Vancouver-based land trust is buying a 136-acre island in the Columbia River near Beacon Rock State Park.
Columbia Land Trust officials say Pierce Island is one of the last remaining locations for persistent sepal yellowcress, an endangered plant in the mustard family.
Already, land trust members are removing noxious weeds from the island.
The Columbian newspaper reports that the island was purchased from The Nature Conservancy. That group bought Pierce Island in 1984 to protect it from a clear-cut and industrial use.