Science Cafe will be a Zoom series for the rest of this year. It is recommended to register using the link beforehand.
Jill Anderson is an evolutionary ecologist who studies plant responses to global change. She obtained her Ph.D. from Cornell University, where she studied local adaptation in a southeastern species of blueberry (Vaccinium elliottii) and seed dispersal by fruit-eating fishes in the Peruvian Amazon. After her Ph.D., she completed a postdoc at Duke University with Tom Mitchell-Olds, then began a faculty position at the University of South Carolina before moving to the University of Georgia in 2015.
The abiotic and biotic environment varies across the landscape, exposing local populations to different selective pressures. Over evolutionary time, divergent selection can favor the evolution of local adaptation, wherein ecotypes have elevated fitness in their home environment and depressed fitness in the contrasting environment. Human activities are simultaneously modifying multiple abiotic and biotic agents of selection, decoupling linked cues like photoperiod and temperature that contribute to local adaptation, and likely leading to growing discrepancies between current and optimal phenotypes. We hypothesize that novel selection imposed by climate change shifts fitness landscapes, disrupting local adaptation. As a consequence, local populations could contract.
Climatic variation across mountains affords the opportunity to test hypotheses about the evolution local adaptation to continuous environmental variation. We predict that in future climates, local ecotypes will have reduced fitness in their home sites relative to low elevation families, whose modern climates are similar to projections for higher elevations. We test this prediction in the mustard Boechera stricta, which is native to the Rocky Mountains, where it inhabits elevations as low as 1500m and as high as 3500m. In this region, warming winter temperatures reduce snowpack and warming spring temperatures cause the remaining snow to melt early. We can simulate these climate change dynamics effectively via snow removal experiments. We have found clear evidence for adaptation to local environments over short geographic distances in Boechera stricta. Poor performance of high elevation families at lower sites foreshadows future maladaptation as temperatures warm. Furthermore, lower elevation families outperform local families even under control conditions, suggesting that climate warming has already disrupted local adaptation.