Home – Home – Jornals – Contemporary Problems of Ecology 2024 number 3

The spatial divergence of climatic changes necessitates the creation of predictive models of the state of vegetation cover. Our proposed solution for spatial modeling of the biological productivity of natural ecosystems creates the basis for further quantitative assessment of the potential absorption of CO₂, which is currently considered one of the most urgent environmental issues. In the proposed work, using the methods of geo-analysis of growing conditions, an original technology for modeling the potential spread of biocenoses and their productivity has been developed, reflecting the internal attractor of the development of biocenoses under the influence of local hydrological and climatic conditions of their growth. The methodology was implemented for the territory of the south-east of Western Siberia within the framework of the publicly available GIS Saga based on a digital terrain model and data from the WorldClim 2.0 climate reanalysis. To forecast data for the period of the third decade of the XXI century, V. V. Paromov’s regional climate forecast was used on the basis of an adaptive model - the exponential smoothing method. Verification of the simulation results was carried out on the basis of the database “Productivity of ecosystems of Northern Eurasia”. As a result, spatially distributed data were obtained in the form of rasters with high spatial resolution for the average long-term potential bioproductivity according to reanalysis data for the period 1970-2000 and predicted data for the period 2021-2030. Both positive and negative trends of potential bioproductivity for various natural zones of the south-east of Western Siberia have been revealed, due to the spatial divergence of changes in heat and energy resources and precipitation over the territory. In general, the observed warming in sufficiently drained areas contributes to an increase, and in hydro-morphic to a decrease in the biological productivity of agro and biocenoses.

In 2010-2023 the dynamics of population numbers and changes in the share of species in the community of small mammals (insectivores and rodents) inhabiting a slope larch forest in the vicinity of Magadan (Northern Coast of the Sea of Okhotsk) were traced. Сensuses of animals were carried out using trap-line methods, using Gero traps and cones. A total of 4.700 trap-days and 15.720 cone-days were worked. 3.384 individuals of 9 species belonging to the families of shrews (Soricidae), squirrels (Sciuridae), mice (Muridae) and hamsters (Cricetidae) were caught. During the period under review, the relative abundance and the amplitude of its interannual fluctuations decreased in the populations of the equal-toothed shrew (Sorex isodon) and the red-gray vole (Craseomys rufocanus). The shares of the Laxmann’s shrew (S. caecutiens) and the East Asian wood mouse (Apodemus peninsulae) in the community increased by 2.6 and 2.5 times, respectively, while simultaneously decreasing in the equal-toothed shrew by 2.8 times and in the red-gray vole by 3 times. As a result, about 50 % of the individuals in the samples began to belong to the Laxmann’s shrew and about 30 % to the red-backed vole (Clethrionomys rutilus). This, in turn, led to increased dominance (the Simpson index increased from 0.21 to 0.34), a decrease in evenness (the Pielou index decreased from 0.87 to 0.61) and a significant decrease in the species diversity of the small mammal community (the Shannon Index decreased from 1.7 to 1.3; t = 10.90, p < 0.001).

The content and distribution of fluorine in two soil catenas located in the basins of the Burla and Kulunda rivers on the territory of the Kulunda Plain was studied. The use of the catenas method made it possible to compare the content of fluorine in soils of different geochemical relief positions, in zonal and intrazonal soils. It is not just the presence of fluorine in soils that matters, but its concentration, which underlies the dual nature of his biological role - positive or negative, which requires the introduction of sanitary and hygienic standards for his content. In the studied soils, the total content of fluorine varies from 13.9 to 711.03 mg/kg, the water-soluble form varies from 0 to 34.65 mg/kg. It was found that in saline solonetzes developing in superaquatic landscapes, the content of total and water-soluble fluorine have, respectively, ecologically critical and unacceptable concentrations, therefore, the use of these soils in agricultural production is associated with the risk of accumulation of excess amounts of fluorine in the body of animals and humans.

Based on the computation of the coefficients of interspecific conjugacy of Brave, the modern structure of vegetation is established, represented by eight pleiades: forests with Abies sachalinensis; spruce forests with Picea ajanensis; thickets of Sasa senanensis (Franch. et Sav.) Rehder (Shikotan Island), ilm-maple forests with Acer ukurunduense Trautv. & C. A. Mey and Acer mayrii Schwer. (Kunashir Island), maple-oak forests with Acer mayrii Schwer. and Quercus crispula Blume (fr. Iturup); Juniperus sargentii (A. Henry) Takeda ex Nakai (Shikotan Island) thickets and communities with Pinus pumila (Pall.) Regel (O. Iturup, Kunashir); alder-birch phytocenoses, reed-grass and coastal meadows, ruderal vegetation. The species diversity of plants is ensured by local species of East Asian origin. An amphipacific group is represented along the coastline, demonstrating the affinity of local species with the North American flora. The proportion of weeds increases on sites with violations. The indigenous phytocenoses are fir and spruce forests, as well as thickets of Pinus pumila and Juniperus sargentii in the mountains and on the rocks. Under the influence of unfavorable factors, indigenous groups are replaced by birch forests with Betula ermanii and secondary meadows, including ruderal-grass-grain cenoses; in places of felling and fires - bamboo forests with Sasa senanensis. According to preliminary estimates, the share of disturbed lands in Shikotan accounts for 40 % of the territory, of which 30 % is due to anthropogenic impact, and 10 % is due to natural factors. In Kunashir, these numbers are 16 and 17 %, respectively, in Iturup - 23 and 16 %. It is shown that despite the secondary nature of the Sasa senanensis thickets, these communities play a key role in preventing further degradation of natural complexes, soil erosion and the development of exogenous geological processes.

The outbreak prediction is one of crucial components of forest pest management. Weather plays substanial role in the leaf-eating insects outbreaks esteblishment. The weather-based prediction models in this field are numerous and more or less precise. We attempted create such model for Siberian moth (Dendrolimus sibiricus Tschetv.) - one of most harmful defoliator in southern taiga of Siberia. For territory of interest (southern taiga and hemiboreal forests of Tomsk Oblast, Kemerovo Oblast and Krasnoyarsk Kray) the gradient boosting (XBGoost) model was created with accuracy 0,952. The temperatures of vegetation period 4th and 5th years before onset of outbreak are better predictors.

A geobotanical analysis of 160 steppe and ecotone plant communities with the participation of cereals in the north of the Lower Volga region (within the Saratov region) was carried out. The species diversity of apomictic cereals is significantly inferior to the diversity of their amphymictic relatives in the flora of the region and in the studied phytocenoses (24 apomictic and 109 amphymictic species in the flora; 17 and 34 species in the phytocenoses, respectively). At the same time, the dominants of the studied communities are equally represented by both amphymictic (14 species) and apomictic cereals (9 species). It was established that cereals with amphymictic mode of reproduction dominate in 64 phytocenoses, apomictic cereals dominate in 48 ones. The number of phytocenoses in which apomicts are codominants significantly exceeds the number of plant communities with amphymicts codominance (46 and 22, respectively). The studied plant communities are similar in species richness and evenness. The obtained data indicate successful competition between apomictic cereals and amphymicts and their significant contribution to the composition of steppe and ecotone phytocenoses in the northern Lower Volga region.

The analysis of modern scientific ideas has shown that there is no consensus on the definition of the energy of organic matter in ecosystems, and current methods need to be detailed. The article presents the results of the application of the method of component-by-component assessment of the amount of energy of the organic matter of the ecosystem using the energy approach. The methodology is the determination of energy indicators for pools of phytomass, mortmass and soils, as well as the study of the main energy sources involved in the formation of the ecosystem. The research was carried out on the first above-floodplain terrace of the right coast of the Ushayka River in the Tomsk region. The materials for testing the technique were obtained in the field on a scale at the level of landscape facies. In laboratory conditions, the energy potential was calculated by methods of determining the heat of combustion during direct combustion using a calorimeter for fractions of model wood, phytomass and mortmass. According to the results of the study, the main sources of energy for the ecosystem are the Sun and precipitation, which provide 3.357∙10⁹ J/m²/year. The total amount of energy of the organic matter of the ecosystem at the moment, representing its energy potential, is 1.523∙10¹³ J/ha, of which the energy potential of grass cover phytomass is 55.01∙10⁹ J/ha, common pine tree stands - 1.29∙10¹³ J/ha, mortmass - 43.058∙10⁹ J, soils - 6.754∙10¹² J. The results of the work carried out can be applied to agriculture, territorial zoning, monitoring, recreation, creation of special ecological zones.

Long-chain alkenones are produced exclusively by certain species of microalgae Isochrysidales of the order of haptophytes (Haptophyta). These are polyunsaturated methyl and ethyl ketones C35-C42 with 2-4 trans double bonds in the aliphatic chain. The length of the hydrocarbon chain and the degree of unsaturation of double bonds of a given class of lipids can vary depending on the environmental conditions of their producers. This class of substances is well preserved in the bottom sediments of seas and lakes, and therefore can serve as a paleo-indicator of climate change. Currently, studies are being actively conducted to identify the functional dependences of the composition of long-chain alkenones on the temperature and salinity of water in continental water bodies. In arid regions, saline drainless lakes sensitively react by changing the volume of water and its salinity to variations in the “precipitation-evaporation” balance, and, consequently, the sediments of such lakes are sources of information about climate humidity variations in the past. In this work, we analyzed the vertical profile of long-chain alkenones in the upper part of the bottom sediments of the Utichye-3 salt lake located in the steppe region of southern Siberia and compared it with changes in the surface level and salinity of the lake water recorded over a period of about 100 years. It has been shown that the content of long-chain alkenones in sediments can increase during periods of high salinity. Consequently, the composition of alkenones can be used to reconstruct changes in salinity from bottom sediments of drainless lakes, and therefore to reconstruct dry periods in the history of the climate of the steppe zone of southern Siberia.

The problem of differences in the rates of evolution among different species of animals and plants has been discussed very intensively in recent years, and, in connection with this, the question of whether the so-called molecular clock hypothesis is valid is acutely raised. We conducted a search for scientific papers providing median networks that include mitochondrial gene haplotypes for closely related boreal and Arctic (or dispersed through the Arctic) fish species. In all seven cases analyzed by us, in Arctic taxa or taxa that passed through the Arctic during their phylogeny, the rate of nucleotide substitutions was higher, and this difference, as it turned out, is statistically significant. Thus, the formation of new fish taxa in polar latitudes is accompanied by rapid evolution of mitochondrial DNA, which, apparently, is the manifestation of their adaptation to a new habitat. In addition, speciation in fish in the Arctic is usually accompanied by multiple chromosome fusions. Thus, both our and the literature data give new strong reasons to doubt the validity of the molecular clock hypothesis.

The paper presents information on the population parameters of black scorpionfish from different coastal regions of Crimea, its growth rate, as well as its nutritional spectrum. The modern food supply of scorpion fish from the south-eastern part differs from that in 1940-1950: in the Sevastopol region, scorpion fish mainly consume fish, and in the waters near Feodosia - crustaceans. The main changes in food items depending on the age of the Scorpaena porcus are associated with the components - decapods or fish. In the southeastern part of Crimea, small fish species predominate in the diet of scorpion fish, which affected the higher growth rate of the studied object. At the age of 6 years and older, the S.porcus in these waters consumes mainly decapods. In Sevastopol waters, the diet does not change significantly depending on age, so the fish component in the stomach of scorpion fish of older age groups allows it to grow faster. However, no significant differences in the growth rate of fish from the two areas were obtained. The data presented on the physical and chemical parameters of water, as well as the distribution of bottom macrophyte in the two main study areas, demonstrate small differences in the quality of the habitat and are satisfactory for the bottom predator studied. The average age of the scorpion fish from Karadag was 5.9 years, the most numerous age group was 4 years old, the average age of individuals from the water of Sevastopol area was 3.72 years, the most numerous age group was 3 years old. In the Sevastopol region, scorpion fish up to 5 years old are larger than in the Feodosia region, and from 6 years old - vice versa. Despite this, in most cases the condition factor of fish from the waters of southeastern Crimea was higher.

In order to obtain understanding of trematode diversity in the invasive mollusk Viviparus viviparus, the prevalence of larval trematode species (cercariae and metacercariae) in the Tura River near Tyumen, Western Siberia was investigated. A total of 53 snails with a shell height of 17-32 mm were studied. Three species of trematodes were found: cercaria Cercaria nigrospora (3.77 %), cercaria Neoacanthoparyphium echinatoides (5.56 %), metacercaria N. echinatoides (58.5 %, 47-279), non-encysted metacercaria Leucochloridiomorpha constantiae (62.3 %, 2-69).