In Moab, Utah, a town constantly visited by jeepers and hikers from all over the world, the arrival of 300,000 beings from Kazakhstan hasn't received much press. But as the newcomers flutter in and make themselves more at home, people are starting to take notice.
Diorhabda elongata is their sexy name, and most of us, not being big on Latin, simply know them as tamarisk beetles. In the Colorado River corridor, the animals have one mission: to kill invasive tamarisk trees. Importing beetles for use as lethal weapons represents a major shift in our approach to tamarisk control, and many people are saddling these tiny, green-and-gold creatures with big expectations.
They do our biological bidding by continuously stripping the leaves from tamarisk and sending the tree on the slow boat to die-off — a process that takes three years or more. And they work for a pittance: The three-year cost for the beetle in the Moab area is $10,000, whereas removing tamarisk mechanically would run about $3 million.
After two years feeding at our tamarisk buffet, the Diorhabda clan is already leaving its mark. The tamarisk the bugs have attacked are browning out and dying, and the lack of foliage at the riverbank now affords brief glimpses of the mighty Colorado River. It's a sight for sore eyes. The pink-flowered trees the beetles are meant for were brought here during the 1850s, mainly to control erosion. Over time, the trees began to choke many of our waterways from southern Canada all the way down to Mexico. We in the Southwest are especially aware of these noxious weeds — referred to by some as the "cockroach tree" — because of the damage they do to our delicately dry ecosystems.
Tamarisk, which is sometimes called salt cedar, drives out native plants and sucks up gallons of water faster than you can say "Colorado River Compact." One mature tamarisk tree can guzzle 200 gallons of water each day, adding up to 2.5 million acre-feet of water "stolen" from the Southwest each year.
Tamarisk eradication legislation has come up for years on both the national and state levels, and in 2003, Colorado Gov. Bill Owens, R, pledged to eliminate tamarisk from the state within 10 years. While no one is holding their breath on that one, it's a worthy goal. This October, even President Bush got in on the action, signing a tamarisk-control law that authorizes spending $15 million each year to help eradicate tamarisk.
Over the years, land managers have tried everything they can think of to beat back tamarisk — from turning loose ravenous goats to stomp the trees, to bulldozing river banks. The most effective tammie-killer has proven to be the labor-intensive method of cutting the trees down and then quickly painting each stump with herbicide. Such an effort costs upwards of $3,000 an acre and requires a lot of sweat equity. I recently completed a week of invasive-species removal using this method along the Escalante River in Utah, and my lacerated skin and sore muscles bear witness to the nasty disposition of these trees. But if all goes well, our imported experts-in-eradication might save us money, time and the frivolous use of curse words directed toward plants.
We have a local test case to examine: Over the past two years, state, county and private landowners have released hundreds of thousands of the Diorhabda beetles along the Colorado River near Moab. (Federal land management agencies did not participate in the release because they haven't completed a regional environmental assessment on these critters. However, the BLM is preparing for the after-effects of this feeding frenzy, knowing that beetles pay no mind to jurisdiction.)
Most people are aware that these little Kazakhstani creatures raise more questions than they answer. Will the bugs create a greater risk for wildfire? What kind of erosional effects will we see? Will all the dying or dead trees harm tourism? And will these beetles stick to the tamarisk and leave the native plants alone, as they have shown in test cases? The answers, of course, will come with time, but given too much time, any harmful impacts might be irreversible.
The Diorhabda beetles are dormant now. They'll sleep until May when they unleash their hunger upon the landscape once again. Until then, all we can do is speculate on the intentions of these new members of our community and keep our fingers crossed that the bugs stick to their job and make us proud. Jen Jackson is a contributor to Writers on the Range, a service of High Country News in Paonia, Colorado (hcn.org). She writes in Moab, Utah.