Climate drives global functional trait variation in lizards.

Area of Science:

• Ecology and Evolutionary Biology
• Physiological Ecology
• Climate Change Biology

Background:

• Broad-scale variation in ectotherm traits is challenging to explain mechanistically.
• Climate is hypothesized to drive trait evolution and variation due to its impact on ectotherm thermal performance and fitness.
• Previous studies often lacked mechanistic explanations for climate-driven trait variation.

Purpose of the Study:

• To develop a mechanistic model predicting how climate affects ectotherm thermal performance.
• To determine how climate-driven thermal performance influences selection on functional traits.
• To explain macro-evolutionary patterns in ectotherm traits and trait variation.

Main Methods:

• Developed a mechanistic model linking climate to ectotherm thermal performance.
• Predicted the direction and strength of selection on functional traits based on thermal performance.
• Analyzed macro-evolutionary patterns in lizard body size, cold tolerance, and preferred body temperatures.

Main Results:

• Climate was shown to drive macro-evolutionary patterns in lizard body size, cold tolerance, and preferred body temperatures.
• Trait variation was found to be more constrained in regions with stronger predicted selection.
• The model provides a mechanistic link between climate, thermal performance, and trait evolution.

Conclusions:

• The study provides a mechanistic explanation for how climate drives trait variation in ectotherms via thermal performance.
• Findings offer an integrative framework connecting physical, physiological, and macro-evolutionary principles.
• The model can predict organismal responses to current and future climate change.