Home – Home – Jornals – Contemporary Problems of Ecology 2025 number 2

In evolutionary biology, the dominant idea is that the mechanisms of intraspecific evolution and speciation are the same, and intraspecific forms are, in essence, emerging species. The extensive literature on the evolutionists’ model species, the three-spined stickleback, allows us to verify whether this is so, and the analysis shows that although this fish, when living in fresh water, give a variety of forms that are morphologically very different from marine ones, postzygotic reproductive isolation between representatives of different forms does not usually occur. No such form of isolation has been found between populations from different parts of the species’ range. The adaptation strategy of the three-spined stickleback includes long-distance migrations that facilitate the inhabiting of newly emerging favorable habitats and the exchange of genes between populations, acceleration of selection, and a decrease in the probability of recombination of alleles of genes necessary for adaptation. This strategy does not facilitate speciation in representatives of the genus Gasterosteus, so it occurs extremely rarely and occurs due to the fusion of chromosomes (similar chromosomal rearrangements within the species G. aculeatus have not been noted). Thus, at least in this case, the mechanisms of speciation (saltation mechanisms) are completely different from the mechanisms of generation of forms within the species.

In this work, the dynamics of the temperature profile in the soils of Central Siberia were restored and analyzed based on data from weather stations, revealing the patterns of the long-term (1963-2022). The relationship between the temperature regime of soil in the permafrost zone and the long-term dynamics of air temperature during winter and summer was quantified. The current trends in soil temperature regimes along the depth gradient were evaluated in relation to climate changes in the region. An increase in the average annual temperature for each soil layer was typical for all variants of the degree of permafrost closure. The increase in the average annual soil temperature is manifested up to a depth of 320 cm, with a growth coefficient of 0.66-0.70 °C/10 years. Maximum values of the coefficients (0.67-1.64 °C/10 years) are typical for the permafrost zone of the coast of Central Siberia. At the same time, the average annual soil temperature parameters correlate with the dynamics of air temperature. The correlation is most significant for the upper soil horizons (r ~ 0.8) and naturally decreases with the depth of the soil profile. This pattern is most prominent in the coastal zone of continuous permafrost (>75° N). Predictive temperature profiles of soils were obtained with reference to permafrost zoning in Central Siberia. The projection of soil temperature regimes until 2050 indicates the potential for significant modifications in seasonally thawed layers. According to our estimates, the increase in thickness could be between 3-12 cm/10 years.

The ecological and geographical differentiation and dynamics of the autumn migration of passerine birds of the Putorana Plateau are analyzed. In 1988-2004 on an area of 150000 km², 8 points were surveyed in the western and central parts of the region. The route accounting method was used. The passerine fauna of Putorana during the autumn migration period includes 42 species. Birds fly along a narrow coastal-edge strip along the banks of large rivers or lakes in the southern, southwestern or western directions. There are species distributed everywhere ( n = 16; 38 %), locally ( n = 9; 22 %), and locally ( n = 17; 40 %). Bird population density is 239-643, on average ( n = 8) - 440 individuals/km². The population density of passerines during autumn migration is maximum in the south of Putorana, less in the middle part of the region, and minimal in the north of the plateau. At multi-day observation points on the days of the most intense flight, the population density was 420-796, with an average ( n = 2) of 608 individuals/km². Passerines fly at 8.00-12.00. For most species, the average duration of the entire autumn migration is 20-26 days, the main one is 7-12 days. The vast majority of individuals of almost all migratory species are united in monospecific and polyspecific flocks. The configuration of the autumn flight is a combination of four waves with four well-defined maximums. The most powerful surges of migration activity are associated with a decrease in air temperature and the absence of precipitation. The bulk of individuals of different species of the same genus usually migrate on different days. Synchronization of waves of maximum passage is rare in related species. The population is dominated numerically by the Arctic Warbler, the Common Redpoll, and the Little Bunting.

The distribution patterns of plant families along the aridity gradient with regard to their role in the floristic composition and structure of grasslands in Inner Asia were studied. We determined the relationships between the aridity, diversity and activity of 35 leading plant families using Thornthwaite index on the basis of formalized analysis of 6256 relevés. The studied aridity gradient covers most territory of the Eurasia (88 %). Communities were analyzed from subalpine tall-grass meadows in the hyper humid areas of the Altai-Sayan mountains to the deserts of Central Asia. Different results had been obtained when comparing family-species spectra with different levels of aridity considering species composition and importance values (activity). The correlations between the aridity index and 35 families in 16 synoptic species indicated that the ten most rich families Asteraceae, Chenopodiaceae, Fabaceae and Poaceae showed strong positive relationship with aridity index, the family Brassicaceae showed a moderately positive relationship with aridity index, the family Ranunculaceae showed a strong negative relationship with aridity index, and Apiaceae, Caryophyllaceae and Rosaceae had a moderately negative relationship with aridity index. The correlation analysis of the importance values of the 35 families with the aridity index showed that Asteraceae, Fabaceae and Poaceae were not associated with the aridity gradient, suggesting their significant ecological and phytocoenotic heterogeneity. Among other top families Chenopodiaceae and Brassicaceae had strong positive relationships with aridity - Caryophyllaceae, Lamiaceae and Ranunculaceae had strong negative relationship with aridity and moderately negative relation - Apiaceae and Rosaceae. The use of species constancy and abundance in taxonomic spectra analysis can take into account the phytocoenotic importance of plants. This approach can be used to search for indicators of climatic processes, including those related to aridification of Inner Asia.

The influence of catastrophic forest fires on the ground cover in the forests of the Lena-Vilyui interfluve has been studied. Obtained results showed changes in species diversity, and reserves of aboveground phytomass of the ground cover in the larch and pine forests in natural and in burnt state. The correspondence analysis species composition on the control and the burnt sites showed that the control pine and burnt forests have similar distributions, and the control larch and burnt forest differ in the distribution of species. Compared with 2022, in 2023, the burning of larch and pine forests showed an increase in aboveground phytomass by 1.6 and 4.4 times, respectively.

The aim of this work was to study the bioproductivity, C-biomass and elemental composition of humic acids as a single ecosystem of dry-steppe soils. The objects of the study were virgin chestnut soils of the southern steppes of Western Transbaikalia. It was revealed that chestnut soils are formed under dry-steppe plant associations with sparse and low-growing grass, with a poor species composition. The net primary production in chestnut soils of the study region is 4.80 ± 3.48 kg/m² year, where the underground mass exceeds the aboveground mass by 9 times. Plants of more continental steppes, with a greater moisture deficit, direct a larger proportion of photosynthetates (up to 90 %) to the root mass compared to plants of the western steppes. The ratio of BNP to ANP is 1 : 9 and can reach 1 : 25. The participation of C-biomass of microorganisms in the total reserve of organic carbon of chestnut soils is up to 2.5 % of Corg. The dynamics of accumulation of C-biomass is limited by soil moisture and the reserve of energy resources. The elemental composition of HA of cold, chestnut soils is characterized by a low carbon content; relatively high content of nitrogen and hydrogen. The molecule of HA of chestnut soils has a weakly condensed aromatic nature, the aliphatic part predominates in it. The consequence of the weakened condensation reaction is an insignificant level of the degree of benzenoidity. ¹³C-NMR spectroscopy showed that the humic substances of chestnut soils are characterized by a reduced content of aromatic components.

Climate warming leads to a wider distribution of heather shrubs, with biochemically very active ericoid mycorrhiza, in mountain meadows of temperate latitudes, where less active arbuscular mycorrhiza predominates. Our working hypothesis was: the expansion of heathers can increase the microbiological activity of soils (basal respiration, respiratory metabolic coefficient, activity of hydrolytic enzymes, rates of nitrification and ammonification), specifically change the taxonomic composition of the prokaryotic complex, nitrogen, carbon and phosphorus status of soils. These indicators were compared in different relief elements in the humus-accumulative horizons of Umbric Leptosol under shrubs and grasses in regions contrasting in climate and soil-forming rocks: the alpine wastelands of the North-Western Caucasus and the mountain tundra meadows of the Khibiny. The same heather species grow in these regions, which makes it possible to isolate the direct specific influence of plants, regardless of other environmental factors. The specific effect of the presence of heathers has not been established. The soil properties were primarily influenced by the location of sampling (position in the relief, soil-forming rock). The second is the region of study (climate). The features of the prokaryotic complex specific to each sampling site are not interrelated with the studied chemical parameters and microbiological activity. Nevertheless, general differences in the prokaryotic complex are associated with pH_Н2O, indicators of carbon (C_SOM), phosphorus (P_{ext. min}, C/P_SOM) and nitrogen (N_micr, C_SOM/N_ext, N-NH₄⁺) state of soils.

Impending climate and environmental changes will require robust species distribution modeling to inform management decisions to mitigate their impacts on biodiversity. Such modeling needs the appropriate data (often including many variables) that have influenced species’ distributions over time. The Daurian Pika is a good model species for climate warming feedbacks because of its habitats climate extremes (very hot summers, very cold winters) and its key role in ecosystems of the northern Asian steppes. In this study, we quantified the predictors of pika abundance at a local scale. In 236 plots (10 × 10 m²), we measured 8 environmental variables and counted the openings of pika burrows as an index of the relative pika abundance. Generalized linear models were used to identify the dependence of the openings number on chosen environmental predictors. In the independent field study, we counted the number of pika burrow openings in the plots of the same size and used it to test the best models. The best models include percentage coverage of dense tall vegetation, slope aspect, and soil thickness as predictors. Pikas are more abundant in the plots with thick soil covered by dense, tall vegetation. Also, there are trends to set burrows on gentle slopes and plains, on grounds with slightly dense or dense and plastic soil, with low stoniness. The number of burrow openings is significantly lower on the northern and eastern slopes. Our best model predicted number of burrow openings in test plots in two localities reasonably well. Our results demonstrate that a set of abiotic factors accurately predicts the Daurian pika distribution at a local scale. We suppose that among analyzed factors, some directly relate to pikas and possibly affect their distribution in a similar way in any environment. These are soil characteristics that allow pikas to construct burrows and likely vegetation cover. Other factors mediate the impact of climate on microclimate and food resources, and their effects vary depending on local environment characteristics.

Our study is devoted to foraging strategies of sympatrically nesting Glaucous Gulls (Larus hyperboreus) and Vega Gulls (Larus vegae) in two locations on the Chaunskaya Bay of the East Siberian Sea. Both species of gulls nested both in colonies and single pairs, and their foraging methods were similar: scavenging, collecting, and active predation on eggs and chicks. Anthropogenic food sources were prioritized by both species. The second most important food source for Glaucous Gulls was birds, whereas for Vega Gulls it was isopods. Differences in diet between gulls breeding in colonies vs gulls breeding as single pairs were more substantial than differences in food spectrum between different species with the same nesting strategy. This pattern is especially prominent in with Vega Gulls. Single pairs of both species could not afford long foraging trips and foraged in the cloth vicinity of their nests, using other bird species as a prey (a stable available resource in the nesting habitat). Colonial gulls foraged mostly on landfills (a stable resource but located far away from the nesting sites).

The anthropogenic impact on various components of aquatic ecosystems and, in particular, on the structure of river zooplankton communities requires comprehensive study in modern conditions of intensive environmental natural resource management. The aim of our study was to assess the impact of urban wastewaters on the chemical composition of water and structural parameters of river zooplankton of the River Stepnoy Zay, a small river from the industrial zone of the Middle Volga region, a left tributary of the Kama River. Sampling was carried out from 2008 to 2019 upstream and downstream of municipal wastewater discharges of the four cities located in the upper, middle and lower reaches of the river. Our results showed that the main chemical compounds that significantly differed in their concentrations in the areas above and below urban drains were ammonium, nitrates, phosphates, organic substances (BOD₅). These pollutants were also the most significant variables explaining variations in the species composition and quantitative indicators of zooplankton. In relation to the leading environmental factors, 3 groups of species were distinguished: indicators of organic pollution; species tolerating increased mineralization; species sensitive to oxygen content. 114 zooplankton taxa were identified in the river. The abundance and biomass of zooplankton varied significantly at stations above and below cities. Zooplankton communities below cities in the upper and middle reaches of the river (Bugulma, Leninogorsk, Almetyevsk) are influenced by the influx of planktonic organisms from biological treatment facilities with wastewaters. The stations in the lower reaches of the river belong to the mouth section and zooplankton communities here are formed under the influence of the river Kama. Observations of the development of zooplankton communities will continue.