Ecosystems on our planet are, as we have learned over and over as a species that seems to live outside them, much more fragile than we've given them credit for. Sometimes it only takes the introduction of one species to upend the whole boat. This can happen naturally... say a flood or a windstorm blows an invader into a new biome that is not prepared for it... but it is usually humans that are responsible for bringing these invaders in. Sometimes it is by accident, and other times we do it to solve a problem that we, ourselves, have created; then going on to make it so much worse. Insects and viruses can be carried across oceans by boats, on livestock or even our clothing. Animals can be imported as pets and then let loose... or imported as a possible resource, and then found to be deeply destructive and impossible to control. Island ecosystems are deeply vulnerable, often having completely endemic, carefully balanced food chains and interspecies relationships. The introduction of a single new animal can, and has, completely upended that balance. Large-scale agriculture is also vulnerable to a single invader that it has no defense against. We can struggle to right these human-caused wrongs, but often find ourselves helpless in the face of an imbalance we have no way to fight. This is a list of the most destructive invasive plants, animals and diseases on Earth. Vote up the ones that you have experienced the impacts of, either directly or indirectly.
Going by several not-so-flattering nicknames, Kudzu is well known to areas that is is not native to. It's hard to miss, as it covers everything. The Kudzu vine is native to Japan, but arrived in the US in 1876 when it was featured at an expo as a hardy, fast growing vine that could fight soil erosion. Well. They weren't wrong about that part. Also known as the 'mile a minute' vine and the 'the vine that ate the south', Kudzu has been spreading across the country at 150,000 acres a year. In the right conditions, a length of vine can grow a foot in a single DAY. The vines themselves grow up to 100ft long and the plant can smother trees, houses, power lines and whatever else that can't move out of the way. It is drought and frost tolerant and practically unstoppable. Nothing can compete with it, and thus, it wins. This invasive easily sits in the top 10 of the worst case scenarios that happen when an organism has no natural barriers built into its ecosystem.18369Is this an invasive where you are?
Red imported fire antPhoto: Metaweb (FB) / Public domain
Origin: Brazil and Argentina
Originating in Argentina and Brazil, there are few that have never heard of the fire ant, one of the worst invasives in the world. In the US, it is thought that the first ant arrived in Mobile, Alabama via cargo ship somewhere between 1933 and 1945. In Australia it is believed to be closer to 2011. It has since caused billions of dollars in damage to the areas it now infests. The ants thrive in urban areas, so their presence may deter outdoor activities, but more damagingly, nests can be built under structures such as pavements and foundations, which may cause structural problems, or cause them to collapse. They also can damage equipment and infrastructure and impact business, land, and property values. As the workers are attracted to electricity, they can swarm electrical equipment and destroy it. In agriculture, they can damage crops, damage machinery, and threaten pastures. They are known to invade a wide variety of crops, and mounds built on farmland may prevent harvesting. They also pose a threat to animals and livestock, capable of inflicting serious injury or killing them, especially weak or sick animals. So far, the only ways of controlling these ants has been found to be baiting and pesticides. Due to its capability for damage, the ant has become one of the most studied insects on earth.17464Is this an invasive where you are?
Origin: E. Europe and W. Russia
Another ballast water hitch-hiker, the fingernail sized Zebra mussel arrived from Europe in 1988 and established a colony in the great lake region. They soon spread their way through the lakes, down the Mississippi and throughout the eastern US. Ravenous filter feeders, they rapidly deplete the water of food, out-competing the native organisms. They cluster by the millions, clinging to every solid surface. They create a costly problem for power plants, cities and residents when they clog water intakes. They kill native mussels and they slice open the unsuspecting feet of any swimmer or pet that steps on them. There has yet to be found an efficient way to control them, but researchers have tried special paint that keeps them from adhering to docks and pipes. There has been some experimentation with ion emitters that the mussels seem not to like, but for the most part nothing has worked yet.13442Is this an invasive where you are?
Origin: Europe and Asia
Originally from Europe and Asia, the common carp has been cultured far and wide as a valuable food source for over 2,500 years. It is the third most introduced species in the world. They are an aggressive, omnivorous fish known for consuming resources to the point of depletion. This carp is one of the most damaging aquatic invasive species due to its wide distribution and severe impacts in shallow lakes and wetlands. On top of the fact that they outcompete native fish, their feeding also disrupts shallowly rooted plants muddying the water. They release phosphorus that increases algae abundance and they cause a decline in water quality that then causes declines of aquatic plants needed by waterfowl and fish. In the US, many people do not consider this fish to be an invasive because it has been around for so long and they also enjoy it as a sporting fish. In some countries, however, control methods are employed that include barriers, harvesting, traps and water level manipulation as well as electric barriers, bubble curtains and sonic barriers.10524Is this an invasive where you are?