Regional problems

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.