Kudzu, water hyacinth, and zebra mussels in rivers and streams, nutria on coastal marshes – all are invasive species that create huge problems. Invasive species can be introduced accidentally or intentionally. Because there are no natural checks on their populations, their rampant spread can quickly overtake native species and sometimes even cause their extinction. Invasive species are very costly to control and it is almost impossible to eradicate them.
About 2.4 million acres of the 97-million-acre National Wildlife Refuge System are infested with invasive plants, according to the 2007 Refuge Annual Performance Plan. In addition, 4,423 invasive animal populations live on refuge lands. National wildlife refuges spent more than $11 million during the last fiscal year fighting this pervasive problem.
Cheatgrass is an invasive plant whose uncontrolled spread was partly to blame for the fires at Hanford Reach National Monument/Saddle Mountain National Wildlife Refuge in Washington. Giant salvinia has covered entire lakes in the south, preventing native aquatic plants from getting sunlight. Nutria were imported for their fur, but when the fur trade collapsed, the nutria kept on reproducing, eating their way through levees and dams and obliterating coastal marshes in New England, Louisiana and the northwest.
Some Dos and Don’ts
People can have a major impact in the fight against invasive species. The Center for Invasive Plant Management and the National Wildlife Refuge System designed an online training course, www.fws.gov/invasives/volunteersTrainingModule, for volunteers who want to help fight invasive plant species.
Everyone can adopt daily practices that will help counter the spread of invasives:
* Clean your outdoor recreation gear, such as boats and boots (See: http://www.protectyourwaters.net/)
* Do not release unwanted pets into the wild. Do not dump the contents of an unwanted aquarium into a backyard stream. (See: www.habitattitude.net)
* Educate yourself about invasive species ecology and management by visiting the Refuge System’s online training program, www.fws.gov/invasives/volunteersTrainingModule
Choose plants carefully:
* Whenever possible, use only native plants appropriate for your region.
* Ask local nurseries to start carrying more native plants. Search online for a local native plant society that can recommend nurseries.
* Consider native wildflowers that can rival ornamentals in beauty and color; their nectar is also an important food source for honeybees, butterflies and hummingbirds that rapidly burn carbohydrates during flight.
* Remove weeds before transplanting potted plants.
* If you remove weeds or invasive plants from your garden or backyard, be sure to remove the entire plant and dispose of it carefully so seeds and roots aren’t carried to new areas.
* If you use a non-native plant, ask the nursery if it’s invasive.* Contact your local Cooperative Extension office (often on the grounds of the nearest large university) to identify plants that are appropriate for your area.