Intraspecific diversity is often the result of genetic and plastic responses to spatiotemporal environmental gradients. However, we lack broad surveys of intraspecific diversity across species ranges across centuries of anthropogenic change. While major phenotypic changes, especially in phenology, over the course of anthropogenic climate change have been observed, the role of evolution in this is unclear. We studied genotypes and phenotypes of herbarium samples of Arabidopsis thaliana from across the species range and across 200 years of history. We tested if phenology, physiology, and genomic variation exhibit hypothesized adaptive responses to anthropogenic change and spatial climate gradients.
Results/Conclusions
Date of collection was significantly later in recent years across most of Eastern Europe, although it was earlier in the west. Moist summers were associated with later collections in regions with a high density of rapid-cycling genotypes, suggesting that moisture allows a second generation within the year or these populations exhibit a drought escape strategy. Leaf N decreased with year, suggesting increased efficiency of photosynthesis over time. The substantial differences among populations in phenotypic response to climate anomalies suggest global change impacts interact with population genetic structure or additional site-specific environmental conditions. Similarly, regional heterogeneity indicates complex phenotype responses to spatial climate gradients potentially arising from variation in local adaptation and plasticity.