Nonnative plants and animals are gaining a foothold in the state and threaten the environment. Some were purposefully introduced, while others arrived on their own. For example, purple loosestrife was introduced as an ornamental in the 1800s. In wetlands, though, loosestrife crowds out other plants and can affect nearby duck populations because its seeds are not a good food source. While some nonnative plants are good, such as corn and soybeans, others can, without their normal pests and climate limitations, grow out of control.