Functional Groups Response to Water Deficit in Mediterranean Ecosystems.

Area of Science:

• Plant Ecology
• Climate Change Biology
• Mediterranean Ecosystems

Background:

• Mediterranean regions face increasing drought and precipitation variability due to climate change.
• Drought is a major stressor impacting plant communities, altering composition and species dominance.

Purpose of the Study:

• To assess the physiological and trait-based responses of diverse Mediterranean plant functional groups to water deficit.
• To understand how different species cope with drought stress under controlled conditions.

Main Methods:

• Controlled experiment evaluating moderate and severe water deficit.
• Analysis of plant traits (leaf dry matter), biomass, and physiological parameters (water status, photosynthesis, pigments, carbohydrates).
• Comparison of responses across functional groups: annual grass, annual forb, annual legume, and perennial shrub.

Main Results:

• Species exhibited varied responses to water deficit; legumes (Ornithopus compressus) showed significant decreases in RWC, pigments, and carbohydrates under severe drought.
• Grasses (Agrostis pourreti) and forbs (Tolpis barbata) maintained relative water content (RWC), indicating better drought tolerance.
• Perennial shrubs (Cistus salviifolius) displayed the least response to water deficit, suggesting high drought coping ability.
• Severe water deficit negatively impacted plant biomass across all studied species.

Conclusions:

• Plant functional groups and species possess distinct strategies for coping with drought.
• Understanding these differential responses is crucial for predicting Mediterranean ecosystem dynamics under climate change.
• The findings inform predictions of plant diversity and species composition shifts in grasslands and Montado ecosystems.