The panda-tree colony in Utah's Fishlake National Forest – considered the largest organism on Earth – threatens to disappear.
Paul Rogers and Darren McAvoy, researchers at Utah State University, studied a 72-year series of aerial photographs for a paper published Wednesday in PLOS One magazine. They found that a combination of human activity and lack of regulation of the herbivore had caused the colony to shrink.
Pando contains approximately 47,000 genetically identical trees – all cloned from an original – and is most likely thousands of years old. The 106-hectare cluster consists of male aspens known to support high biodiversity and many animals rely on them to survive. Aspens are threatened by various human-induced phenomena worldwide, including global warming and fire fighting.
The decline in Pando has also been partly attributed to cattle and mule deer that moved into the colony due to human activity. When these animals graze, they can make the growth of new trees more difficult.
But there are not enough fences to keep the wildlife out of the colony, and people's decision to build cabins and open campgrounds has also contributed to the shrinkage, the New York Times reported. In addition, humans have removed animals like wolves that have previously hunted on the mule deer.
According to the US Department of Agriculture, insects such as bark beetles and diseases such as root rot also attack some of the Pando trees.
Rogers and McAvoy predicted that the 1
"If this were a community of people, it would be as if an entire city of 47,000 had only 85-year-olds in it," Rogers told the Times. "Where is the next generation?"
Pando can regenerate, but he can not bounce back without keeping the animals out.
Rogers told the Times that saving Pando could help people figure out how to save so many species around the world. And the plan is not hopeless – trees in a part of Pando, where fences have been installed, have increased significantly, the newspaper reported.
But Rogers and many other scientists are opposed to building fences throughout the colony. Rogers told Science magazine he did not want to visit an iconic place like Pando, just to look at fences.
Instead, Rogers said he was pushing to kill the deer population around Pando.
"The real problem," said Rogers Science, "is that there are too many mouths to feed in this area."