August 27, 2021

12:00 – 1:00

Dr. Nic Kooyers

Host: Dr. Michael McKain

The double-edged sword of rapid adaptation: facilitating or constraining invasions or responses to climate change?

The ability of selection to act on ecologically relevant timescales has become increasing apparent during the Anthropocene. Rapid adaptation can be beneficial to conservation interests when populations are able to quickly adapt in response to changing climates, but can be destructive when introduced species evolve to become more invasive. Here we explore these divergent roles for adaptation in the context of a native North American species of wildflower, Mimulus guttatus, that faces substantial climatic changes to its subalpine habitat as well as for a perennial herb, Trifolium repens, that has been introduced across the world from its native Eurasian range. To assess the role of adaptation in climate change, we first examine whether M. guttatus populations are locally adapted to their current conditions at their home sites or whether populations exhibit maladaptation because they are better adapted to historic conditions at their home site – a pattern termed adaptation lag. We investigate the climatic factors driving potential adaptation lags and whether future adaptation is constrained by lack of phenotypic variation or genetic tradeoffs between traits. To determine the role of adaptation in invasions, we assess how patterns of genetic and phenotypic variation differ across continent-wide ecological gradients in the native and introduced ranges and use common garden experiments to examine patterns of local adaptation. We use these data to examine the tempo and mode of adaptation as well as to test whether convergent evolution occurs across independent introduction events. While our results suggest that rapid adaptation impacts each of these species, they also suggest that adaptation is limited by the genetic architecture of ecological important traits and the variation present within the target populations.