Invading weeds threaten Antelope Island ecology

ANTELOPE ISLAND — All those flowing seas of plants swaying with every breath of a breeze that passes are attractive, even beautiful at times, but are of little value. In truth, some are downright threatening to the island ecology.

If left unattended, Antelope Island could well become a garden of noxious weeds, devoid of healthy plants and animals.

As it is now, there are plans to lower the number of buffalo, because of the shrinking supply of food, on the island until more beneficial plant life can be established.

The underlying reason for this growing concern over weeds is fire. The island is a target for every thunderstorm and lightening strike that passes by in the summer.

And, after every fire, opportunistic weeds move in and set up dominance in an area. Beneficial plants, like clover, flux, alfalfa, sagebrush and blue bunch wheat grass, have a difficult time finding clear ground to grow.

Instead, large patches of cheat grass, dalmatian toadflax and Canada thistle, have taken hold.

"The problem with cheat grass," explained Steve Bates, wildlife range manager with the Division of Parks and Recreation on the island, "is that once established it sucks out all of the moisture from the ground and doesn't allow other species to survive."

After it has taken all the moisture, which is early in the summer, it then dries up and becomes tinder for fires. And, once it's dry, grazing animals choose not to eat it. Most of the island is carpeted with cheat grass.

Also of concern, said Bates, is the dalmatian toadflax, a long-stem weed that produces a beautiful little yellow flower in the spring.

"They refer to it as the 'silent wildfire' because it expands at such a rapid rate you don't notice," he said.

How it got to the island he isn't sure — on the tire of a vehicle or with a strong wind blowing in from the mainland. Currently, about 4,000 acres are infested with toadflax.

"All we know is we have it and we've got to get rid of it," Bates added.

To help fight it, he has been calling upon volunteers to come out and pluck the weed from the soil by hand. Also, there are new herbicides on the market that are proving successful in eradicating the weed.

Bates has also introduced a small beetle onto the island that feasts on toadflax. It is helping to control the weed, he explained, but it will never eradicate it.