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.

Two years ago, another noxious and threatening weed sprouted — Canada thistle — that is cause for concern.

Slowly and steadily, Bates is trying to establish pockets of plants, especially blue bunch wheat grass and sagebrush, to combat the spread of noxious weeds.

The two are among the plants that not only support wildlife but hold moisture over the summer, which therefore can slow the spread of fire.

"Fire management is a priority with us right now," he said. "What we're trying to create are vegetative firebreaks. We're planting a swath of clover and flax, for example, about a 100 yards wide running through a hillside of cheat grass."

Because the two plants hold moisture, any spreading fire is not as intense. "It's a lot easier to fight a fire burning only a foot high as opposed to one burning 3 to 4 feet high, which is what happens with cheat grass," he pointed out.

"This way we are able to get on top of a fire and put it out as fast as possible."

The spread of weeds has also limited the supply of food for buffalo and antelope. And because of it the stable herd size that has been maintained over the past decade for buffalo has been dropped this year from 550 to around 400. The extra bison will be rounded up and sold in late fall.

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Bighorn sheep, also found on the island, tend to hang out at higher elevations, where there are still pockets of wheat grass, and are therefore doing better than their neighbors.

It will be a long time before plants can get the upper hand over weeds. Bates said he doesn't expect to see it happen during his career on the island. "At best guess, it may take 50 years or more," he offered.

The task now is to stop the weeds from overrunning the island. And here, he added, with new herbicides, better planting technology and volunteers willing to bend down, grab a handful of weeds and pull, there are definite reasons for optimism.


E-MAIL: grass@desnews.com

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