36-year study reveals the effects of microhabitats on a wild wheat population

Abstract

AbstractLong-term genetic studies of wild populations are very scarce but are essential for connecting ecological and population genetics models, and are also necessary for understanding how climate change can affect biodiversity. We present a study of the wild ancestor of modern wheat, carried out over a 36-year period during which atmospheric CO2 increased by 70 ppm and temperature by 1.5°C. We genotyped 832 individuals from regular sampling along transects during the course of the experiment. Genotypes were clustered into ecological microhabitats over scales of tens of meters, and this clustering was remarkably stable over the 36 generations of the study. Simulations indicate that neutral processes alone are insufficient to explain this spatial and temporal stability, suggesting a role for fine-scale local adaptation to ecological parameters. Using a common-garden experiment, we showed that the genotypes found in distinct microhabitats differ phenotypically, further supporting the hypothesis of local adaptation. Our results provide a rare insight into the dynamics of a natural population at the scale of individuals over a period of environmental change.