Cost of Invasive Species

A recent article by Mark Riddix of Investopedia (published in the March 25,2010 San Francisco Chronicle) highlights the costs of invasive species to our environmental and economic well-being. Invasive species are organisms that are not native to a particular habitat that when present in a non-native habitat have deleterious effects on that new environment.

The reason for their negative effects stems from their advantages over native species in two distinct areas.First, when an invasive species arrives to a new environment, it is like someone who arrives with a machine gun in a place where man only had bows and arrows. The new species can totally out compete the native species and their advantage often results in environmental devastation because there are no natural (i.e. non-human) checks on the invasive species growth or activity. Second, successful invasive species tend to be generalists so they can adapt to a wide variety of food sources and habitats. Fortunately, only about 10% of invasive species introduced tend to survive and thrive. But the impacts of the species that do can be enormous.

Here are a few invasive species and their impact on the United States that Mr. Riddix mentioned in his article.
1. Nutria--a large aquatic rodent from South America that was introduced in Louisiana. This rodent has a large appetite for vegetation and can significantly reduce the plant life in swamps leading to the swamp's death and therefore allow greater erosion and threat from hurricanes because there is less vegetation to hold the soil and slow water movement. This species is now found in Maryland, Oregon and Washington State. According to the National Wildlife Federation, nutria damage 500-1000 acres of wetlands a year at Maryland's Blackwater National Wildlfie Refuge alone.

2. Feral Pigs--These are pigs that are now wild. They are now present in 37 states. Aside from their damage to habitat due to their feeding practices, feral pigs threaten livestock production through the transmission of diseases such as brucellosis, encephalitis, pseudo-rabies, and leptospirosis.


There is much more. But why not read it yourself at San Francisco Chronicle. 

Remember, wildlife damage management isn't always about controlling animals that "bother" or inconvenience humans. Sometimes and in some cases increasingly so, wildlife damage management is necessary to protect the integrity and continuity of our environment. 

Stephen M. Vantassel is project coordinator for the Internet Center for Wildlife Damage Management http://icwdm.org/ which is dedicated to providing research-based information on wildlife damage control to the public.