Vol 28, No 2 (2025)
- Year: 2025
- Articles: 27
- URL: https://journals.rcsi.science/1605-220X/issue/view/19802
Full Issue
Mathematical Modeling
Influence of the control parameter on the modes of the Moran-Ricker model dynamics with time lag
Abstract
In this paper, we consider the Moran-Ricker model with a one-year lag, taking into account the removal, which allows analyzing and evaluating possible scenarios for the development of populations. It is assumed that measures aimed at reducing the population size are taken annually, as a result of which the share of individuals that die is proportional to the total number.



Optimal control of a homogeneous population under natural selection
Abstract
The study examines the impact of equilibrium harvesting with an optimal withdrawal rate on the dynamics and evolution of a population with non-overlapping generations, which is described by the Verhulst model with genetically determined parameters. It has been analytically shown that in a state providing the maximum level of seizure, the genetic composition value remains the same as in a population without withdrawal, while the equilibrium population size reduces by half. The type of genetic equilibrium may also shift.



. Harvesting affect on the r-K selection in populations with non-overlapping generations
Abstract
The study examines how harvesting with a fixed removal rate affects population dynamics and evolution in non-overlapping generations under density-dependent selection. We show that exploitation can reverse selection outcomes: while K-strategists dominate in unharvested populations, fishing pressure may favor r-strategists. Threshold conditions for this evolutionary shift are identified.



Influence of individuals natural selection by fertility on scenarios of populations with simple age structure development
Abstract
The paper studies the model of evolution for a two-stage population with birth rate limitation, under the influence of natural selection regulating individual fertility. The model analytical and numerical research has been carried out. With a reduced reproductive potential of heterozygotes, the model is shown to reveal multistability when, depending on the initial values of allele frequencies, stable polymorphism can be realized along with the «bistability trap».



Optimization of hard-to-renew resources extraction
Abstract
Based on a mathematical model of the predator-prey type interacting populations, we have investigated consumption of natural resources in a system with slow recovery of harvested resource. The proposed model incorporates the saturation effect in the predator population, whose reproduction is limited by the volume of available food and the way of its consumption. The focus of the study is on the problem of optimizing predator and prey production. It is shown that there is an optimal withdrawal rate that ensures maximum income with the sustainable development of the community.



Simulation modeling of selective cutting in the spruce forest stands of the Russian Far East
Abstract
The author has studied the process of the stock and structure of spruce stands restoration after selective cutting with different tree removal intensities, based on simulation modeling. The modeling results show that when the stock reaches the value which was before the cutting, the forest stand structure does not restore to its initial state. With a removal rate of 10–40%, the forest stand structure restoration requires 10–15 years more, than that of the stock.



Modeling the population dynamics of the musk deer taking into account the sex structure and harvesting
Abstract
The author has made the analysis of musk deer population dynamics in the Jewish Autonomous region. The sexual structure, density limitation of juvenile survival and harvesting is taken into account by means of the proposed discrete-time model of population dynamics. The model parameters were estimated using an approach that accounts the total population size and allows the original structured model to be presented as a one-dimensional recurrent equation with a delay. It is carried out a comparison of demographic parameters estimates in the models of musk deer population dynamics, both with and without considering harvesting.



BIOLOGY
Dynamics of old-growth spruce forests in the Moscow Region
Abstract
The authors have studied the dynamics of spruce (Picea abies) forests in the Moscow region over the past four decades, and have traced main trends after the decay of old-growth spruce forests, as well as changes in ecological conditions of habitats. It was revealed the two multidirectional forms of secondary successions: with restoration of spruce undergrowth and with active development of shrubs.



Flora and vegetation of the Tygranaya ecological trail in the Bastak Nature Reserve
Abstract
The author notes the role of specially protected natural areas in the development of ecological tourism. Quantitative and qualitative characteristics of vegetation cover on the Tigrinaya ecological trail in the Bastak Reserve of the Jewish Autonomous region are given in the work. Vegetation of the Tigrinaya ecological trail is represented by a coniferous-broadleaf shrub-forb forest. The predominant tree species is The Amur linden Tilia amurensis, the dominant shrub is the thin-leaved mock orange Philadelphus tenuifolius, the most common herbaceous plant is the Asian celandine Chelidonium asiaticum.



Conservation of wild bees (Hymenoptera: Apoidea) as an important component of biological resources
Abstract
Wild bees represent an important component of natural resources which needs to be preserved. The work draws attention to the uniqueness of the wild bee fauna in specially protected natural areas. The survey, conducted in nature reserves and national parks in the south of the Far East, shows a violation of environmental legislation by institutions. Among them, there is a lack of understanding of how important it is to devoid placing honey bee apiaries within and near the borders of protected areas. At this, wild bees are being «squeezed out» by honey bees, which leads to the destruction of pristine ecosystems.



Protein degradation in the tissues and organs of the Kola Peninsula Pink salmon Oncorhynchus gorbuscha during the downstream and the spawning migration
Abstract
In the work, it is assessed the intensity of protein degradation in tissues of the Kola Peninsula pink salmon during its downstream migration from the Indera River to the White Sea and in skeletal muscles of pink salmon spawners during its spawning migration from the White Sea to the Indera River. The authors have shown a relationship between the level of protein degradation and the life cycle stage of the pink salmon. They have established peculiarities in the physiological state of the Kola Peninsula spawning pink salmon, estimated by the level of intracellular protease activity and the content of carbonylated proteins, as compared to pink salmon species beyond migration.



Methodology for assessing birds as a biological resource during seasonal migrations
Abstract
The article proposes a technique that allows to significantly expand the information received on bird migrations. Due to minimal labor costs, it is most convenient for use in specially protected natural areas. Particularly valuable in this technique is the ability to reliably define the biomass of migratory bird species throughout the migration period.



Study of the sable population structure in the north of the Jewish Autonomous region: morphotypic analysis
Abstract
Intermolar palatine folds were studied for 91sable specimens from the northern part of the Jewish Autonomous region during four hunting seasons of 2015–2016, 2021–2022, 2022–2023 and 2023–2024. From 7 to 10 transversely extended palatine folds were found in animals. One of them is antimolar, situated between the canines, and from 6 to 9 folds are intermolar. Symmetrical and asymmetric morphotypes of intermolar palatine folds, including full-size and half-length variants, have been studied. The total sample revealed 6 symmetrical and 9 asymmetric morphotypes. In all seasons, the most common morphotype is symmetrical right-left (7.5–7.5). It was revealed a seasonal change in various morphotypes occurrence. The share of asymmetric morphotypes in the total sample was 24%, while in the last season (2023–2024) it was observed a decrease in their diversity to two variants, and a decrease in their share - to 14%.



Areas of brown bear habitat and movement in the Russian Far East
Abstract
Studies on the use of space by brown bear (Ursus arctos) have been conducted in five regions of the Russian Far East: Middle Sikhote-Alin, Southern Kamchatka, Eastern Kamchatka, Central Kamchatka, and Eastern Sakhalin. Telemetry was used to determine the locations and movements of 45 brown bear individuals equipped with radio or GPS collars. Annual habitat of the brown bear on Sikhote-Alin is, on average, 891.3 and 349.9 km2 for adult males and females, respectively. These indicators are larger than those on Kamchatka and Sakhalin: 153.1 km2 for adult bear males and 6.1-27.6 km2 for adult females. Their areas are smaller in spring than in summer and fall. Averaged daily movements of adult females are 1.7, 1.8 and 1.0 km for the Middle Sikhote Alin, Eastern Kamchatka and Eastern Sakhalin, respectively. Males in the Middle Sikhote-Alin move, on average, 3.1 km per day. Tagged bears moved long distances any season except for the denning period. Knowledge of the spatial ecology of the brown bear is important for managing this species populations.



Spatial and temporal characteristics of brown bears forced shooting cases in the Sakhalin Region
Abstract
In the Sakhalin Region, for the period of 2014–2024, it was registered a highly frequent forced shootings of the brown bear (Ursus arctos L., 1758) in populated areas (98 individuals per year, on average). The overall dynamics of brown bears forced shootings tends to increase. Most of the cases are in the urban districts of Yuzhno-Sakhalinsk, Anivsky, Korsakovsky and Kholmsky (>80 cases). In July-August (summer food period) the highest number of forced brown bears shootings were recorded.



GEOECOLOGY
Assessment of the abandoned arable land to agricultural use return effectiveness (by the example of the Selenga River middle course, southwestern Transbaikalia)
Abstract
On the example of abandoned arable land in the middle course of the Selenga River, ithe author has made an assessment of their return effectiveness to agricultural circulation. The abandoned arable land re-development efficiency is defined by the income obtained when growing crops on them. The income received is compared with the cost of reforestation of abandoned arable land. At this stage of the study, we have calculated net operating or rental income (NPV) for each of the previously growing crops that could be re-cultivated in the study area.



Features of the soil and vegetation cover in the construction area of the Moksky hydroelectric complex
Abstract
The authors have carried out expeditionary studies of natural complexes at the Moksky hydroelectric complex influence zone. It was laid 6 supporting soil sections along the Bargalino transect – the village of Bargalino, Muisky district, Republic of Buryatia (RB). The soil sections morphological description and that of the vegetation cover has been given by the authors. It is defined the features of plant communities structural and dynamic organization and analyzed the stages of regenerative succession on the abandoned agricultural lands. Phytocenotic diversity and features of the plant communities spatial and temporal organization have been revealed.



Research of the vegetation species composition dynamics in the Nadezhdinskaya drainage system (Jewish Autonomous region) different age fallows
Abstract
This paper contains research results for the vegetation composition dynamics on fallow lands of the Nadezhdinskaya land reclamation system in the Jewish Autonomous region. It was determined that on lands that were withdrawn from agricultural circulation more than 5 years ago, a grassy cover is formed, belonging to the wormwood-grain-mixed-grass association. In such areas, perennial and annual weedy-ruderal plants predominate. As the fallow age increases, the proportion of weedy-ruderal vegetation decreases and overgrowth occurs with woody and shrub species, among which the Salicaceae family species are represented as pioneer ones. They grow separately in young and middle–aged fallows, and form separate groupings in older fallows. The maximum species richness is observed in the middle–aged deposit (15 years) – 35 species, the minimum – in the 10–year deposit – 13 species. The Asteraceae family dominates in the fallow areas species composition, but with an increase in the age of the deposit the proportion of other families – Fabaceae, Poaceae and Rosaceae – is also significantly increasing. In addition, the geobotanical analysis revealed the fallow lands stages of overgrowth: weedy – rhizomatous – woody-shrubby.



Soil compaction on the Bastak Nature Reserve ecological trails
Abstract
The upper soil horizons density measurements were made on the Bastak Nature Reserve ecological trails of Uchebnaya and Tigrinaya. The author assessed the upper soil horizons condition. In was noted that soil conditions were favorable for plant growth. It was revealed that the Bastak Nature Reserve soil cover state on the ecological trails depends on recreational effects. The author has proposed the measures aimed to minimize the recreational impact on the Bastak Nature Reserve ecological trails.



Ecological state of the Birobidzhan dendroflora: monitoring and forecasting
Abstract
Taking into account the development trends of Birobidzhan, the author gives an assessment of dominant tree species living state, and, in general, the dendroflora ecological condition as an indicator of the urban environment quality. On the base of identified pathological changes in the state of green space, it is given an assessment and forecast for the urban environment development. Basic principles are formulated and proposed, aimed to improve the environmental strategy of the town development through its landscaping.



Soil condition as an indicator of terrestrial ecosystems bioresource potential (by the Prikhankai Lowland example)
Abstract
An assessment of some meadow, marsh soils and agrobiocenoses at the Prikhankai Lowland was made according to two indicators, most important for defining soil fertility and availability of mineral nutrition elements for plants. In terms of humus/organic matter content, the soils fall into the range of gradations «low» – «very high». At the same time, 82% of soils belong to gradations with medium and higher humus contents. A little more than 50% of soils have an optimal slightly acidic and neutral reaction. The remaining soils with an acidic and strongly acidic reaction require its optimization to avoid the loss of soluble nutrients by the soil.



Retrospective analysis of green space system formation in Birobidzhan
Abstract
In the paper, the author analyzes the stages of green space system formation in the town of Birobidzhan, starting from the establishment of Tikhonkaya station and to the present day. He identifies five stages, each differing in greening methods, their reasons, species composition, the areas being greened, and other factors. It has been determined that the main landscaping was done between 1950 and 1980, majority of these trees still growing today. The tree plantings primary species are the Manchurian ash, Small-leaved elm, Flat-leaved birch, Maximovich poplar, Fragrant poplar, and Ayan spruce. Starting from the fifth stage of the town’s green space system development, there has been a noticeable shift away from using poplars in greening efforts. Currently, Birobidzhan is carrying out landscaping works as part of national projects, introducing new species of woody and shrub plants, creating public spaces, etc.



Current state and prospective directions for the use of specially protected natural areas in the Jewish Autonomous region
Abstract
The project provides a brief overview of the current network of specially protected natural areas (SPNA) in the Jewish Autonomous region (JAR). The diversity of plant and animal species is emphasized. Particular attention is paid to the potential use of biological resources and territories for scientific, educational and recreational purposes. It is determined that the key factors for the development of recreational infrastructure within SPNA are the proximity to settlements and logistical accessibility, as well as the presence of well-maintained ecological trails and well-designed excursion routes, which form the regional modern tourism network. It is highlighted that tourism concepts and potential directions for the regional biodiversity integrated use are currently being developed in the JAR.



Measures to optimize rational nature management in the Lukashov Nursery Nature Park
Abstract
The author considers the issues of rational use of biological resources in the protected area of Lukashov Nursery Nature Park, located in Khabarovsk. After the inventory of the park green space, it is proposed to optimize the measures aimed at preserving and restoring the protected area.



Designing a national park in the Khingan Gorge Area
Abstract
The article describes the history and problems in the creation of federal protected area at the unique landscape formation – the Khingan Gorge on the Amur River. According to the results of the new justification, prepared in 2022, it is proposed the two clusters compromise option, on base of the regional reserves of Dichun and Zhuravliny, with a total area of 160 thousand hectares. At this, there will be no reason for conflicts with miners and loggers, as their activity area is excluded from the national park borders.



Ecology
Relationship of ndvi pine forests with temperature and precipitation in the Lower Amur Region
Abstract
The authors research linear links between the vegetation index NDVI of pine forests, climate characteristics and geographical directions in the Lower Amur region. The relationship of NDVI with precipitation in the cold period is negative (rs=-0.49). The link of NDVI with mean annual and the warm period temperature is positive (rs=0.43 and 0.52 respectively). To the southwest and to the south, NDVI of pine forests increases (rs=0.51), and precipitation in the cold period decreases. To the north, NDVI decreases (rs=-0.44) in conditions of climatic cooling.



Forest resources of the Bastak State Nature Reserve (Jewish Autonomous Region)
Abstract
The article provides information on forest resources of the Bastak state nature reserve. The author identifies age structure features of the forests in a specially protected natural area, and gives a brief taxational description of main forest-forming agents.


