Phenotypic plasticity and genetic diversity shed light on endemism of rare and its potential vulnerability to climate warming.

The rapid pace of contemporary environmental change puts many species at risk, especially rare species constrained by limited capacity to adapt or migrate due to low genetic diversity and/or fitness. But the ability to acclimate can provide another way to persist through change. We compared the capacity of rare (Braun's rockcress) and widespread to acclimate to change.