Home – Home – Jornals – Contemporary Problems of Ecology 2026 number 2

The relevance of studying the structure of food chains in high-latitude lakes characterized by oligotrophy and a significant influx of allochthonous organic matter from adjacent marshes is beyond doubt. In this study, an attempt was made to identify carbon sources in various trophic groups (zooplankton, zoobenthos, fish) and analyze trophic relationships between them, taking into account seasonal dynamics in a small subarctic humified lake located in the north of Karelia (White Sea coast). To achieve this goal, an isotopic analysis of stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes was carried out in the tissues of consumers and potential producers in different seasons (summer, autumn, winter and spring) of 2019-2020. The results of the study revealed significant differences in the structure of the lake food web between the open water and ice-covered periods, which is likely due to changes in the level of phytoplankton primary production, sources and rates of allochthonous organic matter input, and a significant energy contribution from heterotrophic organisms associated with methanotrophs. The important role of methane carbon in the formation of organic matter in this reservoir was indicated by low δ¹³C values (<-40 ‰) in consumers such as zooplankton (dominated by Eudiaptomus graciloides) and chaoborids (Chaoborus sp.), apparently actively involved in the transfer of methane carbon within food chains. In summer, a significant contribution of diazotrophic nitrogen fixed by planktonic cyanobacteria acted as an important source of nutrients. Seasonal variations in δ¹⁵N values and trophic position were determined for the common perch (Perca fluviatilis). The obtained data contribute to the understanding of the mechanisms of energy and trophic links formations in humified lake food web with an influence of allochthonous organic matter.

Multimetric indexes (MMI) are an important biomonitoring tool that is widely used to assess the ecological status of aquatic ecosystems worldwide. The effectiveness of MMI lies in their ability to combine both the structural and functional features of communities of organisms, as well as the features of the entire ecosystem. The use of organisms such as macroinvertebrates in the development of MMI is most common in lake biomonitoring. No such work has been carried out in Russia to assess the ecological state of lakes. In this study, a multimetric index based on the composition and structure of macroinvertebrate communities was developed for low-altitude Altai lakes experiencing high recreational and agricultural stress. The studied lakes were grouped into two groups according to the degree of organic pollution: reference and disturbed. Using a step-by-step statistical analysis, five metrics were selected from 55 indicators of macrozoobenthos communities, which were included in the final multimetric index. The selection tests included sensitivity (discrimination), stability (seasonality), redundancy, and correlation with environmental variables (abiotic factors). The new index was compiled by the following metrics: the Pielou Evenness index, the number of mayflies, the occurrence of shredders, the number of caddisflies and gammarids. These indicators were evaluated on a continuous scale and divided into 6 classes of water quality in accordance with the classification adopted in Russia. The developed index demonstrated the ability to distinguish not only dirty and clean lakes, but also moderately polluted reservoirs. The new index can become an informative tool for monitoring and assessing the ecological status of lakes.

In 2023-2024, the composition and quantitative indicators of zoobenthos of Lake Teletskoye were studied for the first time during the period of glaciation in annually freezing areas of the reservoir. A comparison of water quality according to the state of zoobenthos in the same type of communities in the water area with increased anthropogenic load (North-western shallow) and in the water area of the reserve (Kamginsky Bay) is given. The current standards for environmental monitoring of the reservoir have been optimized.

Changing hydrothermal regime together with dendrophages outbreaks, are the main factor that determining the vitality, growth dynamics and changes in the ranges of conifers. The causes of mass dieback of Abies sibirica Ledeb in the taiga of the Eastern Sayan Mountains (the Krasnoyarsk Stolby National Park) and fir trees vitality within the area of fir dieback were studied. The mortality fir was preceded by a chronic decrease in the trees growth index (GI) associated with water stress which was observed since warming start in the 1970s. The unprecedented dieback of the fir forest was triggered by the abnormal drought in 2012, which led to an abrupt increase in water stress and a strong decrease of the GI of trees. The extreme deterioration of the fir forests vitality stimulated the outbreak of the bark beetle Polygraphus proximus Blandford. The trees dieback, the maximum of which was observed in 2013-2018, resulted in the mortality of up to 75 % of fir-dominant forests. The reaction of fir to P. proximus attacks included the formation of a “physic-chemical” barrier in the tree rings, consisting of closed rows of traumatic resin ducts and xylem lignification. Currently, the number of viable fir regeneration (3-10 thousand/ha) is potentially sufficient for the fir restoration in most zone of fir mortality. However, the predicted worsening of hydrothermal regime in fir habitat in synergy with P. proximus outbreaks suggested future cycles of fir mortality and partial restoration in the 21st century. The considered unprecedented fir forests mortality is within the phenomenon of conifer mesophytes health status worsening in the southern parts of their ra range.

This publication provides a current assessment of the synurbic population of Magpie in Belarus. The current distribution of Magpie in urban territories is given based on quantitative surveys of this species in 2024-2025, which covered all the most favourable habitats in 19 of the largest cities and 12 smaller cities in various regions of the country. Studies of the habitat preferences and breeding densities of Magpies were conducted in 2015-2025 in the largest synurbic population of this species, which is found in Minsk. As a result, it was established that the current distribution of synurbic populations of Magpie across the territory of the republic is highly uneven. The total estimated synurbiс population of Magpie in Belarus is 6-6.3 thousand breeding pairs. More than 80 % (5-5.4 thousand breeding pairs) of the entire synurbiс population of this species is concentrated in Minsk. In Baranovichi, the city with the second highest number of breeding pairs of Magpie, there are no more than 130 breeding pairs of this species. In the 13 largest cities in Belarus, Magpie nests in single pairs (up to 10 pairs) or is absent. Our results suggest that synurbiс population groups of Magpie in different cities of Belarus formed independently. The current average breeding density of Magpie in Minsk is 27 pairs/km² and the number of this species has increased compared to 2015-2016. The breeding density of Magpie decreases from individual and low-rise residential buildings (0,26±0,26 pairs/ha), as well as small-area tree and shrub plantations (0,36 ± 0,61 pairs/ha), to multi-storey modern residential buildings (0,2 ± 0,12 pairs/ha) and large-area tree and shrub plantations (0,2 ± 0,1 pairs/ha). Although the synurbic population of Magpie in Minsk is generally increasing, there are noticeable fluctuations in numbers from year to year and a constant redistribution of breeding pairs within the city.

The diversity of ecosystems and soil cover in the floodplain-delta part of the Uldza River were studied for the first time. Marshy, meadow-marshy, meadow and steppe-meadow ecosystems are the most common. The small area of the territory under the study is characterized by a variety of soils - from poorly developed stratified alluvial to highly-humused alluvial dark-humus and dark-humus (quasi)gley soils. They are supplemented by highly waterlogged and subaqueous soils of swamps and swampy depressions, where alluvial processes proper are less pronounced, and accumulation of humus, peat, formation of gley or quasi-gley horizons prevail. The main and additional (cryo-, eolian- and halogenesis) soil-forming factors for different types of soils are characterized. In the area of detailed soil survey, alluvial dark-humus (meadow) and light-humus (turf) carbonate soils prevailed, which are loamy in the upper horizons and sandy-sandy loam in the underlying ones. They are characterized by strongly alkaline pH values and carbonate saturation, insignificant humus content, except for the organogenic horizon (AU) of the alluvial dark humus (meadow) soil. The absorption capacity is at an average level of provision, but significantly decreases in sandy-sandy loam sediments. The exchangeable cations are dominated by Ca²⁺ and Mg²⁺, but the proportion of Na⁺ increases with depth. Alluvial soils are slightly saline, and the salinity chemistry is predominantly magnesium-sodium according to the cation ratio, and chloride-soda, taking into account anions. Geochemical features of the soils were established to be the accumulation of Ca, Sr, As and dispersion of iron group elements. A weak degree of chemical weathering (CIA), low biological activity, high heterogeneity of sediments (HM) were revealed according to geochemical coefficients. Soils under the study should be preserved as protected natural objects, as the basis for the diversity and functioning of original protected ecosystems. The obtained materials will be necessary for monitoring of possible functional and dynamic changes in the ecological status of floodplain-delta landscapes both under global and cyclic climate changes.

Peat soils (Drainic Hemic Histosols) of a drained mesotrophic swamp of the South taiga subzone of Western Siberia occupied by pine forests (Pinus sylvestris L.) were studied. The most favorable conditions for the development of soil catalase activity were observed in the regime of moderate hydro-reclamation. By this level, the oxidase activity of weakly and intensively drained soils was 71 % and did not differ statistically from each other. A reliable relationship by parabola-type between seasonal catalase activity and time factor has been established. Parabolic trends of weakly and intensively drained soils show: Catalase activity accelerated weekly on average by 1.04 and 1.27 absolute values with weekly average deceleration by 0.12 and 0.14 units, respectively. In soils of moderate drainage, the average weekly decrease was 1.31 with a weekly average acceleration of 0.076 units. Analytical indicators of the time series made it possible to identify intra-seasonal periods of catalase activity, determine the direction and intensity of changes, and differentiate the soil profile by 0-5, 5-10, and 10-30 cm in terms of the intensity of processes. An area of 5-10 cm, equivalent to the concept of median (growth coefficients increase up the profile, decrease down by about one and a half or two times), corresponds to one approximation or another to the indicators of seasonal enzymatic activity of the soil profile as a whole (0-30 cm) per season. A highly significant advantage of the parabola type has been established: a positive regression relationship between the catalase activity of soils and bulk moisture >17…<71 %, pH 3.6-4.4, redox potential >600 mV, negative - with a temperature from 2 to 17 °C. According to the canonical analysis, the interrelated effect of the discussed indicators in soils of weak drainage was 82 %, moderate - 40 % and deep - 57 %. The coefficients of the factor structure postulated bulk moisture as the dominant environmental parameter for regulating the enzymatic activity of peat soils.

This study presents the results of a model experiment investigating the effects of atmospheric pollutants - sulfuric and nitric acids, ammonium sulfate, and ammonium nitrate - on the epiphytic organisms Parmelia sulcata and Orthotrichum speciosum. The experiment simulated the deposition of polluted atmospheric precipitation. The assessment included spectrophotometric analysis of photosynthetic pigment content (chlorophylls a and b) and evaluation of morphological changes. All tested pollutants induced stress responses manifested by reduced pigment content and structural tissue damage. Ammonium sulfate ((NH₄)₂SO₄) exerted the most pronounced inhibitory effect, leading to sharp pigment decline and morphological degradation. In contrast, ammonium nitrate (NH₄NO₃) had the least damaging effect, likely due to its high bioavailability and balanced nitrogen composition. The lichen P. sulcata exhibited more pronounced changes and higher sensitivity, while the moss O. speciosum showed signs of resistance and compensatory reactions. Cluster analysis confirmed differences between the taxa and revealed two stable response types: sensitive (P. sulcata) and compensatory (O. speciosum). The findings highlight the diagnostic value of a comprehensive approach combining biochemical and morphological indicators for assessing the state of the atmospheric environment within ecological monitoring frameworks.

The article presents the results of the accumulation of metals by the epigeal lichen Flavocetraria nivalis, which is widespread on the island of Vaigach. Lead-zinc ore deposits are one of the sources of environmental pollution on the island. However, the influence of lead-zinc ore mines on metal concentrations in F. nivalis has not been established, since the metal content in lichen only increased with distance from the mines. Concentrations of chemical elements in lichen differ in different biotopes, and they are higher on the cliff tops than in the tundra on the slopes of the native shores. A comparison of the results of metal accumulation on Vaigach Island with other territories has shown that the concentrations of most metals in F. nivalis are lower or close to the Marmorilik area of western Greenland, where lead-zinc ore mines are also located. The excess of zinc and lead at sampling points near the mines in the Maarmorilik area over the concentrations obtained in lichen thallomas on Vaigach Island may be due to the recent closure of mines in Maarmorilik. So, if the mines on Vaigach Island were closed back in the late 30s of the last century, then in the area of Maarmorilik only 20 years ago. The concentration of metals in lichen on Vaigach Island is much lower than in the industrialized areas of the Kola Peninsula, which is especially typical for nickel.

This study evaluates the relationship between soil chemical contamination and the state of the microbiome in urban soils from transportation, transport-industrial, and recreational zones of Bishkek city, as well as the Ala - Archa Nature Park. Total concentrations of Pb, As, Zn, Cu, Co, Mn, Cr, Cd, Hg, and Sb were determined in soils using a DELTA X - ray fluorescence spectrometer. It was shown that the degree of heavy metal contamination depended on traffic intensity and emissions from thermal power plants. Functional diversity of soil microbiomes was assessed via multisubstrate testing, and functional activity was measured by carbon dioxide emission using chromatographic methods. Microbial community health and stability were evaluated by the shape coefficient (d) of the rank distribution of substrate utilization spectra, serving as a measure of microbial system destabilization. A distinct microbial community state was observed in soils from the western part of the city, characterized by reduced substrate utilization, decreased metabolic activity, and community destabilization. The studied heavy metals were grouped according to their influence on biotic indicators such as microbial respiration and substrate consumption. The As - Pb - Cu - Co group was more strongly associated with the integrated heavy metal contamination index (Z_st) and most strongly inhibited substrate-induced respiration and consumption of pentose monosaccharides. The Hg - Cr - Mn group mainly suppressed amino acid and organic acid consumption. The Cd - Zn - Sb group reduced basal respiration intensity and slightly increased oligosaccharide consumption and entropy parameters (H_k and χ²) of substrate utilization spectra. It was found that contamination with the ten studied heavy metals did not exert a direct specific effect on the microbiome, as the overall heavy metal contamination index (Z_st) showed no significant correlations with any biotic indicators. The conclusion was made that only the combined consideration of abiotic (chemical contamination) and biotic (microbiome responses) criteria should be used to assess ecological risks of soil degradation.