Evolutionary and plastic changes in a native annual plant after a historic drought

Area of Science:

• Evolutionary Biology
• Plant Ecology
• Climate Change Science

Background:

• Severe droughts are increasing globally due to climate change.
• Resurrection studies are key to understanding population responses to environmental shifts.
• California experienced a prolonged drought from 2011-2017, impacting native flora.

Purpose of the Study:

• To investigate contemporary evolution in response to a historic drought using the California native plant Leptosiphon bicolor.
• To assess how populations along a moisture gradient evolved in response to drought.
• To examine phenotypic plasticity in response to experimental drought.

Main Methods:

• Utilized a resurrection approach with seeds collected before and after the 2011-2017 California drought.
• Conducted a common garden greenhouse study with three L. bicolor populations from varying moisture availability.
• Implemented a drought experiment to evaluate plant plasticity.

Main Results:

• The wettest population evolved earlier flowering post-drought; plasticity to drought was observed across all populations.
• Trade-offs with earlier flowering included lower water-use efficiency in the driest population.
• Flower size evolved differently: two populations showed smaller flowers with drought, one evolved larger flowers without plasticity.

Conclusions:

• Leptosiphon bicolor populations exhibit varied evolutionary and plastic responses to drought.
• Contemporary evolution and plasticity contribute to drought adaptation in plants.
• Understanding population-specific responses is crucial for predicting biodiversity changes under global change.