Ants save trees from elephants

Ants known to defend certain species of Acacia trees from elephant predation deter the massive herbivores so effectively that they are impacting entire savanna ecosystems, according to a study published online today (2nd September) in Current Biology.

Ants on a whistling-thorn tree Image: Todd Palmer

"I don't think any one had suspected how strong an effect the ants [had] in terms of driving elephants to avoid the Acacia," said ecologist David Augustine of the linkurl:US Department of Agriculture,;http://www.usda.gov/wps/portal/usda/usdahome who was not involved in the study. "It's a very nice demonstration of [how] this small-scale mechanism can explain a large-scale and pretty important pattern in the savannas in this region." Savannas are made up of a mixture of trees and grass, and the amount of tree cover in a given area is largely variable, depending on such factors as rain, fire and herbivory. Elephants can kill large expanses of...