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Group 3's Ecology Project

Introduced Species Problem

Interview Page
Temperate Biome
Introduced Species Problem
Introduced Species Into North America
Bibliography and Useful Websites

"If newcomers arrive from far away as the result of large-scale alterations in geography or climate, the change in selective regime and the evolutionary responses to this change could be dramatic." (Vermeij, 1996)

The abiotic environment is being changed greatly because of the climate changing and the land use alteration. However, change is occurring in the biotic communities as well. As a result of the changes the physical and biotic environments that exist now are quite different from recent times. Species have been introduced to new areas because of international commerce. Everyday staggering amounts of species are transported “The actual numbers of individuals and species being transported across biogeographical barriers every day is presumably enormous. However, only a small fraction of those transported species become established, and of these generally only about 1% become pests.” (Williamson,1996) “Biotic homogenization within continents is equally as striking as mixing among oceans. For example, in the United States pairs of states on average now share 15 more species than they did before European settlement.” (Rahel, 2000) Arizona and Montana, never had any fish species in common, however, now they have thirty-three species in their fauna.  

 Introduced Species can devastate farms, forests, lakes, ponds and invade natural areas and more importantly replace native species. Over the last 500 years, introduce species have taken over 3% of the Earth’s surface.

Facts About the Effects of Introduced Species 

  • Compared to other threats to biodiversity, invasive introduced species rank second only to habitat destruction, such as forest clearing. 
  • Of all 1,880 endangered species in the United States, 49% are endangered because of introduced species.
  • Introduced species are a greater threat to biodiversity than pollution, harvest, and disease combined. 
  • The results of Introduced specie damage to agriculture, forestry, and fisheries, introduced species lead to an enormous economic cost, estimated at $137 billion per year to the U.S. economy alone. 

Zebra Mussel- Harmful Invasive Specie to the Sea 


Cane toad Illustration

Feral Cane Toad- Invasive Specie

What is Being Done to Alleviate the Problem

           The Rio Convention of Biological Diversity internationally recognized the threat and called for action to limit it.

           A Global Invasive Species Program, formed by the United Nations and other international organizations is beginning to answer the Rio Convention of Biological Diversity’s call with a series of programs designed to deal with particular sorts of introduced species.

            “In the United States, a Presidential Executive Order in 1999 called for the formation of a Federal Invasive Species Council to render the federal response to introduced species more effective, and to foster cooperation among federal agencies, state agencies, and other stakeholders such as conservation organizations and private landowners. The Council has formulated a Management Plan that includes many activities to slow the influx of invasive introduced species and to deal with them more effectively once they are present.” (Simberloff, 2000)

What Can be Done to Alleviate the Problem


Biological control- Introduce a natural enemy from the native country of the introduced pest.

Chemical control- Use a pesticide, such as an herbicide or insecticide.


Mechanical control- Take out introduced species manually, or use machinery to help alleviate the problem.


Ecosystem Management- For example, simulated a natural fire because it tends to favor the native species rather than the introduce invaders.