This article is devoted to the structural-functional organization of the forest geosystems of Komsomol’sky Nature Reserve located in the south of the Lower Amur Region. It considers a landscape organization model built using the information theory methods. The model is represented as a block diagram consisting of digraphs, in  whose center there are landscape features. This model is a modified version of the previously published one for the studied territory. It is built on the basis of richer field data and with the addition of previously unused landscape features. Weak links of medium density predominate in the model, which may indicate the stability of the forest geosystems formed there. Our analysis shows that  the main factors determining the structure of Komsomol’sky Nature Reserve’s forest geosystems are altitudinal-exposure zonality, altitude, lithology of parent rocks, and soil  hydrothermal conditions. It is established that the stand of timber is directly related to the humus soil horizon lithomass: it decreases with an increase in  lithomass. Plants biomass is highly dependent on the steepness of slopes: it decreases with its increase. Separate relationships have been revealed for plant layers. The herbaceous layer height decreases with an increase in the altitude and lithom ass in the soil. The herbage floristic diversity differs greatly in land facie groups and has a maximum  in the ridge-top areas of the slopes and at the foot hill. The shrub layer height depends on soil moisture content, lithology of parent rocks and lithomass: it de-creases with increasing soil moisture content most of all and increases with increasing lithomass in the soil. A relationship has been found only with the lithomass in the soil for all tree layer features. A lithomass increase has a depressing effect on trees.

Our analysis of metabolic and ecological features of fungi indicates a high bioremediation potential of fungal mycelium. The relevance of the problems solved in this work is conditioned by insufficiently studied mechanisms and conditions of micromycetal activity on heavy metal detoxication. The effect of copper on the development of two micromycete species, namely, melanised Alternaria alternata (Fr.) Keissl., 1912 and hyaline  Fusarium oxysporum Schltdl., 1824 cultivated on Czapek agar (with 2 or 3% sucrose) was compared;  the ability of mycelium to sorb copper cations when grown in a liquid culture with 0, 0.05, 0.1, 0.25, and 0.5 mg Cu²⁺ / L was evaluated. F. oxysporum had noticeable advantages in terms of  growth rate, tolerance, conidia production on medium with Cu2+. The effective concentration of copper (EC₅₀), indicating the resistance of the fungus, increased for  F. oxysporum by 1.5 times with increasing sucrose content in the medium. The melanised culture of  A. alternata  was superior to  F. oxysporum in terms of sorption capacity. The percentage of Cu²⁺ extraction by fungal mycelium from the medium reached 40% in the case of  F. oxysporum and twice as much in the case of  A. alternata . The vast majority of copper was sorbed by the cell walls of hyphae and washed away by water. A small amount (a maximum of 0.16 µg Cu²⁺ /g dry mycelium of  A. alternate ) penetrated inside the mycelial cells. F. oxysporum, which had no intracellular protective melanins, accumulated Cu²⁺ (2 to 14 times) less. The results show that the mechanisms of resistance to Cu²⁺ and sorption are different in the studied species: in Fusarium they are  determined mainly by the barrier functions of hyphae cell walls, while in Alternaria melanin plays a significant role in protection against Cu toxic action.

The history of golden jackal dispersal in Russia and adjacent countries, as well as in  southern, central, eastern and northern Europe, is  considered. Data confirming the demographic  explosion of this species on the European continent territory are given. Materials on the dispersal  of golden jackals in the European Russia are considered in more detail. The main emphasis is  made on the study of the process of golden jackal penetration into the territory of Saratov region,  from its first sightings in the Saratov Volga region in the late 1980s – early 1990s in the Dyakovsky (Saltovsky) forest to dispersal in adjacent territories. The penetration  of the species into the  Saratov Right Bank and its further dispersal throughout  the region on both banks of the Volga river is  described. It is shown that the areas of the modern jackal range are approximately the same both in  the Right Volga Bank and Left Volga Bank of the  Saratov region. However, the number of jackal  is currently higher in the areas of  the region located on the right bank of the Volga river. Probably,  this is explained by more favorable conditions for the golden jackal habitat in this part of the region, associated with its higher afforestation. Gold en jackals breed in the southern districts of the  Saratov region, located on both banks of the Volga river. However, golden jackals are also found  in the northernmost parts of the region, and most likely there, as well as in the south of the region,  its stable reproductively active groups appear. In the  Saratov Volga region, in spite of its very low  forest cover, the golden jackal  is recorded both in the south-eastern and north-eastern areas, but its  numbers are high enough only in the vicinity of the forest on the Prieruslan sands and in areas  along the Volga river, where there are areas of floodplain and bairn forests. In the Right Volga  Bank of the Saratov region the golden jackal is most abundant in upland oak forests of the  Privolzhskaya Upland, occurs in floodplain forests of the Medveditsa river and in the Medveditsa–Khopyor interfluve.

The article considers the probability of Foster's  rule, or the island effect manifestation in a population of the nominative subspecies of the secret toad-headed agama (Phrynocephalus mystaceus mystaceus Pallas, 1776) living on an isolated  sandy massif of Sarykum, Dagestan. Materials on morphometric data, body length and tail length were collected  at two points in the habitat of the nominative subspecies. Data on the Sarykum sand massif were collected in May 2021. At the second point of the range, in the vicinity of  v. Dosang, the Astrakhan region, data were obtained during the spring field seasons of 2010–2014. Our processing of the materials shows that mature individuals of the population on Sarykum are significantly smaller than lizards of the same age group from the Astrakhan region. Our analysis of the published data confirms the smallest possible size of this population of the nominative subspecies. Thus, the population of the secret toad-headed agama on the Sarykum sandy massif may be  a typical example of an island shift, in which large animals tend to become dwarfs, and small ones to become giants,  respectively. In this case, we are dealing with dwarfism of the largest species of  Phrynocephalus genus in the isolated territory of the Sarykum sandy massif. It should be  noted that immature individuals of the populations have no dimensional differences from other populations of th e habitat, which may indicate the physiological dimensional optimum of this age group.

The article is devoted to studying the siberian silkmoth ( Dendrolimus sibiricus Tschetverikov, 1908) outbreaks, which is highly relevant today. The study was aimed at improving the system of forest pathology monitoring by revealing factors contributing to forest stand resistance to the pest attacks. We analyze the habitat conditions that are favorable for the siberian silkmoth in the early stages of its development and during the outbreak in dark coniferous taiga in the mountains of Southern Siberia (particularly, the Krasnoyarsk region). The research was based on remote sensing data combined with field data obtained in disturbed forests where we also con-ducted a pest population assessment. The habitat characteristics were based on the forest type and silvicultural and forest inventory details. We an alyzed environmental conditions and their influence on the pest reproduction. As a result, we divided  the forest stands by their resistance to insect attacks. Primary habitats are stands with moss-covered forest floor, secondary habitats are stands with herbs-covered forest floor, and tertiary habitats are depressions with wet soils (forests along streams or swamp forests). We revealed the  D. sibiricus population density dynamics related to the forest stands structure. The present research lets us  determine forest sites vulnerable to pest attacks and conduct spatial monitoring of  their dynamics and resistance.

The body temperature dynamics of  the Ciscaucasian hamster (Mesocricetus raddei) during winter hibernation was studied in semi-natural conditions (a mesh cage buried in the ground,  where animals could dig burrows) in mountainous  Dagestan. Thermologgers were implanted intraperitoneally to seven adult animals (three females and four males) to record body temperature at  30 min intervals. All individuals successfully overwintered and exhibited regular episodes of hypothermia. The average of total duration of one heterothermia period was 192±6.8 days, that of one hypothermia and normothermia episode was 15 5.3±6.2 h and 16.5±1.2 h, respectively. The minimum body temperature reached +0.5°C. It has  been shown that the body temperature and the  duration of hypothermia episodes are negatively correlated with the  temperature inside the burrow.  Adaptive hibernation mechanisms of the Ciscaucasian hamster and other hibernating mammalian species are discussed.

The work investigated the spectra of resistance to a certain set of antibiotics and the frequency of occurrence of resistant strains among typical soil bacteria – actinomycetes. Equal samples of isolates from sod-podzolic soil were used,  selected at sites typifying various types of economic activity, namely: the production areas of a plywood factory and a chemical plant, the territory of a medical institution, and a solid waste collection and storage site. A total of 58 isolates with features characteristic of actinomycetes of the genus Streptomyces of the sections Cinereus, Helvolo-Flavus and Albus were obtained. It has been established that various types of economic activity lead to specific changes in the antibiotic resistance, which characterizes the soil of a natural grass-grass meadow (back-ground). Isolates with resistance to nalidixic  acid, amoxicillin and ceftriaxone were found in the sample taken on the territory of the chemical plant more often than in the soil of the background site. The proportion of strains resistant to nalidixic acid, lincomycin and azithromycin was significantly (P<0.05) higher in the soil samples  taken at the MSW collection site and the territory of the medical institution, while those resistant  to nalidixic acid and amoxicillin were in the sample from the plywood factory Groups of antibiotics (quinolones – nalidixic acid, and  β-lactams – amoxicillin and ceftriaxone) were identified, the resistance to which in streptomyces isolates from soils involved in economic activity  was significantly higher than in soil isolates from the background territory. The data obtained in  the work indicate the need to monitor the spread of antibiotic resistance in soils that are not only at risk of accumulation of residual concentrations of antibiotics, but also other  consequences of anthropogenic influences.