Early Life History Divergence Mediates Elevational Adaptation in a Perennial Alpine Plant

Area of Science:

• Evolutionary biology
• Plant ecology
• Genetics

Background:

• Spatially divergent natural selection drives adaptation and ecotype evolution in contrasting environments.
• Perennial plant adaptation is shaped by life history traits across life stages, but their expression is poorly understood.
• Understanding life history trait contributions is crucial for comprehending adaptive evolution in perennial species.

Purpose of the Study:

• To investigate elevational adaptation in *Dianthus carthusianorum* by examining genotype-environment interactions in life history traits.
• To quantify the fitness contributions of early life stages to adaptation in contrasting environments.
• To explore trade-offs in life history traits and their role in the evolution of divergent ecotypes.

Main Methods:

• A multi-year reciprocal transplant experiment with low and high elevation *Dianthus carthusianorum* seedlings.
• Assessment of genotype by environment interactions in fitness components and application of matrix population models.
• Trade-off analyses to evaluate life history trait advantages across elevational gradients.

Main Results:

• Evidence of genotype by environment interactions indicating elevational adaptation across early life cycle stages.
• Local genotypes exhibited a significant fitness advantage, confirmed by population growth rate estimates.
• Early reproduction and survival were identified as key contributors to adaptation at low and high elevations, respectively, linked by trade-offs.

Conclusions:

• Climate-driven selection has led to the evolution of divergent life histories and elevational ecotypes in *Dianthus carthusianorum*.
• Low elevation favors early reproduction due to high energy and competition, while high elevation favors self-maintenance with limited resources.
• Co-gradient plasticity in high-elevation populations may enhance persistence under future climate warming scenarios.