Invasive species

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.
Examples of invasive species:

10) Kudzu
Also known as the "mile-a-minute vine" and "the vine that ate the South," the Kudzu vine is native to Japan, but was first brought to the United States in 1876 when it was featured at the Philadelphia Centennial Exposition as a hardy, fast-growing vine that could help inhibit soil erosion. What they failed to mention at the Exposition was just how fast they meant when they said Kudzu was "fast growing." Since its introduction, Kudzu has been spreading across the U.S. at a rate as fast as 150,000 acres annually, due primarily to the fact that its individual vines can grow upwards of a foot per day in the right conditions, as the seasonal photos of this house (via) help illustrate.

9) The Black Rat
The black rat is most likely one of the first invasive species to ever be inadvertently distributed by humans. The species originated in tropical Asia, but is believed to have reached Europe by the first century A.D. before spreading across the world, hitching rides en masse on European ships. Since then, the black rat has thrived in just about every region of the world, and has adapted exceptionally well to rural, urban, and suburban environments alike. Unfortunately, its success as a species, in combination with the success of numerous other species of rats, is believed to have come at the expense of dramatic population declines and even extinction of countless bird, reptile, and other small vertebrate species the world over.

8) The Asian Tiger Mosquito
This Asian tiger mosquito is characterized by its distinctive black and white stripe pattern, and while it's native to tropical and subtropical areas of Southeast Asia, scientists believe it has quickly become one of the planet's most widely-distributed animal species, spreading to at least 28 countries outside its native range in the last two decades alone. The tiger mosquito is believed to be spread through — of all things — the international tire trade, as tires stored outside tend to retain rainwater, and provide the ideal breeding and living conditions for the mosquito. It poses a distinct threat to populations worldwide, not only because it carries viruses like Dengue and West Nile, but because it tends to associate closely with humans, and is known to feed 24 hours a day (many species of mosquito only feed at dusk and dawn).

7) The Cotton Whitefly
The cotton whitefly is living proof that some of the most hard-hitting invasive species come in tiny packages. Adult whiteflies measure just a millimeter long by the time they reach adulthood, but are known to feast (in staggering numbers) on 900 different kinds of plants worldwide, and are capable of transmitting upwards of 100 different plant viruses. While whiteflies are believed to have originated in India, you'll find them thriving on every single continent but Antarctica. (Image via)

6) The Snakehead Fish
The snakehead is an absolutely nightmarish animal. In fact, National Geographic went so far as to nickname the Northern Snakehead "Fishzilla," and with good reason. Snakehead fish are a veritable force of nature — they have sharp, shark-like teeth; an appetite for for blood; can grow to over three feet in length; can lay up to 75,000 eggs a year; and can even breathe and migrate on land, searching for other bodies of water for up to four days at a time through the use of a primitive breathing organ.

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
The Asian longhorned beetle actually spends the most destructive period of its life in a larval stage, during which time it tunnels and feeds on the layer of trees found between their bark and their wood. In large enough numbers, these larvae can eventually kill the tree. To prevent new infestations, officials often must resort to cutting down and burning infested trees.

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
The Burmese Python provides the perfect example of what can happen when a large, predatory species is introduced into an environment where the native wildlife offers little-to-no competition for resources. The huge snakes — which can grow to upwards of 20 feet in length — are native to the tropic and subtropic areas of Southern Asia, where they are just as at home hanging out in and around water as they are slithering around in the treetops. Their accidental introduction to the wild in Florida, however, has shown that the species also does particularly well in the semi-aquatic environment of Everglades National Park, where an estimated 30,000 Burmese Pythons have made a habit of feasting on a variety of endangered birds and alligators (yes, alligators). (Image via)

3) The Cane Toad
Sometimes invasive species are introduced into regions as a form of biological pest control. Sometimes these non-native species actually do a pretty good job of handling the initial pest problem. And sometimes they dosuch a good job that they become an enormous pest problem themselves. The cane toad is often cited as the perfect example of an introduced species gone horribly wrong. The cane toad is native to South and Central America, but when its introduction to regions of Hawaii, the Caribbean, and the Philippines to fight pests in sugarcane fields yielded impressive results, it was quickly imported to various other regions worldwide.

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)  European/Common Rabbit
The common rabbit is native to southern Europe and north Africa, but the tendency for rabbits to... overproduce... has led to their introduction and unchecked expansion on just about every continent but Antarctica and Asia. The most famous case of population explosion probably occurred in Australia, where, in 1859, an English farmer by the name of Thomas Austin introduced just 24 grey rabbits to his plot of land to remind him of home; Austin surmised that "the introduction of a few rabbits could do little harm and might provide a touch of home, in addition to a spot of hunting."

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
The Nile Perch is native to a number of freshwater African lake and river systems. When it was introduced to Lake Victoria in the 1950's however, the lake's ecosystem was not prepared for it. While populations of the fish were kept in check through commercial fishing for several decades, the population exploded in the late 1980's, leading to the extinction or near extinction of several hundred native species. The devastating impact of the gigantic fish — which can grow up to 2 meters in length and weigh in at over 200 kg — is believed to be the result of its voracious appetite for key ecosystem-supporting members like fish, crustaceans, insects, and zooplankton. (Image via).

source: http://io9.com/5833022/10-of-the-worlds-worst-invasive-species

European/Common Rabbit

native: thickets, forests, meadows, and woods

Now:  dry areas, grassland, some forests and near human settlements

Original Distribution: The European rabbit is the single common ancestor of all 80 or so varieties of domestic rabbits today. The last ice age confined it to the Iberian Peninsula and small areas of France and perhaps even Northwest Africa.

Current Distribution: Highly adaptable, the European rabbit now inhabits every continent except Asia and Antarctica. It is widespread in Western Europe including the Balearic Islands, Corsica, Sardinia, Sicily, and the British Isles; and Northwest Africa. It has recently been introduced to Southern South America; North America; Australia; New Zealand; and even, apparently, one Hawaiian Island. Of all these, it has been particularly detrimental to the Australian ecosystem.

Site and Date of Introduction: The European rabbit's introduction to non-native areas is an historical phenomenon. The people originally responsible for its expansion were the Romans, who, having seen it in its native Iberian peninsula(which was then part of the Roman Empire), took it back to Italy for food. In 1066 the Normans conquered England and introduced the rabbit there. Through the middle ages the rabbit kept spreading throughout Europe. During the age of exploration it was brought to many islands by ship crews and wreaked havoc on the islands' small, limited ecosystems. But in a most devastating blow for a continent, the European rabbit was introduced to Australia in1859 by a rich British landowner named Thomas Austin. Mr. Austin was living in Winchelsea, Victoria and missed the hunt from back home. So innocently enough, he bought 24 rabbits and had them shipped to his estate in Australia. He set them loose on his grounds and proceeded to have some hunting fun.

Mode(s) of Introduction: The European rabbit was introduced to all of its present non-native habitats by humans, including the afore-mentioned Mr. Austin, who had his first 24 rabbits shipped to Victoria, Australia, by boat. Unfortunately for the continent, there were males and females in this shipment.

Reason(s) Why it has Become Established: The European rabbit is a highly adaptable animal. It is not a picky eater and breeds very fast. In Australia, the rabbit was particularly successful at spreading like wildfire because its natural predators from back home, the weasel and fox, were not originally present Down Under. The dingo and Tasmanian wolf, Australia's native carnivores(and potential rabbit consumers), were themselves being kept in check by local sheep and cattle ranchers, so they were not effective at keeping the rabbit populations down. The rabbits' spread was also aided by early hunters whose interest lay in having the animals spread so they could hunt more of them.

Ecological Role:  In its original habitat, the European rabbit's population was kept in check by its natural predators, so its role in the habitat balanced out with that of the other animals and plants. But in Australia (and many small islands where it has been introduced), the rabbit, virtually unchecked by local predators, decimates plants, affects soil composition, and changes entire ecosystems. In Australia, the rabbit competes for food and shelter with native animals such as the wombat, the bilby, the burrowing bettong and the bandicoot, and therefore has contributed to the decline of these native species.

Benefit(s): Australia has benefited very little from the introduction of the European rabbit. The most important benefit is that thanks to the sheer quantity of rabbits, Australia has made money from exporting canned rabbit meat and fur. And, let’s not forget a much less relevant, but pretty serendipitous bit: European rabbits were directly responsible, via Aussie wit, for giving us the wonderful phrase "breeding like rabbits."

Threat(s): In Australia, the European rabbit is a downright pest. And because it has been an exotic introduction to the Australian ecosystem for over a century already, the threats it poses to the land have been well-documented and far outnumber the benefits. Few countries have been more ecologically and economically affected by a single introduced species. Because of its extremely high population--has fluctuated but has been believed to reach almost a billion at one time--and indiscriminate eating habits, M it has continually decimated most of the local sheep and cattle's grass, turning once-thriving sheep ranches into wastelands and thus at one point cutting wool production in half. Many other plant species and competing animals have been driven to the brink of extinction by the rabbits' unstoppable appetite. Selective grazing by the rabbits has changed whole ecosystems and has contributed to soil erosion. Also, the rabbit has been known to drive some smaller mammals (such as native mice) out of their burrows, helping foxes (also recently introduced to Australia) catch these smaller mammals, hurting their populations. Native wildlife has also been hurt by the poison and traps left out to catch the rabbits.

http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Oryctolagus_cuniculus.htm
http://carnivoraforum.com/topic/9638683/1/