This Soil Community webinar brought together experts from leading EU projects and institutions to explore a central question:

How does soil fauna contribute to soil health, and how can it be effectively monitored and integrated into biodiversity assessment frameworks?

From microscopic mesofauna to ecosystem-engineering earthworms, the session highlighted the complexity of soil life, the challenges of monitoring it, and the need for more integrated and standardized approaches across Europe.

Soil Mesofauna as Soil Indicators – Potential, Limitations, Land Use Effects

Christine van Capelle (BIOSERVICES project, Thünen Institute of Biodiversity) explored the role of soil mesofauna, particularly mites and springtails, as key indicators of soil health.

Although small in size, these organisms have a disproportionately large impact on soil ecosystems, contributing to nutrient cycling, soil structure, water regulation, and overall ecosystem resilience. Their sensitivity to environmental and management changes makes them valuable tools for assessing soil conditions.

She also addressed current monitoring approaches. While traditional sampling and identification methods remain reliable, they are time-consuming and resource-intensive, requiring specialized expertise. Emerging tools such as eDNA offer promising opportunities for scaling up monitoring in the future.

Using preliminary results from the BIOservicES project, she showed that soil biodiversity patterns vary significantly across Europe, depending on both land use and biogeographical region. Microarthropods tend to be more abundant in semi-natural, agricultural, and forest soils, but their response to land use is strongly context-dependent.

As she highlighted:

“The first results from BIOserviCES indicate that collembolans and mites are widespread and abundant in the Alpine, Continental and Mediterranean region, so that here they have the highest soil indicator potential. The results indicate that land-use effects on soil microarthropods depend on biogeographical conditions and that impacts differ among microarthropod groups by region. In the Atlantic region, collembolan abundance and diversity are lower, so we recommend making a case-by-case decision. And in the Boreal region, we would recommend the use of alternative indicators as abundances are very low.”

Overall, the presentation showed that a single metric cannot capture soil health. Effective assessment requires combining multiple indicators and interpreting them within their environmental context.

Management and Land Use Effects on Earthworms on a European Scale

Building on this, Stefan Schrader (Thünen Institute of Biodiversity, Braunschweig, Germany) focused on earthworms as key indicators of soil health and on their responses to land use and management across Europe.

Earthworms act as ecosystem engineers, regulating soil structure, nutrient cycling, and organic matter decomposition. Their presence and activity provide valuable insights into soil functioning and ecosystem services.

Using data from the SoilDiverAgro and BIOservicES projects, he showed that pedoclimatic conditions are major drivers of earthworm communities, shaping their abundance, biomass, and species richness.

As he summarized:

“From the SoilDiverAgro study, the pan-European gradient of pedoclimatic conditions forms earthworm metrics. Conventional farming is increasingly converging with organic farming by adopting sustainable practices, blurring management differences between the two systems. This is reflected in our case by the lack of differences in earthworm metrics.

And in the BIOservicES study, across the land-use types studied, agricultural and semi-natural systems are most favorable to earthworms, while industrial areas are most detrimental. Finally, depending on management measures, the intensity of land use can either negatively impact earthworms or promote them.”

A key and somewhat unexpected finding was that no significant differences were observed between conventional and organic farming systems at the European scale. This reflects a broader shift in which conventional systems increasingly adopt more sustainable practices, making the two systems more similar in practice.

A key finding was that differences between conventional and organic farming systems are not always clear-cut, reflecting the increasing adoption of sustainable practices in conventional systems.

This highlights that soil biodiversity responses are highly context-dependent and must be interpreted in relation to climate, land use, and management practices.

Comparing Molecular and Morphological Approaches for Soil Fauna Biodiversity Assessment

Julia Köninger (SOB4ES, University of Vigo) examined how different monitoring methods shape our understanding of soil biodiversity.

She compared traditional morphological methods, which rely on visual identification, with molecular approaches such as environmental DNA (eDNA). While morphological methods are accurate and well-established, they require significant time and expertise. Molecular methods, on the other hand, enable large-scale, faster assessments, though they are still evolving.

Using data from large European initiatives such as the LUCAS Soil Survey, she showed that land-use intensity generally decreases biodiversity across multiple taxonomic groups. At the same time, croplands often showed relatively high diversity, but also higher homogenization, meaning communities become more similar across sites.

She also highlighted legacy effects, where soils retain biodiversity signals from previous land uses.

As she emphasized:

“It is still important which methods we are using, and that land use impacts on biodiversity depend strongly on these methods. Molecular methods with eDNA are powerful, but they are still not perfect and are still evolving. Morphological assessments remain essential, and we need to integrate both approaches better so that the results can be interpreted in ways that support policymaking. We also need more standardization and validation as a critical aspect for the Soil Monitoring Law and future biodiversity targets.”

In this context, initiatives such as the SHARE Protocols Handbook developed within SOB4ES are key, as they provide harmonized guidance for soil biodiversity assessment, helping to standardize methods and improve data comparability across Europe.

The key takeaway is that no single method is sufficient. Combining molecular and morphological approaches, alongside improved standardization, is essential for reliable and policy-relevant soil biodiversity monitoring in Europe.

How to Engage farmers in soil monitoring and what can be learned from Citizen Science

Pia Euteneuer (BOKU University, SoilRise Austria) presented an innovative approach to soil monitoring through citizen science, with a focus on farmer engagement.

The SoilRISE project combines data collection with awareness-raising, using a mentor-based network where students recruit farmers from their personal networks. This approach achieved almost 100% participation rates, demonstrating the power of trust and community connections.

To date, the project has collected data from over 280 sites across Austria, covering diverse environmental conditions and land uses. Outreach activities, including workshops and field days, have reached around 9,000 participants, significantly increasing awareness of soil biodiversity.

A key element of success was strong community engagement, including workshops, field days, and training sessions, which reached around 9,000 participants. This helped build trust, increase awareness, and support long-term participation.

As she shared:

“If you haven’t yet worked with citizen science, you should not be afraid. It’s actually quite fun if you like to talk to farmers. Farmers are increasingly open to engaging with scientists; they understand results very well and try to implement them into their daily work. This makes collaboration even more valuable, as they bring very practical ideas and actively support soil life.”

Importantly, the results showed that citizen science can generate data comparable to, and in some cases even greater than, that from professional surveys.

The main takeaway is that citizen science is a powerful and scalable tool for soil monitoring, especially when combined with expert validation. It not only supports data collection but also strengthens the connection between science and practice, making farmers active contributors to soil health assessment.

Operational Soil Biodiversity Monitoring at National Scale: Lessons from the French RMQS Network

Jérôme Cortet (RMQS Biodiversity, Univ. Montpellier Paul-Valéry) presented the RMQS Biodiversity project, a large-scale initiative extending France’s national soil monitoring network.

The project builds on the long-standing RMQS soil monitoring network, which has been sampling soils across France since 2000 using a systematic grid approach. The new biodiversity extension expands this framework by integrating a wide range of biological indicators, including microorganisms, nematodes, mesofauna, and macrofauna.

Currently, around 300 sites across France are being sampled, covering multiple land-use types and environmental conditions. The project combines traditional field methods, laboratory analyses, and eDNA approaches, aiming to create a comprehensive overview of soil biodiversity.

The first results from this biodiversity campaign are already being analyzed and published, offering valuable insights into national-scale soil biodiversity patterns.

You can explore the study here: https://www.sciencedirect.com/science/article/pii/S0929139325007474?via%3Dihub

A key focus of the presentation was the importance of methodological choices in monitoring. Results showed that:

• the number and type of sampling methods directly influence the biodiversity detected
• different datasets and reference systems can lead to different interpretations of the same site
• increasing sampling effort generally leads to detecting more species, but it must be balanced with feasibility

As he noted

“Depending on the purpose of your study, you always need to find a balance between the sampling effort and what you are actually able to detect in your sites.”

He also highlighted that different indicators often produce different results, reinforcing the need to treat them as complementary rather than interchangeable.

This is especially relevant for the Soil Monitoring Law, where debates continue around the role of eDNA and the need for harmonized approaches.

Post-Webinar Reflections

• Soil organisms play a key role in nutrient cycling, soil structure, and ecosystem functioning.
• Biodiversity patterns and soil organism responses vary strongly across regions, land uses, and climatic conditions, meaning there is no one-size-fits-all interpretation.
• Indicators such as abundance, species richness, and functional diversity can show different trends, highlighting the need for careful, context-specific interpretation.
• The choice of monitoring approach, morphological vs molecular, strongly influences results. No single method is sufficient on its own.
• Combining eDNA, traditional taxonomy, and functional indicators is essential for building reliable and policy-relevant soil monitoring frameworks.
• Sampling intensity, methods, and reference datasets all affect outcomes. Monitoring systems must balance scientific accuracy with practical feasibility.
• Differences between systems like conventional and organic farming are not always clear-cut, and management practices can both support and reduce biodiversity.
• Engaging farmers directly in data collection is not only effective for gathering data but also for raising awareness and bridging science and practice.
• Policy relevance depends on standardization. To support frameworks like the Soil Monitoring Law, there is a strong need for harmonized methods, validated indicators, and clear interpretation guidelines.

The full webinar recording is now available on YouTube. Watch it here.