Rapid changes in plasticity across generations within an expanding cedar forest.

Area of Science:

• Ecology
• Evolutionary Biology
• Forest Science
• Plant Physiology

Background:

• Phenotypic plasticity, the ability of an organism to change its phenotype in response to environmental changes, is crucial for adaptation.
• Understanding the evolution of plasticity and its variation within populations is key to predicting species' responses to climate change.
• The 'cost of plasticity' hypothesis suggests a trade-off between stress tolerance and phenotypic plasticity.

Purpose of the Study:

• To investigate inter-individual variation in phenotypic plasticity and its evolutionary changes over three generations in a forest ecosystem.
• To assess the relationship between radial growth and plasticity in response to summer rainfall.
• To examine the covariance between growth and plasticity at the individual level.

Main Methods:

• Dendrochronological data were used to assess radial growth and plasticity in situ.
• A linear mixed model was employed to account for spatial, temporal, and age-related effects.
• Analysis spanned three generations of trees within an expanding forest.

Main Results:

• Significant inter-individual variance in both radial growth and plasticity was observed within each generation.
• Mean values and variances of growth and plasticity exhibited significant changes across the three generations.
• A positive covariance between growth and plasticity was detected at the individual level.

Conclusions:

• The study reveals substantial variation in phenotypic plasticity and growth within forest tree generations.
• Evolutionary changes in plasticity and growth occur across generations, driven by potential environmental and genetic factors.
• The detected positive covariance contradicts the cost of plasticity hypothesis, suggesting plasticity may not always incur a growth cost at the individual level.