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The attempt to analyze morphological, genetic, and typological landscape-analogs in Steppe Eurasia enveloping the vast transcontinental space of Inner Eurasia from the Danube basin to the Amur River basin has been made for the first time in the paper. Despite considerable provincial differences of a latitudinal row of steppe and forest-steppe regions connected with a degree of climate continentality, geological-geomorphological peculiarities, high altitude of low-laying, elevated and upland plateau-like plains within the all steppe Eurasian space, thanks to the comparative-geographical method, we can define landscape-analogs of a different type that are distant from each other at thousands kilometers. Steppe landscapes of Eurasia have a long and rich history of economic development, having the standard features of zonal nature management, anisochronous in time for hundreds, sometimes thousands, years. Steppe nature management experience in different longitudinal sectors can be used to solve zonal ecological problems of which countries and regions of Steppe Eurasia have met.

The cartographic data on anthropogenically transformed areas within the Ural River basin were analyzed to reveal the features of their spatial heterogeneity. The characteristics of the distribution and long-term development dynamics of the main types of nature management, settlement system, transport infrastructure facilities, and large industrial plants were taken into account. The main factor of the spatial distribution of various types of economic activity was found to be the difference in the natural-resource potential due to the latitude-zonal and geological-geomorphological diversity of landscapes in the drainage area. It has been found that the most deeply transformed areas are located along the Ural River valley, which is due to the existing settlement system and the presence of guaranteed reserves of water resources. An important factor of the transformation of the Ural River drainage area is the mining industry, which forms large industrial agglomerations and serves as the main source of pollutants that enter river water.

Long-term variations of ecological and hydrological parameters governing the natural reproduction of sturgeon are analyzed. It was found that long-term variations of hydrological characteristics are taking place against the background of cyclic development of phases with different water abundance and transformation of the annual redistribution of runoff. The contribution of long-term runoff regulation by the Iriklinskoe Reservoir to water regime variations in the Ural River is considered for its middle reaches. A conclusion is made regarding the need to restore the sturgeon herd in the Northern Caspian Sea. Recommendations are made regarding the priority measures for preserving the potential of sturgeon spawning grounds in the middle reaches of the Ural River.

The purpose of these studies was to determine the current trends in the change in the meteorological conditions of the growing season of field crops in the post-virgin regions of the Urals and Western Siberia and to identify their regional characteristics and influence on the yield of spring wheat. The research object was information on the average daily air temperatures, precipitation, and spring wheat yield. When processing the digital material, the generally accepted methods of statistical analysis were used. It has been established that current trends in an increase in climate aridity are accompanied by a significant change in the growing conditions of field crops, especially in the post-virgin areas of the Orenburg region. The steppe natural and climatic zone of the Omsk region, with all the humidification conditions’ intensity, is characterized by more favorable hydrothermal indicators and their temporary stability. The most significant dependence (r = 0.75 – 0.79) of the yield of spring wheat on hydrothermal conditions was found in the Svetlinsky district of the Orenburg region, which is characterized by the least amount of precipitation (139 mm) of the active growing season. The results obtained indicate the feasibility of developing and implementing adaptive moisture-saving agricultural technologies and techniques focused on the rational use of water resources in a changing climate.

One of the main directions of the modern study of landscape structure is the timely updating of the structural and dynamic features of geosystems, taking into account the degree of anthropogenic load. This article examines the historical prerequisites for the development of ideas about the physical and geographical division of Orenburg oblast. A geoinformation analysis of remote sensing data has been carried out using neural network algorithms based on self-organizing Kohonen maps in order to compare the structure of natural boundaries with the actual structure of natural–anthropogenic complexes. For this purpose, we have calculated quantitative indicators (namely, the area of the physical-geographical region, the number of classes (types of tracts), the number of landscape contours, the average number of contours in a class, the average area of one contour, the density of contours in the physical-geographical region, the coefficient of complexity, the maximum possible complexity of a landscape, the absolute organization of a landscape (a measure of imbalance), the relative organization of a landscape, and the coefficient of landscape fragmentation) and indices of differentiation of the landscape structure (coefficients of entropic complexity and Shannon diversity and Ivashutina–Nikolaev, Odum, Gleason–Margalef, and Simpson indices of heterogeneity). Moreover, schematic maps of the region’s territory have been compiled, reflecting their spatial distribution over landscape areas. Based on the results of the study, tendencies of changes in the landscape structure of Orenburg oblast have been determined. They include changes in the degree of contouring of geosystems, dynamics of the severity of interlandscape boundaries, anthropogenic dispersion of geosystems, and the degree of dominance of individual elements of the landscape. Differences in the tendencies of changes in the landscape structure of forest-steppe, petromorphic, and hydromorphic geosystems, in comparison with the arid steppe landscapes prevailing in the region, have been identified depending on the degree of agrogenic and technogenic transformation.

An analysis of interannual variability in the surface air temperature of the summer season for individual regions of Russia, as well as for most of its territory between 1930 and 2020, has been performed. For the analysis, average daily air temperature data from 526 stations of the Roshydromet observation network and the ECMWF-ERA and NOAA-CIRES reanalyses are used. Based on the meteorological station’s observations and on the calculated number of days with extreme temperature values, the spatiotemporal distribution of ground air temperature for some summer months and for the summer season as a whole are evaluated. It is established that, over the past 60 years, the number of days with extremely high temperatures increased by a factor of 1.5 in most of Russia, with the largest number of such days occurring in July. Both the secular records of average monthly air temperature in the summer months as well as the absolute maximum temperature are established to be extreme. For the 30-year-long periods of instrumental observations, the maximum air temperature exceeded +39°C in some regions of Russia. It is shown that abnormally hot years have been unprecedented in the history of meteorological observations in Russia in terms of both record temperature values and the duration. The temperature regime of most areas of Russia is characterized by a spatiotemporal inhomogeneity. The analysis of temporal variation of extreme air temperature values suggests that the circumpolar and high-mountain areas are characterized by a fall in temperature in the summer months, whereas the temperate climate zones and southern regions of the country undergo a rise in temperature. It is established that, at the end of the 20th century and the early 21st century, the number of days with extremely high surface air temperature increased in the territory of Russia, which may be a precondition for the occurrence of dangerous meteorological phenomena.

To detect the current challenges to spatial development, we attempted to identify and theoretically explain the basic notions of stages of challenges’ formation. Such concepts as “challenge,” “danger,” “treat,” and “risk” were defined. The revealed determinants were classified according to five blocks of challenges, and multi-scale levels of their formation were detected. Eighteen region-subjects of the RF steppe mesoresion were chosen as the territory of the study. The methodological approach to see challenges using assessments of the rate of increase (2019 to 2010) was offered. There are 28 principal indicators grouped in blocks: inter-regional contrasts (economic development and a state of the social sphere), the imbalance of the natural-ecological and socio-economic frameworks, a compression of developed space, the formation of seats of potential ecological catastrophes, and threat of food security. The table of the rate of increase was designed. Based on this table, we could reveal prevailing negative processes and increased risk of challenge’s emergence in every region. According to the study results, the examined challenges in the least degree emerged in the Republics of Adygei and Kalmykia. In the most degree (or more evident), they displayed themselves in the Republic of Bashkortostan, Volgogradskaya, and Chelyabinskaya oblasts. Some suggestions were stated to work out long-term steppe region development plans in the frame of economic-geographical and socio-economic research.

The article deals with the study of intra-annual discharge distribution of the Ural River basin runoff. Norms, coefficients of variation, and average standard deviations of monthly, seasonal and annual runoff, as well as maximum and minimum flow and the tendencies of its changes, were determined for rivers in the area. The average and maximum water discharge spring high water and the ratio of maximum and minimum monthly and the annual runoff were calculated. Based on the wavelet transform method applied to the river flow data of the area under study, a cyclical pattern of water availability was identified. Moreover, the closeness of the correlation between average monthly expenditures and annual average water consumption, as well as the average monthly water costs was revealed. The statistical significance of the detected correlations was defined.

Among all agrarian-social megaprojects realized in the steppe zone, the Virgin Land [Tselina] (1954-1963) and the Land reform of the 1990s exerted the most considerable influence on the state and properties of current agro-landscapes. It was the projects of opposite orientation which every on its stage set the highest in history pace of the landscape dynamics in the steppe zone. The consistent impact of these megaprojects, one of which practically annihilated steppes, and the other created terms to realize steppe restoration potential, allows considering them in totality as the united experiment of the global scale for revealing and evaluation of steppe self-restoration. Thanks to this experiment in the steppes of Eurasia, new dynamic space – after virgin land was formed. Using new data, including field studies and discovered novel factors, we estimated the Virgin land campaign’s consequences and the Land reform. A further fundamental generalization of these megaprojects’ effects, landscape, and scientific heritage required developing an adaptation of steppe land use was conducted as a response to climatic and other current challenges.

In the XX century, the USSR developed and realized agrarian-social megaprojects to arrange steppe agrolandscapes and control water resources to resist droughts. The first ideas emerged in the XIX century; its realization happened in the second part of the XX century. The study of the interconnection of steppe egaprojects and their system consequences is urgent under the projective style of development. An analysis of the integral impact of megaprojects on the steppe zone has a special significance, at the first line, to reduce the ecological expenses of future projects. We paid particular attention to the general conclusion taking into account little known and new facts. It promoted to specify a role and significance of fundamental science in developing ideas and in the practical realization of megaprojects, their scientific and organizing heritage, first of all for steppe science. We emphasized the scientific-organizing heritage of a megaproject of the river flow transfer and discussion about its renaissance. The project’s fundamental idea left a deep imprint in the development of real science in Orenburzhie dealing with the actions of steppe conservation has turned 150 years; official closing of the Soviet project of redistribution of the Ob water flow has turned 35 years. Due to increasing irrigation of the Arctic accompanied by the Arctic Ocean desalination that is disastrous for the climatic system and an increase of a water deficit in Central Asia, the idea of redistribution of the water runoff becomes more topical. The most typical steppe region-Orenburgskaya oblast is an epicenter of all steppe megaprojects; it is considered a model according to the evaluation of their consequences and heritage.