The contribution of biotic factors to the variation of soil carbon stock in forests of the Republic of Karelia, Leningrad oblast (Karelian Peninsula), and Bryansk oblast (Bryansk Forest Nature Reserve), formed on soil-forming rocks of light granulometric composition, is assessed. Groups of biotic predictors characterizing the vegetation and macrofauna are analyzed, and their contribution to the variation of the soil carbon stock in soil layers and horizons is estimated using the hierarchical decomposition method. It is shown that in coniferous-broad-leaved forests the relative contribution of biotic predictors to the variation of litter carbon stocks is higher, while in boreal forests, it is in the mineral layers of 0–50 cm. The most informative predictor for the OFH subhorizon of the litter and mineral horizons was the indicator of litter quality of the C : N ratio.

Enchytraeids are key organisms in the functioning of terrestrial ecosystems, but despite this, the fauna and population of enchytraeids of the European part of Russia (ER) have been studied rather poorly. Based on our own collections from 193 sites across the main biomes of the ER from 2019 to 2023, 74 species of enchytraeids belonging to 15 genera were identified. The presence of tundra, boreal, nemoral and desert faunal complexes of enchytraeids, as well as a group of polyzonal species, was shown. From a faunal perspective, the Caucasus, which is inhabited by a group of species that are not found anywhere else in Russia, stands out within the ER. Analysis of enchytraeid communities in various biomes of the ER at the species level will allow for a more correct assessment of their role in detrital food webs and the functioning of ecosystems overall.

Оценка связей между факторами почвообразования и запасами органического углерода в лесных почвах Карелии и Карельского перешейка по тематическим спутниковым продуктам

Enchytraeids are among the key organisms in the functioning of terrestrial ecosystems. Despite this, the fauna and population of enchytraeids of the European part of Russia (ER) have been studied rather poorly. Based on our collections gathered at 193 sites in the territory of the main biomes of European Russia in 2019–2023, 74 species of enchytraeids assigned to 15 genera were identified. The presence of tundra, boreal, nemoral, and desert faunal complexes of enchytraeids, as well as of a group of polyzonal species, was shown. From a faunal point of view, the Caucasus, which is inhabited by a group of species that are not found anywhere else in Russia, is distinguished in the European part of the country. Analysis of enchytraeid communities in various biomes of the European part at the species level would allow a more correct assessment of their role in detrital food webs and the functioning of ecosystems in general.

A comparative assessment of the processes of the initial stages of decomposition of plant residues (pine needles, spruce needles, leaves of boreal shrubs, moss thalli) in lichen-shrub pine forests and shrub-green-moss spruce forests formed under natural conditions at the northern limit of distribution was carried out. The characteristics of the litterfall initial composition, the rate of decomposition, and changes in the chemical composition of plant residues in the process of destruction caused by the forest type were studied. The higher initial content of Corg in the plant tissues of pine forests is associated with favourable lighting conditions under the forest canopy, while the high content of Mn in the tissues of ground cover plants in spruce forests is due to the direct influence of spruce needle litterfall rich in this nutrient. The results of the study clearly demonstrated that the forest type has a significant impact both on the initial quality of the litterfall of the same plant species and on the rate of decomposition: in the spruce forest, spruce needles and lingonberry leaves with a higher content of nutrients (Mg, Mn, P) and narrow ratios of elements (C:N, C:P) were characterised by more active decomposition processes. However, green moss litter, despite its high quality in spruce forests, decomposed more actively in pine forests, which may be due to a large amount of precipitation in pine forests. Thus, differences in the rate of decomposition of plant residues are influenced by a combination of the plant material quality, temperature conditions, and precipitation amount associated with the forest type.

The present study focuses on investigating the taxonomic richness and composition of selected groups of soil microfauna, specifically soil ciliates and nematodes, within municipal solid waste landfills located in European Russia.Faunistic surveys were conducted across two landfills, with soil samples collected in the three zones: core sites within the landfill, at the edge of landfills, and control sites located 1 kilometer away from the edges.We revealed distinct faunistic patterns between the landfills core and edge sites vs respective controls.Core sites within the landfills exhibited higher ciliate species richness and nematode abundance.This highlights the landfill effect on soil microfauna community composition.Importantly, certain species of ciliates were exclusively found within the landfills, indicating the presence of a faunistically distinguished community associated with communal waste deposition.Knowing peculiarities of soil microfauna communities in landfills brings ground to further knowledge understanding of soil ecological processes in the landfills.This further opens perspectives for a development of adequate management practices for sustainable communal waste disposal and landfill remediation efforts.

Проведена сравнительная оценка процессов разложения растительных остатков (хвоя сосны, хвоя ели, листья бореальных кустарничков, слоевища мхов) на начальных этапах в сосняках лишайниково-кустарничковых и ельниках кустарничково-зеленомошных, формирующихся в естественных условиях на северном пределе распространения. Изучались особенности исходного состава опада, темпы разложения и изменения химического состава растительных остатков в процессе деструкции, обусловленные формацией леса. Более высокое исходное содержание Сорг в тканях растений сосновых лесов связано с благоприятными условиями освещенности под пологом леса, тогда как высокое содержание Mn в тканях растений напочвенного покрова в ельниках обусловлено непосредственным влиянием богатого этим элементом питания опада хвои ели. Результаты исследования наглядно продемонстрировали, что формация леса оказывает значительное влияние как на исходное качество опада одних и тех же видов растений, так и на скорость разложения: хвоя ели и листья брусники с более высоким содержанием элементов питания (Mg, Mn, P) и узкими соотношениями элементов (С:N, C:P) в еловом лесу характеризовались и более активными процессами разложения. Однако опад зеленых мхов, несмотря на более высокое качество в ельниках, разлагался активнее в сосновых лесах, что может быть связано с большим количеством осадков в сосновых лесах. Таким образом, на различия в скорости разложения растительных остатков влияет сочетанием качества растительного материала, температурного режима и количества осадков, связанных с формацией леса.

Marine macroalgae are often used as biofertilizers in the coastal regions across the world. However, the effects of soil fauna in macroalgae decomposition are not fully understood. We conducted a microcosm experiment to assess the possibility of using a mixture of native Enchytraeidae and the model earthworm species Eisenia fetida to accelerate decomposition of dominant algae taxa from White Sea (Fucus spp.) and Black Sea (Cystoseira spp.) after their amendment to soil with simultaneous mitigation of the associated carbon dioxide (CO2) emissions. During 45 days of the microcosm experiment, we measured CO2 emission from the soil and evaluated changes in macroalgal biomass, 813C and 815N isotopic signatures of soil, macroalgae, earthworm faeces and enchytraeid tissues as well as bulk carbon and nitrogen content in soil. The mass of Cystoseira spp. residues, unlike that of Fucus spp., significantly decreased during the experiment (by approximately 73 % of the initial level). This effect was amplified by the co-action of E. fetida and Enchytraeidae (by 65 % of the initial). The addition of Enchytraeidae into microcosms led to the more than two-fold reduction of CO2 emission in all treatments. Differential enrichment of soil and earthworm casts with macroalgae-derived carbon and nitrogen, as suggested by stable isotope analysis, indicated that macroalgae-originating carbon pathway is rather driven by a synergistic activity of enchytraeids and earthworms (813C enrichment up to 4.8 parts per thousand). Nitrogen transfer was dependent on the microbial activity and could be modulated and channelized by enchytraeids, whose 815N values strictly corresponded to algal taxa. This highlights the importance of annelids in increasing the value of macroalgae as biofertilizers.

The paper provides a brief analysis of well-known works containing evidence of carbon accumulation in old-growth forests. The analysis of the current state of the problem allows us to conclude that old-growth forests continue to accumulate carbon. A map of old-growth forests in Russia, identified on the basis of tree age higher than 200 years, using remote sensing data, is presented, and estimates of carbon pools in these forests are discussed. According to the estimates obtained, the area of old-growth forests in Russia was 163 mln ha as of 2021, and carbon stocks in phytomass reached 7.33 bln t, with the contribution of larch forests and larch woodlands of 86%. It is shown that the most important cause of uncertainties in the estimates of carbon cycles in old-growth forests is the uncertainty of the concept of “old-growth forests.” The mosaic structure of forests, that is, the high horizontal structural diversity, contributes to the accumulation of nitrogen and carbon in soils due to the creation of functioning conditions for various plant species, including light-loving ones, and, accordingly, due to the presence of litter of different quality, which is important for soil biota. Old-growth mosaic forests in Moskvoretsko-Oka Plain accumulated more nitrogen and carbon in soils than forests at an earlier stage of succession with a low mosaicity (in average 80 t/ha versus 60 t/ha in the 30-cm layer). The old-growth fir-beech dead-cover forests of the Northwestern Caucasus, whose tree stand is characterized by the highest productivity in Russia and Europe and high carbon reserves in the tree stand, are characterized by low carbon stock in soils compared to forests at an earlier stage of development (in average 58 t/ha versus 99 t/ha in 30-cm layer). This is due to the low quality of beech and fir litter and the absence of a pronounced window mosaic, which prevents the colonization of light-loving plant species, including with a high quality of litter. It is shown that, along with microorganisms, it is necessary to take into account such agents of decomposition, mineralization and humification as earthworms, which play a key role in carbon cycles. Carbon stock in the litter of northern taiga spruce forests is an order of magnitude higher than in coniferous-broad-leaved forests; in the litter and in the mineral layer of 0–30 cm, the carbon reserves under the crowns of spruce trees for about 200 years turned out to be significantly higher than in the spaces between the crowns, exceeding 80 t/ha.

This article dwells upon the current understanding of the multifunctionality of forest ecosystems and links between multifunctionality and biodiversity, as well as the trade-offs and synergy between the ecosystem functions (EFs) and services of forests. The relevance of studying ecosystem services (ES's) is determined by the modern societal needs that have emerged as a result of global economic and population growth. Forest ecosystems provide multiple services simultaneously; i.e., they possess a multifunctionality trait. The majority of studies, however, focus on the relationships between biodiversity and individual ES's. Therefore, the impact of biodiversity loss on ES's is greatly underestimated due to the underdeveloped methodology and tools taking into account the multifunctionality of ecosystems. We propose a conceptual scheme of the linkages among biodiversity, multiple functions, and multiple services, including the factors affecting these links. The interdisciplinary concept of links and their introduction to support administrative decision-making necessitates addressing the following: identifying informative indicators of the links and assessing the synergies and trade-offs between various EFs. Reaching those objectives will allow us not only to obtain new fundamental knowledge about processes involved in the functioning of forest ecosystems, but also create markets for ES's that have not been considered marketable previously and ensure steady, sustainable forest use.

A comparative assessment of carbon accumulation in the soils of pine forests in western Russia (the Republic of Karelia, the Karelian Isthmus, and Bryansk region) developed on coarse-textured parent materials has been made. The total carbon stock in the litter and upper soil layer (0–50 cm) varied from 47 t/ha in the soils of pine forests of Bryansk region to 116 t/ha in the soils of pine forests of the Karelian Isthmus. It has been shown that the main factors of carbon accumulation in the soils of pine forests in western Russia were the climate, parent materials, vegetation, agricultural activity, and fires. The influence of climatic conditions has been clearly manifested in the levels of carbon accumulation in the litter and in the upper humus-accumulative soil horizons. In the pine litter within the zone of mixed forests (Bryansk region), the level of carbon accumulation was the lowest, whereas the litter layer of pine forests in the northern taiga (Karelia) has the highest stock of carbon. At the same time, the lowest carbon stocks in the upper mineral soil layers has been noted for the soils of northern taiga forests, which had no humus-accumulative mineral horizon. The variability of carbon stocks in the litter layer was largely controlled by the C/N ratio, as well as by the fraction of deciduous undergrowth and grasses producing high-quality litter. The influence of agricultural activity on soil carbon stock in pine forests was especially pronounced on the Karelian Isthmus with the high agricultural activity in the past, as well as in Bryansk region, where pine forests are formed from pine plantations. The effect of fires on soil carbon stock was most pronounced in heather and lingonberry pine forests of the northern taiga of Karelia.

This study is devoted to assessing the interbiogeocenotic and intrabiogeocenotic variation and long-term dynamics of the composition of rain deposition in coniferous forests that are exposed to contamination from the Severonikel Copper-Nickel Smelter Complex (Murmansk oblast), the largest source of pollutant emissions into the atmosphere in Northern Europe. Spruce forests with dwarf shrubs and green mosses and pine forests with dwarf shrubs and lichens, which are common in the boreal zone, are studied at different stages of pollution-induced degradation. The chemical composition of rainwaters is characterized by a significant intra- and intrabiogeocenotic variation. Long-term data confirm that the content of elements is significantly higher below the crowns than between them, with the concentrations and deposition of elements being significantly higher in spruce forests than in pine ones. This difference is determined by different sorption capacities of tree crowns and different levels of leaching of elements from them. The fallout of the main pollutants with rainwaters exceeded the critical levels even in the background areas and was significantly higher in defoliating forests and pollution-induced sparse forests. It is shown that the excess of the critical levels is much more pronounced in rainwaters than in snow ones. The determination of the intra- and interbiogeocenotic differences in the composition of atmospheric fallout allows an earlier and more accurate diagnosis for the excess of critical loads at all degradation stages. The long-term dynamics of the fallout of chemical elements with rainwaters in pine and spruce forests is characterized by a high variability both below and between tree crowns. An increase in nickel concentrations in the background areas from 2013 to 2017 is revealed, which is explained by the growth in the content of pollutants in aerosols spreading over considerable distances.