Reintroducing large mammals could restore the world's ecosystems

Bringing back animals around the world could improve the state of the environment.

A report funded by the United Nations found that the return of large mammals could shore up the health of the natural world and tackle climate change.

Reintroduction of just 20 species of large mammals could help restore the world's biodiversity.

The conditions needed to allow these species to expand their ranges could be created by introducing these animals back into their historic ranges. It would help to restore the environment, lock away excess carbon dioxide and boost populations of other species.

The results give hope and scope for reversing the depletion of intact fauna groupings via proactive, strategically implemented restoration programs.

We are seeing a real drive of funding and attention towards nature-based solutions. We need to make sure that restoration efforts bring along the diversity and abundance of life on Earth.

The analysis was published in the journal Ecography.

What is rewilding?

Rewilding is a process of reestablishing large mammals to their historic ranges in order to reestablish a natural state.

The opinion on which time period is considered natural varies. Some suggest a baseline of around 1500AD, while others want to restore the environment to how it was in the last Ice Age.

Rewilding offers an opportunity to improve the ecology, but it also has drawbacks. The conditions for some environments are no longer present. Large animals could pose a threat to humans and livestock.

This is the case for predatory mammals such as wolves. Studies show that these animals have a significant impact on the environment through controlling their populations.

Reintroduction of herbivores can have a significant impact on the environment through the dispersal of seeds, recycling of resources and helping to control fire.

The researchers behind the current study wanted to find out how the reintroduction of large mammals could be achieved. They found that only 20 key species, including 13 herbivores and seven predator, were needed to help the world's biodiversity bounce back.

Exploring ecoregions.

The researchers divided the planet into ecoregions or areas with distinct natural communities. The number of mammals in each was compared to previous records.

Only a small percentage of places have the same large mammal communities as they did 500 years ago. Around 16% of the Earth's surface contains mammal communities at any level of intactness.

The researchers looked at which ecoregions were the best to restore. Most of northern Asia, northern Canada, as well as parts of South America and Africa were found to be suitable, with only a few large mammals required to bring these ecosystems back to their former state.

Large mammal populations have been lost in 35 regions in Europe due to the introduction of animals such as the European bison and wolf.

The area of Africa in which healthy mammal populations live could be doubled by following similar steps for species such as the Hippopotamus.

In addition to altering the environment in a way to benefit other species, the reintroduction of some of these animals would also help conserve them.

The dama gazelle is predicted to have the most impact if reintroduced. These animals are Critically Important with only 200 adults left in the world.

The scientists acknowledge that there are many changes that need to be made. The factors that caused large mammals to become threatened in the first place would need to be brought under control.

If the animals were to be brought back, international co-operation would be required.

An ongoing conversation about the importance of biodiversity in the run up to the COP15 conference is fed into the findings of this study.

There is work to be done, but UNEP's Joe Gosling says it is possible with concerted efforts.

Local assessments will judge if the recommendations are suitable for the area, for example, hunting pressures or the lack of an adequate prey base.

We are in a critical decade for nature, the UN's Decade on Ecosystem Restoration. The restoration of large mammal populations is an explicit ambition at international and national levels. Without the buy-in of governments, effective restoration of nature will not be possible.

More information: Carly Vynne et al, An ecoregion‐based approach to restoring the world's intact large mammal assemblages, Ecography (2022). DOI: 10.1111/ecog.06098 Journal information: Ecography Citation: Reintroducing large mammals could restore the world's ecosystems (2022, February 18) retrieved 18 February 2022 from https://phys.org/news/2022-02-reintroducing-large-mammals-world-ecosystems.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.