AFRICA— In order to protect its prairie, Kenya fenced off a research site to prevent leaf-eating elephants and giraffes from entering to feed on the Acacia trees. A few years ago, Todd Palmer, a zoologist at the University of Florida, went there to investigate he found a very strange phenomenon: instead of thriving, the Acacia trees that were protected from leaf-eating elephants and giraffes were withering and dying.
Palmer and his colleagues then carried out an investigation and reported their findings in the magazine. As reported in Scientific American, in the absence of animals, the whistling acacia stopped producing little ant houses in hollow thorns and excreting the sweet nectar that its bodyguard ants eat.
But instead of spurring more growth, the acacias found themselves more than twice as likely to be providing a home to another type of ant, which does not defend the trees and rely on invasions of the bark-boring beetle larvae to build the holes in which they dwell.
The cavity-nesting antagonistic ants actually promote the activities of the stem-boring beetle.
This, in turn, stunts the growth of the tree and causes them to die twice as often than when they are being regularly eaten by giraffes, elephants and other large African herbivores. “The trees are actually making a shortsighted decision by defaulting on their end of the mutualism bargain,” Pringle says. “If they sustained the production of ant rewards in the absence of large mammals, they would reduce their probability of being taken over by this somewhat nasty antagonistic ant.”
These findings show the unquestionably intricate relationships between animals and plants and that these relationships are more complicated than we thought.
This adds to evidence that relationships between plants and animals species can be surprisingly complex and that even seemingly benign interference can have devastating effects.
These observations definitely spurred our inspiration. The Three Gorges dam is the largest hydroelectric power plant on earth. It spans the Yangtze River and is considered to be a masterpiece in Chinese engineering. It redirects water from the south to the north.
Long-term effects should be considered as rivers are also “lives” in a sense.
A scientific survey of the world’s longest rivers using aerial maps shows a majority of them are no longer able to complete a natural flow, unimpeded by human interference.