High standing genetic variation in an invasive plant allows immediate evolutionary response to climate warming

Abstract

AO_SCPLOWBSTRACTC_SCPLOWPredicting plant distributions under climate change is constrained by our limited understanding of potential rapid adaptive evolution. In an experimental evolution study with the invasive common ragweed, we subjected replicated populations of the same initial genetic composition to simulated climate warming. Pooled DNA sequencing of parental and offspring populations showed that warming populations experienced a greater loss of genetic diversity, and greater genetic divergence from their parents, than control populations. In a common environment, offspring from warming populations showed more convergent phenotypes in seven out of nine plant traits, with later flowering and larger biomass, than plants from control populations. For both traits, we also found a significant higher ratio of phenotypic to genetic differentiation across generations for warming than for control populations, indicating stronger selection under warming conditions. Our findings demonstrate that ragweed populations can rapidly evolve in response to climate change within a single generation.