Invasive species are non-native species that, upon introduction into an ecosystem, proceed to thrive and wreak havoc on habitat, resource availability, and general health of the environment. Other organisms suffer, and the balance and wellbeing of the area is threatened. Invasive species come in many forms, including plants, mammals, amphibians, fish, and birds. The following is a random collection of notable killer animals, starting from the waters of Ontario.
Asian Carp
In North America, one of the most prominent invasive species for aquatic environments is the asian carp. Recently, scientists found that the fish species has now reproduced in the Great Lakes water basin. The finding is not definite, as it is based on the detection of the asian carp’s DNA in water samples in Lake Michigan. While carp have been found in the past, it is hard to determine whether or not they’ve managed to breed and spawn through just the presence of DNA alone. This is the second positive hit, the last one being in 2010. Researchers hope to conduct more surveys in order to determine the likelihood of a potential environmental disaster. Several invasive carp subspecies, such as the asian grass carp, have already been detected in the area, but no populous asian carp communities have been found thus far. A notable and alarming development is the discovery of one such specimen in the Grand River, central to our own Waterloo region’s aquatic habitats. This was not such a serious threat since it was sterile, as such is was released, thought it should be noted that it did not originate from the area. However, its presence is very dangerous due to the fact that the Grand River empties into Lake Erie, a sensitive area that also happens to be the perfect breeding ground for the carp.
Asian carp were imported for various reasons and subsequently escaped, creating communities in areas such as the Mississippi River basin in the United States. It is likely that any carp in the Great Lakes originated from there, or else through the release of live specimens into the wild by humans. An electric barrier was set up in Illinois in order to prevent their passage into Lake Michigan, but a grass carp specimen was found beyond that point, indicating that the solution may not be working as well as environmentalists had hoped. The biggest fear is that the bighead and silver carp may find their way northward into Canada, as they are more prolific breeders and consume vital organisms of low trophic levels, such as plankton. In essence, these fish compete directly with the native species for resources.
Sea Lamprey
Another Great Lakes invasive species is the sea lamprey. First detected in Lake Ontario in the 1830s, and possibly originating in Lake Erie, it soon spread to the rest of the lakes. It attacks primarily large predatory fish, such as trout, whitefish, and herring. Sea lampreys have suction-cup mouths which they se to latch onto fish, tear away the flesh, and suck their blood. Typically, the fish die from loss of blood, or infection. As with the asian carp, electric barriers were used in an attempt to control their numbers, along with lampricide poisons. In general, the efforts have been unsuccessful.
Common Rabbits
Common rabbits originated in Europe and northern Africa, but they’ve now just about permeated the globe. They’re pests (though adorable) that reproduce at an alarming rate with destructive grazing and burrowing habits. In some areas, their effects have been devastating. No other place on Earth has felt it as bad as Australia has. Within a decade after their introduction, their populations were so huge that they’d spread partway across the country, and are currently credited with being the number one reason for loss of species and biodiversity. Plant species have been decimated by their overgrazing and wastefulness. The death of plants exposed soil to erosion will not be repaired for centuries. The Australian government has taken drastic measures to control them, building a long fence spanning more than 3,000 kilometres, vertically separating the length of the country, in order to prevent rabbit passage from the east into the western agricultural areas. This proved to be somewhat ineffective, since rabbits can both jump and burrow. Hunting, trapping, and baiting are the most common forms of rabbit control, and have been successful in lowering their numbers. Biological control methods were also used, such as infecting the rabbit population with specialized diseases, though these processes are generally slower.
Burmese Python
Burmese pythons were first introduced to the United States from Southern Asia, as an exotic pet. They are one of the five largest snakes in the world, capable of reaching up to 6 metres in length. They thrived in Southern Florida, where the Everglades are located. Many of these snakes were released into the wild by pet owners who could no longer keep them, but an even greater number escaped from homes and a python breeding facility during a 1992 hurricane. The Everglades are a region of tropical wetland with high biodiversity, most famous for its abundance of alligators. The pythons multiplied and a new top predator was introduced into the area, capable of killing even the alligators themselves. The already endangered bird, amphibian, and fish species in the area are now in even more danger, as are the regional predatory mammals such as the coyote and the panther.
There are many other interesting types of species similarly destroying the habitats of regions they did not originate from. The Nile river system contains 200 kg fish that eat up just about everything. Giant Cane Toads have been decimating nearly everything they see in island regions such as Hawaii and the Philippines. The Snakehead fish, a creature thirsty for blood and able to survive for days migrating on land, has made is home all over the United States. Meanwhile, the southeast part of the country is being smothered by vines that grow 1ft/day, covering 150 000 acres per year. Evidently, humans seem to be the common factor in how these species got to where they were not supposed to be. It is clear that further research and education is needed in order for people to realize that while these organisms seem harmless in small quantities at first, they pose huge threats to the health and balance of other habitats.
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