Abstract
The temporal and spatial scales over which local adaptation operates is of great importance for our understanding of plant ecology and evolution, and its implications for agriculture, conservation and responses to climate change. We carried out a study of local adaptation of Arabidopsis thaliana in Sweden across two years and multiple field sites in the north and south of the country. Fitness was measured in traditional common-garden experiments, and also in evolution experiments that let plants compete and complete their entire life cycle naturally. We found evidence of strong selection on multiple scales, often affecting different fitness components in different directions. Conditional on survival, southern lines generally had higher fertility, but northern lines appear to have higher chance of surviving winter. Lines sampled from Baltic beaches in southern Sweden had low fertility, but performed exceptionally well in evolution experiments, consistent with their larger seeds providing an advantage in seedling establishment. Slug herbivory in a single southern common-garden site and year reversed the normal direction of selection, as attacks focused on southern lines.
