There are probably many more earthworm species than are officially recognized.
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There are likely tens of thousands of species of earthworms crawling in the world’s soils, but it will likely be more than 100 years before scientists discover them.
Earthworms play an important role in recycling organic nutrients in ecosystems. Researchers fear that if they don’t identify all these species, they could go extinct before we even know they exist.
More than 5,700 species and subspecies of earthworms have already been described by scientists. But when Thibault Descaens of the University of Montpellier in France noticed the diversity of earthworms while working in the Amazon, he wondered if this was an underestimate.
To learn more, Decaens and his team conducted sampling surveys in French Guiana, often flying by helicopter to remote parts of the Amazon rainforest and spending up to two weeks collecting everything they could find in a one-hectare plot. I collected insects.
“In French Guiana, only 55 described species have been recorded,” says Descaens. “But there are probably at least 2,000 species out there.” The scientists conducted similar sampling in France and found that earthworm diversity must be greater than previously thought. suggested.
In another part of the experiment, they worked with statisticians to estimate the number of undiscovered earthworm species around the world, based on existing records and the rate of new species descriptions.
“Globally, it is estimated that there are at least 30,000 species of earthworms on Earth,” says Decaens. Based on the number of nematode taxonomists in the world and the speed with which they classify specimens, it will take 120 years to identify them all, he says.
Team member Helen Phillips from the University of Helsinki in Finland said: “Conserving groups of species, such as earthworms, helps us understand how many species are likely to exist and where those species are located. If you don’t understand that basic thing, it will be even more difficult.”
Keiron Brown of the UK’s Biological Recording Company said the study highlights how little we know about earthworms. “It is puzzling how we have been so slow to understand such an ecologically important group of animals.”
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