Continental-Scale Invertebrate Distributions Are Mainly Associated With Climate but Modulated by Soil and Land-Use Gradients

Abstract

Aim

To quantify the relative influence of climate, soil and land-use on the distributions of terrestrial invertebrate species and to assess whether their importance is consistent among taxonomic/trophic groups, biogeographical regions and land-use-intensity gradients.

Location

Europe.

Time Period

Contemporary.

Major Taxa Studied

6844 species in 13 invertebrate groups spanning decomposers (earthworms, springtails), herbivores (gastropods, grasshoppers, moths), predators (spiders, ground beetles, dragonflies), omnivores (ants), pollinators (bees, hoverflies, butterflies), and parasitoids (parasitoid wasps).

Methods

We aggregated > 18 million presence records to a 1-km grid and fitted ensemble species-distribution models with target-group background sampling and spatial block cross-validation. SHapley Additive exPlanations (SHAP) quantified the contribution of climatic, soil, land-cover, and land-use-intensity variables to occurrence probabilities. Predictor importance, direction of effect, and land-use-mediated effects were compared across taxa, European biogeographical regions, and species niche characteristics.

Results

Climatic variables had the highest predictive importance for species distributions (mean ± SD = 44% ± 5% of weighted summed SHAP importance), followed by soil (30% ± 6%), with land cover and land-use intensity each contributing ~13%. Although average variable hierarchies were similar among invertebrate groups, intra-group variation was high, and the importance of soil increased with niche specialization. Limiting environmental variables shifted geographically: snow cover governed Arctic-Alpine ranges, whereas precipitation seasonality and the number of growing degree days constrained species in the Mediterranean region. High land-use intensity was negatively associated with species occurrence, especially in grasslands.

Main Conclusions

Continental-scale invertebrate distribution patterns are mainly associated with climate and modulated by soil properties, but species-specific niches and regional contexts generate diverse responses to land-use change. Instead of relying on single-taxon surrogates or uniform prescriptions, conservation strategies should better integrate soil management and habitat restoration in sensitive areas, such as the central Danube basin, and for sensitive species, such as grassland butterflies and hoverflies.