Local adaptation of Erysimum capitatum across altitudes: Implications for responses to climate change

Background/Question/Methods

Alpine plant communities are at risk because of recent climate change. Assessing the performance of alpine plant species across different altitudes is important for predicting how they may respond to changing climate. Seed germination and seedling establishment are crucial life-history stages for the persistence of sexually reproducing alpine plants, yet compared to adult life stages, less information exists on natural selection and adaptation of these early life stages of alpine plants. To evaluate past adaptation and the potential to accommodate future climate conditions, seeds and seedlings of Erysimum capitatumwere reciprocally transplanted between alpine and low-altitude populations. 

Results/Conclusions

When grown in a common environment, plants from alpine and lower-altitude populations differed significantly from each other in germination, size, and morphological traits, and they showed home-site advantages in survival and growth. In addition, plants grew to a larger size at low altitude. In situ altitudinal differences in plant performance across altitude are therefore due to plasticity to altitude as well as genetic differentiation or maternal effects. Low-altitude sites had harsher environments and favored faster growth and faster reproduction of those that survived. Because climate change is expected to cause alpine environments to become more similar to lower-elevation environments, alpine E. capitatum is expected to suffer reduced seedling recruitment and higher mortality as a direct response to altered environmental conditions as well as a result of past adaptation to alpine environments.