The article presents a methodology for large-scale mapping of settlements to study an urban shrinkage phenomenon, which becomes evident through depopulation and structural transformation of housing stock. The work is of immediate importance because the intraurban spatial differentiation of shrinkage processes is insufficiently studied, particularly for the single-industry towns. The authors aim to develop a mapping methodology integrating high resolution remote sensing data (WorldView-2, GeoEye-1, Pleiades-1), housing stock statistics (AIS PLC “FRT”), municipal master plans, the OpenStreetMap vector base, and field surveying data. The methodology includes analyzing urban development dynamics, the state of housing facilities, remoteness from city centers and core industrial enterprises, as well as data verification through sociological surveys and visual inspections of buildings.   The single-industry city of Kirovsk in the Murmansk region was selected for mapping. The mapping results revealed a “doughnut-shaped” pattern of urban shrinkage: the maximum housing vacancy was found in peripheral areas, such as the 25th km (Kukisvumchorr) district. It was found that nearly 10% of residential space in the area remains unoccupied, compared to about 7% in the city center. Key factors of depopulation include the aging housing stock, remoteness from public and cultural centers, and distance from population hubs. Data visualization confirmed a contradiction between plans for extensive development and the actual reduction of housing. The analysis demonstrated that the proposed methodology is effective for identifying spatial patterns of urban shrinkage. However, limitations were noted, including challenges in analyzing individual housing and dependence on temporal density of satellite data coverage. The results emphasize the need to adapt territorial planning strategies to account for intraurban differentiation of demographic processes. The study contributes to the advancement of urban cartography methods by offering tools for monitoring structural crises under the depopulation processes.

Soil maps of cities, as a new branch in soil geography and cartography, differ both in content (presentation of soils) and methodology of their compilation. The review analyzes 23 maps of 18 cities of the Russian Federation, published in journals, monographs, dissertations, and atlases of cities. Historical, social and economic factors turned out to be more significant for the formation of urban soils than the natural ones. The compilation of urban soil maps is based on city plans, space images, maps of natural soils, geological formations and   Quaternary deposits, relief, as well as terrain observations, i. e. the descriptions of soil profiles. The maps were analyzed by the following aspects: map content, number of legend units, and organization of the legend   as a reflection of the map’s concept. The predominant part of maps is compiled using the M.N. Stroganova classification system which focuses on the functional zones of the city. Later, elements of the classification of Russian soils were introduced into map legends. Structured map legends reflect the authors’ concepts regarding the arrangement of a city soil cover: the priority of natural factors and modifications of natural soils or the priority of anthropogenic factors, namely, functional zones. A grouping of soils in the legend by the functional zones of the city differs in the composition of functional zones and the details of their soil content. There is an experience of compiling maps in terms of the theory of soil cover structures. The analysis of soil maps of Russian cities has shown their significant diversity in terms of content, scale, methods of presentation, as well as a trend to more complicate content, i.e. the increasing volume of information, the systematization (identification) of spatial patterns and the refinement of cartographic units using the advanced technics. The methods of cartographic representation of urban soils and soil cover structures are considered.

The Ivankovskoye Reservoir is a shallow reservoir of the valley-basin type. Low banks and overgrowing of shallow waters cause difficulties in determining its coastline and water surface area. In the Order of Rosvodresursy dated 31.05.2019 no. 125, the area of the reservoir is indicated as 316 km², while the earlier   publications gave the value of 327 km² . However, even a preliminary analysis of remote sensing data proves   that the actual area of the Ivankovskoye Reservoir differs significantly from those mentioned in publications. The work is devoted to clarifying the water surface area of the reservoir using satellite data. The available cartographic materials and remote sensing data, starting from the filling of the reservoir to the present were assessed. According to retrospective data, it was established that the area of the reservoir on the maps compiled in the first years after filling was significantly larger than on later maps, which show a significant decrease of the part of the Shoshinsky reach. The total area of the reservoir is equal to or less than the reference values. The first available satellite images of the Ivankovskoye Reservoir water area date back to the early 1970s, which allows estimating the area of the reservoir from that period to the present. The Sentinel-2 satellite images were used for interpretation and analysis. Based on remote sensing data, the values of the actual area of the Ivankovskoye Reservoir water surface were identified at different water levels during the period of no ice formation. According to the obtained data, the actual area of the reservoir at levels close to the normal backwater is in most cases within 220–240 km2 , which is 22–31% less than in the interpolation table of the surface area of the Ivankovskoye Reservoir at different water levels given in the “Rules for the Use of Water Resources of   the Ivankovskoye Reservoir on the Volga River” (Order of Rosvodresursy dated 31.05.2019 no. 125). The use of an overestimated water surface area of the reservoir in research and design projects distorts the assessment of the reservoir’s impact on the environment and other ecological and hydrological characteristics. The paper provides an example of calculating methane emissions from the Ivankovskoye Reservoir, which turned out to be 20–25% lower based on the adjusted area. It is recommended to clarify the morphometric characteristics of the Ivankovskoye Reservoir in the coming years.

In recent decades, climate change and human activities increasingly impact rivers, which could provoke or enhance the dangerous riverbed processes, e.g. riverbank erosion. The availability of satellite images with   global coverage provides ample opportunities for the study of horizontal channel deformations and their quantitative assessment. This became the basis for an active development of remote sensing methods that could be widely used for all the variety of river sizes and their channel types. The article deals with the general analysis of dangerous fluvial processes (riverbank erosion) on the lowland rivers of Western Siberia using modern methods of their investigation. Satellite images of CORONA, Landsat and Sentinel were used for the analysis, which make it possible to detail changes in banks with high accuracy by applying both traditional (manual) and semi-automated GIS tools-based methods of image interpretation and digitizing. The results showed that the rate of stream-bank erosion varies depending on the natural conditions of riverbed formation, the hydrological   conditions and the river size. The rate of stream-bank erosion on the Ob and Irtysh rivers varies primarily due to the local factors, such as the dispersion of runoff in the branches, the influence of indigenous banks, the   spread of channel types and morphologically homogeneous areas, the parameters of their shapes, etc. The highest erosion rates (2–3 m/year or more) among the large and medium-size rivers were recorded for the Tom and Chulym rivers. But in general, the rivers of Western Siberia are characterized by relatively low stream-bank erosion rates, which is due to the natural features of the region.

The paper presents the study of spatiotemporal variability of surface sediment flow and the assessment of its influence on suspended sediment yield in the outlet section of a small river basin, i.e. the upper part of the Vorskla River (Belgorod Oblast), with an area of 1,85 thousand km². Time series of average annual suspended sediment yield from 1960 till 2021 were analyzed according to the data for the Kozinka – Vorskla gauging station (116 km from the river source). High heterogeneity of the sediment yield was found, during the period under review it decreased by 6,7 times (according to average values, from 0,27 to 0,04 kg/s). It was found that the   surface (basin) component predominates in the sediment balance, which is predominately soil matter eroded from the arable lands of the agriculturally developed catchment areas. The content of suspended sediment in river runoff has a greater response to changes in the intensity of snowmelt erosion than the rainfall one. However, a critical decrease in the snowmelt runoff layer caused by the climate changes of recent decades has led to   a decrease in the contribution of snowmelt erosion to annual soil losses. As a result, suspended sediment yield in the outlet section of the river has decreased. A quantitative assessment of rainfall erosion rates using the WaTEM/SEDEM model showed that the main source of sediment is plowed areas; annually 228,8 thousand tons   of soil matter are removed from the arable lands. At the same time, 76 thousand tons enter the river network, i. e. 66% of soil material mobilized by rainfall runoff accumulates within the catchment area. The dynamics of river flow regulation by ponds is considered. To date, sediment yield from 62% of the catchment area is intercepted by ponds. Over the past 40 years, the interception area of solid runoff has increased by 30%, and the volume of sediments entering the unregulated river network has decreased by 47%. The ponds and the upperlying gully network hold 61,4 thousand tons of sediments, which is 81% of the surface erosion in the basin. Thus, the climate-related decrease in snowmelt runoff from the catchment area, combined with the reduction of water yield during floods and the water management measures to regulate river flow by ponds, has resulted in a sharp reduction of suspended sediment discharge since the 1980-s and their further gradual decline.

Accumulation of sediments in the upper sections of a fluvial network is among the main evidences of accelerated erosion on the slopes during the period of agricultural use of the catchment area. The study of the vertical distribution of technogenic ¹³⁷ Cs within the Chernobyl-induced pollution areas makes it possible to estimate the intensity of accumulation over the period after its fallout. The paper presents an attempt of assessing changes in sedimentation rates in the bottom of a small dry valley (balka) with totally plowed catchment area in the southern Tula region. The dynamics of deposition of soil erosion products was identified for the periods 1986–2010 and 1986–2023 by repeated layer-by-layer sampling in the bottom and determining the depth of the Chernobyl-induced peak of ¹³⁷ Cs concentration. Manual drilling was also carried out in the valley floor to determine the thickness of agrogenic sediments that began to accumulate since the end of the 17th century. The results of the study showed that in the post-Chernobyl stage the accumulation was more intensive in comparison with the entire period of agricultural use. The sedimentation process is characterized by significant spatial and temporal heterogeneity. An increase in the rate of accumulation is observed in the upper reaches of the valley and in the bottom narrowings (from 0,4–0,7 to 1,6–3 cm per year). No increase in the depth of the accumulated stratum was recorded in the lower and estuary parts; there is a predominance of overflowing and removal of previously deposited material away from the catchment area. On the average, 39,9–42,3 tons of sediment accumulated in the balka annually after the Chernobyl accident, which is more than twice the average for the entire period of economic development (19,3 tons per year). In the future, while maintaining the observed trend, the slope of the bottom will become steeper, thus activating the existing bottom cuts and producing new ones. The experience gained has shown that repeated radiocesium studies could be an important tool for assessing long-term changes in erosion-accumulative processes and sediment balance within catchments with high anthropogenic load.

The article concerns changes in the composition and distribution of alien vascular plant species in the vegetation cover of the Ustya and Kokshenga rivers interfluve (middle taiga of the Arkhangelsk region) in the 20th – early 21st centuries. The article compares the data of own studies (1992–2024) and the flora data by A.I. Perfil’ev (1925). It was found that the current list of alien plants includes 56 species belonging to 22 families and five life forms. Representatives of the Asteraceae, Fabaceae, and Rosaceae families predominate; among the life forms, annual and perennial grasses are most widely represented. According to their natural ranges, more than a half of alien species come from the southern and western regions of Europe, the Mediterranean, Asia Minor, and the Caucasus. The main ways of alien species penetration into the middle taiga area are, first of all, intentional introduction and subsequent spread of plants from plantations, as well as unintentional distribution along railways, highways and as a result of the transportation of agricultural products. Changes in the composition of alien species over almost a century have showed a significant increase in taxonomic diversity. The total number of species has become almost one and a half times larger, and the number of families increased by 36%. The number of aliens from North America increased threefold, and plants from East and South Asia have appeared. In terms of penetration and spread, transport routes, especially railways, have acquired greater importance. More than 30% of alien species grow now in natural communities (secondary forests, meadows and overgrown fallow lands), which is twice as much as at the beginning of the 20th century. Other species grow in disturbed communities, along roadsides and field edges, as well as in old settlements. At present 16 species of alien plants identified within the studied area are on the lists of invasive species according to the Black Books of the Central Russia and neighboring regions. Therefore they are of a real threat to the biodiversity of natural communities.

Possible application of the concept of cascading landscape geochemical systems (CLGS) in relation to islands with active volcanoes is analyzed. The object of the study is the Matua Island with the Sarycheva volcano, which is the most active within the Kuril Islands. The structure of the island’s CLGS has three altitudinal levels which differ in morphological and lithological base, exogenous processes, vegetation cover and the elements’ migration conditions. It was found that the main lateral flows connecting all levels are the gravitational displacement of tephra, underground runoff with discharge in the lower level at the contact of marine terraces, as well as volcanic mudflows. The surface runoff is almost completely absent, due to high permeability of the soil-pyroclastic cover; as a result, there are no typical catenae associated with water runoff. It is shown that the volcanic CLGS is characterized by pulsing functioning and different types of lateral flows during and between the eruptions. During the period of volcano activation, aerial and gravigenic flows, such as tephra deposition and associated pyroclastic flows and waves, lava flows, gas emissions and lahars, prevail, the solid matter is forced into the mechanical migration. The flows connect the geochemical landscapes of all levels, i.e. upper, middle and lower, and reach the adjacent marine area. During the periods between eruptions, the role of modern exogenous processes, namely avalanches, mudflows and rock falls, and underground water increases; new lateral connections are being formed within the island CLGS. The coastal zone is a characteristic structural element of the CLGS of all volcanic islands. Specific features of its structural and functional organization are determined by multidirectional flows of matter with different chemical composition from the volcanic core and from the ocean, which results in a heterogeneous and mosaic landscape-geochemical structure.

Sediment dynamics in alpine catchments is highly variable both in time and space which should be considered in nature management. The study deals with investigation of the alpine catchment of the Donguz-Orun Lake, located on the northern slope of the Central Caucasus. We followed a morphodynamic approach to assess the denudation rate, which was supported by sediment delivery ratio assessment and two independent methods to verify the results. It was found that about 29,300 m³ of material is mobilized annually by the background exogenous geomorphologic processes in the catchment, corresponding to a local denudation rate of 2,2 mm/year. However, with an average sediment delivery ratio of 58%, only about 17,000 m³ reaches the catchment outlet, corresponding to the basin-wide denudation rate of 1,3 mm/year. Most of the sediment load in the lake basin is supplied by fluvial processes, predominantly gully erosion and sheet wash, as well as rock falls, glacial, and fluvio-glacial processes. Verification by independent methods, including estimation of sediment volume in the lake basin and the sediment fingerprinting technique, showed that used approach did overestimate the basin denudation volume by about 3000 m³ . The total denudation of the catchment under study exceeds the average value for the high mountain zone of the Alps.

The flood protection of Yakutsk includes 75 km of dams, covering about 40% of the left-bank part of the valley bottom (270 km² ). The dams reduced the width of flooding in the Yakutsk area by 1,3–5 km (by 15–30%). The construction of the protective perimeter is accompanied by the development of the floodplain and the transformation of its urochisches. Four types of basins have emerged on the floodplain. The first type is a regularly flooded riverbed zone. The flood flow transformation is local there; meadow and forest complexes of the floodplain are preserved. The second type includes the central floodplain areas, which have preserved the hydraulic connection with the riverbed. The probability of their flooding has decreased by 2–3 times. They dry out, their swamps and hydromorphic complexes degrade, meadows are being drained; pasture digression has increased, and the floodplain is actively being built up. The third type is isolated, dammed pools. Depending on the water balance, they undergo drying or water logging. In the residential area water logging prevails, which is facilitated by the disruption of the network of floodplain hollows blocked by dams. Lack of the flowing worsens the drainage of the floodplain: flooding of quarters is common; water accumulates under buildings, destroying piles and foundations, which lead to accidents. The fourth type includes the basins of small rivers flowing through the floodplain. Currently, their flooding is limitedly possible; drying contributes to the spread of dry and steppe meadows on the slopes of low ridges and into the bottoms of hollows. The pastoral use of the floodplain has led to the replacement of forest urochisches by meadow-shrub communities; however, the restoration of forests and woodlands takes place around new rural settlements. Non-flooded areas are being built up. During further development of the floodplain, not only water protection measures should be provided, but also environmental protection measures and measures to improve floodplain areas leaving the flooding zone

The ecological and geographical structure of bird population on the Onekotan Island was analyzed using the technique of route count along the transects of unlimited width. The avifauna of the Onekotan Island forms under the system of general zonal-landscape and altitudinal-belt patterns and unites ecological groups of marine and terrestrial species, including mountain ones (n = 7). The zoogeographic originality of the avifauna is due to a combination of elements of the Pacific, Siberian, Far Eastern island, and Arctic faunistic complexes, as well as Siberian-American and widespread species. The species richness, bird population density, and abundance of most species decrease with altitude. There are 26 species in the avifauna of the forest belt, 17 in the subalpine belt, 14 in the alpine belt, and 29 species in the marine and coastal areas, with population densities of 559, 306, 221, and 129–223 ind./km², respectively. Dominants or subdominants in the population of terrestrial habitats include the Buff-bellied Pipit, Brown-headed Thrush, Siberian Rubythroat, Middendorff’s Warbler, Arctic Warbler, and Pine Grosbeak. Seven species numerically dominate in the population of the marine area, namely Harlequin Duck, Red-faced Cormorant, Slaty-backed Gull, and Pigeon Guillemot (in the coastal part), and Northern Fulmar, Common Guillemot, and Tufted Puffin (at a considerable distance from the coast).

The purpose of the article is to describe the current stage of the Astana agglomeration development, including gradients between the agglomeration center and its surroundings, based on official statistics and the results of 2015 and 2024 sociological surveys. Despite the increasing development coefficients the capital agglomeration is still coming up mainly due to the rapidly growing capital city itself with a rather slow development of the suburban area. The main contributor to the population growth is migration while the natural growth is stable, with higher values found only in the capital and some of the immediate suburbs. The migration attractiveness   of the agglomeration is limited to Astana, the satellite town of Kosshy and the nearest Tselinograd district. The territories outside the 30-km accessibility zone are characterized by stable depopulation. So far, the capital does not stimulate rapid economic development of the suburbs, where the agro-industrial complex and services related to the construction industry are developing. Despite the persistently large gap between the capital and the surrounding settlements in the level of income of the population, labor-oriented commuting is still developing rather slowly. According to the results of sociological surveys, there are no significant changes in the access time of Astana from the suburban settlements because of insufficient transport connectivity between the capital and its surroundings. As the survey data show, the low availability of places of employment and services in the suburban zone leads to a slight increase in the intensity of labor-oriented commuting, which retains a center-periphery character. The delivery of multi-apartment housing mainly in the capital itself and in new microdistricts of the town of Kosshy has become a marker dividing Astana from its predominantly rural suburbs. In them, the new housing is mainly delivered by individual developers and concentrates in municipalities directly adjacent to the capital. At the same time, the infrastructure development and municipal improvement of both new and old residential areas leave much to be desired, which was noted by respondents during sociological surveys.

For the first time in Russia the study provides a comprehensive analysis of ethnic contact zones (ECZ) in the Moscow region using data on the location of foreign migrant users from the mobile operators. The B.M. Ekkel’s Index of Ethnic Mosaicity (IEM), tailored to the specific features of cellular data, has been used to identify the ECZs. Previously, the index has been primarily calculated for countries and regions. It was not applied at the intra-urban and intra-agglomeration levels because of the lack of reliable statistical databases. The high spatial resolution of cellular operator data allowed for the consideration of interethnic contact density at the level of localities measuring 500×500 m². As a result of the analysis, approximately 60 ECZ were identified in the Moscow region, which differ significantly in their spatial and functional characteristics. Most of these areas are located in or near Moscow or in the closest urban districts. A typology of ECZ is proposed based on the leading factors of their origin. About one-fifth of all ECZ coincides with major transport hubs, such as airports, bus and railway stations, and the intersection of major highways. Approximately the same number of ECZ is in the residential areas of Moscow and its satellite cities, with affordable housing and good transport accessibility to the center of the agglomeration. Another common type of ECZ is formed in the areas of active housing development. Specific types of ECZs associated with social, business, and cultural activities of foreigners have also been identified near large universities, diplomatic missions, and religious sites. Finally, the development of the largest ECZ (Novomoskovskaya, Yugo-Vostochnaya, and Yuzhnoportovaya) could be attributed to several factors at once, making them a specific complex type of ECZ. In addition, other parameters such as the area, the amount of potential migrant contacts, and their intensity within a given territory were taken into account. It is believed that the developed approach to ECZ delimiting and analyzing may become one of the tools for geospatial analytics of ECZ and monitoring risks of inter-ethnic conflict at a local level.