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Invasive plants can have long "invasion shadows"

May 30, 2017

Japanese stiltgrass is an invasive plant.
Credit National Park Service

Invasive plants are really good at being bad. They’re hard to get rid of, and a new study finds that even if you rip them out, they can have lingering effects for years.

Dan Tekiela is an invasive plant ecologist at the University of Wyoming. He studied Japanese stiltgrass, and calls it one of the top three worst invasive plants in the eastern U.S.

Tekiela says they removed the plant from several sites. Three years later, things were worse.

“We found the disturbance of us removing that invader actually promoted other weedy and invasive species,” he says.

He says the invasive plant robbed the soil of nutrients too. These lingering effects are known as "invasion shadows."

Tekiela says we spend millions of dollars managing invasive plants, "and we kill them and we say we’re successful and walk away. But if you don’t actually look at what happens afterwards, you might just be opening up a niche for other invasive and weedy species."

He says the key to restoring native ecosystems is to try and take invasive plants out as early as you can, and then monitor to make sure you have the right kinds of plants coming back in.