Just 3 per cent of the land on Earth is still ecologically intact



A group of cheetahs in the Serengeti National Park, Tanzania


Most of Earth’s terrestrial habitats have lost their ecological integrity, including areas previously categorised as being intact.

Ecological integrity encompasses three measures of intactness. Habitat intactness is a measure of the extent to which people have made changes to the land, faunal intactness is a measure of the number of animal species lost from a habitat, and functional intactness measures the degree of functional densities of fauna, that is whether there are enough animals of individual species to effectively play their part in a functioning ecosystem.


“We only find about two to three per cent of the Earth[’s land] is where you could be considered as having the same fauna and flora that you had 500 ago, in preindustrial times, before major human impacts had occurred,” says Andrew Plumptre, who is head of the Key Biodiversity Areas Secretariat, and an employee of BirdLife International in the UK.

Plumptre and his colleagues combined data on human impacts and loss of animal species from various global databases to map the ecological integrity of different regions.

Only 11 per cent of ecologically intact sites lie within environmentally protected areas. However, many other of the intact sites, including parts of the Sahara, Amazon, and northern Canada, are within territories managed by indigenous communities, which have played a role in maintaining ecological integrity.

“Conservation of intact ecosystems is critical for the maintenance of biodiversity on Earth, and in turn for the services that these ecosystems provide to humans,” says Kimberly Komatsu at the Smithsonian Environmental Research Center in the US.

The team determined that by reintroducing one to five different species to sites that are not completely degraded, ecological integrity could be restored across about 20 per cent of Earth’s land.

“At the moment we’re living in this decade from 2020 to 2030, called the decade of restoration and everyone is thinking about restoring degraded habitat to make it better,” says Plumptre. He says it’s important not to focus simply on restoring habitat intactness, but also on faunal and in particular functional intactness.

“While species reintroductions are a much harder task than protecting currently intact ecosystems, these sites still represent a great opportunity to invest in conservation to promote the health of our planet,” says Komatsu.

Journal reference: Frontiers in Forests and Global Change, DOI: 10.3389/ffgc.2021.626635

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