A quarter of all known species live in the soil, but global biodiversity protection strategies have, so far, given this habitat little attention. To increase awareness of the services soils provide and their condition, the researchers outline their plan for a systematic analysis based on uniform standards.

“So far, protective measures have focused primarily on life above ground, such as with the designation of protected areas,” said Wall, one of three senior authors on the paper and the director of the School of Global Environmental Sustainability at CSU.

But these measures do not necessarily benefit underground biodiversity. As examples of concrete protective measures, the researchers suggest implementing a halt on ploughing and the conservation of deadwood.

To facilitate decisions about which regions of the world are particularly in need of protection and which protective measures are most worthwhile, sufficient information about the condition and development of biodiversity in soils must be available.

To gather this data, the researchers have launched the Soil BON – Biodiversity Observation Network – monitoring initiative, led by Carlos Guerra, senior author of the paper and a postdoctoral researcher at iDiv, and Wall.

The purpose of Soil BON is to gather equivalent soil data, comprehensively and over extended periods of time. The researchers propose a holistic system for this, using Essential Biodiversity Variables, which are key parameters for measuring biodiversity.

The concept includes criteria such as soil respiration, nutrient turnover and genetic diversity. Indicators are derived from these variables, which serve as a basis for soil status evaluation and subsequent decisions regarding the level and type of protection necessary for the soils.

“We want conservation efforts to put greater emphasis on biological diversity in the soil,” said Soil BON co-founder and iDiv Professor Nico Eisenhauer. “To do this, we have to provide politicians with the necessary decision-making tools and data.”

Life depends on soil organisms

As the authors note, soil is one of the most species-rich habitats in existence. Living under one square meter of healthy soil you can find up to 1.5 kilograms of organisms, including nematode roundworms, earthworms, springtails, mites and insect larvae. There is also a multitude of microorganisms, including bacteria, protists and fungi. They eat and transform living and dead animal and plant material into nutrients which become the basis for growth and new life. Without soil organisms, no plants would be able to grow and no humans could live.

The appeal from these scientists goes out to the 196 nations currently negotiating a new strategy to protect biodiversity within the framework of the UN Convention on Biological Diversity.

“Until now, the focus on soil has too often been limited to its physical aspects and its importance for agriculture,” said Guerra, first author of the paper. “It’s time that politicians start considering soil protection beyond food production terms and as a cross-cutting task. In this way, many sustainability goals such as climate protection, nutrition and biodiversity can be served.”

According to the researchers, the proposed monitoring and indicator system will enable the worldwide condition of soils and their capacity to function to be recorded efficiently and monitored long-term. It should also serve as an important early warning system.

Using this new system, it will be possible for researchers to identify, at an early stage, whether existing nature conservation goals can be achieved with current measures.