Mining activities in France have left a legacy of persistent soil contamination by trace metal elements (trace metals). These pollutants pose serious risks to soil biodiversity, ecosystem functions, and human health. Soil microarthropods, such as Collembola and Oribatida, are essential components of soil functioning and are recognized as effective bioindicators of trace metals pollution. This study examined the impacts of trace metals on the density, diversity, and community composition of these microarthropods in soils near a former mining site in the French Occitanie region, Saint-Laurent-le-Minier. Sampling from sites with varying contamination levels of Pb, Cd, Zn, and Al revealed that microarthropod communities can persist despite high trace metals concentrations. No effect of metal contamination was observed on collembolan taxonomic diversity. However, the effect of trace metals on Collembolan density differed depending on their ecomorphological group, with euedaphic species more affected by higher trace metals concentrations than epiedaphic species. Conversely, Oribatida exhibited reductions in taxonomic diversity rather than density. To our knowledge, this is one of the only studies to simultaneously include both oribatid mites and collembolans, offering a more holistic view of decomposer communities and their responses to contaminants.

Land use can impact the abundance and diversity of soil organisms at both the plot and the landscape scale. Of soil organisms, Collembola and Carabidae are good bioindicators of anthropogenic activities. The objective of this study was to analyze the effects of land use category (forest, grassland, cropland, market gardens or vineyard) and agricultural practices (grass cover, tillage and use of fertilizers) on the abundance and diversity of Collembola and Carabidae on a regional scale (3500 km2) in France, with over 300 sites sampled. The results indicate that in terms of land use, the species composition of Collembola and Carabidae was different in forests compared to croplands and grasslands, with a lower abundance of Collembola in croplands and of Carabidae in vineyards than in other land uses. Carabidae abundance was higher in market gardens than in vineyards, grasslands or forests. Species richness of both groups was lower in vineyards and higher in forests compared to other land uses. In terms of agricultural practices, these only affected species richness: permanent grass cover favored Collembola richness in vineyards, and the absence of tillage favored Carabidae richness in croplands. These findings show the importance of land use and agricultural practices on soil organisms. In general, less disturbed soil habitats were associated with more Collembola and Carabidae biodiversity. This study’s multi-taxa approach confirms the importance of taking different biodiversity indicators into account and working at a territorial scale with numerous samples, which enables the results to be generalized.

Soil biodiversity indicators are increasingly used to inform environmental assessment and policy, yet their robustness is often constrained by heterogeneous sampling designs and imperfect species detection. Surface-active arthropods, such as ground beetles (Carabidae), are widely monitored using pitfall-based methods, but differences among trapping protocols and sampling effort complicate comparisons across sites and programmes. Using data from the French Soil Quality Monitoring Network (RMQS-Biodiversity), we analysed how sampling protocol and trapping intensity shape species detectability and how these effects propagate to inventory completeness and taxonomic diversity estimates. We applied species-level occupancy models to explicitly estimate detection probabilities as functions of sampling protocol, effort and species traits, and propagated these estimates to community-level diversity metrics using coverage-based standardisation. Detection probability increased strongly and monotonically with sampling effort, approaching saturation under the 10-pitfall traps configuration. GPDs exhibited detectability comparable to intermediate pitfall configurations (6 pitfall traps), but remained below 8 and 10 pitfall traps. Body size showed a consistent positive effect on detectability across protocols, whereas wing development effects were weak. Coverage-based standardisation substantially reduced protocol effects on diversity estimates, but species richness (Hill q = 0) remained more sensitive to protocol identity than Shannon or Simpson diversity. Together, our results show that harmonising sampling effort alone is insufficient to ensure comparability among biodiversity monitoring protocols. Instead, combining detection-aware modelling with coverage based standardisation provides a robust framework for improving the comparability and policy relevance of biodiversity indicators under heterogeneous monitoring schemes. More broadly, this study highlights the importance of explicitly integrating observation processes into large-scale soil biodiversity monitoring frameworks.

Viticulture is a major agricultural sector in France, which ranks third worldwide in terms of vineyard surface area. Productivity-oriented practices in this sector have negatively affected soils and their biodiversity. In response, alternative practices have gained increasing attention. This study assessed the effects of different soil management practices on three soil fauna taxa representing distinct functional roles: Collembola (decomposers), ants (ecosystem engineers), and spiders (epigeal predators), across 37 vineyards in southern France. Vineyards were selected to encompass various agricultural practices, including variation in inter-row vegetation cover, presence or absence of organic matter input, and tillage intensity. A multi-taxa, integrative approach was employed to investigate the responses to management practices of the three soil fauna groups while also taking into account soil and landscape properties, such as the proportion of semi-natural areas, that shape these communities. Spiders and ants were sampled using pitfall traps, and Collembola were extracted from soil cores. Generalised linear models showed that the predominant factor in structuring soil fauna communities was agricultural practices, to a greater extent than that of soil and landscape properties. Soil tillage intensity negatively affected all fauna groups studied, while ant communities additionally showed a negative response to pesticide intensity and a positive response to organic matter inputs. Overall, the findings highlight a convergent response of soil fauna to tillage intensity, alongside taxon-specific responses to soil properties and organic matter input. We found that only spider communities were influenced by landscape properties. These results demonstrate that integrated, multi-scale and multi-taxa approaches are valuable tools to develop relevant, sustainable management practices that preserve soil biodiversity and their associated functions in vineyards.

Soil contains a high level of biodiversity, estimated at around 60 % of known terrestrial life. Yet life in the soil is largely unknown by non-specialists: a case in point are springtails (Collembola), millimetric hexapods whose abundance can be tens of thousands of individuals per square meter. This lack of knowledge can compromise soil conservation, despite this being increasingly urgent due to the detrimental impact of human activities. Since an emotional response – for example, to charismatic species – is known to be valuable for species conservation, this study aimed to evaluate the emotional perceptions (positive or negative, and low or strong intensity) of young adults when shown photographs of Collembola. Indeed, Collembola seemed a good candidate for a perception study regarding soil fauna as they are very common in most soils at all latitudes and altitudes. The results show that the morphology of the individuals presented was decisive, in particular a visible eye patch (the presence was perceived as positive, while absence was perceived as negative) and body shape (spherical was perceived as positive, while elongated was perceived as negative). The color of the taxon and the number of individuals in the photograph could also modulate the perception of the viewers: blue and green were perceived as positive, while more than two individuals in the photograph provoked negative emotions. The artistic choices made in the photographs, such as background color, also had a significant influence on emotions. These results are of interest for education and outreach efforts on soil biodiversity; this pilot study with young adults and Collembola could help inform future communication campaigns for soil conservation.

Springtails are abundant in forest litter and soils, where they play a crucial role in the transformation and decomposition of organic matter. However, most data on springtail communities originates from studies at the local and regional levels, while larger-scale studies are lacking. To address this gap, we applied standardized methods to investigate springtail communities in forests from a Europe-wide study, covering a pedo-climatic gradient across 25 sites in 17 countries. We evaluated which environmental factors influence springtail density and alpha- and beta-diversity. We sampled forest litter and underlying soil separately and applied both morphological identification and soil DNA metabarcoding. On average, we recorded approximately 2500 individuals m−2 for litter-dwelling and 10,500 individuals m−2 for soil-dwelling springtails, with the highest values recorded in the Arctic and Boreal regions and the lowest in the Mediterranean region. Species richness averaged 5.2 in the litter and 7.0 in the soil applying morphotaxonomy, whereas using metabarcoding indicated a higher richness of 10.2 in the soil. Using morphotaxonomy, the key factor influencing density and alpha-diversity of litter-dwelling springtails positively was litter dry mass, whereas mean annual temperature had a negative effect, and the key factors positively influencing the density of soil-dwelling springtail were soil N and clay content, whereas bulk soil density had a negative effect. When data from metabarcoding were used, similar key factors emerged. Our results demonstrate that metabarcoding represents a promising approach for future large-scale studies when simple and reliable methods are needed to rapidly assess shifts in springtail community profiles.

Soil biodiversity indicators are increasingly used to assess soil health and support environmental monitoring frameworks. Their interpretation typically relies on reference distributions from which indicator thresholds are derived, implicitly assuming that these thresholds reflect underlying ecological conditions and are transferable across contexts. However, the extent to which sampling strategy shapes these reference systems remains poorly understood.Here, we investigate how contrasting sampling designs influence the construction and performance of soil biodiversity indicators using Collembola communities as a model system. We analysed multiple French datasets collected under comparable field and laboratory protocols but differing in spatial scale, site selection rules and sampling design. For each dataset, we constructed reference distributions for species richness and density, derived quantile-based scoring schemes, and applied them to independent test sites. We further evaluated the discriminant power of each reference framework by quantifying its ability to detect known local contrasts between treatments and controls.We show that sampling strategy is a primary driver of reference distribution shape, leading to substantial differences in indicator thresholds. These differences propagate directly into soil health classifications, with identical sites receiving contrasting scores depending on the reference framework used. Importantly, reference frameworks also differ in their discriminant power, with some consistently amplifying ecological contrasts while others attenuate them.Our results demonstrate that soil health thresholds are not intrinsic ecological properties but outcomes of methodological choices embedded in sampling design. Consequently, indicator interpretation is contingent on the reference framework employed, challenging the assumption of universal and transferable thresholds. We argue that evaluating discriminant power, alongside distributional robustness, should become a central criterion in the development of soil biodiversity indicators. More broadly, our findings highlight the need to explicitly integrate sampling design into indicator science to ensure robust, comparable and policy-relevant soil health assessments.

Soil biodiversity is fundamental to ecosystem functioning but remains underrepresented in conservation policies and large-scale monitoring. Here, we present RMQS-Biodiversity, a nationwide soil biodiversity survey integrated into the French Soil Quality Monitoring Network (RMQS), and illustrate its potential for soil ecology research. In this pioneer study, we examine three major ecological aspects: (i) how systematic grid-based sampling captures micro-food web patterns using nematode communities, (ii) the spatial turnover of detritivore communities (Collembola, Isopoda, Diplopoda) in response to environmental and geographic gradients, and (iii) the influence of macroecological drivers on predator (Carabidae) morphological traits. Across 69 sites, we identified a few widespread species coexisting with numerous rare taxa, underscoring the value of large-scale surveys for detecting cryptic biodiversity. Nematode indicators revealed high variability in food web structure across land uses, with increased facultative phytophagous nematodes in forests. Isopods and diplopods were strongly structured by dispersal constraints, while springtails exhibited weaker environmental responses, likely due to their higher dispersal capacity. Additionally, sexual size dimorphism in Carabidae varied by habitat, with female-biased dimorphism in closed habitats but no dimorphism in open environments, highlighting habitat stability's role in shaping morphological traits. This study demonstrates the value of multi-taxon, multi-trophic biodiversity assessments in long-term soil monitoring. RMQS-Biodiversity provides a robust framework for soil biodiversity monitoring and conservation, refining bioindicators of soil quality and informing policies such as the EU Soil Monitoring Law.

Soil fauna is one of the most important components of the soil ecosystem. It is highly diverse and abundant, supporting essential ecosystem services. However, its use in management decisions has been limited by now. This is partly a result of missing data and knowledge for large-scale mapping and application. In this study, our objective was to shed light on these aspects by mapping the spatial distribution of representative groups of macro- and mesofauna. Specifically, we used publicly available data for Earthworms, Millipedes, and Springtails and mapped their abundance, richness, and diversity across Europe. We applied machine learning techniques to understand the spatial configuration of these soil fauna taxa as influenced by topography, climate, vegetation, land use, and soil properties.Springtail abundance ranged from 1000 to 15,000 individuals per m2, while rarefied species richness ranged from 2 to 7 species per sample, with higher values in mountainous regions compared to plains. Earthworm abundance ranged from 20 to 300 individuals per m2, while richness ranged from 2 to 6 species, with higher values in Scandinavia compared to central and eastern Europe. Millipede abundance ranged from 20 to 400 individuals per m2, while species richness ranged from 1 to 6 species, with the highest values in central Europe and the lowest in northern Europe. Although the three taxonomic groups displayed marked differences in spatial patterns, in general, the diversity values were higher in northern and central Europe compared to South Europe. In the case of the latter, however, the data available were less, which might have led to underestimations of diversity in this area. Our results showed further that for Springtails, Earthworms and Millipedes, altitude, climate, vegetation, and land use were among the strongest predictors of species richness and diversity patterns, while abundance was mainly influenced by vegetation and soil properties. Our results indicate that climate changes, particularly rising temperatures, might impact on the evolution of soil fauna communities in the coming decades, especially in the mountain areas. Although mapping provides a visual presentation of soil ecosystems and conservation trends, as well as soil biodiversity hotspots, we also found that soil mapping has a high degree of uncertainty (e.g. in areas of low data availability, such in the case of Southern Europe), largely underestimated due to the highly endemic and patchy nature of soil fauna, with significant disparities in current data, including historical differences in methodologies, sampling efforts and scope of studies. Our mapping methodology can be applied at regional, national or European scale, providing actionable management and policy implementation pathways. Our study highlights the need to continue soil biodiversity monitoring efforts, especially in areas with less data, promote data sharing and conduct further research on soil biodiversity conservation and management.

In a world undergoing climate and usage change, soil biodiversity, which accounts to 25 % of the terrestrial biodiversity, is under severe threats. However, scenarios of climate change are based on known sensitivity of aboveground communities while there are differences on the responses to these changes with soil biodiversity. Here, we investigate the effects of an extreme climatic - due to an exceptionally drought year in 2011 - in various land use types (grassland, arable land, forest) through a study conducted at a regional scale (146 sites in Meuse, France) during 5 years. We characterized the responses of Collembola communities to climate change using (i) taxonomic indices and species dynamics, and (ii) species' functional traits and trait-based indices to reveal community assembly mechanisms. Our results demonstrated a total of 98 Collembola species collected during the five year project over the three land uses. Density and species richness were modulated by year, by land use and by their interaction. Three different distribution patterns in response to extreme drought events were demonstrated according to land use. Our findings thus reveal various effects according to land use, with a fast recovery of communities in arable lands, a long term effect for grasslands, and almost no effects observed in forests. These results show that the diversity of Collembola communities may be used as indicators of the resilience of ecosystems facing extreme climatic events.

• The earthworm population in Montpellier exhibits remarkably high genetic diversity. • Haplotypic and nucleotidic diversities of earthworms are influenced by environmental factors. • Cryptic lineages were identified in three earthworm species. • Human-mediated transports significantly contribute to the distribution patterns of earthworms in Montpellier. • This study confirms molecular barcoding's efficacy in uncovering genetic diversity within urban habitats.

Soil and soil-biodiversity protection are increasingly important issues in environmental science and policies, requiring the availability of high-quality empirical data on soil biodiversity. Here we present a publicly available data warehouse for the soil-biodiversity domain, Edaphobase 2.0, which provides a comprehensive toolset for storing and re-using international soil-biodiversity data sets, following the FAIR (Findable, Accessible, Interoperable, and Reusable) principles. A major strength is the possibility of annotating biodiversity data with exhaustive geographical, environmental and methodological metadata, allowing a wide range of applications and analyses. The system harmonises and integrates heterogeneous data from diverse sources into standardised formats, which can be searched together using numerous filter possibilities, and offers data exploration and analysis tools. Edaphobase features a strict data transparency policy, comprehensive quality control, and DOIs can be provided for individual data sets. The database currently contains >450,000 data records from >35,0000 sites and is accessed nearly 14,000 times/year. The data curated by Edaphobase 2.0 can greatly aid researchers, conservationists and decision makers in understanding and protecting soil biodiversity.

The trait-based approach is increasingly used for soil invertebrates. Complementary to the taxonomy based approach, the trait-based approach can provide a more mechanistic understanding of the responses of organisms to environmental disturbances and of their effects on soil functioning. However, this approach has several limitations linked to the conceptual development of functional traits. There is a large ambiguity and variability in using the term "functional traits” by zoologists and ecologists working with soil invertebrates. In this study, we used a questionnaire and literature scanning to review the practical use of functional traits concept in soil ecology over the last decade. We clarifed and expanded the functional trait definition as "A functional trait is a measurable characteristic of an individual organism or its colony that has a clear link to the organism's fitness and/or its effect on other organisms and/or the environment”. We also reviewed existing trait databases showing a high amount, but also high heterogeneity and low accessibility of data on the functional traits of soil invertebrates. We suggest synthesising existing trait data and databases, using the functional trait-based approach consistently and reproducibly, and disseminating it to facilitate mechanistic research in soil ecology.

Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.

Earthworm communities within urban environments remain an intriguing subject. This study aims to unravel the intricate relationship between these communities and the heterogeneous urban soils they inhabit. Urban soils, shaped by past and present human activities, harbor a rich diversity of earthworms, yet the specific factors influencing these communities remain poorly understood.Earthworm communities were sampled across 13 urban parks of Montpellier, a Mediterranean city in France. The effect of four variables at two scales were assessed: (i) landscape attributes within a 100-meter radius surrounding each sampling point and (ii) site-specific factors, including soil properties such as organic carbon content and pH levels, soil age, and management practices. Variation partitioning was employed through partial canonical correspondence analysis in order to disentangle the effects of these variables on earthworm community composition.A total of 16 species were identified out of 1270 individuals collected. Most are ubiquist, with a limited number being endemic to the Mediterranean region, potentially indicating biotic homogenization due to urbanization. In addition, multivariate analyses emphasized the substantial influence of landscape characteristics, composed by the rate of green spaces and the number of patches. These landscape-level attributes and especially the connectivity of green spaces emerged as primary drivers, surpassing the influence of management practices, soil age and soil properties.Thus, this research underscores the importance of considering diverse scales, and particularly landscape-level factors, in comprehending and restoring soil fauna such as earthworm communities within Mediterranean urban parks.

In 2023, the European Commission released a legislative proposal for a Directive on Soil Monitoring and Resilience which aims to define a legal framework to achieve healthy soils across the European Union (EU) by 2050. A key component of the initial Directive is the mandate for Member States to establish basic geographic soil governance units, referred to as soil districts, and appoint a district-specific authority to oversee the implementation of soil health assessments. This paper proposes an operational definition of the districts following the conditions outlined in the proposal for the Directive and discusses various attention points for their implementation. Tentative districts were developed for seven EU countries, considering soil type, climate, topography, and land cover factors, starting from the smallest existing administrative unit (i.e. municipalities). Experts were asked to report on the applicability of the proposed districts within well-known pedo-ecological regions and discuss the relevance of the districts for establishing an EU-wide monitoring network and reporting on soil health and degradation. The outcomes highlight the need for detailed soil maps to account for specific soil types when stratifying countries into soil districts. The soilscape approach allows for a consistent method to defining soil districts across Member States. This enables contrasting soils within a district to be managed in a similar manner, with soil degradation/health thresholds applied to each district based on land cover. However, it is unclear whether soil districts as currently formulated in the Directive are in fact the right tool to support local soil management and monitoring of soil health. Districts can help ensure that all soil conditions are covered in a monitoring system, but they may not provide support for soil management or monitoring at a local scale due to short-scale soil variability and threats affecting soil management within the same soilscape. Beyond the use of districts for designing a European/national scale monitoring system, the districts can help create animations and other educational tools to promote soil literacy and connectivity of users to soils locally.

Collembola are very abundant organisms in soils (several thousand individuals per square meter) and are considered to be good indicators of soil quality. These indicators are mainly based on the number of individuals observed (abundance per square meter of soil), but also the singularity and number of species present (species richness). A limitation that comes with the usage of collembola as an indicator is the complexity of the identification of the species under a microscope, how time-consuming it is, and the morphological similarity between some species. Deep learning approaches have been very successful in the resolution of image-based problems. Still, no work yet exists that uses deep learning in the recognition of collembola on a microscope slide. This could be a valuable tool for experts seeking to use Collembola as a metric on a larger scale. In this work, we explore and evaluate the performance of state-of-the-art deep learning techniques over the identification of Collembola on a new manually annotated dataset.