By Susan Milius
On Kenya’s savanna, good fences make bad neighbors. Protecting acacia trees there from giraffes and other browsers sets off a chain reaction that ruins the partnership between trees and their bodyguard ants, says Todd Palmer of the University of Florida in Gainesville.
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He first noticed something odd about the protected trees when walking among whistling-thorn acacias cordoned off since 1995. With hole-riddled thorns, the wind whines through these acacias, which are “spindly, knobby trees” at best, Palmer says. Those behind fences looked even worse.