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

Drought represents one of the main sources of stress for plants in the Mediterranean region, and climate change is further escalating this stress. Plants can employ several response strategies to cope with stress, reflected in the adoption of specific Plant Functional Traits (PFTs). Trait-based approaches commonly meet three issues: they may overlook Intraspecific Variability (ITV), they could focus on large spatial scales, or they could focus on few traits. Here we present evidence that it's possible to observe ITV in morphological and anatomical trait syndromes between three local populations of Phillyrea latifolia, Pistacia lentiscus, and Quercus ilex, distributed along an aridity gradient. Thicker, physiologically expensive leaves and lower heights found in the drier sites mainly conform to drought-resistance strategies, while trait spectra from Cistus salviifolius were found not to vary significantly across sites. Thus, the amount of ITV observable at a local scale varies between species. We conclude that climate can easily drive a significant amount of ITV for several species, reflected in their trait spectra, among plant populations that are geographically close to each other. This highlights the importance of local environmental variability and implies that different populations hailing from nearby sites might respond differently to climate change.