Of resilience, population growth, and genetic diversity

Ivan Scotti, Thomas Boivin
Symposium 23

We have developed a simple model that combines population growth,
genetic diversity, and resilience to disturbances.
By introducing heritable variability in growth rates and sensitivity to
disturbances, we show that genetic diversity interacts non linearly
with the frequency of disturbances, pushing the population away from
the equilibrium frequencies that can be predicted based on theoretical
differences in fitness among genotypes.
Depending on the genetic covariance of survival and growth traits and
on their genetic architecture, the interactions between disturbance
frequency and genetic diversity generate varying long-term population
growth rates.
This theoretical model shows that population resilience can be
interpreted as a genetic property of populations and that disturbances
can maintain genetic diversity in non-equilibrium systems, somehow
recalling the intermediate disturbance hypothesis (IDH), applied at the
genetic-diversity level.
We finally posit that the parameters of the model can be validated
using field data to measure genotype-level growth and mortality traits.

This will further allow us to predict the long-term fate of genetic
diversity and resilience under climate change.
The model is generic, can be made arbitrarily complex, and can be
applied to any biological system.