Attack of the dromedaries
It's sunrise on the Colorado River, and a dozen sand-colored lumps stir by the banks. Bodies rise on spindly legs. Mouths open with a sound like pulling dentures. In a flash of gums, twelve sets of teeth clamp down on the nearest tamarisk plants. Chomp. Chomp. Leaves, bark and thorns disappear in a rhythm of steady chewing. The year is 2011, and the camel invasion has begun.
Such a future would make rancher Maggie Repp proud. While camels are known for three things -- they spit, they have humps, and they can survive for long periods without water -- Repp, the owner of 15 camels in Loma, Colo., believes they could be great at controlling tamarisk. The tough, salty tamarisk bushes are perfect camel food. "They will eat all day if given the opportunity," says Repp, who plans to set up a demonstration project this spring. "My camels have killed every tamarisk on our place, so why not give it a whirl?"
Photo credit: Ltshears
The invasive tamarisk is notoriously hard to kill. First introduced from Eurasia to the U.S. in the 1800s, it spread relentlessly across the West, choking up rivers and out-competing native plants (for a history of the tamarisk, see Paul Larmer's 1998 article "Tackling Tamarisk"). Tamarisk has survived chainsaws, fire and chemical herbicides. In 2001, scientists released the foreign Diorabda beetle to control the plant's spread. Since then, the leaf-eating beetles have attacked thousands of acres of tamarisk (see Michelle Nijhuis' 2007 story Beetle Warfare).
But even a brown, leafless tamarisk can spring back to life. It sometimes takes several years of de-leafing by beetles to kill a tamarisk, and camels would work in much the same way. Repp hopes the camels will eat away at any new growth until the tamarisk finally dies. In an effort to publicize her plan, she left some pamphlets at the 2010 Tamarisk Symposium, where hundreds of people had gathered to discuss tamarisk beetles and their effects on the endangered Southwestern willow flycatcher.
"I've heard of people using goats," said one scientist. "But it would take a LOT of goats [to really get anywhere]." Camels, he said, would likely pose the same problem.
Repp estimates that 10 camels could destroy half an acre of tamarisk in 2 days. That's small-scale compared to tamarisk beetles, which can spread over a hundred miles in two years. So for full riparian restoration, stick with the beetle. But if you want to clear the odd tamarisk patch off your pasture, it might be easier to rent a camel.