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.
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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.
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