Tamarisk Eradication:
Mesa Verde Destroys Plants

During the autumn of 1999, a National Park Service team destroyed thousands of plants along the Mancos River on the eastern boundary of Mesa Verde National Park. Destroyed plants? In a national park? Absolutely - the plants were tamarisk, a vigorous invader of rivers and streams throughout the western United States.

Jump to a Section:

[ The Unwelcome Alien ] [ Public Problem, Cooperative Solution ]
[ A Manageable Problem? ] [ Other Invaders ]
[ What Happens Next? ] [ What Can I Do? ]

The Unwelcome Alien

Tamarisk, also known as "saltcedar," was introduced to the U.S. in the early 1800's. Originally from Asia, it was imported as an ornamental plant, and for erosion control, windbreaks, and shade. With its prolific regeneration, hardy adaptations, and lack of natural controls, tamarisk quickly spread throughout the American West. Many scientists believe the spread of tamarisk has been aided by dams and other flood control projects. Tamarisk now occupies virtually every river system in the Southwest.

Tamarisk creates many problems in riparian (riverside) areas. It can form dense uniform stands, crowd out native trees and shrubs, and ruin wildlife habitat. The dense stands are susceptible to destructive fires, further harming riparian areas. Tamarisk also decreases available surface water, sometimes drying up streams, ponds, and even lakes. Tamarisk thrives in saline (salty) soils. These salts, exuded from the tamarisk leaves, collect under the plant, further increasing soil salinity and discouraging native plants.

Public Problem, Cooperative Solution

National Park Service funding was not sufficient to undertake the entire project of eradicating tamarisk along the Mancos River. Fortunately, a grant from Canon, USA, Inc., through the National Park Foundation, made this project a reality. Canon funded 90% of this project, donating $20,000 through their program, Expedition Into The Parks. This money was used for salaries for tamarisk eradication specialists, travel costs, herbicides, fuel for chainsaws, and other supplies, as well as funding the production of educational and interpretive materials.

The State of Colorado also funded $2,000 toward this project, which covered the costs of tamarisk control on state lands in the project area. The Bureau of Land Management (BLM) completed the compliance documents required by the National Environmental Policy Act (NEPA), and also allowed National Park Service crews to work on BLM land.

A Manageable Problem?

In many areas of the West, the tamarisk problem seems overwhelming. In Mesa Verde National Park, however, tamarisk was limited to the Mancos River canyon and a few side canyons. Now that tamarisk has been eliminated from this area, the outlook for total eradication is excellent. Since the team of tamarisk eradication specialists has finished removing existing plants, park staff can remove new sprouts and seedlings as necessary in the future. With tamarisk under control, the park can concentrate on managing other noxious weeds.

Other Invaders

Tamarisk is only one species of exotic plant (although an especially noxious one) found in National Park Service areas. Land managers throughout the U.S. struggle with the increasing problem of non-native plants and animals displacing native species.

In Mesa Verde National Park, musk thistle, Canada thistle, spreading pepperweed, smooth brome, cheatgrass, houndstongue, and three kinds of napweed are considered problem species.

Elsewhere in the U.S., other exotics take the headlines: kudzu in the Southeast, purple loosestrife in the Northeast, leafy spurge in the Northern Plains. Many park areas are truly fighting an alien invasion. Exotic species disrupt complex ecosystems, reduce biodiversity, jeopardize endangered plants and animals, and degrade habitats. Exotic plants and animals also may hybridize with, or transmit exotic diseases to native species.

What Happens Next?

Each season, Mesa Verde National Park staff will monitor the Mancos Canyon drainage and eradicate new tamarisk seedlings and shoots as necessary. The park will continue to work with its neighbors, including the Bureau of Land Management and the Ute Mountain Ute Tribe, to continue tamarisk control on both sides of the park boundary.

The nationwide problem of exotic species is challenging and complex. Only through extensive control efforts and continued cooperation between private landowners and public land managers will tamarisk and other exotic species begin to loosen their stranglehold.

What Can I Do?

Concerned individuals can help in several ways. Volunteer to help with inventories, mapping, and eradication of exotic species. Learn about and support efforts by public and private land managers in your area. Be a good neighbor by controlling weeds and exotics on your own property. Use only native plants or non-invasive ornamentals in landscaping your yard and property. Contact your local county extension office for information on identifying and controlling noxious weeds.

To learn more about exotics, visit the NPS Web site at www.nature.nps.gov/wv/exotics.htm.

This project was made possible by a generous grant from Canon, USA, Inc., through the National Park Foundation. This project is a part of the Expedition Into The Parks, which funds priority conservation projects in National Parks.