Soil fauna regulates litter decomposition and soil organic matter transformation, acting as both litter and microbial feeders. Whether these feeding modes shift along environmental gradients remains unclear. We tested if microbivory increases with decreasing litter quality and in colder climates, both factors limiting detritus digestion by fauna. Using stable isotope composition (δ13C, δ15N) of 7408 soil invertebrate samples from 228 forest sites across temperate to tropical biomes, we determined δ15N values are positively associated with litter C:N ratio and mean annual temperature, indicating a shift from detritivory toward microbivory under low litter quality with additional modulation by climate. In contrast, δ13C values showed no consistent association with litter C:N ratio or climate, reflecting context dependent microbial carbon routing. Our findings highlight litter quality as the primary driver of the detritivory-to-microbivory shift in soil fauna, with implications for predicting changes in climate and plant communities on carbon cycling in terrestrial ecosystems.

ABSTRACT Understanding the status and global trends of soil invertebrate diversity requires accurate and comparable data across geographical regions. However, soil animal extraction approaches still vary among laboratories, and no commonly accepted, openly available and well‐documented protocols exist across taxa. Here, we present harmonized methodologies, assembled by an international group of experts, for extracting soil‐ and litter‐inhabiting nematodes, enchytraeids, microarthropods, and larger invertebrates. Illustrated with images and videos, the protocols include advice for overcoming the most frequently encountered issues (’expert tips’) for maximizing extraction efficiency and reproducibility. In addition, we provide results from two pilot experiments that test certain steps in nematode and large invertebrate extractions. We show that using two layers of milk filters instead of one in wet extraction of nematodes yields very similar extraction efficiency and has little effect on the sample cleanliness. Further, we demonstrate that on average 31.3% of large soil animals (body length 3 mm and longer) are overlooked during hand sorting but were captured by heat extraction of the sorted samples across three geographically distinct laboratories. Observed differences among the laboratories call for standardized tests of extraction efficiency of large soil animals across regions and research groups. Overall, we provide openly available expert protocols for assessing soil animal taxa in ecological studies worldwide, ultimately facilitating comparisons for a better understanding of the distribution and dynamics of soil biodiversity.

Biodiversity change has elicited widespread concern over the consequences for functions and services provided by ecosystems1-3. Despite extensive evidence for a positive effect of biodiversity on ecosystem functioning within a single trophic level4,5, how this biodiversity effect varies with multi-trophic food web structure remains unresolved6 even though most ecosystems contain two to six trophic levels7. We investigate how food web complexity modulates biodiversity-ecosystem functioning relationships in nature by quantifying energy fluxes as proxies for two principal ecosystem functions8-primary consumption and predation-in 318 highly resolved, complex food webs from marine, lake, stream and soil ecosystems. Ecosystem functioning increased consistently with taxon richness across all trophic levels and ecosystems, which arose from greater vertical diversity (that is, maximum trophic level9) and trophic complementarity of predators in more taxonomically diverse food webs. Furthermore, predator trophic complementarity10,11 increased predation fluxes in all freshwater ecosystem types. These findings highlight the threat of trophic downgrading to critical ecosystem functions (for example, biological control and maintenance of biodiversity and ecosystem stability) provided by predators12,13, which are typically most vulnerable to anthropogenic disturbances14,15. Our study demonstrates that the consequences of biodiversity change are deeply entangled within the web of life, emphasizing the need to conserve the trophic complexity underlying biodiversity-ecosystem function relationships.

The role of enchytraeids (Enchytraeidae: Clitellata: Annelida) in sois is hard to underestimate. However, there is little knowledge of their spatial distribution and species richness both globally and regionally. In this paper, we aim to analyze the preliminary patterns of species richness spatial distribution across Central and Eastern sectors of the Northern Palearctic, specifically in Eastern Europe, Siberia, the Russian Far East, Central Asia, and Mongolia. The analysis is based on the mapping of 79 species occurrence records and interpolating species richness from 322 sampling points across the study region. Only own material was used for the analysis due to potential methodological inconsistencies with earlier data. The highest interpolated species richness of enchytraeids, was observed in the temperate coniferous and broadleaf and mixed forests of European Russia, seaside sectors of the North Caucasus (both the Black and the Caspian seas), the south of West Siberia, and the Russian Far East, up to 16 species per location. Temperate natural grasslands and deserts were characterized by low interpolated enchytraeid species richness ranging between one and two species. Species richness in the sampling locations within the Arctic did not differ from that in boreal forests pointing to the important role of Enchytraeidae in the total Clitellata diversity at higher latitudes. In the future, broader species distribution modelling with involving literature data, molecular-based taxonomic identification results and habitat abiotic parameters data will help in discovering mechanisms standing behind the revealed enchytraeid species richness spatial patterns in the Palaearctic.

The study of Palaearctic enchytraeid taxonomic richness revealed the limitations of applying morphological identification methods to certain species of the genus Cognettia. The use of molecular approaches enabled the identification of individuals belonging to C. chlorophila among immature and fragmented enchytraeids that had initially been identified morphologically as C. sphagnetorum s.l. These findings substantially extend the known distribution range of C. chlorophila eastward. Reliable distribution data for C. chlorophila and C. sphagnetorum s.s., obtained through genetic analysis, complement existing evidence of their coexistence in shared habitats and highlight questions concerning their biotopic preferences. It is hypothesized that the relatively low level of genetic diversity in these species is associated with potential postglacial dispersal routes of C. sphagnetorum s.l. from Scandinavian refugia and with species-specific biological characteristics.

Soil fauna perform a plethora of vital ecological functions and are often used as indicators of ecosystem disturbances. Investigating their taxa, functional diversity, and abundance is essential to assess ecosystem resilience, detect environmental stress, and guide conservation efforts. In this study, we investigated the taxonomic richness, diversity, and total and functional group abundance of soil macrofauna, as well as the environmental parameters of five model forests with different types of forest management (referred to as the “forest type”) within a temperate region of European Russia. These model forest types were subject to various types of forest management and were located in and around the Central Forest State Nature Biosphere Reserve (Tver Oblast, Russia): zonal forest (hereinafter referred to as the “zonal forest” treatment), forest disturbed by recreation (“recreational forest”), spruce forest monoculture (“monoculture”), secondary birch forest (“secondary forest”), and clear-cut site (“clear-cut”). We found that there was a significant difference in the total and average taxonomic richness of the macrofauna between the studied model forests, but no difference in mean abundance. The greatest difference was observed between the recreational (26 taxa, 11.2 ± 1.3 per site), monocultural (12 taxa, 4.8 ± 1.9 per site), and zonal (13 taxa, 4.5 ± 1.3 per site) forest types, while the macrofauna taxonomic composition was similar between the monocultural and control forests and significantly differed from that in the recreational and secondary forests and clear-cuts. Mobile taxa, mainly predators, were prevalent in the clear-cuts, while saprophages and phytophages dominated in the zonal forests and monocultures. The most important environmental factors influencing the macrofauna communities were the depth, mass, and composition of the litter, which depended on the presence of spruce (Picea abies), but not on soil parameters, the projective vegetation cover, or the abundance of microorganisms. Our study showed that anthropogenic disturbance in natural forests may not significantly alter the total abundance of the macrofauna, but it can impact the taxonomic composition and diversity of soil invertebrates. Therefore, greater attention should be given to analyzing functional and taxonomic diversity rather than relying solely on abundance data. Our findings highlight the importance of studying both the roles and diversity of soil species, not just their abundance, to better understand and protect natural ecosystems in the face of human impact.

Background Enchytraeids, commonly known as potworms, are small oligochaetes found worldwide in various terrestrial, freshwater and marine ecosystems. Despite their crucial role in ecosystem functioning, the diversity and abundance of Enchytraeidae are seldom studied due to the labour-intensive process of species identification. This study aims to address this gap and expand knowledge on the distribution and abundance of enchytraeids within the Northern Palaearctic Region. The provided dataset represents the latest and most comprehensive field sampling of enchytraeid communities within the European part of Russia within the Northern Palaearctic. It consists exclusively of an original set of soil samples systematically collected across the region from 2019 to 2023, without any previously published data included. New information The dataset includes occurrences from 204 georeferenced sites, encompassing 73 species from 17 genera, totalling 61,254 records, with 1,419 records having the "present'' occurrence status. This comprehensive, species-specific dataset (Darwin Core Archive - DwC-A) provides insights into the distribution and abundance of terrestrial enchytraeids across a wide geographic area, covering the eastern sector of the East European Plain and the North Caucasus Region within the Northern Palaearctic. Compiled from field sampling campaigns, this dataset is essential for exploring and understanding local and regional enchytraeid diversity over time and space. It also serves as a valuable resource for monitoring and conserving soil biodiversity in the studied region.

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.

Terrestrial isopods (Isopoda: Oniscidea), commonly known as woodlice, are among the most recognisable soil-dwelling invertebrates and are crucial for soil functioning. They are widely distributed from temperate to equatorial ecosystems, and their distribution is strongly influenced by environmental factors, such as soil type, temperature and humidity. Terrestrial isopods have fascinated taxonomists for centuries, with over 4,100 described species across 568 genera and 38 or 39 families. These animals contribute significantly to key ecosystem processes, such as litter decomposition, nutrient cycling, and carbon sequestration. However, data on patterns of their diversity, abundance, or biomass, which are crucial for assessing their importance in ecosystem functioning worldwide, are lacking. This is partly due to the incomplete taxonomy in regions such as the tropics and the scattered nature of local georeferenced datasets. To better understand the global taxonomic patterns, species distributions, and functional roles of terrestrial isopods, we call for the compilation of a comprehensive global database that integrates taxonomy, georeferenced species records, and trait data. This database would help answer fundamental questions about the response of terrestrial isopods to environmental changes and their role in ecosystem functioning and soil health. OniscidBase, a recently launched initiative, aims to consolidate such data, facilitating the analysis of taxonomic gaps and assessing the distribution and functional importance of terrestrial isopods. The database aims to include georeferenced data on the distribution, abundance and biomass of terrestrial isopod species, and metadata on environmental parameters. Our main goals are to strengthen the taxonomic backbone for terrestrial isopods, make distribution data available for macroecological studies, and collect trait data to understand species responses to environmental changes and effects on soils. Using these data leads to a deeper understanding of the importance of terrestrial isopods as components of terrestrial ecosystems and, at the same time, highlights future research directions.

Enchytraeids, also known as pot worms, represent one of the least studied groups of soil mesofauna. These organisms can be found throughout the globe from coasts to deserts reaching high densities and biomass, but their specific roles within the soil food web remain a stark knowledge gap. Enchytraeid species are involved in belowground trophic interactions, which could be distinguished by their morphological characteristics and ecological traits. To quantify this, we analyzed stable isotopes δ13C and δ15N in 16 enchytraeid species across various biomes and habitats in European Russia. Their isotopic niches were compared with different potential food sources and other soil invertebrates. We found that the total δ13C and δ15N range by across single enchytraeid samples reached 8 and 11‰, and isotopic niche of species depends on soil stratification and is reflected in the chaeta number per bundle, and, to a lesser extent, on the size or genera identity. These findings enabled us to split enchytraeids into three guilds within the functional group of secondary decomposers: (i) epigeic – that include litter-dwelling species that predominantly feed on plant material but also can ingest microorganisms; (ii) epi-endogeic – inhabiting upper humified soil and F-litter horizons, and feed primarily on various saprotrophic microorganisms; (iii) endogeic – consuming old processed humified and dissolved organic matter in lower H-horizon and even mineral A-horizons beneath. Our results are an important step forward in integrating enchytraeids into the next-generation food web models, not as a single black box, but as multiple blocks delivering different functions.

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.

Enchytraeids, also known as pot worms, represent one of the least studied groups of soil mesofauna. These organisms can be found throughout the globe from coasts to deserts reaching high densities and biomass, but their specific roles within the soil food web remain a stark knowledge gap. Enchytraeid species are involved in belowground trophic interactions, which could be distinguished by their morphological characteristics and ecological traits. To quantify this, we analyzed stable isotopes 8 13 C and 8 15 N in 16 enchytraeid species across various biomes and habitats in European Russia. Their isotopic niches were compared with different potential food sources and other soil invertebrates. We found that the total 8 13 C and 8 15 N range by across single enchytraeid samples reached 8 and 11 parts per thousand, and isotopic niche of species depends on soil stratification and is reflected in the chaeta number per bundle, and, to a lesser extent, on the size or genera identity. These findings enabled us to split enchytraeids into three guilds within the functional group of secondary decomposers: (i) epigeic - that include litter-dwelling species that predominantly feed on plant material but also can ingest microorganisms; (ii) epi-endogeic - inhabiting upper humified soil and F-litter horizons, and feed primarily on various saprotrophic microorganisms; (iii) endogeic - consuming old processed humified and dissolved organic matter in lower Hhorizon and even mineral A-horizons beneath. Our results are an important step forward in integrating enchytraeids into the next-generation food web models, not as a single black box, but as multiple blocks delivering different functions.

Background Enchytraeids, or potworms, are tiny oligochaetes that are distributed worldwide in many terrestrial, freshwater and marine ecosystems. Despite their key role in the functioning of ecosystems, the diversity and abundance of Enchytraeidae are rarely studied due to the laborious process of species identification. The present study addresses this gap and sheds some light on the distribution and abundance of enchytraeids in the lands of the Northern Palearctic. The provided dataset constitutes the latest and comprehensive field sampling of enchytraeid assemblages across the Asiatic part of the Northern Palearctic, encompassing an original set of soil samples systematically collected throughout the region from 2019 to 2022.New information The dataset includes occurrences from 131 georeferenced sites, encompassing 39 species and 7,074 records. This represents the first dataset providing species-specific information about the distribution and abundance of terrestrial enchytraeids across an extensive geographic area covering the Asian sector of the Northern Palaearctic. The compiled dataset is the key for exploring and understanding local and regional enchytraeid diversity. It may also serve as a valuable resource for monitoring and conserving the entire soil biodiversity.

More than half of all life on Earth lives belowground and regulates a wide range of ecosystem functions via their diverse trophic interactions. However, information on how trophic diversity of soil animals varies across functional groups and major environmental gradients is lacking. Here, we use stable isotope analysis (13C/12C and 15N/14N ratios) of 28 high-rank taxa of soil animals from 343 sites across 15 countries to inspect the variability in trophic diversity across climate regions and land-use types. We found that trophic diversity of soil-animals communities is higher for microbial than for detritus feeders and predators, and increases in agricultural ecosystems compared to woodlands (+38%) and in tropical compared to temperate climates (+53%). The larger trophic diversity was related to both exploration of more diverse basal resources and longer trophic chains, possibly because of greater niche partitioning in resource-limited environments. Overall, this first comprehensive assessment of soil animal trophic diversity highlights that soil animals may broaden their trophic niches under global change, which potentially buffers global-change impacts on ecosystem functions and stability in the short term, while the increased flexibility in foraging may pose risks with long-term biodiversity and ecosystem health implications.

No special studies on the millipede fauna of the Chechen Republic have hitherto been performed, the known published records being quite few and highly sporadic. The fauna is summarized here and it presently totals 19 species from 14 genera, 11 families and seven orders, all records thereby being mapped, both new and old, several species illustrated, and each species account supplied with notes on its distribution.

Saprophagous soil macroinvertebrates may potentially degrade agricultural wastes. However, it is not known, to what extent and representatives of which taxa may help reintegrating carbon from crop residues back into soil without triggering massive carbon release into the atmosphere. To tackle this problem, we conducted a three-month-long microcosm experiment with 21 different species of macrofauna (each treatment replicated four times) belonging to 13 families to test their ability to degrade wheat straw. Simultaneously CO2 release from the microcosms was measured. Five species did not survive under experimental conditions. Among the remaining 16 species, three significantly increased wheat straw decomposition with Oryctes nasicornis larvae having inflicted the highest straw mass loss (64%) in comparison with the control, where no animals were added (29%). None of the tested species increased cumulative CO2 evolution from the microcosms, while two species significantly reduced it. The reduction of carbon loss with aerobic respiration was recorded for Cetonia aurata larvae and the earthworm Dendrobaena veneta (respectively 2.5 and 2-fold in relation to the control – 53.8±4.6mg CO2-C g-1 soil dry weight during the entire experiment). The original integrative Carbon Sequestration Index by Macrofauna (CSIM) calculated for both of the measured parameters suggests that the woodlouse Armadillidium vulgare and to a smaller extent the earthworm D. veneta appear to be the most promising organisms for industrial climate-friendly organic waste recycling in terms of survival, straw processing and simultaneous reduction of CO2 emissions from soil. Our results proved that the engagement of saprophagous macrofauna in crop residue decomposition is a viable technique of carbon reincorporation into the soil. It is accompanied with CO2 release mitigation into the atmosphere.

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.

The role of earthworms in the direct transfer of dissolved soil organic carbon to plants is poorly understood. We quantified this effect by examining the root uptake of carbon from 13C-labeled rice straw in a greenhouse experiment with three non-flooded Philippine soils that greatly differed in texture (from light sandy to loam). Measurements of carbon stable isotope signatures of aerobic rice and maize over a two-month period revealed that earthworms positively affected 13C transfer from rice straw to rice plants but not to maize plants. However, this effect was significant only in loamy and not in sandy soils. Although the direct uptake of dissolved carbon from soil had no impact on rice production, it indicated a widely ignored option to mitigate carbon loss from crop residue decomposition and associated climate risks. Its enhancement by earthworms confirms the important role of this taxon as soil engineers.

‘Hidden hunger’ occurs in humans and livestock and stems from deficiencies in microelements, essential amino acids, and vitamins. Triggered by insufficient intake of micronutrients in food and feed, even when macronutrients are abundant, hidden hunger can result in the development of serious diseases and pathological conditions. Finding sufficient micronutrients is often challenging because they are either obtained from limited external natural sources or synthesised de novo . Soil-dwelling saprophages comprise one of the largest proportions of zoomasses on Earth but remain surprisingly overlooked as a potential micronutrient source. To assess their nutritional content concerning micronutrients, we selected 31 invertebrate species obtained from natural ecosystems of European Russia or widely cultivated species originating mainly from tropical regions. They belong to major soil saprophage taxa: cockroaches (Blattodea), beetle (Coleoptera) larvae and imagoes, springtails (Collembola), millipedes (Diplopoda), fly (Diptera) larvae, earthworms (Haplotaxida), woodlice (Isopoda), crickets (Orthoptera). We assessed their proteinogenic amino acid, microelement, and vitamin composition. Taxonomic differences in the composition and ratio of micronutrients were determined and we identified specific taxa naturally enriched with micronutrients for future consideration as potential candidates for incorporation into food and feed supplements to alleviate hidden hunger in livestock and humans.