It is easy to assume that getting rid of invasive plants will allow a local ecosystem to return to its natural state, with native vegetation flourishing once again. But a new study featured in the journal Invasive Plant Science and Management shows the impact of weedy invaders can linger for years.

Researchers from the University of Wyoming and Virginia Tech explored what happened after they eradicated Japanese stiltgrass, one of the worst invasive species in the Eastern U.S. Their three-year study found that removal of the species failed to result in the restoration of the local ecosystem.

While some soil nutrients began to shift towards an uninvaded state, they never fully recovered. In addition, vegetation became less like the original native plant community. Many of the plants that emerged after Japanese stiltgrass was removed were themselves from weedy species, creating a new wave of control challenges.

"Fortunately, newly established invasive populations don't produce the same level of lingering legacy effects as those that are long established," says researcher Daniel R. Tekiela, Ph.D., of the University of Wyoming. "That makes early eradication an important imperative."

When an invasive plant is well-established and early eradication is no longer an option, researchers say it is important to carefully assess the management techniques used. Simply removing the invader could result in undesirable, long-term changes to the resident plant community.