Izvestiâ Rossijskoj akademii nauk. Seriâ geografičeskaâ

The results of a comparative study of the changes in the flow of the large rivers of the Russian Plain (Volga, Don, Northern Dvina, Pechora, Neva rivers), Siberia (Ob, Irtysh, Yenisei, Angara, Lena, Vilyui rivers) and the Far East (Amur River) under conditions of modern global warming and during the period of scenario anthropogenic climate changes in the 21st century are presented. It is based on a comparison of the annual and seasonal river runoff of the reference period and the period of modern global warming; calculations based on the monthly water balance model developed at the Institute of Geography of the Russian Academy of Sciences; estimates of changes in annual river flow obtained by the method of the average long-term annual water balance and atmospheric precipitation and evaporation data calculated within the framework of the CMIP5 program on an ensemble of global climate models for periods of modern and scenario global warming. During the period of modern global warming, compared with the previous base period, an increase in annual runoff and runoff of the main hydrological seasons was observed on the Volga, Kama, Don, Northern Dvina, Pechora, Ob, Irtysh, Yenisei, Angara, Lena and Vilyui rivers, especially noticeable in winter, as well as in summer-autumn hydrological seasons. Whereas, on the Don, along with the most significant of all the rivers considered, the relative increase in winter runoff, as well as a noticeable increase in summer-autumn runoff, the greatest decrease in snowmelt flood runoff, as well as annual runoff, was revealed. The coincidence of the sign of changes in the annual runoff of the Volga, Don, Northern Dvina, Pechora, Ob, Yenisei, Lena and Vilyui rivers during the period of modern global warming, calculated from observations and the equation of water balance using atmospheric precipitation and evaporation data obtained by averaging the results of calculations on the ensemble of global climate models of the CMIP5 program, has been established. Relative scenario changes in the annual runoff of the Volga, Neva, Northern Dvina, Pechora, Ob, Yenisei, Lena, Vilyui, Kolyma and Amur rivers in comparison with the runoff of the base period correlate quite closely with the corresponding changes in annual atmospheric precipitation amounts, and scenario changes in total evaporation with changes in annual air temperature.

The results of 5-year observations in the warm season of the year (from mid-April to early November) on the chemical composition of natural waters in the system atmospheric precipitation — undertree water — soil water during a change in the precipitation regime in the catchment area of Gusinoe Lake on the Valdai Hills are summarized. According to Selyaninov’s hydrothermal moisture coefficient, three periods of moisture supply were identified: dry, sufficient hydration, and excess hydration. The article examines the distribution of precipitation intensity during the inter-sampling periods. Changing periods of moisture does not affect the type of precipitation and undertree water (hydrocarbonate type I, according to Alekin), however, the predominant cation changes from calcium to potassium. The dry period is characterized by maximum mineralization values in the system atmospheric precipitation — unedtree water — soil water, which is due to the washing away of a large amount of dust accumulated in the ground air and settled on the crowns of trees. During the period of excess moisture, the lowest values of mineralization of atmospheric precipitation and sub-canopy waters are observed (6.2 and 8.3 mg/L, respectively). When the dry period is overly humidified, the pH value of atmospheric precipitation decreases, and the redox potential increases. The change in the pH values of soil waters is influenced by the content of organic acids (correlation coefficient = 0.8). It was revealed that during the dry period and the period of excessive moisture, the intake of calcium into soil waters mainly determines the biotic factor, as well as the intake of potassium in the subsystem undertree waters — soil waters.

The representativeness of the federal network of nature protected areas (PAs) (108 state reserves and 66 national parks of the Russian Federation) in terms of soil diversity was calculated based on the Soil Map of the Russian Federation (1 : 2.5M scale) by using geoinformation analysis. The composition of the soil cover was analyzed for groups of genetically similar soils. The areal and typological representation of soil diversity in PAs in 2022 was evaluated in comparison with the corresponding indicators in 2012. Currently, 2.6% of the soil cover area in Russia is preserved in federal nature protected areas, which is 0.7% higher than ten years ago. The areal representation of mountainous soils in PAs has increased to the greatest extent. In general, the soils of the mountainous territories and the soil cover of the Arctic are quite well represented in PAs, contrary to the soil cover of southern regions: steppes, dry steppes, semi-deserts also as saline and alkaline soils. The representativeness of the federal protected areas network in terms of the typological diversity of soils is 63%, which is 7% higher than in 2012. The diversity of the smallest soil group (subtropical soils) is fully protected. The level of protection of natural soil diversity for taiga and coniferous-deciduous forests increased by 13% over the decade and reached 75%. The situation of protection of steppe soils has improved: the representativeness index has increased by 10% and is at 48%. Representation of the saline and alkaline soils diversity, considering solonetzic complexes, in state reserves and national parks remains very low (20%).

The purpose of the study is to analyze the current state of forest vegetation on the shores of the Irkutsk Reservoir and Lake Baikal, to calculate the direct economic damage as a result of possible direct losses of forests due to the negative impact of water on flooded and abrasion areas. The relevance of the study is determined by the need to minimize the damage to the coastal forests when water levels in the reservoirs change by introducing changes in the rules for the use of water resources, land use, forest management, etc. The main research methods were: geobotanical, forest taxation, geoinformation, expert, etc. The damage was determined in relation to the forest vegetation actually growing in 2022–2023, it is of a potential nature and does not reflect the damage from its death or damage in previous years. The calculation of damage was made in relation to wood resources, tree greens, bark, forest litter, mushrooms, berries, nuts, birch sap, medicinal plants, etc. To calculate it, standard payment rates per unit volume of forest resources were used. In turn, the determination of the volume of forest resources was based on indicators of biological productivity calculated using regional methods. The study made it possible to determine and map the distribution of forested areas within land categories and individual land uses, the qualitative characteristics of forests, and the economic damage by forest resource types at potential water rise levels. Among the municipalities, the highest values of economic damage were noted in the Irkutsk district due to the high taxation characteristics of forests, mostly located on the abrasion banks of the Irkutsk Reservoir. The quantitative parameters of the trend toward an increase in forest area and economic damage were determined depending on the increase in the absolute altitude of the terrain. This trend is especially pronounced for the coasts of the Irkutsk Reservoir, where from an altitude of 457.0 m to 457.85 cm, for every 10 cm of relief cross-section height, the forest area increases by 5603.1–7344.7 m², and the economic damage increases by RUB 85879.2–125512.1. For the shores of Lake Baikal, the trend of a steady increase in these indicators is disrupted after the 457.4 m mark, which is associated with the peculiarities of the geomorphological structure of the lake shores and the specific development of steppe (Olkhon region) and swampy forest vegetation complexes.