Selection and Phenotypic Plasticity Shape Plant Performance in a Grassland Biodiversity Experiment

Area of Science:

• Ecology
• Evolutionary Biology
• Plant Science

Background:

• Long-term biodiversity experiments reveal increasing positive effects on plant productivity with diversity.
• Species-level responses to biodiversity are mixed, with unclear origins: adaptation or plasticity.
• Understanding these responses is crucial for predicting ecosystem functions in changing environments.

Purpose of the Study:

• To distinguish between adaptive and plastic responses of plants to varying biodiversity and community history.
• To investigate the role of selection and community legacy in shaping plant traits.
• To elucidate the influence of plant-soil feedbacks on plant adaptation in diverse communities.

Main Methods:

• A transplant experiment using nine species from a 17-year-old biodiversity experiment (Jena Experiment).
• Comparison of offspring from selected and naive (unselected) plants.
• Two experiments: 'Community History Experiment' (testing different environments) and 'Selection Experiment' (comparing selected vs. naive plants).

Main Results:

• Increasing species richness decreased individual biomass, reproductive output, growth rate, height, leaf greenness, and nitrogen, while increasing specific leaf area (SLA).
• Selected plants showed less biomass decline, greater height, and higher leaf carbon/nitrogen than naive plants with increasing richness.
• Community history and soil conditions significantly impacted plant survival and trait expression, with original environments favoring performance in high diversity.

Conclusions:

• Selection in biodiversity experiments drives adaptive phenotypic responses in plants.
• Plant community history and established plant-soil feedbacks are key drivers of these adaptations.
• Phenotypic plasticity is important, but adaptive evolution plays a significant role in plant community dynamics.