Skip to main content

Alien Invaders: Destructive Invasive Species

Nile Perch

nile-perch-100623-02

(Image credit: Jens Bursell)


The 1954 introduction of the Nile Perch to Lake Victoria, Africa, was a cascading disaster for the ecosystem.

Common myna bird

myna-bird-100623-02

(Image credit: stock.xchng)


The common or Indian myna is native to central and south Asia, but the pet trade has spread the birds across Southeast Asia and the Pacific. They're also found on islands in the Atlantic, in southern Africa and in Australia and New Zealand.

Mynas roost by the thousands, elbowing out native species, damaging crops and creating a health hazard with their droppings. On isolated islands like Saint Helena in the Atlantic, mynas prey on the nests of endangered birds, stealing eggs and eating newly-hatched chicks.

Housecat

house-cat-100623-02

(Image credit: stock.xchng)


It may seem strange to think of your feline companion as an invasive alien, but domestic cats were one of the first species to be spread around the globe by humans.

Domesticated in the Mediterranean 3,000 years ago, cats were prized for their ability to kill another human hanger-on, the rat. Sailors took cats to sea and to new lands, often abandoning any feral offspring. Native birds and small mammals suddenly found themselves hunted by a new predator.

Cats' impact continues in the modern day. According to the IUCN, cats have contributed to the decline of 76 bird species in New Zealand, six of which are found nowhere else.

Stephanie Pappas is a contributing writer for Live Science. She covers the world of human and animal behavior, as well as paleontology and other science topics. Stephanie has a Bachelor of Arts in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz. She has ducked under a glacier in Switzerland and poked hot lava with a stick in Hawaii. Stephanie hails from East Tennessee, the global center for salamander diversity. Follow Stephanie on Google+.