Adaptive potential of maritime pine under contrasting environments

Area of Science:

• Ecology
• Evolutionary Biology
• Forest Genetics

Background:

• Predicting forest tree adaptability to climate change requires understanding trait adaptive significance and evolvability.
• Phenotypic plasticity, genetic variation, and phenotypic integration influence population genetic structure.
• Empirical data on these factors in forest trees are scarce.

Purpose of the Study:

• To analyze adaptive traits in maritime pine populations across their distribution.
• To assess genetic variation, plasticity, and integration of traits related to resource acquisition and water-use strategies.
• To evaluate the potential for micro-evolution under changing climate conditions.

Main Methods:

• Common garden experiment with 11 maritime pine populations (119 families, ~1300 trees).
• Two contrasting productivity sites were used for planting.
• Measured traits included plant height (fitness surrogate), carbon isotope discrimination (mean and plasticity), specific leaf area, needle biomass, and phenology growth index.

Main Results:

• Additive genetic variation suggests adaptation potential to future environments.
• Phenotypic integration and selection gradients were higher at the high productivity site.
• Selection favored traits related to photosynthetic organ size and drought avoidance, not water use efficiency.

Conclusions:

• Variation in photosynthetic organ size and resource acquisition drives selection in maritime pine.
• High genetic variation and evolvability, including plasticity, support rapid micro-evolution.
• Population differentiation is expected to increase under more productive future Atlantic conditions.