Muck Is Last Frontier of Biodiversity, Experts Argue

John Roach
for National Geographic News
February 6, 2003
"Biodiversity" evokes lush, tropical forests teeming with animals and
carpeted with vibrant vegetation. But for many scientists and soil
specialists, biodiversity signifies the wet, clammy muck beneath the
forest floor.

That muck, they say, is the last frontier in the science of biodiversity, and it deserves international conservation focus.

Just below the Earth's surface, tens of thousands of bacteria, fungi, bugs, and worms wait to be discovered and studied. These organisms are believed to allow trees, grasses, and crops to grow, to make water potable, and to regulate the climate.

Scientists are concerned that these organisms will disappear before they are even studied.

"For the last several decades, due to human activities, soil fertility has been degrading at an alarming rate in many parts of the world, particularly in tropical countries," said Mike Swift, of the Tropical Soil Biology and Fertility Institute in Nairobi, Kenya.

Swift is managing the U.S. $22 million project, titled Conservation and Sustainable Management of Below Ground Biodiversity, for the United Nations Environment Programme with funding from the Global Environment Facility, the Rockefeller Foundation, and other donors. The study examines the sub-surface scientific frontier and how it can be managed and conserved in tropical agricultural landscapes.

The project involves Brazil, Côte d'Ivoire, India, Indonesia, Kenya, Mexico, and Uganda. These seven countries have a commitment to intensify agriculture to enhance food production and economic status.

Project scientists hope to determine how these countries can increase their agricultural production and conserve below ground biodiversity, which is believed to be crucial to the maintenance of a healthy planet.

Benefits of Soil Critters

For example, earthworms, termites, and other soil-burrowing organisms influence the amount of rainwater soils can absorb. Soils depleted in such organisms are more drought-prone and at risk for catastrophic runoff. This in turn increases the risk of flooding and erosion, and affects river water quality and habitats such as coral reefs.

Bacteria and fungi help to eliminate pollutants and disease-causing germs from groundwater as it percolates through the soil to reservoirs, boreholes, and other sources of drinking water.

Organisms living in soil play a key role in the release of carbon dioxide, methane, and other greenhouse gases from the land to the atmosphere. The interaction of climate change and soil degradation will probably aggravate conditions.

"If we do not learn about the organisms in soil and how to manage them to conserve and enhance these services, then we can only expect yet more catastrophic degradation of our resource base," said Swift.

Dirty Threat

Biodiversity conservation campaigns have made people aware that escalating agriculture and clearing forests for farmland threatens extinction to many plants and animals on Earth.

Scientists believe that the same can be said for below ground biodiversity, with negative consequences for both the environment and long-term agricultural production.

"Most developing countries have intensification of agriculture a goal for food and wealth production," said Jon Anderson, a soil biologist at the University of Exeter in England and an advisor to the project.

Preliminary research shows that in places where single crop agriculture is the norm, there is a sharp decline in the abundance of species in the ground with adverse impacts on yields, moisture content, and fertility.

While some of these losses can be ameliorated by using industrial fertilizers and pesticides, dependence on chemical substitution is biologically and economically inefficient. It may also have unintended environmental consequences, according to the scientists.

"We are well fed because of modern agriculture. Most developing countries have not had that luxury," said Anderson. "However, we are now increasingly recognizing…that environmentally friendly agriculture may be more desirable than simply maximizing production."

The below ground biodiversity project will test the hypothesis that diverse agricultural fields, such as those with trees interspersed or planted with several kinds of crops, are beneficial to both the dirt's viability and agricultural production.

"We shall be comparing traditional practices with those more characteristic of industrial agriculture," said Swift. "On the basis of this, we should be able to make recommendations for soil management practices that support food production that is sustainable as well as profitable."

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