Can a Soil Index Reveal Ecosystem Recovery? The Biodiversity Soil Resilience Index: A new index to assess resilience in environmentally stressed ecosystems

Ecological resilience remains a central yet challenging concept to operationalise. In this study, we present the Biological Soil Resilience Index (BSR-Index), a composite, field-deployable metric that integrates three complementary bioindicators: soil microarthropods, entomopathogenic nematodes and fungi (EPNs, EPF), and earthworms. Raw values are normalised to fixed theoretical maxima and combined using a weighted mean (40% microarthropods, 30% EPN/EPF, 30% earthworms), producing a unitless score on a 0–100 scale that is classified into four resilience levels. The index was applied across forest, agricultural and agroforestry systems arranged along a stress gradient. Results show that the BSR-Index effectively discriminates between soils of high and low biological integrity, capturing both structural composition and functional depth of soil communities. By integrating multiple biological compartments into a single metric, the BSR-Index advances beyond traditional single-taxon approaches, offering a robust and reproducible framework for resilience assessment. Standardised scoring facilitates cross-ecosystem comparisons and provides a practical decision-support tool for land management, conservation and environmental policy. The BSR-Index highlights the pivotal role of soil biodiversity in maintaining ecosystem services and offers a scalable framework for monitoring, restoration prioritisation and adaptive planning in the context of ecological resilience.