Feral cats listed among top invasive species in the West
HELENA, Mont. — Look all you want, but Bigfoot did not make the first-ever list of top 50 invasive species in the West.
Feral cats did.
Also on the list from the Western Governors Association were plants such as salt cedar and Eurasian watermilfoil plus critters such as carp, nonnative crayfish and feral hogs. The governors who are members represent 19 states from that second tier of states west of the Mississippi and westward and the U.S. territories of American Samoa, Guam and Northern Mariana Islands.
Not every species on the list is a problem in every locale, said Bill Whitacre, the association's policy adviser for public land and agriculture.
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“It’s a good list that highlights concerns of the environment,” said Tom Woolf, aquatic invasive species bureau chief with Montana Fish, Wildlife and Parks. “It’s a great education tool.”
The list is divided into two categories, the top 25 aquatic invasive species and the top 25 terrestrial invasive species.
Some of the species on the list, such as tamarisk, were introduced intentionally 100 years ago. The shrub or small tree, also known as salt cedar, was brought in from Asia to halt river-bank erosion, Whitacre said.
Other invaders hitchhiked to the area, clinging on to the bottom of boats, he said.
States were asked to rank their 15 most potent and and potentially problematic terrestrial and aquatic invasive species. Then state invasive species managers were asked to rank their list on cumulative environmental and economic effects, Whitacre said.
Seventeen states participated in one or both studies: Alaska, Arizona, California, Colorado, Hawaii, Montana, North Dakota, Nebraska, Nevada, New Mexico, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington and Wyoming.
Compiling Montana's response was a challenge, said Stephanie Hester, Montana Invasive Species Council coordinator.
“How do you compare a tree pest against a feral hog?” Hester said. “Why is one one and why is one 25?”
Didymo, an algae also known as “rock snot,” was ranked No. 18 on the Western list but did not make Montana’s list because it is a native species, she said.
Topping the Western Governor's terrestrial list was tamarisk, which lowers the water table and creates large deposits of salt in the soil, hence its common name of salt cedar, according to the National Invasive Species Information Center.
Cheatgrass, Canada thistle, hoary cress and emerald ash borer complete the top 5. Some intriguing animals also pop up: feral hogs at No. 6, European starlings at No. 10, feral cats at No. 13, coqui frogs at No. 19 and fire ants at No. 25.
Those feral cats are an interesting addition to the list because they mostly are in urban areas, Hester said.
“It’s a legitimate invasive species for sure,” she said.
No one knows exactly how many stray and feral cats are on the loose across the USA. They are, by nature, elusive.
“Feral hogs (are) something we are keeping an eye on,” Hester said. They, too, are tough to track, and a couple of flights over some areas where the state has received complaints didn't show any activity even with fresh snow on the ground.
The top of the aquatic list has the Eurasian watermilfoil, a plant that grows in thick mats that crowd out native vegetation and can grow anew from a stem severed by a boat propeller; quagga and zebra mussels that choke irrigation systems and clog drinking water intakes on lakes and rivers; New Zealand mud snails, Asian clams and curly leafed pondweed.
Taxpayers pay for these invasions. Officials estimate that they will have to spend $500 million a year to keep the Columbia River basin free of the zebra mussel, which came to the United States in the mid-1980s via the Great Lakes in ballast water from a Ukrainian ship, Whitacre said.
“They attach to everything,” he said.
Some of these invasive species are the size of a grain of rice, Woolf said.
Contributing: Karl Puckett, Great Falls (Mont.) Tribune. Follow Phil Drake on Twitter: @GFTrib_PDrake