12 Feb 2024

In January, mathematicians and ecologists joined forces to launch a collaboration focused on the mathematics of rewilding, a new and controversial approach to rebuilding ecosystems. The launch of this collaboration is one of the first initiatives of the new ICMS Mathematics for Humanity programme.

Rewilding is a radical idea that differs from traditional ecological restoration in important ways. To understand the philosophy of rewilding, we can turn to a metaphor offered by ecologist Johan du Toit. Suppose that you are the owner of a classic 1950s Chevrolet. At some point the car breaks down, and several parts need to be replaced. If you have the means and the resources, you could track down exactly the right replacement parts, manufactured for the original make and model of your car. This is analogous to traditional restoration: you’ve recreated a faithful replica of the original car. But what if the 1950s Chevrolet is your only car, and you’re a taxi driver, and you have no way to get the original parts? You might replace the parts with whatever you have access to — parts of different cars, for example, or parts from other machines — as long as the parts work. You won’t have an exact recreation of the original car, but you will have a functioning car. This is analogous to rewilding: prioritising what is possible and what works, not bringing back the past.

In the changing climate and environment of the world today, ecological restoration can be impossible: some ecosystems simply can’t exist in their former glory in current conditions. But rewilding, as du Toit emphasised, is always possible, because its goal is to build ecosystems that flourish in the present. The word rewilding is similar in meaning to “reorganising” or “rethinking” — the goal is to reimagine the wild, not to bring back the wild of the past.

The philosophy of rewilding is designed to be practical and effective in the real world. But currently, there is no mathematical theory of rewilding to help guide strategies, or to help measure and ensure effectiveness. In other areas of biology, including ecology, mathematics has made important contributions and helped to ground ideas in theory and evidence. The goal of the *Rewilding Mathematics* collaboration is to bring this power of mathematics to bear on rewilding.

The first seminar of the collaboration focused on introducing rewilding and beginning the discussion on the mathematical challenges posed by rewilding. Read on to learn more!

Author - **Tara Abrishami**, University of Hamburg