Researchers study earthworm diversity


By Mary Guiden

Special to The PREVIEW

Researchers from Colorado State University (CSU) are among 140 scientists across the globe who have compiled the largest earthworm dataset in the world, encompassing 6,928 sites in 57 countries.

The research team found that in any single location, there are typically more earthworms and more earthworm species in temperate regions than in the tropics. The scientists also found that global climate change could lead to significant shifts in earthworm communities worldwide, threatening the many functions they provide.

Results from the study, “Global distribution of earthworm diversity,” were published online Oct. 24 in Science. The research project known as sWorm was led by scientists from the German Centre for Integrative Biodiversity Research (iDiv) and from Leipzig University in Germany.

Diana Wall, a co-author, soil ecologist and director of CSU’s School of Global Environmental Sustainability, said that CSU scientists have studied earthworms and their ecosystem functions in different continents, so their data were important for the lead researchers to better understand earthworm biodiversity on a global scale.

The Global Soil Biodiversity Initiative is a collaborative of scientists that inform the public and help shape environmental policy for the sustainability of soils. Wall, University Distinguished Professor, serves as the scientific chair of the initiative, which includes more than 4,000 researchers.

“People don’t know about global soil biodiversity, but they do know about earthworms and their great impact on ecosystems, so one of the questions we tackled was: How do you handle data ranging from museums to molecular data, not to mention all the taxonomic names that exist for earthworms?” she said.

Earthworms can be found in many ecosystems. Where the soil is not frozen, too wet, acidic or completely dry, earthworms substantially shape the way ecosystems function. They dig holes, mix soil components and eat organic debris. By doing so, they drive a wide range of ecosystem services, such as nutrient provision, freshwater supply, carbon storage, climate mitigation or seed dispersal. This is why earthworms are considered highly important “ecosystem engineers.”

This important role is also reflected by the large amount of biomass that accumulates in earthworms: the total earthworm biomass is often larger than that of all mammals living in the same area.

Helen Phillips, a researcher at the German Centre for Integrative Biodiversity Research and Leipzig University and lead author of the study, said that until now, scientists had been unable to quantitatively investigate global patterns for earthworms, since there was no worldwide dataset. The results of this huge effort show that patterns of belowground biodiversity do not match those observed for organisms living aboveground.

Plant, insect or bird diversity increases from high to low latitudes, meaning that the number of species is highest in the tropics. For earthworms, however, the researchers found the opposite pattern. In fact, the highest local earthworm diversity was found in Europe, the northeast U.S. and New Zealand. Similar patterns were found for earthworm abundance and earthworm biomass.

Steve Fonte, assistant professor of agricultural systems science at CSU, provided earthworm data or connected the lead authors with former students in South America — including Bolivia, Colombia, Ecuador, Honduras, Nicaragua and Peru — as well as California and Colorado in the U.S.

“We as scientists have been talking for a long time about the influence of earthworms, how they are distributed and where they’re important in the world,” he said. “The study gives us new revelations of where earthworms are important drivers of soil function.”

Andre Franco, a soil ecologist and postdoctoral researcher in the Department of Biology at CSU, said that he contributed data from his doctoral thesis at the University of São Paulo in Piracicaba, Brazil.

“This was brilliant work, and a heroic collaborative effort” on the part of lead authors Helen Phillips, Nico Eisenhauer and Erin Cameron, said Franco.

“Now, we can identify where these species are and where they are more vulnerable to changes in the climate,” he explained. “It also gives us the potential to see where earthworms are more threatened and more at risk of becoming endangered than in other places.”

Franco’s data, which looked at pastoral lands that were being used to produce sugar cane in Brazil, found a nearly 98 percent reduction in earthworm abundance with changes in land use.

“By losing those earthworms, we are losing the ecosystem services that they provide,” he said. “We are losing the structure of the soil, and the soil is less stable and more vulnerable to erosion. We are also losing carbon. If the earthworms are not there anymore, a lot of the carbon is lost to the atmosphere.”

Healthy Lands Workshop

The Healthy Lands from the Bottom Up Workshop will be on Nov. 12 from 10 a.m. 2 p.m. at the Extension office. Please call the San Juan Conservation District office at 731-3615 to register. There will be a free lunch.

Colorado Master

Gardener program

applications being taken

The Master Gardener program is innovative and flexible in its outreach and works to match volunteer skills and schedules. Each year, Colorado Master Gardeners all over the state help people make the right choices for their garden care. Anyone who would like to play an active role in the education of gardeners of all ages is invited to join our Colorado Master Gardener team.

Classes typically meet once a week on Thursdays from 9 a.m. to 3 p.m. for 11 consecutive weeks. The cost of the Master Gardener apprentice training is $170 and the Colorado Gardener Certificate is $530. Partial scholarships are available as well for the apprentice program.

If you would like to learn more about successful gardening in Archuleta County, be sure to call the CSU Extension office in Archuleta County today at 264-5931. To register for the 2020 Colorado Master Gardener Program, which tentatively begins Jan. 23, 2020, please go to Hard copies are accepted at the local office, too. Applications will be accepted until Dec. 15. Apply today.

Testing of dial pressure canner gauges

The CSU Extension — Archuleta County office is now offering to test dial pressure canner gauges for $5 to Archuleta County residents. For more information, contact Terry Schaaf at 264-5931.

CPR and first aid classes

CPR and first aid certification classes are offered monthly by the CSU Extension office on the second Monday and Wednesday of each month from 6 to 10 p.m. Anyone needing to receive or renew certification can register by calling the Extension office at 264-5931.

We will also attempt to schedule classes on additional dates with five or more registrations. Cost for the classes is $80 for combined CPR/first aid and $55 for CPR, first aid or recertification. The type of first aid information provided will vary by the needs of the audience.