Physiological cold tolerance evolves faster than climatic niches in plants.

Area of Science:

• Plant evolutionary biology
• Climate change ecology
• Physiological adaptation

Background:

• Predicting plant responses to climate change requires understanding thermal stress adaptation.
• Evolutionary rates of plant physiological tolerance versus climatic niches are poorly understood.
• Phylogenetic comparative approaches are needed to assess these evolutionary dynamics.

Purpose of the Study:

• To compare evolutionary rates of physiological temperature tolerance with climatic niche shifts in vascular plants.
• To investigate the influence of hardening on the relationship between physiological and niche evolution.
• To assess plant vulnerability to projected climate change, particularly warming temperatures.

Main Methods:

• Phylogenetic comparative analysis across three major vascular plant groups.
• Quantification of evolutionary rates for physiological cold and heat tolerance.
• Assessment of evolutionary rates for coldest and warmest climatic niche temperatures.
• Inclusion of hardening effects in the analysis of physiological and niche rate associations.

Main Results:

• Physiological cold tolerance evolves faster than heat tolerance across all studied plant groups.
• Evolutionary rates of coldest climatic niche temperatures exceed those of warmest temperatures.
• Evolutionary rates of physiological cold tolerance are faster than climatic niche changes.
• An inverse association was found between physiological cold tolerance and climatic niche shifts in non-hardened plants.

Conclusions:

• Plants exhibit faster evolution in cold tolerance and coldest niche temperatures compared to heat tolerance and warmest niche temperatures.
• Slower evolutionary rates of heat tolerance indicate potential sensitivity to increasing temperatures.
• Findings have significant implications for modeling climate-related plant extinctions.