Materials from National census of woodcock on the evening roding and hunting bag data from the State Registration Service on the territory of European Russia were used in the study. The impact of hunting bans due to viral infections in 2006 and 2020 (bird influenza A H5N1 and human coronavirus Covid-19, respectively) on the population of the Eurasian Woodcock Scolopax rusticola was described. An increase in roding intensity (the number of contacts) by 9.4% was detected in European Russia in 2007, possibly due to the ban. In 2019–2021, the roding intensity increased by 14.5% in the year of the ban (2020) only. The increase in the number of hunters in European Russia from 2006 to 2020 probably affected indicators of the National census of woodcock. This fact is consistent with the total (spring and autumn) shooting volume and the indicator of individual hunting bag in European Russia in 2021. After the hunting ban, the indicators of hunting bags remained almost the same as in 2019, and there was an increase in these indicators in 2007 as compared to 2005. Thus, the short-term and incomplete ban of spring hunting in European Russia (23 of 41 regions), based on the available data on roding and hunting bag, does not allow us to speak unambiguously about its positive effect on the number of woodcocks.

The cyanobacterial communities of Lake Pskov were studied in several seasons of 2021, and a comparison was made with the data of earlier studies. Data on the taxonomic composition and quantitative characteristics of cyanobacteria have been obtained, and some species toxic to living organisms are shown. 196 species taxa of phytoplankton in total were recorded at four permanent stations of the lake, 15.8% of which were cyanobacteria. The cyanobacterial communities were most similar in terms of the specific composition in summer and autumn. Some quantitative indicators of cyanobacteria, such as their abundance and biomass, were minimal and maximal in spring and summer–autumn, respectively. Toxic and potentially toxic species belonging to the genera Anabaena, Aphanizomenon, Lyngbya, Microcystis, Nodularia, and Nostoc were present among the detected cyanobacteria in each of the studied seasons of the year. The total contribution of representatives of these genera to the total abundance of phytoplankton varied from 4.0% in spring to 65.0% in autumn. In summer, the share of cyanobacteria from the above genera in the total number of microalgae accounted for ~40.0%. The greatest role was noted for the algae Microcystis aeruginosa (Kützing) Kützing, which causes “blooming” of reservoirs and also produces the toxin microcystin with hepatotoxicity. Any study of Lake Pskov requires constant monitoring of the content of cyanotoxins, especially in autumn, when the maximum biomass content of cyanobacteria, including toxic species, is observed, which may lead to serious consequences.

Based on our analysis of long-term (2015–2021) observations carried out at a registration spot in the park named after Yu. A. Gagarin (Simferopol, Crimea), patterns were revealed in the spatial distribution of burrows of the Common hamster (Cricetus cricetus L., 1758) depending on the state of the tree and shrub layer, as well as disturbance factors. It is shown that the leading factor influencing the spatial distribution of burrows is the location of trees, and the total number of burrows is mainly affected by the projective covering by shrubs; these factors were revealed as a result of cluster analysis for the spatial-geographical formulation of the problem and crosscorrelation analysis. It is assumed that the use of spatial modeling makes it possible to identify environmental factors, including plant communities, influencing the choice and exploitation of microhabitats by animals, as well as to find approaches to the analysis of the implementation of behavioral patterns during the development and exploitation of a habitat.

As a result of our studies of the macro- and nectozoobenthos of the rivers of the semidesert zone (the Volgograd reservoir basin), 16 Malacostraca species were recorded, most of which are representatives of the Ponto-Caspian complex. Compared to the Volgograd reservoir, there is an increase in the quantitative indicators  of mysids and isopods and a decrease in the number of species, abundance and biomass of amphipods and cumaceans in the semi-desert zone rivers. The average abundance and biomass of crustaceans in the surveyed rivers are approximately 2.5 times lower than in the Volgograd Reservoir. Crustaceans of the Ponto-Caspian and PontoAzov complexes, as well as the isopods Asellus aquaticus (Linné, 1758) inhabit fresh and oligohaline waters, while the gammarids Gammarus lacustris (Sars, 1863) live in oligohaline and polyhaline waters. Amphipods are characterized by the largest number of species, which, taking into account their morphology and the type of substrate which they live on, are assigned to three ecomorphs, namely: clingers, crawlers, and diggers. No symbionts in the Yeruslan basin rivers were found. The noted amphipod ecomorphs are distributed relatively evenly with a slight dominance of crawlers (45%). It has been revealed that two types of crustacean cenoses are formed in the surveyed rivers. The first type is formed mainly by consortium interactions of the edificatory mollusks Dreissena with amphipods Chelicorophium curvispinum Sars, 1895, Dikerogammarus haemobaphes (Eichwald, 1841), mysids Paramysis ullskyi Czerniavsky, 1882, P. lacustris (Czerniavsky, 1882), and associated species. The second cenosis in the rivers is represented by a complex of small coastal mysid species Katamysis warpachowskyi Czerniavsky, 1882, Limnomysis benedeni Sars, 1893, and amphipods Chaetogammarus warpachowsky (Sars, 1894), the relationships within which are based on common biotopic conditions and feeding patterns.

A study was made of the mass drying of the eastern spruce (Picea orientalis (L.) Link) in the Teberdinsky Nature Reserve (North Caucasus). The main cause of the drying was an outbreak of the number of bark beetle (Ips typographus L.) whose mass reproduction occurred in the hot seasons of 2012 and 2015. The existing undergrowth was not affected. By 2019, 7 years after the beginning of the mass drying of spruce, most of the groups of drying had died out, single active bark beetle foci were noted. There are almost no live spruces of the upper tiers left. In small numbers, they have been preserved in the Dombai forestry in mixed stands of Picea orientalis (L.) Link, Abies nordmanniana (Stev.) Spach and Fagus orientalis Lipsky. As our study showed, the stands of two of the four forest areas of the reserve originated in a treeless space (250 and 350 years ago). Subsequently, three of the four underwent one strong, but local disturbance during their existence. Reconstruction of the history of dark coniferous stands of the surveyed forest areas shows a high ability for natural self-healing of the Teberdinsky fir-spruce forests after massive disturbances. In the near future (after the fall of dead wood, which is already happening), the stands of sample plots will be a sparse forest from Abies or Abies with Fagus, and most of the sample plots will become open stands with single Abies trees. The modern mass drying of the eastern spruce as a result of bark-borne epiphytotics has a much larger scale of disturbances both in the area and in the degree of destruction of the stand. This is fundamentally different from the disturbances of the past. In such a situation, the shortage of seeds will have a particularly negative impact. Therefore, the preservation of preliminary coniferous undergrowth is especially important.

To reveal features of the distribution of birds in Northern Eurasia, the results of surveys carried out in the period from 1880 to 2019 (with interruptions and mainly since 1960) averaged over the first half of the summer (May 16–July 15) were analyzed. 354 researchers participated in the collection of material (for 110 years). Data processing was carried out using multivariate statistics methods, including cluster analysis and linear qualitative approximation of connection matrices. The classification of bird species by their distribution accounts for 42% of its similarity. The information content of representations decreased by 10–15% only (by 12% on average) with twice as many species analyzed, a significantly larger number of surveyed habitats and the area of the studied territory (as compared to the previously surveyed East European and West Siberian Plains and Altai). This level of explanation can be considered satisfactory (the correlation coefficient is 0.65). The summer distribution of bird species, as well as the heterogeneity of their distribution as a whole, is determined by changes in the hydrothermal regime in the zonal-belt and provincial aspects. The heat-to-moisture ratio determines the type of vegetation and its productivity both on land and in aquatic and semiaquatic habitats. The specificity of the vegetation type in territories and water areas, taking into account anthropogenic transformation, coincides with the heterogeneity of the bird distribution and the formation of ornithocomplexes as a whole. With the division of geographical space into zones, subzones, and especially physiographic countries, the variability in the distribution of birds and their communities is associated to a lesser extent, occupying the second and third places in the hierarchy of significance, respectively.

The time series of dates of the end of wintering and the beginning of spawning migrations of the marsh frog in the valley of the middle reaches of the Medveditsa river (Don basin, Saratov region) was analyzed. It has been established that in the period from 1892 to 2021, the phenological norm of this phase of the annual cycle shifted to earlier dates by an average of 6 days (from May 2 to April 26) against the background of climate warming. Possible consequences of this transformation of the spring phenology of anurans in connection with the changes established are discussed. Continued monitoring of phenological changes in the spring phase of the annual cycle is required to form a forecast of the population dynamics of this anuran species and the scientific basis for their conservation.

The available data on the combined action of rare earth elements and heavy metals are contradictory. Therefore, the goal of the presented work is relevant – to determine the effects of solutions of copper, lanthanum salts and their equimolar mixtures under controlled conditions for Daphnia magna Straus. It has been established that the death of D. magna over 50% in solutions containing Cu2+ is observed at a calculated concentration of 0.05 mg/L (0.0008 mmol/L), and a similar effect of solutions with La3+ occurs at a dose of 50 mg/L (0.36 mmol/L). The potentiation of the lethal effect of copper in the presence of lanthanum is shown. E.g., in solutions of mixtures of Cu and La salts, where the sum of metals is equimolar to non-lethal concentrations of Cu2+ (0.00016 and 0.0008 mmol/L), 100% death of D. magna is observed after 96 and 24 hours, respectively. Further, the potentiation effect was confirmed in bioassays evaluating the locomotor activity of D. magna. Solutions containing a mixture of “Cu2+ and La3+” (1:1) inhibit the motor activity of daphnia similarly to equimolar solutions containing only Cu2+. Thus, despite the significant difference between the effective lethal and non-lethal concentrations of Cu2+ and La3+ (by 1,000), it was found that under the combined action of equimolar doses of the metals, an increase in the toxicity of copper in the presence of lanthanum is observed.