Plants

Non-Native Invasive Plant Species

Non-native invasive species have been identified by the Deparment of Agriculture U.S. Forest Service as one of four critical threats to our nation's ecosystems.

• Fact: Non-native invasive species have significant economic and environmental impacts in the United States. Studies show that economic losses caused by non-native invasive species exceed $138 billion annually.
• Fact: Many species listed by the Federal Government as threatened or endangered have been negatively affected by non-native invasive species.

Mission Statement

The goal of the USDA Forest Service Southern Region is to reduce, minimize, or eliminate the potential for the introduction, establishment, spread, and impact of non-native invasive species across all landscapes and ownerships. To achieve this goal the region has developed the Southern Region Framework for Non-Native Invasive Species.

What is a Non-Native Invasive Species?

A non-native invasive plant is a species that is not native to the ecosystem under consideration, and its introduction causes (or is likely to cause) economic or environmental harm.

Non-native invasive plants, exotic plants, and weeds are terms often used interchangeably, but there differences between them.

• Exotic plants are non-native species introduced to a new area by humans. Unlike non-native invasive species, theses plants cause little to no economic or environmental damage, and do not out-compete or displace native vegetation.
• Weeds are undesirable plants, native or non-native, invading a given area, such as lawn or garden. A good example of a weed is the common dandelion (Taraxacum officinale), a non-native species common throughout the United States.

Why Are Non-Native Invasive Species So Successful?

Once established, non-native invasive species can out-compete native vegetation, including Threatened, Endangered and Sensitive plants for valuable water, light, nutrients and space. Non-native invasive species success is derived from their ability to:

• flourish in habitats where population control mechanisms(i.e. defoliators or pathogens) are absent;
• thrive on disturbed soils;
• produce large quantities of seed;
• disperse seeds over great distances by a variety of mechanisms (wind, birds, mammals, and even humans)
• develop aggressive root systems able to spread quickly over a large space; and
• produce chemicals on one or more parts of the plant that inhibit the growth of nearby plants, or make them unpalatable (even poisonous) to grazing animals.

Non-Native Invasive Plant Pathways

Non-native invasive plant pathways are the means by which plants are moved from one location to another.

Transport of non-native invasive plants can be accidental or intentional and can occur along natural or transportation-related pathways.

Examples of non-native invasive plant pathways include:

• Natural-wind,currents, etc.
• Transportation-aircraft,ships,trains,vehicles,foot travel,pets,etc.
• Rights -of -way-roads, railroads,utility,canals,trails, etc.
• Ecosystem disturbances-clear-cuts, development,dams,stream channelization, etc.

Non-Native Invasive Species Impacts

Non-native invasive species have serious economic and environmental impacts throughout the United States. Studies by Pimental et al (2000) show $138 billion in annual economic and other losses due to non-native invasive species.

Non-native invasive plant impacts include:

• displacement or hybridization of native plant species;
• reduction of native species diversity;
• habitat degradation(especially in areas where threatens, endangered, sensitive, and important plant and animal species reside);
• decline of overall forest health and productivity (particularly in areas with economically important resources)
• alteration of ecosystem processes (nutrient cycling, fire frequency. hydrologic cycles and erosion); and
• intrinsic loss along recreational areas.

Strategies for Controlling Invasive Species

In response to the growing threat of non-native invasive species in out nation's lands, the National Strategy and Implementation Plan for Invasive Species Management (FS-805) was developed by the USDA Forest Service in October 2440; the goal being to"reduce, minimize, or eliminate the potential for introduction, establishment, spread and impact of (non-native) invasive species across all landscapes and ownership."

The National Strategy is based on these four elements:

• Prevention
• Early Detection and Rapid Response
• Control and Management
• Rehabilitation and Restoration

Learn More About Non-Native Invasive Plants

• Controlling Invasive Species
• Southern Region NNIS List
• Partnerships and Collaboration