The dirt on soil: Underground biodiversity holds key to ecosystems

The often overlooked underground world of worms, insects and bacteria plays a greater role in supporting ecosystems than previously realized, according to a study released Wednesday.

Earlier research had established that ecosystems can carry out more functions more efficiently when there is greater above-ground biodiversity, but a study released Wednesday in Nature Communications, indicates that below-ground biodiversity is nearly as important to a properly functioning ecosystem.

“Even Darwin recognized that these communities can be diverse and important,” the study, led by Peking University and the Center for Macroecology, Evolution and Climate at the University of Copenhagen, said. “While awareness of the immense biodiversity below-ground is increasing, we are only beginning to elucidate the influence of below-ground biodiversity on ecosystem functions.”

Ecosystem functions include storing carbon, pollinating plants, acting as habitats or shelter, creating soil and acting as raw materials.

Researchers found that around 32 percent of variation in ecosystem functions is due to biodiversity in the soil, compared to plant biodiversity, which accounted for 42 percent, the study said. For the report, researchers took samples at 60 sites on the Tibetan Plateau in China — chosen for its extensive climate variation.

Combining biodiversity from above and below ground increased the predictive power of biodiversity on ecological multifunctionality — or the ability of the ecosystem to carry out multiple, simultaneous functions or services, the study found.

“Ecosystems have multiple functions, which are all important. They store carbon in soil and biomass, which has massive implications for climate change, but they also hold back and release various nutrients which have effects on natural areas as well as agricultural yield,” study co-author Xin Jing, of Peking University, said in a press release Wednesday.

The study is unique in that it relates underground biodiversity to a host of ecosystem functions, rather than focusing on just a few. For example, a recent report found that soil biodiversity helped with carbon sequestration, but did not look at its effect on other ecosystem functions.