Taxonomic diversity and abundance of enchytraeids (Annelida, Clitellata, Enchytraeida) in the Northern Palaearctic. 1. Asian part.

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.

Disproportionate declines of formerly abundant species underlie insect loss.

Studies have reported widespread declines in terrestrial insect abundances in recent years1-4, but trends in other biodiversity metrics are less clear-cut5-7. Here we examined long-term trends in 923 terrestrial insect assemblages monitored in 106 studies, and found concomitant declines in abundance and species richness. For studies that were resolved to species level (551 sites in 57 studies), we observed a decline in the number of initially abundant species through time, but not in the number of very rare species. At the population level, we found that species that were most abundant at the start of the time series showed the strongest average declines (corrected for regression-to-the-mean effects). Rarer species were, on average, also declining, but these were offset by increases of other species. Our results suggest that the observed decreases in total insect abundance2 can mostly be explained by widespread declines of formerly abundant species. This counters the common narrative that biodiversity loss is mostly characterized by declines of rare species8,9. Although our results suggest that fundamental changes are occurring in insect assemblages, it is important to recognize that they represent only trends from those locations for which sufficient long-term data are available. Nevertheless, given the importance of abundant species in ecosystems10, their general declines are likely to have broad repercussions for food webs and ecosystem functioning.

The effect of natural disturbances on forest biodiversity: an ecological synthesis.

Disturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human-induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land-use change. Conversely, the suppression of natural disturbances threatens disturbance-dependent biota. Using a meta-analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on α-diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground-dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest α-diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta-analysis by applying a unified diversity concept based on Hill numbers to estimate α-diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity-disturbance relationships are shaped by species relative abundances. Our synthesis of α-diversity was extended by a synthesis of disturbance-induced change in species assemblages, and revealed that disturbance changes the ß-diversity of multiple taxonomic groups, including some groups that were not affected at the α-diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape. Hence, the relationship between α-diversity and disturbance severity in disturbed forest stands was strikingly similar to the relationship between species richness and disturbance extent in a landscape consisting of both disturbed and undisturbed forest habitats. This result suggests that both moderate disturbance severity and moderate disturbance extent support the highest levels of biodiversity in contemporary forest landscapes.

Enchytraeidae (Annelida: Oligochaeta) from Eastern Dagestan, Russia, with the description of a new species.

The first ever list of terrestrial enchytraeids of Eastern Dagestan includes 12 species belonging to five genera. Several species from studied localities may be assigned as undescribed, therefore additional comprehensive research of enchytraeid fauna from Eastern Dagestan is required. A new enchytraeid species of the genus Fridericia Michaelsen, 1889, Fridericia samurai sp. nov., is described from Eastern Dagestan, Russia. It clearly differs from other species of the genus by short and simple oesophageal appendages, not subdivided spermathecal diverticula, and the absence of spermathecal ectal glands and clitellum on ventral side.

Long-term abundance trends of insect taxa are only weakly correlated.

Changes in the abundances of animals, such as with the ongoing concern about insect declines, are often assumed to be general across taxa. However, this assumption is largely untested. Here, we used a database of assemblage-wide long-term insect and arachnid monitoring to compare abundance trends among co-occurring pairs of taxa. We show that 60% of co-occurring taxa qualitatively showed long-term trends in the same direction-either both increasing or both decreasing. However, in terms of magnitude, temporal trends were only weakly correlated (mean freshwater r = 0.05 (±0.03), mean terrestrial r = 0.12 (±0.09)). The strongest correlation was between trends of beetles and those of moths/butterflies (r = 0.26). Overall, even though there is some support for directional similarity in temporal trends, we find that changes in the abundance of one taxon provide little information on the changes of other taxa. No clear candidate for umbrella or indicator taxa emerged from our analysis. We conclude that obtaining a better picture of changes in insect abundances will require monitoring of multiple taxa, which remains uncommon, especially in the terrestrial realm.

Feeding habits and multifunctional classification of soil-associated consumers from protists to vertebrates.

Soil organisms drive major ecosystem functions by mineralising carbon and releasing nutrients during decomposition processes, which supports plant growth, aboveground biodiversity and, ultimately, human nutrition. Soil ecologists often operate with functional groups to infer the effects of individual taxa on ecosystem functions and services. Simultaneous assessment of the functional roles of multiple taxa is possible using food-web reconstructions, but our knowledge of the feeding habits of many taxa is insufficient and often based on limited evidence. Over the last two decades, molecular, biochemical and isotopic tools have improved our understanding of the feeding habits of various soil organisms, yet this knowledge is still to be synthesised into a common functional framework. Here, we provide a comprehensive review of the feeding habits of consumers in soil, including protists, micro-, meso- and macrofauna (invertebrates), and soil-associated vertebrates. We have integrated existing functional group classifications with findings gained with novel methods and compiled an overarching classification across taxa focusing on key universal traits such as food resource preferences, body masses, microhabitat specialisation, protection and hunting mechanisms. Our summary highlights various strands of evidence that many functional groups commonly used in soil ecology and food-web models are feeding on multiple types of food resources. In many cases, omnivory is observed down to the species level of taxonomic resolution, challenging realism of traditional soil food-web models based on distinct resource-based energy channels. Novel methods, such as stable isotope, fatty acid and DNA gut content analyses, have revealed previously hidden facets of trophic relationships of soil consumers, such as food assimilation, multichannel feeding across trophic levels, hidden trophic niche differentiation and the importance of alternative food/prey, as well as energy transfers across ecosystem compartments. Wider adoption of such tools and the development of open interoperable platforms that assemble morphological, ecological and trophic data as traits of soil taxa will enable the refinement and expansion of the multifunctional classification of consumers in soil. The compiled multifunctional classification of soil-associated consumers will serve as a reference for ecologists working with biodiversity changes and biodiversity-ecosystem functioning relationships, making soil food-web research more accessible and reproducible.

Global data on earthworm abundance, biomass, diversity and corresponding environmental properties.

Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change.

InsectChange: a global database of temporal changes in insect and arachnid assemblages.

Insects are the most ubiquitous and diverse group of eukaryotic organisms on Earth, forming a crucial link in terrestrial and freshwater food webs. They have recently become the subject of headlines because of observations of dramatic declines in some places. Although there are hundreds of long-term insect monitoring programs, a global database for long-term data on insect assemblages has so far remained unavailable. In order to facilitate synthetic analyses of insect abundance changes, we compiled a database of long-term (≥10 yr) studies of assemblages of insects (many also including arachnids) in the terrestrial and freshwater realms. We searched the scientific literature and public repositories for data on insect and arachnid monitoring using standardized protocols over a time span of 10 yr or longer, with at least two sampling events. We focused on studies that presented or allowed calculation of total community abundance or biomass. We extracted data from tables, figures, and appendices, and, for data sets that provided raw data, we standardized trapping effort over space and time when necessary. For each site, we extracted provenance details (such as country, state, and continent) as well as information on protection status, land use, and climatic details from publicly available GIS sources. In all, the database contains 1,668 plot-level time series sourced from 165 studies with samples collected between 1925 and 2018. Sixteen data sets provided here were previously unpublished. Studies were separated into those collected in the terrestrial realm (103 studies with a total of 1,053 plots) and those collected in the freshwater realm (62 studies with 615 plots). Most studies were from Europe (48%) and North America (29%), with 34% of the plots located in protected areas. The median monitoring time span was 19 yr, with 12 sampling years. The number of individuals was reported in 129 studies, the total biomass was reported in 13 studies, and both abundance and biomass were reported in 23 studies. This data set is published under a CC-BY license, requiring attribution of the data source. Please cite this paper if the data are used in publications, and respect the licenses of the original sources when using (part of) their data as detailed in Metadata S1: Table 1.

A new species of the genus Lucasioides Kwon, 1993 (Isopoda, Oniscidea, Agnaridae) from Siberia, Russia.

A new species of the family Agnaridae, Lucasioides altaicus sp. nov., is described from the Altai Mountains, southwestern Siberia, based both on morphological characters and molecular data. This species is the first record of Lucasioides from Russia, whose location is the northernmost habitat of terrestrial isopods in indigenous habitats presently known to Eurasia. The diagnostic characters of the new species and a preliminary phylogenetic analysis within Agnaridae are provided.

Forest fire induces short-term shifts in soil food webs with consequences for carbon cycling.

We tested for fire-induced (5-6 years post-fire) changes in the structure and functioning of the soil food web along a 3000-km north-south transect across European Russia, spanning all major forest types in the northern hemisphere outside the tropics. The total biomass of the detrital food web, including microbes and invertebrates, was not affected by fire. However, fire reduced the biomass of microfauna and mites, but had no impact on mesofauna or macrofauna. Fire also reduced rates of carbon (C) mobilisation by soil biota. Our results demonstrate that fire-induced shifts in soil food webs have significant short-term effects on forest soil C cycling, but that these effects vary across forest types and geographic locations.

Response to Comment on "Meta-analysis reveals declines in terrestrial but increases in freshwater insect abundances".

Desquilbet et al take issue with our data inclusion criteria and make several other dubious claims regarding data processing, analysis, and interpretation. Most of their concerns stem from disagreement on data inclusion criteria and analysis, misunderstanding of our goals, and unrealistic expectations. We maintain that our synthesis provides a state-of-the-art analysis of patterns of trends in insect abundances.

A history of study and new records of terrestrial enchytraeids (Annelida, Clitellata, Enchytraeidae) from the Russian Far East.

A list of terrestrial enchytraeids of the Russian Far East is compiled based on literature and extensive field data collected by the authors in 2019. A database has been created consisting of geographic coordinates, habitat type, species, and data source. For some species collected by the authors, barcoding using COI, 16s, and 12s rRNA genes has been performed. In total, there are at least 62 species of enchytraeids belonging to 12 genera. Seven species (Achaeta macroampullacea, Cognettia sphagnetorum, Enchytraeus dichaetus, Fridericia cusanica, Globulidrilus riparius, Marionina southerni, Mesenchytraeus gigachaetus) are reported in the Russian Far East for the first time. Cognettia sphagnetorum and F. cusanica are most probably introduced. Taxonomic and biogeographical remarks on some of the species found and differences from the original descriptions are provided. Some of the specimens may be undescribed species, but this requires a more in-depth examination. The Russian Far East, especially its southeastern part, is of great interest as a possible location for new species of enchytraeids.

Meta-analysis reveals declines in terrestrial but increases in freshwater insect abundances.

Recent case studies showing substantial declines of insect abundances have raised alarm, but how widespread such patterns are remains unclear. We compiled data from 166 long-term surveys of insect assemblages across 1676 sites to investigate trends in insect abundances over time. Overall, we found considerable variation in trends even among adjacent sites but an average decline of terrestrial insect abundance by ~9% per decade and an increase of freshwater insect abundance by ~11% per decade. Both patterns were largely driven by strong trends in North America and some European regions. We found some associations with potential drivers (e.g., land-use drivers), and trends in protected areas tended to be weaker. Our findings provide a more nuanced view of spatiotemporal patterns of insect abundance trends than previously suggested.

Global distribution of earthworm diversity.

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.

Mechanisms of soil macrofauna community sustainability in temperate rice-growing systems.

Rice growing requires highly destructive and highly invasive field management negatively affecting soil biota and its functions. We aimed to compare taxonomic and functional trait compositions of soil macrofauna at different stages of rice cropping cycles in the three temperate rice-growing regions in Russia. Samples were collected in 2016 at four different biotopes in each region: flooded rice paddies; upland crops planted one year after flooded rice; rice paddy bunds; and relatively undisturbed seminatural control grasslands. Collected soil macrofauna were allocated to different traits according to their feeding preferences, vertical distribution, mobility and flood tolerance. The lowest macrofaunal abundance across all regions was observed in rice paddies. Cultivation of upland crops after paddy flooding consistently decreased the abundance of resident macrofauna, but not that of mobile soil macrofauna. In the upland crops, the abundance of belowground and mobile belowground macrofauna was significantly higher than that in control grasslands. The abundance of aboveground phytophages was significantly lower in the upland crops than in control sites. Flood-associated taxa showed low colonization ability after the paddies were drained. In contrast, representatives of other traits recorded in flooded fields increased their abundance at the next stage of crop rotation, demonstrating high resilience within an entire rice-growing system, including bunds. This finding indicates a high potential of seminatural grasslands and especially bunds as sources of rapid restoration of soil macrofauna functional diversity in rice-growing agroecosystems, thus maintaining the sustainability of soil food webs in the rice paddies.

Description of a new species of the genus Protracheoniscus Verhoeff, 1917 and redescription of Protracheoniscuskryszanovskii Borutzky, 1957 from the southeast of European Russia (Isopoda, Oniscidea, Agnaridae).

A new species of woodlice, Protracheoniscuspokarzhevskii Gongalsky & Turbanov, sp. n. is described from Kalmykia, NE Pre-Caspian region, Russia. Protracheoniscuskryszanovskii Borutzky, 1957 from the same area is also redescribed. Diagnostic features of these species as well as affinities within the genus are provided and discussed.

The first record of the genus Desertoniscus Verhoeff, 1930 (Isopoda, Oniscidea, Agnaridae) from Europe, with the description of a new species.

A new woodlouse species, Desertoniscus zaitsevi sp. nov., is described from Kalmykia, Cis-Caspian region of Russia. The diagnostic features of the new species, as well as its affinities within the genus are provided and discussed. The new species is the northwesternmost in Eurasia, expanding the known distribution of this genus into Europe.

First record of Orobdellakawakatsuorum (Hirudinida: Arhynchobdellida: Erpobdelliformes) from Kunashir Island, Kuril Islands.

Specimens of the genus Orobdella Oka, 1895 from Kunashir Island, the Kuril Islands, are identified as Orobdellakawakatsuorum Richardson, 1975. Mitochondrial tRNA(Leu) and ND1 data confirm the species identification of the Kunashir specimens. This is the first record of the genus Orobdella from the Kuril Islands.

Isotopic niche (δ¹³Ð¡ and δ¹5N values) of soil macrofauna in temperate forests.

RATIONALE: Stable isotope analysis (SIA) is used widely for reconstructing trophic links of vertebrate and invertebrate animals. Soil macrofauna form a substantial food source for a range of predators including amphibians, reptiles, birds and mammals. SIA-based estimations of their trophic niches require knowledge on the full range of isotopic signatures of potential preys. Considering the extremely high diversity of soil animals, this information is not easy to obtain. METHODS: We estimated a typical range of the isotopic signatures of soil macrofauna by compiling published and original data on soil macroinvertebrates in 11 temperate forests. We examined whether the baseline correction (i.e. subtracting δ(13)C or δ(15)N values of local litter) would decrease the between-site variability in the δ(13)C and δ(15)N values of soil animals. The dataset was subsequently used to estimate the frequency distribution of δ(13)C and δ(15)N values in saprophagous and predatory soil animals. RESULTS: The baseline correction reduced the between-site variability in δ(15)N, but not in δ(13)C values of soil animals. Over 95% of the taxa or individuals examined fell into an isotopic space with uncorrected δ(13)С values ranging from -27.9 to -22.5‰, and litter-normalized δ(15)N values from 0.8 to 9.6‰. Saprophagous and predatory soil animals were on average enriched in (13)C relative to plant litter by 3.5 and 2.7‰, respectively, which is likely to reflect the importance of saprotrophic microorganisms as the main energy source in soil food webs. The difference in δ(15)N values between saprophages and predators averaged 2.8‰, which fits the anticipated trophic enrichment per trophic level. CONCLUSIONS: Our results indicate that the range of possible δ(15)N values of soil macrofauna in temperate forest ecosystems can roughly be predicted based on the δ(15)N values of plant litter. On the other hand, no site-specific normalization is usually required when predicting the range of δ(13)C values of soil macroinvertebrates.

Cartographic analysis of woodlice fauna of the former USSR.

An inventory of the woodlice fauna of the former USSR yielded 190 species, 64 of them were recorded from the territory of Russia. According to the cartographic analysis, the limits of distribution of epigean terrestrial isopods over the area, excluding mountains, is explained by temperature. No woodlice records were found outside the isocline of 120 days a year with the mean daily air temperature >10°C. The highest species diversity was found between the isoclines of 180 and 210 days. These areas correspond to forest-steppe and steppe zones.