The results of an experimental study of the transformational flow of heavy metals (copper, zinc, nickel, and lead) from soil-forming rocks into chestnut soils and then into virgin herbage and humic substances are presented. The soil-forming rocks include deluvial and deluvial–proluvial sediments, as well as sand and pebble sediments; their weathering, displacement, and redeposition lead to unequal granulometric, mineralogical, and chemical rock compositions, thereby influencing the composition of the soil cover. Chestnut soils are characterized by an arid climate, a long-term frozen state, low bioproductivity, low thickness, a light granulometric composition, and low humus content. Humic substances were extracted with the Grimme method. The concentrations of microelements were determined via atomic absorption with direct electrothermal atomization of samples. Heavy metals were determined on an atomic absorption spectrophotometer (AAS-15 Perkin Elmer). It has been revealed that the amount of copper and nickel is low in the soils due to the depletion of rocks in these metals, while the content of zinc and lead is higher, which is reflected in the state of vegetation and humus.

This paper discusses the relationship between the slope exposure and chemical and microbiological soil properties on agricultural terraces. Terraces formed on limestone and shale rocks in the medium-altitude zone of the eastern Caucasus were studied. It is established that the slope exposure significantly affects the properties of soils formed on similar parent rocks. The formation of terraces with nearly horizontal arable surfaces changes the sunlight angle of incidence, thus increasing the heat supply to soils on north-facing slopes and reducing the heat supply to soils on south-facing slopes. Such changes in the thermal regime in the upper horizon of terrace soils reduce the differences in chemical and microbiological properties between soils on north- and south-facing slopes as compared to the background soils. On gentle (5°–15°) slopes with the greatest terrace width, the leveling effect of terracing is more strongly expressed in comparison with soils of narrow terraces formed on steep slopes.

In recent decades, various isotopic methods have been widely used to study trophic relationships in soil ecosystems, because the isotopic signature of heterotrophic organisms reflects the isotopic composition of their preferred food objects. The composition of carbon (δ13C) and nitrogen (δ15N) isotopes of biological objects is most often used in such environmental research. However, the correct use of the method to reconstruct detrital food webs is often hampered by the individual (within the body) variability of the carbon and nitrogen isotopic composition in the tissues and organs of many groups of soil invertebrates. The goal of this study is to compare the individual variability of isotopic composition of various tissues and organs of common Mediterranean species of woodlice (Armadillo officinalis, Armadillidae, Isopoda and Armadillidium vulgare, Armadillidiidae, Isopoda) and the Mediterranean banded centipede (Chilopoda, Scolopendromorpha, Scolopendra cingulata). Soil invertebrates were collected on the territory of the Utrish State Natural Reserve (Krasnodar krai, Russia). Isotopic analyses were performed for the exoskeleton, muscles, intestinal walls, fat body (only for centipedes), reproductive system, legs, and a whole, homogenized body. The isotope composition of δ13С and δ15N was estimated with a set of equipment consisting of an elemental analyzer and an isotope mass spectrometer. The differences in δ13C between the tissues of woodlice reached 5–6‰ due to the incorporation of inorganic carbonates in the exoskeleton. The tissues of the banded centipede showed no significant difference in their isotopic composition. The trophic position of the large woodlouse species can be best characterized by the isotope analysis of muscle tissues. The use of limbs is possible only after preliminary assessment of the carbonate content in the integumentary tissues of the species. The homogenization of large species is unfavorable, as well as the remains of exoskeleton fragments and food debris in the analyzed sample. For centipedes, one can use not only muscles but also homogenized samples of the whole body, as well as individual parts of the body and organs, excluding the gut contents. The results are applicable for the optimization of soil-zoological studies via isotopic analysis of the tissues of various invertebrates.

Arid, herb–grass steppes are widespread in the plain zone of Dagestan. Their herbage contains yarrow plants that form vast thickets in the lowland. The accumulation of heavy metals in organs of plants of the genus Achillea L. and in soils under the conditions of Dagestan has been studied for the first time. The concentrations of Fe, Mn, Pb, and Cd have been determined in the aboveground and underground mass of plants of the genus Achillea L. from the background and anthropogenically disturbed areas, as well as in the soils on which they grow. It is found that the accumulation and distribution of heavy metals in plant organs is influenced by vehicle pollution. In Achillea nobilis plants selected from the villages of Uchkent and Stalskoe, the cadmium concentration exceeds the maximum permissible level by 1.2–1.7 times. The calculated indices of biogeochemical mobility have shown that plants from the anthropogenically disturbed habitats are characterized by a high accumulation of Fe and Cd but a low accumulation of Mn and Pb.

Organic matter of modern and buried humus horizons was studied in the soils at the following archaeological sites: the Akberdinskoe II, Shipovskoe, and Okhlebininskoe II ancient settlements (Kara–Abyz culture, early Iron Age, 4th century BC to the cusp of the 2nd and 1st centuries BC). The archaeological sites are located in the forest–steppe zone (Iglino district, Republic of Bashkortostan). The morphological and physicochemical properties of the soils were determined. Spectrophotometry and 13C NMR spectroscopy were also used. The archaeological sites feature dark gray forest soils with loamy granulometric composition. The topside and buried humus horizons are 11–30 cm thick. Organic matter is represented by fulvate–humate, humate, and humate–fulvate humus types. Humic acids predominate in the group composition; the HA-2 fraction predominates among the humic acid fractions. The spectrophotometric data indicate that aromatic parts of humic acid molecules are more mature in buried humus horizons in comparison with modern humus horizons. According to the 13C NMR spectroscopy data, humic acid molecules in organic matter of modern humus horizons conform to the conditions of the chernozem soil formation type. Archaeological data indicate that the current intensification of the climate aridization trend in the forest–steppe zone of the Republic of Bashkortostan dates back to the middle of the 4th century BC and the cusp of the 2nd and 1st centuries BC. No changes in the soil formation type were registered in the soil cover of the archaeological sites at the time of the survey.

The geodynamic potential reflects the energy state of the lithospheric blocks, which affects the safety and comfort of human life. The accumulated geodynamic potential acts on the living conditions of humans through its manifestation and development (evolution) in the natural environment with stress relief in the geophysical fields of the Earth. This works evaluates the level of geodynamic potential of the blocks in the northeastern segment of eastern Caucasus located in the arid climate zone in order to make recommendations for appropriate services that prevent harsh geoecological consequences. Paleoseismogeological and structural-tectonic methods with respect to the geodynamic potential of the regional blocks and analysis of the spatiotemporal distribution of seismicity during the instrumental observation period are the main methods of study. Analysis of the study results shows that the region has the Earth’s crust blocks with a critical level of geodynamic potential. A pattern for potential zones of potential earthquake sources and regional blocks with critical geodynamic potential is constructed. The geodynamic potential of the blocks in the northeastern segment of the eastern Caucasus is assessed under the conditions of steppification of terrestrial ecosystems and its geoecologocal significance is shown. The potential zones of expectation of potential sources of strong earthquakes, which may negatively affect ecological safety in the region, are identified. The studies continue the works on the evaluation of the geoecological situation that for under the impact of potential catastrophic geoecological processes of a natural character in a region prone to steppification and aridization.

The results of a study of the light chestnut soil of an ampelocenosis located in a zone with a semi-desert-steppe regime and a low hydrothermal coefficient are presented. Analysis of the chemical composition revealed that the soil is nonsaline, saturated with bases, and deficient in individual plant nutrients. The study of the taxonomic composition of yeasts, which can act as a model group of microorganisms in the study of soil-microbiological processes, has shown the ability of this soil to play the role of a biological reservoir for storage and distribution in the natural cycle of various physiological groups of yeasts. The yeast complex included 11 species: 2 basidiomycetes and 9 ascomycetes. The yeasts Aureobasidium pullulans and Lachancea thermotolerans were significantly dominant. The yeasts were isolated by a direct plating and enrichment cultivation; the species identification of pure cultures was based on the analysis of the nucleotide sequences of the rDNA region. The accumulation of allochthonous yeasts, as well as other groups of microorganisms, influencing the biodiversity of the ampelocenosis soil, expands the potential for the participation of mycobiota in soil processes.

The paper reports the assessment of the spatiotemporal trends of climatic changes favoring the spread of West Nile fever (WNF) in the southern part of the European Russia. Data from 58 meteorological stations (1997–2018) and ERA-Interim reanalysis data (1981–2018) were used. The degree-day method was employed to assess whether the climatic conditions favor the spread of the West Nile virus (WNV). As a result an increase in the sum of the effective temperatures (ETs) was demonstrated. No increase in the length of the efficient infectivity season was observed. A coincidence of the trends of ET sum growth and the increase in the average air temperature for the epidemic season was noted. This creates favorable conditions for virus development in mosquitoes, because virus circulation becomes more efficient with an increase in ET. The most favorable temperature conditions for WNV form in the Caspian Sea region and the Ciscaucasia, where WNV circulation conditions are further improved due to an increase in the total ET. conditions favoring WNV transmission form more rapidly in the central part of European Russia than in the Cis-Ural region, which may cause further spread of WNF in this region.

The long-term dynamics of the average air temperatures and amounts of annual precipitation confirms the reality of climate change since the 1970s on the territory of Akmola oblast, one of the leading agricultural regions in Kazakhstan. The structure of agricultural production in the oblast is dominated by the rainfed cultivation of grain crops, in particular, spring wheat, which is known to be extremely sensitive to climatic and weather conditions. Analysis of the climatic indicators for 1931–2019 based on available data from meteorological stations identified intraregional features of climate change that led to an increase in the yield of grain crops. Correlation analysis established a high dependence of productivity on the climatic conditions of the warm period. If the current level of farming culture and the continued growth of average temperatures persist, the productivity in the dry-steppe and southern steppe regions of the oblast is expected to decrease. In the northern steppe regions, more intense trends in the climatic indicators of the cold months favor an increase in yields and an expansion of agricultural production. Intraregional differences in the intensity of climatic trends must be taken into account for the further development of agriculture in Akmola oblast. The following measures are proposed in order to avoid the negative consequences of climate change: the introduction of adaptation technologies, the diversification of agricultural production, the development of organic agriculture, and active support for agricultural producers.

The structure of zooplankton communities in the Terek–Caspian coastal region of the Caspian Sea under the conditions of flow regulation of the Terek River and its passage through the Uch–Kosinsky channel are studied. Hydrobiological material collected in the waters of the Terek coastal region of the Caspian Sea was used. Long-term data are given for the zooplankton distribution in the studied region, which reflects the nature of the influence of the sea-level regime, the arid climate, the mass development of the Azov–Black Sea invader Acartia tonsa (Dana, 1849), and the trophic pressure of another invasive species, Mnemiopsis leidyi (A. Agassiz), after the passage Terek River runoff in a new channel. The influence of these factors mainly affected the autochthonous fauna of the waters of the Terek coast. It was shown that the previously leading native species, Calanipeda aquae dulcis and Eurytemora grimmi, faded into the background for a long period. It is only in recent years that C. a. dulcis became a subdominant form in the zooplankton of the studied water area of the Caspian Sea due to a decrease in the pressure of the ctenophore Mnemiopsis leidyi.