Termites can halt spread of deserts

Termites may not be humanity's favourite insects but their large dirt mounds are crucial to stopping deserts from spreading into semi-arid ecosystems, new research suggests.

Termites slow the spread of deserts into drylands by providing a moist refuge for vegetation on and around their mounds, making these areas more resilient to climate change.

"The study demonstrates that termite mounds create important refugia for plants and help to protect vast landscapes in Africa from the effects of drought," said Doug Levey, programme director in the US National Science Foundation's division of environmental biology which funded the research.

In the parched grasslands and savannas or drylands of Africa, South America and Asia, termite mounds store nutrients and moisture and via internal tunnels, allow water to better penetrate the soil.

As a result, vegetation flourishes on and near termite mounds in ecosystems that are otherwise vulnerable to desertification.

Drylands with termite mounds can survive on significantly less rain than those without termite mounds.

"Clearly, not all termites are pests," Levey added.

Because termites allow water to penetrate the soil better, plants grow on or near the mounds as if there were more rain.

"The vegetation on and around termite mounds persists longer and declines slower," noted corresponding author Corina Tarnita, a Princeton University ecologist.

The research was inspired by the fungus-growing termite species called Odontotermes but the results apply to all types of termites that increase resource availability on or around their mounds.

"Even when you get to harsh conditions where vegetation disappears from the mounds, re-vegetation is still easier. As long as the mounds are there, the ecosystem has a better chance to recover," Tarnita continued.

The findings could also inspire a change in how scientists determine the possible effects of climate change on ecosystems.

The paper appeared in the journal Science.