Seed Germination and Climate Change

Seed recruitment is predicted to be one of the most at-risk stages for plant regeneration in a changing climate. Seed dormancy break, germination, and seedling establishment are critical stages in plant regeneration, with consequences for plant fitness, population persistence, and colonization of new sites. Understanding how early life stages vary–among species and at the population level–is essential to accurately predicting responses to climate change and implementing successful restorations. To test this relationship, we are studying three common, restoration-relevant congeners: Asclepias incarnata, A. syriaca, and A. verticillata.  These species vary in pollination syndrome, breeding system, habitat, and degree of clonality and therefore presumably also neighborhood size. Seed collected along a north-south gradient from Minneapolis to St. Louis was used to test responses to cold stratification length and incubation temperature in the lab. A space-for-time approach was used to examine the impact of simulated climate change on early life stages for A. incarnata and A. syriaca populations in the field in common gardens in Chicago and St. Louis. By using multiple populations of species representing a gradient of neighborhood sizes, the results should be applicable beyond our study taxa.

Jessa Finch, Ph.D. Candidate at Northwestern University