Top 5 Invasive Species in the U.S.

As stated in Executive Order 13112, an “invasive species” is defined as any species that is (1) non-native to the ecosystem under consideration and (2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.

Park rangers perform invasive species monitoring in the Columbia River. - Credit: Portland Corps via Flickr

Park rangers perform invasive species monitoring in the Columbia River. – Credit: Portland Corps via Flickr

Invasive species can include plants, animals and other organisms, such as microbes, and are primarily introduced to a new environment through human actions. They are a significant threat to many native habitats and species and are a cause of significant cost to agriculture, forestry and recreation.

Here are some facts:

  • Compared to other threats to the native ecosystem, invasive introduced species rank 2nd only to habitat destruction, such as forest clearing.
  • Of all 1,880 species at risk in the United States, 49% are endangered because of introduced species alone or because of their impact combined with other forces.
  • Introduced species are a greater threat to native biodiversity than pollution, harvest, and disease combined.
  • Damage to agriculture, forestry, fisheries, and other human operations, invasive species inflict an economic cost, estimated at $137 billion per year to the U.S. economy alone.
  • Some introduced species (such as most of our food crops and pets) are beneficial. However, many others are very damaging.
Credit: U.S. Army Corps of Engineers via Flickr

Crews search for invasive Asian carp near Chicago. – Credit: U.S. Army Corps of Engineers via Flickr

So what are the top 5 invasive species in the U.S.? They are:

  • Constrictors – Over the past 30 years, these big snakes (including both the Boa and Python) have been bought and sold domestically and internationally. Pet owners often take these snakes into their homes and find that they cannot accommodate them as they grow. When the snakes get too big, owners often release them into the wild (ie: Florida Everglades), where they prey on endangered species. Under the Lacey Act, the U.S. Fish and Wildlife Service proposed to stop constrictor serpent imports into the country and even ban transport between states.
  • Asian Carp – These fish were brought to the U.S. in the 1970s as live vacuum cleaners meant to remove algae and other matter from ponds. They can grow to weight 100 lbs and will eat just about anything, adapting very well to new environments. They now represent 90% of the biomass in the Illinois River! Researchers worry that they will reach the Great Lakes and be problematic to the fragile ecosystem there.
  • Zebra Mussels – Zebra mussels originally made their way into the U.S. the 1980s and have clogged the inside of pipes since. These blockages are not minor —they can cost billions of dollars in fixes. They also cling to motors and to other native mussels, causing grief for boat owners and decimating indigenous wildlife.
  • Mongoose – The small Indian mongoose was originally brought to Puerto Rico and the Hawaiian islands to protect sugar cane fields from pests such as rats and snakes. But instead of aiding in crowd control, the mongoose quickly became the enemy, harming far more wildlife than anticipated. These agile creatures prey on birds and small reptiles, injuring both the poultry industry and game hunters and costs Hawaii $50 million dollars in damages each year. They have so far caused the extinction of 12 reptile and amphibian species from Puerto Rico, the West Indies and Jamaica.
  • Starlings – This petite bird came to the U.S. in the late 1800s as part of an attempt to introduce the animals mentioned in Shakespeare’s works to America. European starlings thrived in the U.S. and disseminated outward from New York City, where they originally arrived. Now starlings occupy most of North America, stealing nesting sites from other birds and robbing the agriculture industry of $800 million dollars annually by damaging fields. Starlings also spread diseases that are infectious to both humans and livestock, costing an additional $800 million a year in healthcare.


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This entry was posted in Awareness, General.