Climate‐Driven Convergence of Chemical Ecotypes in Mediterranean Lamiaceae

ABSTRACT Aim To link the identity of the major monoterpenes in plants to their distribution across climatic gradients, and test whether patterns of chemical ecotypic differentiation are consistent across multiple Mediterranean Lamiaceae species. Location The Mediterranean region, with a focus on the Western Mediterranean region. Taxon Aromatic plant species in the Lamiaceae family: Thymus vulgaris , Thymus zygis , Origanum vulgare and Satureja montana . Methods We combined new data on intraspecific variation in monoterpene composition of T. vulgaris sampled across altitudinal gradients in Southern France with a systematic review of published data on chemotypes in four Lamiaceae species across the Western Mediterranean. Chemical variation was integrated with historical climatic records to test associations between chemotype distributions and environmental conditions. Results In T. vulgaris , phenolic chemotypes predominate in regions with hot, dry summers, while non‐phenolic chemotypes dominate in areas with severe winter freezing. This climatic differentiation between phenolic and non‐phenolic chemotypes also emerges in T. zygis , O. vulgare and S. montana , revealing convergent patterns of climate‐associated chemical divergence across species. Main Conclusions Monoterpenes are functional traits that can help understanding adaptation to environments Mediterranean Lamiaceae. The emergence of phenolic and non‐phenolic ecotypes associated with different environmental conditions across species indicates convergent climate‐driven differentiation in monoterpene composition. These findings highlight the role of monoterpenes in plant resilience to heat, drought and freezing temperatures and provide insights into the evolutionary and ecological responses of Mediterranean flora to climate change.