate, the presence of preferred habitats and trends in their change. The calculations took into account indicators that are significant for the distribution of H. sosnowskyi and reflected in national statistics: the density of roads and railways, the growth rate of road density over the past 10 years, the number of abandoned villages and their trends, the area of unused agricultural land, the density of the river network. The current and predicted distribution of Sosnowsky’s Hogweed in Russian regions is shown on the authors’ maps, reflecting the abundance of H. sosnowskyi, the danger of its distribution in the federal subjects and separately in the Central Federal District under different scenarios for the development of socioeconomic conditions. To date, catastrophic danger threatens five, and very high danger threatens ten Russian regions. In seven federal subjects, this species can potentially populate more than 80% of the territory. The proposed approaches to assessing the distribution of Sosnowsky’s Hogweed as an invasive species will allow visualizing and modeling the results of its long-term monitoring, which will contribute to the adequate and timely development of measures to control the number of a dangerous alien species.

Outdoor tourism and recreational activities highly depend on the meteorological conditions. In this study, we assess the suitability of weather conditions for various forms of outdoor activities and recreation in the Russian part of the Caucasus. 11 weather stations that represent different tourist regions of the Caucasus (seaside, foothills, and mountains) were selected to analyze the suitability of weather conditions for various types of outdoor recreation. A Weather Suitability Index (WSI) was used to evaluate climate suitability for tourism and open-air recreation. An adaptation problem arises when arriving at a resort since most tourists come to the resorts of the North Caucasus from other regions of Russia, the climatic conditions of Russia are very diverse, and the “home” conditions can be very different from those experienced at a place of stay. An Adaptation Strain Index (ASI) was used to assess the level of adaptation that occurs during rapid movement from Moscow, St. Petersburg, Murmansk, Yekaterinburg, and Irkutsk to the Caucasus region at different seasons. As usual, the high tourist season in the study region is observed in the summer months. The results of the study show that passive forms of recreation (sun and air bathing) are preferable from June to September at the locations represented by stations on the coast. For active types of recreation, the Caucasus region is suitable throughout almost the whole year. Moreover, in the mid-seasons, less adaptation is required when moving to the place of stay. This fact offers great opportunities for developing various forms of tourism in the region, and not only in the summer months.

The work solved the problems of analyzing the change in the channel of the Volga near Saratov in the second half of the 19th—early 20th century, attempts to solve the problem of shallowing and assess the effectiveness of the measures taken. The change in the course of the Volga was studied by a retrospective analysis of the cartographic material. The experience of fighting the shallowing of the river has been studied by the methods of historical geography—analytical-synthetic and retrospective mapping. It was established that the reshaping of the channel led to a shift of the fairway k from Saratov to the left bank with a simultaneous shallowing of the river channel near the city. As a result, the conditions for the functioning of the river port and urban water intake were complicated. Shallowing was caused by a combination of natural and anthropogenic factors. Contradictions in the views on the problem of shallowing the Volga between the public and the authorities were revealed: the Saratov self-government fought for the unimpeded approach of ships to the city pier, while it was more important for the state to provide a transit route. Measures aimed at changing the course of channel processes in order to maintain navigation have been studied. It was found that at first they tried to provide an approach to the city from the main channel of the Volga by a combination of deepening the bottom and creating dams in the riverbed, but since 1900 they abandoned the second method and only deepened the fairway. The maintenance of navigation was carried out with the help of constant dredging with dredgers, but, nevertheless, in some years, the connection of the city piers with the main Volga’s riverbed was interrupted. The reasons for the low efficiency of the measures were the lack of a strategic plan for the implementation of works, incorrect hydraulic engineering solutions, insufficient funding and inconsistency of interests of local and central authorities. The problem of river navigation was solved only in the early 1960s after the creation of the Volgograd reservoir. Already in the 21st century, there is an active development of channel processes and there are problems typical of the period before the creation of the reservoir.

The article is devoted to the history of the creation of economic and geographical descriptions of USSR state planning regions (districts) in the second half of the 1920s, shortly after the appearance and regular improvement of the country’s zoning based on the GOERLO plan for national economic recovery and development. This is the first experience of such publications in the Soviet period. According to various sources, seven main series were identified that were published between 1925 and 1930. At the same time, a significant number of brochures were published for three series (more than 10 for each), for two series—four or five brochures each, and two series only with a description of one district. Brochures written by various authors, based on the guidelines of a particular series, somewhat differently reflected the features of the development of the population and economy of the territories described, although they overlapped to a large extent. In most cases, the authors were geographers, most of whom were economic geographers, but there were also specialists in other areas. The series of descriptions published in USSR regions are important evidence of the active popularization of knowledge about the country. They were designed for a different audience—specialists and students in geography, employees of local authorities, public, including separately for schoolchildren. Probably, the experience in the second half of the 1920s of economic and geographical descriptions published was the reason for N.N. Baranskii’s initiative in the same years of creating series of economic-geographical monographs on the regions and the project “Great Geography of the USSR,” which to a certain extent could be realized only decades later.