Rapid evolution predicts demographic recovery after extreme drought

Area of Science:

• Ecology
• Evolutionary Biology
• Genomics

Background:

• Climate change is causing population declines globally.
• Evolutionary rescue is a theoretical concept where populations adapt to survive environmental change.
• Its occurrence in natural populations facing climate change is not well understood.

Purpose of the Study:

• To investigate the role of rapid evolution in the persistence of natural populations during climate change.
• To link population dynamics with genetic changes in response to environmental stress.
• To determine if standing genetic variation and rapid evolution predict population recovery.

Main Methods:

• Whole-genome sequencing of 55 scarlet monkeyflower (Mimulus cardinalis) populations.
• Tracking population demography and allele frequency changes during an exceptional drought.
• Identifying climate-associated genetic loci.

Main Results:

• Observed range-wide population decline in scarlet monkeyflower during the drought.
• Documented geographically variable rapid evolution across populations.
• Found that population recovery was predictable by genetic variation and evolution at climate-associated loci.

Conclusions:

• Demonstrated the possibility of evolutionary rescue in wild populations.
• Showed that genetic variation in adaptive loci, not neutral loci, is key to population recovery.
• Highlighted the importance of standing genetic variation for adaptation to climate change.