Not all invasions come from marauding armies. You can devastate a place just by introducing a non-native species that creates dramatic and unexpected shifts in the dynamics of the ecosystem. It's no coincidence that we refer to non-native species that begin taking over a new environment as "invasive" — when the local environment is ill-equipped to handle the new species, it can lay claim to every resource it can access and hurt countless native species in the process. Here are ten examples of non-native species that quickly became an enormous, invasive problem. In The War of the Worlds, H.G. Wells provides a frightening description of a world overcome by an invasive species of Martian plantlife called simply "the red weed":
The invasion of an alien species that dominates life on Earth has since become a common trope in SF and fantasy, but it happens in real life too. Here's our list: 10) Kudzu 9) The Black Rat 8) The Asian Tiger Mosquito 7) The Cotton Whitefly 6) The Snakehead Fish While they were originally native to East Asian waters, various species of snakehead have decimated native food chains in the US ranging from Maine to California. (Image via) 5) The Asian Longhorned Beetle Originally native to countries in Asia like Japan, infestations of Asian longhorned beetles were first detected in New York around 1996, but quickly spread to the majority of the East coast, where they are estimated to threaten 30-35% of trees on the Atlantic coast's urban areas. They're also found in California, Ontario, and parts of Europe. The economic toll of the Asian longhorned beetle is estimated to number in the tens to hundreds of billions of dollars. 4) The Burmese Python 3) The Cane Toad Unfortunately, cane toads have a nasty habit of not just eating crop pests and insects, but also just about any terrestrial animal that they can fit their grotesquely huge mouths around — which is saying something, given that they can grow to over 30 cm in length. They also secrete toxins capable of killing just about any animal they come in contact with (humans have died after ingesting their eggs), meaning that they tend to be seriously lacking in the natural predator department. (Image via) 2) The European/Common Rabbit Within ten years, however, the rabbits had bred with local rabbits on such a prolific scale that two million could be shot or trapped annually without having a noticeable impact on the population. By 1900, the rabbit population had exploded to a size reflective of an almost exponential population growth, had contributed to serious erosion of soils across the continent by overgrazing and burrowing, and are believed to be the most significant known factor for species loss in Australia's history. 1) The Nile Perch Further Reading |