How does contemporary selection shape oak phenotypes?

Area of Science:

• Forestry science
• Evolutionary biology
• Plant genetics

Background:

• Forests face increasing natural and human-driven selection pressures, exacerbated by climate change and resource demands.
• Understanding how these pressures induce evolutionary changes in forest ecosystems is crucial.
• Temperate European oaks (Quercus petraea and Quercus robur) are important components of forest ecosystems.

Purpose of the Study:

• To investigate the evolutionary changes in temperate European oaks under selection pressures.
• To screen functional traits for selection gradients and genetic changes over two generations.
• To compare the adaptive potential of Quercus petraea and Quercus robur.

Main Methods:

• Screening of numerous functional traits in Quercus petraea and Quercus robur.
• Analysis of univariate selection gradients.
• Assessment of expected and observed genetic changes over two successive generations.

Main Results:

• Growth, leaf traits, and defense traits showed significant selection and predicted shifts in both oak species.
• Phenology, water metabolism, structure, and resilience traits did not exhibit significant changes.
• Quercus petraea exhibited greater phenotypic and genetic variance in fitness compared to Quercus robur.

Conclusions:

• Quercus petraea possesses a higher capacity for adaptive evolution than Quercus robur.
• Quercus robur's adaptive response to contemporary pressures is a concern, potentially leading to its decline.
• Contrasting demographic dynamics suggest Quercus robur may decline, particularly in mixed stands with Quercus petraea.