More than a hundred scientists have worked to develop an atlas out of the ordinary. It was a question of locating and informing the various species of earthworms in the four corners of the globe!
The importance of earthworms
The earthworms (Lumbricina) are repugnant to some people, but they are living beings whose importance is beyond doubt. By digging their underground galleries, they allow the soil to be well ventilated, to circulate water optimally and to develop the roots in good conditions. They also promote the recycling of nutrients such as nitrogen and phosphorus used by plants. They also play a role of carbon sink since their activity allows to bury the carbon more deeply.
However, Science admits it: this underground world still has secrets to reveal. To honor earthworms and support research, a team of 141 scientists brought together by the American Association for the Advancement of Science (AAAS) did a great job! According to their publication in the journal Science October 25, 2019, the researchers are at the origin of the first atlas of earthworms.
A huge data set
The goal of the scientists was to map the diversity and biomass of earthworms. Thus, data concerning 6,928 places in 57 countries have been collected! Each time, the species and the number of worms present on site were informed. As the researchers explain, developing an understandable and actionable database has not been easy. Indeed, if earthworms are for example very well indexed in Europe, this is less the case in the tropics. In these places, new species are regularly discovered.
What observations on the worms?
This research has provided an opportunity to report on several important points. First, earthworms represent an impressive biomass. We find on average between 1 and 150 gr per square meter, and sometimes even up to 2 kg! On the other hand, the number of worms is larger in temperate regions, but in the tropics they are larger. Thus, the biomass is substantially the same. However, species diversity is more prevalent in tropical areas.
Finally, scientists also discuss the possible impacts of climate change on earthworms. According to them, a change in populations could have cascading effects on other ecosystems.