Cows help battle invasive grass at Great Salt Lake wetlands
HOOPER, Utah (AP) — A yearslong battle against an invasive grass has improved hundreds of acres of wetland habitat near the Great Salt Lake, even as lake levels decline.
Water-sucking phragmites moved into Utah wetlands decades ago and firmly took root. The non-native plant is notoriously hard to knock back, choking out native plants and wildlife.
But just in time for duck hunting season, managers at Ogden Bay Waterfowl Management Area are gaining ground, fighting back phragmites with an unlikely weapon — cows.
"Welcome to Ogden Bay Cattle Ranch," joked Rich Hansen, manager of the WMA. "It's a great tool. Chemicals work, but I hate putting chemicals on year after year after year. If we can use a natural bio control and still have a good end product, providing good habitat, why not?"
When Hansen started at Ogden Bay WMA three years ago, he described driving down the management area dikes, completely socked in by a sea of monotypic green.
"This stuff will grow up to 16 feet in a growing season when it's not grazed or sprayed," he said.
Phragmites spread with a tenacious root system and with the thousands of seeds produced by its plume-like flower.
"Once it gets into a wetland, it spreads so rapidly and gets so tall and dense that no wildlife, no human, no duck-hunting dog can move through it," said Karin Kettenring, associate professor of Wetland Ecology at Utah State University. "It's like a dense bamboo forest, it's impenetrable."
Phragmites are also notorious for depleting vast amounts of water.
Researchers with the Utah Division of Water Quality recently calculated phragmites suck 71,000 acre-feet from the Great Salt Lake each season — the equivalent of all water flowing from the Jordan River's for nine months.
The tall, thirsty plant came to North America from Eurasia.
"We think the seed heads were used as packing material, back in the day before Styrofoam existed, in early shipping routes across the Atlantic," Kettenring said.
Phragmites didn't invade Great Salt Lake wetlands until around the 1980s, when the lake began to recede after reaching record-high levels.
"What happened is we basically primed wetland habitats for this species, since it's a high-nutrient specialist," Kettenring said.
Nutrient-rich runoff from agricultural fields and suburban lawns filled Great Salt Lake wetlands. The phragmites thrived, choking out important bird habitat.
"In 2015, my number one priority was to kill the phrag off so we could see what we actually have off the dike," Hansen said.
The Utah Legislature appropriated $500,000 to control phragmites stands in 2017. The Great Salt Lake Advisory Council noted a similar funding would be needed in 2018. It takes years of intensive work to make any progress with the plants.
Hansen manages around 35,000 acres at the Ogden Bay WMA. Like other wetland managers around the Great Salt Lake, he uses a combination of herbicide spraying, rolling, crushing and burning to control phragmites.
Cattle grazing, however, has quickly become Hansen's tool of choice. He contracts with local ranchers to graze around 2,000 cow-calf pairs at Ogden Bay.
"I'm a farm boy and I worked here while I was going to college 20 years ago. I made the observation that where there were cows adjacent to us ... there was no phrag," Hansen said. "I like to think outside the box."
Grazing is less expensive than other methods of phragmites control. Ranchers "pay" for the grazing rights with in-kind work at the bay.
The optics are also better than burning, particularly in the Wasatch Front's notoriously polluted airshed.
After cows munched down acres and acres of wetlands and opened up the habitat, Hansen realized 84 of his water control structures — around a third of all the structures in the management area — had completely failed. He's now working to get the repaired and replaced.
"Every dike out here was like driving through a tunnel. You couldn't see what was going on anywhere," he said. "You can see how they've opened it up in three years just grazing."
Hansen fenced areas within his grazing treatment areas to act as controls. Those confined stands look odd surrounded by fields and bogs where birds now forage.
The grazing is beneficial to the ranchers as well, especially during parched years like this past season.
"It was an extremely dry year out here, especially on our home range. There's basically no grass," said Seth Jones, a rancher based in Box Elder County's Park Valley.
Jones has around 350 head of cattle. This was his first time contracting with Ogden Bay WMA, which ended up saving his operation when his other allotments in the mountains became too dry, he said.
"It was perfect timing," he said. "Without the (Ogden Bay WMA), we wouldn't have been able to keep as many cows as we did."
In exchange, Jones built fences around the WMA and helped plant food plots for pheasants and quail.
"It was a lot of hours, but it's work we're used to," he said. "It's great to be able to have that option so it's not as expensive to us."
While there are loads of benefits to using cattle to knock back phragmites, it's not a perfect solution.
"With grazing, there were a lot of concerns about impacts to water quality," Kettenring said.
Cows can potentially add to the nutrient loading that caused phragmites to grow so rampant in the first place.
One of Kettenring's graduate students, Brittany Duncan, studied grazing impacts to Great Salt Lake wetlands. The study hasn't been made public yet, but Kettenring summarized the findings.
"Basically, if you use cattle for a short period of time, like a month or month and a half, for two years in a row, it's not going to have a large negative impact," she said. "But we're not suggesting you can go out and graze for 10 years in a row."
Grazing can also be effective if used carefully, she added, but it needs to be coupled with herbicide treatment to kill phragmites roots — which can grow 10 feet deep.
Hansen said he's well-aware of cow's impacts. They've trampled and "annihilated" one of his food plots for birds. But at this point, he mostly sees the benefits.
"I would love it if we got to the point where we didn't have to have cows, but I don't see that happening," he said.
As a flock of ducks took flight over a munching herd, Hansen surveyed what used to be a daunting expanse of green weeds.
"I'm getting just a fraction of the complaints about cows compared to what I got on phragmites," he said. "Now you have thousands of acres to hunt."