The article presents the results of investigations of the flora of small rivers within the city of Saratov (Yelshanka, Nazarovka, 1st Gusyolka, and 2nd Gusyolka). The species composition of aquatic plants of the streams studied is represented by 37 macrophyte species belonging to 23 genera, 17 families and three divisions (Charophyta, Polypodiophyta, and Magnoliophyta). The families Potamogetonaceae, Cyperaceae and Lemnaceae predominate by the number of represented species. The values of the Menchinik index indicate that the greatest floristic diversity is characteristic of the Yelshanka and Nazarovka rivers (3.1 and 3.4, respectively). The species composition of aquatic plants of the studied rivers within the urban area has a low similarity coefficient with the flora of rivers with relatively low anthropogenic load. Hydrophytes are the most numerous ecological group (22 species). According to the Paley–Kownacki dominance index, among the macrophytes of the studied rivers, most species are subdominant (57.28%) (Potamogeton perfoliatus, Typha angustifolia, Lemna trisulca, etc.). 37.18% (Phragmites australis, Potamogeton pectinatus, Lemna minor, Ceratophyllum demersum) belong to dominants, and the rest (11.54%) is defined as subdominants of the first order. Exceptional predominance is characteristic of Ceratophyllum demersum and Phragmites australis, which acted as dominants in all studied rivers. A significant part of the rivers is characterized by a low degree of overgrowth by hydrophilous vegetation, from slightly overgrown to not overgrown. The main types of distribution of aquatic and riparian-water vegetation are belted and fragmentary. Macrophyte communities are characterized by a simplified structure (one- or two-tiered), with absolute predominance of one plant species and the presence of two to four associated species with low values of projective coverage. The results of our calculations of indices (macrophyte index for small rivers (Sm), Indice Biologique Macrophytique in Riviere (IBMR)) based on the structural parameters of macrophytes showed that the studied rivers have a satisfactory ecological status. 

Opisthorchiasis in Novosibirsk and the Novosibirsk region is registered annually. Significant differences in the indicators of the epidemic process in Novosibirsk were noted in comparison with those in the Russian Federation, where the maximum and minimum average long-term incidence rate is 6–10 times lower than in Novosibirsk. The urban population share accounts for more than 75% of cases in the structure of the incidence of opisthorchiasis in the Novosibirsk region. The incidence rate of people with opisthorchiasis in different districts of the city varies from 85.0 per 100 thousand people to 170.3 in 2005–2015, an increase in the incidence rate is observed in most administrative districts and in the whole city. The opisthorchids infection rate of domestic carnivores is 15%. Cats are infested more often than dogs – 18.1 and 10.7%, respectively. In two districts of the city, Kirovsky and Sovetsky ones, the level of infection of domestic carnivores and the incidence of people significantly exceed those in other areas. In 6 fish species of the Cyprinidae family (Leuciscus idus, L. leuciscus, Rutilus rutilus, Abramis brama, Leucaspius delineatus, Carassius carassius), caught in urban and suburban water bodies, 3 opisthorchid species were found, namely: Opisthorchis felineus (Rivolta, 1884), Metorchis bilis (Braun, 1890), and M. xanthosomus (Creplin, 1846). The first two ones are of epidemic importance, while the last one is of epizootic significance. The total invasion prevalence of commercial ide by opisthorchid larvae in the Ob River was 71.8%, of which O. felineus metacercariae accounted for 69.1%. The overall infection level in small aboriginal fish in the small rivers Nizhnyaya Yeltsovka, Inya and Tula is 45.8, 55.3, and 22.2%, respectively. Thus, favorable environmental conditions have developed in Novosibirsk for transformation of the natural focus of opisthorchiasis into an anthropic one. 

Studying of animal behavior is important to understand the evolution and ecology of species, as well as to develop strategies and measures to conserve rare species. Investigating the time budget of closely related species allows detecting species-specific patterns of behavior. A comparative analysis of the time budget of the Common crane (Grus grus) and Demoiselle crane (Anthropoides virgo) in their pre-migration period, during which they as a rule feed in agricultural fields, was carried out. Species differences in the foraging strategies were revealed. Demoiselle cranes forage while moving across the field while Common cranes forage while standing still. Thus, Common cranes, which traditionally use fields to feed, forage less energy-intensely than Demoiselle cranes that are a steppe species and began to use agricultural landscapes after virgin lands since the middle of the last century. Common cranes spent more time preening than Demoiselle cranes, and juveniles of both species spend less time to this activity than adults but no statistically significant differences were found. Both species spent the least time to rest and other activities. 

Computer processing of a video sequence with test organisms is a promising direction in the development of biotesting, as the throughput of methods per unit time increases significantly and several test reactions are taken into account simultaneously. The aim of the work is to develop and test an automated method for considering a complex of D. magna test functions for further assessment of the toxicity of aquatic environments. Videos with D. magna were processed using the Python programming language and the OpenCV computer vision library. The developed algorithm makes it possible to detect D. magna individuals of different ages, to determine their linear dimensions, velocities and accelerations. This functionality, applied to model groups of D. magna, makes it possible to assess the acute toxicity (by lethal and sublethal effects) and chronic toxicity of samples (by the number of juveniles born and their physiological reactions). 

The article discusses global prospects for the transition to green energy generation in the Saratov region. The literature data on the current situation in the alternative energy sector (wind energy, solar energy, and bioenergy) in the Saratov region have been studied and systematized. The data were obtained from the most relevant and cited publications in the world databases Scopus, Google Scholar, RSCI and among Internet media articles. The pros and cons are described, as well as the overall impact on the environment of each type of renewable energy that exists in the Saratov region. Much attention is paid to the impact of wind turbines and solar power plants on the environment. It has been established that the use of solar energy is most developed in this area. This is due to climatic conditions and the number of sunny days in the region. In view of the large formation of organic waste in the Saratov region, it is rational to use biomass to obtain bioenergy. The Saratov region government intends to continue to steadily increase the share of renewable energy sources in the energy balance of the region. By 2035, the share of renewable energy sources in the regional energy balance will reach 6%, and in 2050 it will be about 13%. We believe that the global prospects for green energy transitions in the Russian Federation, as well as in the transmission to the Saratov region, consist in a partial transition to alternative energy (solar and wind), using bioenergy and highly efficient technologies for cleaning CO2 emissions from traditional fuel. 

The morphological variability in populations of Chondrilla taxa is poorly studied, and features of its distribution, both spatially and between taxa, are not obvious. The article presents the results of our comparative analysis of the nature of this variability on the example of 28 populations of eight taxa of the genus in the southeastern European Russia and northwestern Kazakhstan. The variability of eight morphological traits, most of which are still used to determine the species of plants, was analyzed. It is shown that the variability level of these characters, four of which are taxonomically significant, in one year of monitoring is so wide that it completely overlaps the boundaries of their variability of all Eastern European taxa. At the same time, populations of different taxa growing side by side in similar environmental conditions demonstrated a very similar (just identical in some cases) range of morphological variability. It was concluded that the causes of this very dynamic and peculiar variability of traits are most likely the local conditions of population growth in a particular year of monitoring. Our comparative analysis of the interannual (2015, 2016 and 2022) variability of these quantitative traits in 14 populations of five Chondrilla taxa showed its significant dynamics over years as well. Using the method of non-metric multidimensional scaling of quantitative morphometric parameters, it is shown that the gradient of their variability takes place in the direction from the conditions of minimum moisture and maximum temperature to that of increasing humidity and decreasing temperature. At the same time, the combinations of these climatic factors in specific habitats of populations affect the values of morphological parameters to a greater extent than their geographical gradients or taxonomic affiliation. 

In the course of this work, the total numbers of heterotrophic microorganisms and the numbers of microbes participating in the nitrogen cycle (ammonifying, denitrifying, nitrifying and nitrogen-fixing ones) in urban and natural (background) soils of Kogalym were estimated. A relation between the obtained results with geochemical indicators was revealed. Our microbiological analysis showed the predominance of nitrogen-fixing microorganisms in urban soils (5.0×104 – 2.0×106 CFU/g of soil), which were on average 44 less than in natural soils. In the last ones the average number of denitrifying microorganisms was 7.0×104 CFU/g of soil, exceeding 1.3 times their number in urban soils. Based on the information obtained, microbial contents in the soils of Kogalym were established as a row: nitrogen fixators > ammonifiers > heterotrophs > denitrifiers; in background samples: denitrifiers > ammonifiers > heterotrophs > nitrogen fixators. According to the data of ecological and geochemical analysis, an excess of the MPC of mobile forms of heavy metals, such as Cu, Ni and Zn, was revealed in the Eastern Industrial zone of the city. A significant inverse correlation was revealed between the number of denitrifying microorganisms in the Kogalym soil microbiocenoses and the content of mobile Ni and Cu forms, which points to a possible negative effect of these metals on the development of denitrifiers. The minimum number of ammonifying, denitrifying and nitrogen-fixing microorganisms was found in the Eastern Industrial zone, especially in the soil samples that were taken near the railway. On the whole, the absence of noticeable differences in the microorganisms` content of the studied groups in urban and natural soils indicates a low level of soil pollution in Kogalym. The obtained results represent the basis for subsequent ecological monitoring of the soils in the city and adjacent oil-producing areas, forecasting the environmental consequences of anthropogenic activities in these territories. 

The paper presents the results of studying the age and growth of the eastern slow worm (Anguis colchica orientalis) in the upper reaches of the Tangeru River (Astara district, Republic of Azerbaijan). Lizards (8 males and 6 females) were caught from March to August in 2011–2019. Their age was determined by the number of lines of arrested growth (LAG) on the cross sections of the tail vertebrae. Sections of the mandibular bone were also examined in three dead individuals. The number of LAG on the mandibular bone sections and the caudal vertebra coincided. The studied animals were aged from 1 to 10 years. The average age of males and females was 4.86 and 5.33 years, respectively. More than half of the males (5 individuals) were 4–5 years old, and a third of the females (2 individuals) were six years old. The life expectancy after the first wintering in females and males was 6.70 (S = 0.84) and 5.93 years (S = 0.82), respectively. It is noted that age determination by cross-sections of the tail vertebrae in slow worms is possible and allows conducting studies on live lizards.