Climatic variations along an aridity gradient drive significant trait intraspecific variability in Mediterranean species

Summer drought represents one of the main stress sources stress for plant communities in the Mediterranean region. Plants can adopt several response strategies to cope with stress, reflected in the adoption of specific Plant Functional Traits (PFTs). Trait-based approaches commonly meet three critical issues: they overlook Intraspecific Variability (ITV), they focus on a large spatial scale, or they focus on single trait responses to stress. In this study, we present evidence for a significant amount of ITV in morphological and anatomical trait syndromes observed between three local populations of Phyllirea latifolia, Pistacia lentiscus and Quercus ilex, distributed along an aridity gradient. Thicker, more physiologically expensive leaves and lower heights found in the drier sites mainly conform to drought-resistance strategies. Interestingly, PFTs from Cistus salviifolius were found not to vary between sites. This implies that not all species vary at the same geographical scale, possibly depending on their different successional role. The main implication behind our findings is that climate can easily drive significant ITV in multiple traits among plant populations, even at a local scale, although trait responsiveness might be species-specific. Different plant populations hailing from the same geographical regions might thus respond differently to climate change. HIGHLIGHTVariations in Plant Functional Traits from several Mediterranean species found along an aridity gradient on a local (<60Km radius) scale; responses consistent to reported drought adaptations.