Regional Invasive Plant Environmental Impact Statement

Related Information

Invasive species impact nearly half of the species currently listed as Threatened or Endangered under the U.S Federal Endangered Species Act (Flather et. al 1994). One Regional example of this is the encroachment of yellow starthistle on the Endangered plant MacFarlane's four clock in the Hells Canyon National Recreation Area. The photos below show a broad view of the species habitat and a close-up of the plants flowers. Just this summer yellow starthistle was discovered in what would be the immediate foreground of the habitat view.

MacFarlane's four o'clock habitat in Hells Canyon

Close-up of MacFarlane's four o'clock flowers

This is just one example of the threat posed by invasive plants to Threatened and Endangered (T & E) species. Other threats include:

• Invasive plants can out-compete and eliminate T & E plants. As invasive populations rise, native species populations fall. This results in a reduction in species diversity, changes in community structure and loss of ecosystem function.

• Invasive plants can displace the native plants that provide food and shelter for T & E wildlife. Their presence reduces the quantity and quality of forage available. Some invasive plants are poisonous or can cause injury to wildlife.

• Invasive plants increase soil erosion. Erosion can cause increase in the amount of sediment that enters a stream and could negatively impact T & E fish.

Do you know how many T & E species occur on National Forests in the Pacific Northwest? See tables below for the answer:

Table of Threatened and Endangered Plants

Table of Threatened and Endangered Animals

USDA Forest Service - Region Six- Invasive Plant EIS
Last Modified:  Thursday, 15 December 2005 at 19:34:34 EST 12/15/05