Why Invasive Species Matter

Managing invasive species matters because we want to create and preserve healthy environments for ourselves and future generations of people and wildlife. Invasive species can lead to the extinction of native plants and animals, destroy biodiversity, and reduce and alter wildlife habitat. The spread of invasive species negatively affects the environment, economy, human and animal health and safety.

All life depends on healthy ecosystems.

Cedar Waxwing on a maple tree
Cedar waxwing on a maple tree. Some invasive plants like nandina (Nandina domestica) are poisonous to local birds like the cedar waxwing.


Invasive plants can cause these negative effects:

  • Displace native plants which
    • interferes with the food web, reducing healthy food for birds, fish, butterflies and other wildlife
    • destroys native habitat and inhibits forest regeneration
    • endangers species through loss of food and habitat, potentially to the point of extinction
    • decreases plant diversity which is essential for healthy forests
  • Smother and strangle trees and other plants
  • Reduce water quality through increased erosion and decreased water filtration, and tree stability affecting the tree canopy 
  • Shade and choke out aquatic plants reducing healthy food and oxygen for fish and other aquatic life
  • Change the soil chemistry and inhibit other plants from growing
wintercreeper thick vines
Wintercreeper vines grow thickly and smother trees

Wintercreeper vines grow thickly and smother trees

Invasive animals are considered to be a major factor in the extinction of numerous fish and wildlife species worldwide due to their ability to

  • Compete with native species for food, habitat and other resources
  • Introduce and spread parasites and diseases to humans, plants and wildlife
  • Prey on native species
  • Damage native plant communities
  • Damage soil and aquatic resources
Snakehead fish prey on young native fish species

Snakehead fish are aggressive predators that may disrupt freshwater ecosystems by feeding on native fishes, amphibians, and crustaceans.

Tree diseases that move into our habitats and can threaten native plants and animals. They do not have the natural controls that exist in their native environment to prevent their spread.

  • Tree diseases play a role in the destruction of native trees and and wildlife habitats and cause similar impacts as invasive plants.
Magnified nectria - need caption
Nectria fungi cause several common canker and dieback diseases, especially hardwood trees

Beech bark disease is a deadly threat to an easily recognizable tree. Red nectria appear like blisters on the bark of beech trees, signaling a fatal end for the tree.


Economists have estimated that all invasive species - plants, animals and diseases - cause $120 billion in losses in the United States each year (Pimentel et al. 2005). Costs are related to farming, forestry and fishing, and infrastructure. The harm to our economy hinders sustainable economic growth by:

  • Lowering crop yields
  • Impacting commercial and recreational fisheries
  • Harming livestock 
  • Degrading soil quality
  • Lowering property and building values and other infrastructure damage
  • Increasing the cost of controlling pests, weeds and diseases

Increased agricultural costs are passed on to the consumer through higher food costs.

invasive bamboo
Bamboo can spread aggressively outside your property limits and be expensive to get rid of. Joy Viola, Northeastern University, Bugwood.org

Bamboo can spread aggressively outside your property limits and be expensive to get rid of.
Photo credit: Joy Viola, Northeastern University, Bugwood.org


Recreational and social opportunities

  • Enjoyment of Trails and Forests: Invasive species reduce the health and quality of our local parks and open spaces which reduces our opportunities to relax, think clearly, refresh and rejuvenate. Invasive species can create impenetrable barriers that limit access to trails and natural areas.

  • Natural Heritage: Our beautiful native Virginia plants, birds, fish and other wildlife are competing for the same food and habitat with invasive species. When they lose out, we can no longer enjoy their natural beauty. We have already lost American Chestnuts and Ash trees. Imagine a spring without Virginia bluebells.

  • Water Recreation: Invasive plants that spread into our waterways can limit our access or desire to boat and fish in our local lakes and streams.

Celandine and Virginia Bluebells
Invasive Lesser Celandine overtaking field of native Virginia Bluebells

Invasive Lesser Celandine overtaking field of native Virginia Bluebells

Human Physical and Mental Health

  • New Diseases: Historic catastrophic health events have been caused by the introduction of non-native pests such as mosquitoes, rats and mussels
  • Disease Vectors: Increases in Lyme disease have been linked to mice harbored in invasive shrubs that have spread into local forests
  • Psychological: The reduction or destruction of healthy forests removes those spaces that provide stress relief and many mental, emotional and physical health benefits. Knowing how invasive species damage our community can also create a personal sense of helplessness. Learn more about What You Can Do.

Learn more at Invasive Species Human Health Impacts

Red imported fire ants (RIFA)
Red imported fire ant (RIFA) can attack and cause painful stings on humans, pets, and livestock

Red imported fire ant (RIFA) can attack and cause painful stings on humans, pets, and livestock


  • Falling Trees: Pest and disease infestations or smothering invasive plants can cause instability or kill a tree creating hazardous conditions on trails and for nearby residents and their property.
  • Visibility: Invasive species can create dense walls of foliage that prevent you from seeing threats. 
Invasive wisteria
Walls of wisteria impair visibility and access.

Walls of wisteria impair visibility and access through open spaces

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