Invasive Species 101 | National Geographic

(birds tweeting)

[Announcer] Rapidly growing, consuming, adapting, they conquer. Jeopardizing local economies, threatening human health, and devastating entire ecosystems.

[Man] As whole rows of cherished landmarks are condemned, brought home to town-dwelling citizens are the rigid precautions being taken by the Department of Agriculture to save this tree from extinction.

[Announcer] Invasive species are non-native organisms that cause considerable damage when introduced to a new area. These species compete with native wildlife for resources and thrive at the expense of the local ecosystem. (tree crashing) The introduction of invasive species is often associated with human activity. Boats that travel between different bodies of water can carry hitchhikers, such as the zebra mussel. One of the most notorious invasive species in the United States, these rapidly reproducing mussels clog pipes and overtake beaches in the Great Lakes. Some invasive species, however, are introduced intentionally. (frog croaking) In the early 20th century, cane toads were brought to Australia as a form of pest control. Today, these poisonous amphibians number in the millions and have caused a decline in native predators on the island.

It's not just animals. Bacteria, fungi, and plants can also become invasive. Brought to South Africa in the 19th century, the black wattle is an invasive tree often used for timber and firewood. This beautiful tree, and other thirsty invasives, are depleting the country's already record-low water supply. Because of their impact on human health, ecosystems, and infrastructure, invasive species cost the global economy over a trillion dollars each year.

Many measures can be taken to help limit the spread of invasive species, but the most effective method is prevention. By carefully cleaning boats before transferring between different bodies of water, not releasing exotic pets into the wild, and planting gardens with native species, we can help prevent the spread of invasive organisms. Every living thing has evolved to play a specialized role within their ecosystem. In the ultimate balancing act, even one invasive species can drastically tilt the scales. If we stay mindful of our role in the spread of these organisms, we can prevent invasions before it is too late. (gentle cinematic music)