Rewilding can help mitigate climate change, researchers highlight after conducting global assessment

Rewilding can help mitigate climate change, researchers highlight after conducting global assessment - University of Sussex

A new study has shown that rewilding can help to mitigate climate change, delivering a diverse range of benefits to the environment with varied regional impacts.

Research led by the University of Sussex and published in the journal Philosophical Transactions of the Royal Society B, provides a global assessment of the potential for trophic rewilding to help mitigate climate change.

Trophic rewilding restores lost species to ecosystems, which can have cascading influences over the whole food web. This typically means reintroducing large herbivores (e.g. elephants) and top predators (e.g. wolves), or species known to engineer more diverse and complex habitats and benefit biodiversity (e.g. beavers).

But reintroducing species not only influences the local environment, it can also influence the climate. Animals, particularly megaherbivores (like elephants) and large ruminants (like bison and cattle) produce methane - a greenhouse gas. Big herbivores also eat large quantities of vegetation which can prevent trees growing. This stops trees capturing carbon, but on the other hand, it can also prevent trees from reducing albedo in the far north and so mitigate warming. Big herbivores also distribute large seeded trees that are particularly good at capturing carbon.

The influence big herbivores have is also partly dependent on the effects of big predators. The larger the predators present, the bigger the herbivore species regularly on the menu. But because of past extinctions the surviving species that can be reintroduced is limited and this changes the number and type of large herbivores that are more likely to reach relatively high densities and so have bigger impact on their environment.

According to this new research, all of these interacting relationships mean applying trophic rewilding in different parts of the world will have different outcomes for climate mitigation.

Read the paper: Christopher J. Sandom, Owen Middleton, Erick Lundgren, John Rowan, Simon D. Schowanek, Jens-Christian Svenning and Søren Faurby Trophic rewilding presents regionally specific opportunities for mitigating climate change. Phil. Trans. R. Soc. B doi.org/10.1098/rstb.2019.0125