Invasive Species

About Invasive Species

Flowering knapweed

Invasive species are a serious worldwide threat to natural resources. Invasive species means, with regard to a particular ecosystem, a non-native organism whose introduction causes or is likely to cause economic or environmental harm, or harm to human, animal, or plant health (from Executive Order 13112, as amended – Safeguarding the Nation from the Impacts of Invasive Species, signed Dec. 5, 2016). E.O. 13112 requires Federal agencies to prevent and control these species and to minimize their economic, ecological, and human health impacts. Environmental and economic costs caused by invasive species in the U.S. alone were estimated by Pimentel et al. (2005) to exceed $120 billion per year.1

Managing Invasive Species in Region 3

The U.S. Forest Service has developed a number of Regional documents for invasive species management and pesticide use in the Southwestern Region (Region 3). Region 3 covers national forests and grasslands in Arizona and New Mexico along with national grasslands in western Oklahoma and the Texas panhandle.

Invasive Species in Region 3

Invasive species threatening Region 3 range from disease pathogens to mammals (see list of invasive species by national forest). Specific information on invasive species affecting national forests and grasslands in Region 3 may be found by accessing the information blocks below.

Invasive Plants

Flowering Malta starthistle

Invasive plants have been introduced into the Southwest from different countries or other parts of the U.S. Although many non-native plants are relatively harmless in their new environment or are even beneficial to society, invasive plants can spread rapidly and threaten native ecosystems.

«more on invasive plants»

Terrestrial Invasive Animals

Two feral hogs and piglets

Terrestrial invasive animals can impact native vegetation, wildlife, and fish.

«more on terrestrial invasive animals»

Aquatic Invasive Species

Quagga mussles

Aquatic invasive plants, fish, and other aquatic invasive organisms can displace and out-compete native species in waterways.

«more on aquatic invasive species»

Invasive Diseases Affecting Fish and Wildlife

Bats with white noses, evidence of white-nose syndrome

A number of diseases affect specific species of fish and wildlife including white-nose syndrome in bats.

«more on invasive diseases affecting fish and wildlife»

Invasive Insects and Diseases Affecting Forest Health

Emerald Ash Borer

Several invasive tree diseases are currently impacting forests in the Southwest. In the future, there may be other invasive insects and tree diseases that will affect forests in the region.

«more on invasive insects and diseases affecting forest health»

Invasive Weeds Affecting Wilderness Areas

Wilderness Volunteers

There are a number of invasive weeds currently affecting wilderness areas in the Southwest. Controlling these weedy species requires implementation of specific processes that are in compliance with the Wilderness Act of 1964.

«more on invasive weeds affecting wilderness areas»

1 Pimentel, D., R. Zuniga, and D. Morrison. 2005. Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecol. Econ. 52(3):273-288.


Southwestern Region Invasive Species

In the Southwestern Region, invasive species range from pathogens to a mammal and everything in between, i.e., plants, molluscs, crustaceans, insects, amphibians, fish, etc.