Birdsong consists of stereotypical song types or syllables which follow each other according to certain rules. Based on these rules, linear and combinatorial syntaxes are identified. The former one implies a fixed sequence of song types repeated cyclically. In the combinatorial syntax, there are clusters of song types, within which song types may be performed in a varying sequence. The structure and organization of birdsong have been described for many species, but still remain unexplored for most of them. We studied for the first time the song structure and organization, as well as song sharing for the Yellow-rumped flycatcher Ficedula zanthopygia (Hay, 1845). First of all, we determined the repertoire of song types in each male. Then, the organization of singing was analyzed using methods of information theory and network analysis. To analyze the patterns of song sharing, we compared all song types of all males. Individual repertoires consisted from 8–31 song types. While singing, male flycatchers avoid repeating the same song type two or more times in a row (continuous variety). At the same time, different song types alternate with a much degree of freedom: we did not reveal any patterns which could indicate the presence of either linear or combinatorial syntax. Males generally shared few song types, and the similarity of the repertoires of any two males was small. Besides, males did not preferably use shared or individual (i.e., found in the only one male) song types. Song sharing was not related to the distance between males. The results were compared to what is known about the song structure and organization of the other three Ficedula species studied to date.

It is generally recognized that environmental pollution with agrotechnical substances is the major problem for the conservation of biological diversity and human food security. However, their use cannot be completely excluded. Of particular importance are modern rodenticides, i.e. superwarfarins, designed to reduce the numbers of rodents damaging agriculture, i.e. to destroy animals. However, these poisons are highly toxic and are passed up the food chains. Besides, it is impossible to draw a line between agrocenoses in their classical sense and the natural or slightly modified environment. The absence of clear physical boundaries of agrocenoses means that the processes occurring therein affect the biological diversity of adjacent territories, which are considered natural. Animals use both fields and the spaces adjacent to them. In addition, there is a water exchange between cultivated fields and the adjacent natural areas and reservoirs. Modern changes in the structure of agrocenoses increase the segment of fields which rodenticides are used on. The plowing of ravines, riversides and other inconvenient lands (due to an improved quality of equipment) facilitates the ingress of rodenticides into water bodies. Data on the consequences of the use of superwarfarins in some anthropogenic biocenoses of the southern regions of the Russian Federation are presented. Facts of mass destruction of consumers of the 1st and 2nd order (the so-called non-target species), directly related to rodenticid use, are given. Complex pathomorphological and toxicological studies of animals died in nature were carried out for the first time in the Russian Federation. The presence of bromadiolone in tissue samples was confirmed by chemical analysis, and the descriptions of autopsies of dead birds have been processed. Recommendations on the specific features for the collecting and storage of materials sent for research have been prepared.

The objective of present study was to assess the physical land capacity for an annual cassava crop, aiming to understanding spatial parameters and environment parameters required for locating potential areas of cassava cultivation. According to FAO guidelines, a spatial model was built to assess the potential land for facilitating sustainable cassava production through the integration of the AHP-GIS-Remote Sensing method. The present study showed that the land analysis indicated

that the high potential land was 6101.1 ha (8% total area), concentrated in the middle and eastern part of the study area. These areas face limitations for the cultivation of cassava due to climatic conditions of the minimum temperature of the coldest month (P₃ < 14°C), average annual sunny hours (P₅ < 1500 h) and potential factors for providing quality products (LULC, annual precipitation and soil pH are the most significant factors). The areas of cassava crop cultivation were simultaneously reduced. Still, the reason for that has been not dependent on the physical environmental conditions, the limiting factors from the domestic market, backward processing technology, and the purchase price of raw cassava may possibly play a prominent role in the local farms.

The paper presents the results of our study on the effect of one type of pyrogenic factor (smoke) after burning coniferous wood chips on several bioindicators (soil enzymes, microorganisms, mesofauna, plants of agricultural crops). Exposition to smoke for 60 minutes was found to significantly affect the enzymatic activity of common chernozem. Fumigation caused a decrease in such enzymes as catalase, peroxidase, polyphenol oxidase and invertase. The enzymes of the oxidoreductase class were the most sensitive to smoke. High toxicity of gaseous combustion products to the soil flora and fauna was revealed. The acute toxicity of smoke to the bioindicators was determined as a result of fumigation. High mortality of test objects (Eisenia fetida, Nauphoeta cinerea) was recorded in our experiments. Soil microorganisms (Azotobacter chroococcum and Penicillium chrysogenum) proved to be informative after 30–120 minutes of fumigation. Resistance of plant sprouts (Raphanus sativus, Triticum aestivum, and Pisum sativum) to combustion gaseous products was revealed. An experiment to analyze the chemical composition of gases in smoke was performed. Such hazardous compounds as sulphur dioxide (SO₂), nitrogen oxide and dioxide (NO, NO₂), carbon monoxide (CO), acetaldehyde (C₂H₄O), formaldehyde (CH₂O), phenol (C₆H₆O) hydroxybenzene and others were found to be contained therein. Our analysis revealed that the concentrations of carbon monoxide were 714 times higher than its maximum permissible concentration (MPC), which acetaldehyde was 24,100 times higher. The nitrogen oxide and nitrogen dioxide concentrations were 100 and 300 times higher, respectively.

The paper presents the results of our expedition studies of bacteriobenthos in the water area of the Kuibyshev reservoir in the autumn period of 2020 and the influence of the dynamics of currents on its spatial distribution. The relevance of the study is determined by the need to study the internal load (secondary pollution) of large reservoirs from bottom sediments. The Kuibyshev reservoir is one of the largest flowing reservoirs in the world, where features of the coastal configuration, the heterogeneity of the bed, the unsteady hydrodynamic regime, the sediment regime and its composition determine the spatial distribution of bottom sediments and the bacteriobenthos community therein, which is an important link in the circulation processes of organic and biogenic substances in the ecosystem of the reservoir. An assessment of the regime of currents and sediments was carried out by calculation on a 2D mathematical model of the Priplotinny Reach of the Kuibyshev reservoir, implemented in the software package «VOLNA». The model was verified, and a series of numerical calculations of the flow velocity was carried out taking into account the regime of water flow control at hydraulic units. The spatial geometry of the currents and the sediment flow distribution dynamics were obtained. According to the data of our expedition studies, the total numbers and biomass of bacteria were estimated, which varied in the range of (2.47–27.55)×10⁹ cells mL^-1 and 0.10–2.43 μg mL^-1, respectively. As a result of the conducted studies, patterns of the spatial distribution of the bacterial community in the water area of the Priplotinny Reach of the reservoir were revealed, and the nature of the relationship between the total numbers of bacteria and the sedimentation rate, the flow velocity, and the content of organic matter in bottom sediments was established. The influence of the circulation zones of currents in shallow waters on the nature of the distribution of bottom sediments and changes in the quantitative characteristics of bacteriobenthos is shown.

Features of the breeding and population structure of the root vole inhabiting the Southern Trans-Urals region during the periods of 1981–2001 and 2020–2022 are considered. Animals were captured during both winter and snowless periods. A total of 754 root voles were captured using ditches with pitfalls (guide fences made of polyethylene film) and trap lines. As in the other parts of their range, root voles in the Southern Trans-Urals region prefer near-water habitats. Winter breeding is characteristic of this rodent in the Southern Trans-Urals region, but the most intensive breeding is observed in May–June. These months are also characterized by the maximum fecundity for both overwintered and young females. Overwintered females can produce up to 4 litters during their reproductive period, while young females can produce 3–4 litters. The fecundity of overwintered females is statistically significantly higher than that of young ones. In February–May, overwintered animals dominate in the root vole population, while in June and the following summer and autumn months, underyearlings predominate. Males dominate among the overwintered and underyearling animals; at the end of summer and in the autumn, the sex ratio among these age groups of root voles levels off.

Technologies with integrated resource applications are probable solutions to the problem of soil pollution with oil and petroleum products. Based on our assessment of the potential for the recultivation of a plot on the territory of a rigged out reservoir tank storage, a biotechnology, including both forestry residues and biological agents capable of enhancing soil remediation processes, was developed. After having been applied, the technology comprising the BIOTRIN biopreparation, the GEOLEX^® biogeosorbent, bark-and-wood waste and seeds to promote revegetation showed a soil cleanup efficiency of 92–95% for 60 days. The dehydrogenase activity increased, confirming intense processes of pollutant oxidation. After 60 days, the plant cover with sown herbs reached 85%, which characterized the purified soil as having no inhibitory effect on the growth and development of plants.