Real-Life+Aliens!

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No, not outer space aliens. These aliens are all from our planet. They are called **__Invasive species__**. They are animals, plants, or microbes (like bird flu) that are transferred, accidentally or purposely, to a completely different environment. Once they are there, they thrive and take over, driving most of the animals or plants that are native to that environment to near extinction. This needs to be stopped before any more species are driven to extinction!

I am interested in invasive species because I would like to help stop the spreading of nonnative animals throughout the world. If we must introduce an animal into another habitat, we should first examine the environment we are putting it in to see if it will cure the problem, or make a new one. I belive that we can completely stop invasive species if we are careful with the ecosystems that we put them in.

I am studying invasive species because I want answers about them. I want to find out what animals are invasive and why. I also want to know why we put animals in habitats where they might take over.

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media type="custom" key="333989" The slideshow above this caption is filled with photos of **__kudzu__**. It is an invasive vine that is native to Japan, but was introduced to Georgia as groundcover. It was introduced because it has pretty flowers(see slideshow at about 19 seconds) and broad leaves. It can grow 1 foot per day, and it "hibernates" like grass during the winter. The people in Georgia actually have to close their windows at night to stop the kudzu from growing into their house. The vine is completely taking over Georgia, and pesticides barely work on it. Most pesticides have little or no effect, but 1 kind actually made the kudzu grow faster!



These 2 pictures are **__cane toads__**. They are native to the southern U.S and Central America, but were introduced to Australia to control sugercane grubs. The grubs were nocturnal, and the toads were active during the day. The toads did not solve the problem. A few years later, scientists discovered a chemical that killed the grubs. Even though the grubs are gone, the toads are still there. They are a problem by themselves because they eat native fauna (animals) and poison other predators that try to eat them. They are quite poisonous, with 2 glands on their shoulders that produce a poison that attacks the heart. The only way to get rid of them so far is to catch and kill them. Scientists are working on a gene in them that, if removed, could interrupt their mating cycle.



To most people, this is not a monster. But in Australia, it is a viciously invasive animal. The European Rabbit has taken over Australia. 24 of them were released into the wild by Thomas Austin in 1859 for hunting purposes. By 1950, ther were 600 million rabbits in Australia. The deliberate release of the __Myxomatotis__ virus brought the population down to 100 million, but genetic resistance in the surviving rabbits let them breed again, and their numbers were around 200-300 million in 1991. To bring the population down farther, scientists released __calcivirus__, also known as RHD, into the wild. Most of the rabbits died, but the rabbits in the wetter climates survived because there was another, less potent calcivirus in those climates that was immunizing the rabbits against the deadly calcivirus. So far, this is the only way to get rid of rabbits in Australia.



This is not an ordinary snail. This is the Giant African Land Snail, or //Achatina fulica.// It can grow to almost 1 foot long, and can be almost 4 inches tall. They are native to East Africa, but have been introduced to North America. In Hawaii, scientists introduced a different carnivorous snail that ate giant snails to control it, but instead wiped out a native type of snail. They can reproduce individually, but normally find mates. They lay about 200 eggs each time they mate, and can mate 5-6 times per year. The eggs have a 90% chance of survival. They can also be used as food in Africa, but in the U.S, people are trying to exterminate them. People have tried using molluscisides, capture, chemical bait, and other methods of capture, to no avail. The only known successful control methods are strict quarentine laws.



These are gypsy moths. They completely defoliate trees, and have no natural predetors. They infest all of the eastern U.S, and are slowly moving west.