Invasive, non-native plants are one of the biggest threats to our native ecosystems. Because of their aggressive growth and lack of natural enemies in our region, these species can be highly destructive, competitive, or difficult to control. These invaders compete with native plants in many ways: occupying space, changing the structure of the plant community, causing physical and chemical alterations of the soil, and covering and shading native plants. Invasive plants interfere with animal life, too, by altering the structure of their habitat and by eliminating favored food plants through competition. Invasive plants are spread both by human activity and by animals that eat them and carry their seeds.
Habitat loss and invasive plants are the leading cause of native biodiversity loss. Invasive plant species spread quickly and can displace native plants, prevent native plant growth, and create monocultures.
A healthy plant community has a variety of ground cover, shrubs, and trees. Invasive plants cause biological pollution by reducing plant species diversity. Changes in plant community diversity reduce the quality and quantity of fish and wildlife habitat.
Invasive species affect us all. They damage our forests, streams and rivers, and property. Nationwide, damages associated with invasive species are estimated to be $120 billion each year. In Oregon, the control of invasive weeds and the cost of the damages they create amounts to about $125 million each year. We know that it costs a lot less to control new invasive plants before they become infestations, so we need everyone’s help.