New local threat revealed

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Siskiyou Mountains Ranger District botanist Barbara Mumblo examines an invasive plant called yellow floating heart, detected this fall in little Squaw Lake near the California border.Jamie Lusch

December 13, 2008

By Mark Freeman

Mail Tribune

APPLEGATE — Tucked into a corner of little Squaw Lake, deep in the recesses of the Rogue River-Siskiyou National Forest, is a little lily that could become the next worst thing to star thistle.

The yellow floating heart could have come on the butt of a duck or the bottom of a canoe, and getting rid of it could become a far bigger project than a few squirts of a spray bottle.

When you're talking noxious weeds such as nymphoides peltata, nothing is as simple as it sounds.

"What a dilemma," said Barbara Mumblo, botanist for the forest's Siskiyou Mountains Ranger District.

This high-mountain lake in southwestern Jackson County is only the third confirmed infestation in Oregon of yellow floating heart, potentially threatening to overrun native species and harm water quality there.

A patch about 50 feet long and 10 feet wide has taken root among native cattails in the stagnant waters at the north end of the smaller of the two Squaw Lakes near the California border.

If left to grow unchecked, the fast-moving lily could out-compete native sedges and rushes for space at the lake.

It could block sunlight from reaching the lake bottom and alter dissolved oxygen levels in the lake, harming habitat for fish and other aquatic life.

"I have no idea how it got here and I have no idea how long it's been there," Mumblo said. "I also don't know how fast it's going to spread."

It likely, however, will grow faster than the paperwork for treating it trudges through the federal system.

Since the lake is on Forest Service land, the National Environmental Policy Act requires an environmental assessment to determine whether spraying chemicals, manually pulling the weed or some other form of treatment should be used, Mumblo said.

"When you're proposing the use of chemicals, it takes more analysis," Mumblo said.

Had yellow floating heart instead been yellow planted heart, things would be different.

The Forest Service and federal Bureau of Land Management have in place the environmental studies that allow the agencies to move in and chemically treat plant invaders on land under certain conditions and protocols.

One such environmental assessment does not exist for aquatic plants, Mumblo said.

Oregon Department of Agriculture agents are keeping an eye on the yellow floating heart, the latest in a growing cache of non-native vegetation moving into Oregon and threatening all sorts of native flora.

"There's a lot of concerns about finding these nasty aquatic weeds," said Ken French, an ODA noxious weed specialist stationed in Canyonville. "The appropriate method for dealing with it, whatever that approach is, has to be well thought out."

The lily was discovered in September by a member of the public, who noticed its smallish leaves were different than the large-leafed native lilies here, Mumblo said.

Mumblo confirmed the species in October.

Native to Asia, the plant sometimes is used in aquariums. The shiny green leaves are heart-shaped and about the size of a silver dollar, and the smallish yellow flower points upward.

The plants can grow into large floating mats that can disrupt everything from recreational boating to algae growth, potentially harming the entire food web.

"It's amazing how some of these invading species can change so many things, right down to the insects," Mumblo said.

Plants like star thistle can spread on the bottoms of vehicles, Mumblo said. But the yellow floating heart, like the invading yellow flag iris before it, could become dislodged and work its way down Squaw Creek to Applegate Lake, she said.

"A lot of invaders are road-runners," she said. "Now we're finding we have some river-runners."

Simply pulling the plant won't kill it because even a small fragment of a leaf and stem can sink and develop into new plants. It's also been known to be transported by waterfowl, so a piece stuck to a duck could be all that's needed to overrun a small lake, according to ODA literature.

The lily earlier was found in Washington and Lane counties, French said. The lily reportedly has been seen in two private ponds in the Umpqua River watershed, but those cases have yet to be verified, French said.

Reach reporter Mark Freeman at 776-4470, or e-mail mfreeman@mailtribune.com.

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