Abstract
Climate change is increasing drought intensity, threatening biodiversity. Rapid evolution of drought adaptations might be requiredfor population persistence, particularly in rear-edge populations that may already be closer to physiological limits. Resurrectionstudies are a useful tool to assess adaptation to climate change, yet these studies rarely encompass the geographic range of aspecies. Here, we sampled 11 populations of scarlet monkeyflower (Mimulus cardinalis), collecting seeds across the plants’ northern,central, and southern range to track trait evolution from the lowest to the greatest moisture anomaly over a 7-year period. We grewfamilies generated from these populations across well-watered and terminal drought treatments in a greenhouse and quantifiedfive traits associated with dehydration escape and avoidance. When considering pre-drought to peak-drought phenotypes, we findthat later date of flowering evolved across the range ofM. cardinalis, suggesting a shift away from dehydration escape. Instead,traits consistent with dehydration avoidance evolved, with smaller and/or thicker leaves evolving in central and southern regions.The southern region also saw a loss of plasticity in these leaf traits by the peak of the drought, whereas flowering time remainedplastic across all regions. This observed shift in traits from escape to avoidance occurred only in certain regions, revealing theimportance of geographic context when examining adaptations to climate change.