There could be 30,000 species of earthworms wriggling around the world

There are likely tens of thousands of earthworm species roaming the world’s soil, yet to be discovered by scientists, and it will probably take more than 100 years to do so.

Earthworms play an important role in recycling organic nutrients in ecosystems. Researchers fear that without identifying all of these species, they may be lost before we even know they exist.

more than 5700 the species and subspecies of worms have already been described by scientists. But Thibaud Decaëns At the University of Montpellier in France, he wondered if this might be an understatement when he noticed the diversity of earthworms while working in the Amazon rainforest.

To learn more, Decaëns and his team conducted sampling surveys in French Guiana, often flying by helicopter to remote parts of the jungle. They spent up to two weeks collecting all the earthworms they could find in the one-hectare plots, discovering many species that were new to science.

“We have only recorded 55 species described in French in Guyana,” says Decaëns. “There are probably at least 2000 species in there.” Scientists conducted similar sampling in France, and together they suggest that the diversity of earthworms may be greater than previously thought.

In another part of the experiment, they worked with a statistician to estimate the number of earthworm species yet to be discovered, based on existing records and the rate at which new species are being described.

“On a global scale, we estimate that there are at least 30,000 species of earthworms on the planet,” says Decaëns. Depending on the number of worm taxonomists worldwide and the rate at which specimens are classified, it will take 120 years to identify them all, he says.

“It’s more difficult to conserve a group of species, such as earthworms, if we don’t know the basics of how many species there might be and where those species are,” says the team member. Helen Phillips at the University of Helsinki in Finland.

Keiron Brown The UK’s Biological Recording Company says the research highlights how little we know about earthworms. “It’s amazing how we’ve fallen so far behind in understanding this ecologically important group of animals.”