Invasive Species Defined

What's Being Done

 National Invasive Species Information Center

Submodule 1: Introduction

Why We Should Care About Invasive Species

Invasive species can adversely affect Americans’ quality of life. Just a few examples include:

Economic costs:

• Increased cost of food because pesticides against weeds and pathogens need to be applied
• Clogged waterways due to invasive plants and marine invertebrates
• Decreased property values for private property and public lands primarily due to invasive plants

Health costs:

• Allergic reactions from invasive plants
• Potentially serious illness due to West Nile virus
• Injury and potential disease from feral dog and cat bites

Ecological costs:

• Loss of native plants and animals
• Decreased species diversity from infestations
• Increased fire danger due to infestations of highly flammable plants

Social/Recreational costs:

• Loss of sport fishing from sea lamprey infestation of the Great Lakes
• Change in international travel plans due to outbreaks of new diseases (such as “bird flu” or SARS) around the world
• Inability to use hiking trails because of weed infestations

          Left: Sea Lamprey (Petromyzon marinus) (photo courtesy USGS)

          Right: Hell's Half Acre Lava Trail

Many of these examples could easily fit into more than one category. For instance, waterways cogged by invasive plants in certainly an economic cost to fishing companies, and industries using pipes for water disposal. But waterways clogged by invasive plants growing on the surface can also cause an ecological disaster by blocking life-giving sunlight for submerged plants. Clogged waterways can also cause social costs by making recreational rivers and lakes unusable for boating, fishing, and swimming.