From fire to soil: the role of prescribed burns in land snail communities for improve conservation

As climate change increases fire intensity and frequency, prescribed burns have become a key tool in ecosystem management. This study examines the effects of prescribed burning, burn frequency, and habitat heterogeneity on soil-dwelling snail communities in Mediterranean ecosystems, aiming to improve fire management to conserve biodiversity while reducing fire risks. Conducted in the Massís del Montgrí (NE Iberian Peninsula), 40 subplots with varying burn histories were sampled. Gastropods were surveyed through active searches for larger snails and soil samples for smaller ones. Vegetation cover, leaf litter, and organic matter content were also measured. Prescribed burns generally reduced snail abundance and richness, with unburnt control areas hosting more snails. Small species were more common in unburnt plots with higher tree cover and organic matter content, while larger species generally thrived in frequently burned areas with higher herbaceous cover. Burn frequency and vegetation cover were key factors shaping snail communities, highlighting the role of fire-driven microhabitat changes – particularly through their effects on organic matter availability – in shifting soil-dwelling snail assemblages. By identifying species-specific responses to fire, this study contributes to our understanding of how fire shapes soil biodiversity and offer insights for prescribed burn regime management. We advocate for context-dependent Integrated Fire Management strategies that balance fire recurrence and intensity with habitat recovery. Adaptive management approaches and ongoing interdisciplinary monitoring will be essential to optimizing fire practices for biodiversity conservation. • Prescribed burns reduce snail abundance and richness in Mediterranean ecosystems. • Snail species show distinct responses to burn frequency and microhabitat conditions. • Small snails favour unburnt areas with higher tree cover and soil organic matter content. • Larger snails thrive in frequently burned areas with herbaceous vegetation. • Context-dependent fire management is needed to balance biodiversity conservation.