Population Resilience

Small populations are vulnerable to extinction. Bad luck can be enough to tip the balance between population growth and decline. Add inbreeding depression and low genetic diversity, and the long-term prospects of coping with environmental change seem pretty grim. Yet, many small populations of lizards persist – sometimes for a very long time and despite drastic changes in their environment. How do they do it?

One possible explanation is that small populations can purge deleterious alleles. Whether or not purging occurs in nature remains poorly understood. We study Swedish sand lizards and Mediterranean wall lizards to identify conditions that facilitate purging and maintain evolvability in small populations.

Other potentially important factors for population persistence include behavioural and physiological flexibility – avoiding heat, switching diet, and so on. Microbiomes can be helpful too because they evolve faster than the hosts. Experiments, comparative studies, and reconstruction of the past can help us understand what organisms can and cannot do – and therefore how to avoid extinction now and in the future.

These projects have just begun, so if you want to join us please get in touch.

If you want to know more:

Feiner, N., Brun-Usan, M., Uller, T. 2021. Evolvability and evolutionary rescue. Evol Dev e12374