The Colorado River is under attack...from millions of invasive tamarisk bushes. Wildlife and native greens have been choked out and recreational activities have dwindled as the banks of the river are barraged by the black-trunked salt cedars. But people aren't letting these obtrusive bushes take over the river without a fight. The bushes are being assailed by millions of tamarisk leaf beetles, nonprofit organizations and the Bureau of Land Management, including Ranger Troy Schnurr, who's leading the battle in the McInnis Canyons National Conservation Area.
Schnurr has been with the BLM for 21 years, and fighting invasive species has always been part of his job.
"From 2000-2001, we treated roughly 65 acres for tamarisk and knapweed," Schnurr said during a recent day spent with him and his crew on Colorado's Western Slope. "In that time, there were also 121 cottonwoods planted and 273 others have been protected."
If you float through this 25 mile stretch of the river, it is easy to tell the areas that have had invasive species removed from the ones that haven't. The spots given assistance are filled with green willows and young cottonwoods, enhancing the view of the river.
The untouched areas are a lot less aesthetically pleasing and prevent native vegetation growth and limit wildlife habitats. The tamarisk patches can be very dense and many of the bushes have been stripped of a lot, if not all, of their leaves due to beetles that have attacked and defoliated trees over the past eight years or so. The bushes aren't very pretty to look at anyway, but their impact makes worsens the situation, leaving groves of black trunks marked by tangles of white branches protruding into the air.
The beetles aren't native to the area. After extensive research, they were transplanted from Asia to different areas in the Rocky Mountain and along the West Coast. They arrived at the Colorado River near Moab in 2005, and by the following year, they had successfully defoliated eighteen miles of tamarisk. The beatles only feed on tamarisk plants, and after repeated defoliation over a three-to-five year period, the average shrub loses its ability to survive.
"The beetles are doing their job," Schnurr said. "But they'll never take care of all the tamarisk."
This is where nonprofits and the Western Colorado Conservation Corps (WCCC) come in.
The corps is highly trained to remove invasive species and restore riparian environments. It's also only group of its kind in the state that is licensed to apply herbicides crucial to tamarisk removal.
"You have to spray the stumps before they start to scab over," corps member Lacy Carter said.
Continue for more about the continuing Colorado River battle against a serious enemy -- invasive tamarisk. Staaffers cut down the tamarisk, spray the stumps and then stack the foliage in habitat piles.
"During a heavy winter with a lot of snow, we burn the piles," WCCC Director Trevor Wickersham added.
The cleared areas are then replanted with natural vegetation. Cottonwood and willow starts are surrounded by cages to protect them from wildlife, along with a piece of rebar for support.
"We haven't had real good luck with the willows," Schnurr admitted. "But the cottonwood are good if you can keep the beaver off them."
Members of the BLM office does some of the work themselves, including seeding, but the WCCC is used for the bigger clearing jobs.
"In the past, we got at least three-to-four work weeks with the conservation core," Schnurr said. "But the sequester stopped that."
This year, thanks to a grant, there was enough money for the WCCC to complete one week of work. In addition, the Royal Bank of Canada gave an outright donation of $10,000 through the Conservation Lands Foundation (CLF) for eight workers to each spend forty man-hours rehabilitating the river. During this week, the crew cleared tamarisk, made a campsite and filled barrels that are on a drip system to water newly planted cottonwoods.
"We are a nonprofit specifically interested in protecting, restoring and expanding conservation areas," CLF River Coordinator Charlotte Overby said. "Restoring is the piece we've just began."
The Colorado is a long way from being completely restored, but there is a noticeable difference.
We Believe Local Journalism is Critical to the Life of a City
Engaging with our readers is essential to Westword's mission. Make a financial contribution or sign up for a newsletter, and help us keep telling Denver's stories with no paywalls.
Support Our Journalism
"I try to remember what it used to look like, but I can't," Schnurr said.
Campsites have been cleared of meddling vegetation and many other tamarisk stands have been killed or are dying, leaving a sort of barren feel to some stretches of the river.
The tamarisk will never be completely eradicated, Schnurr acknowledged, but "in my 25 mile river section, it will be in check."