環(huán)球英語(yǔ) — 411：Foreign Plants and Animals
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Welcome to Spotlight. I’m Marina Santee.
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And I’m Joshua Leo. Spotlight uses a special English method of broadcasting. It is easier for people to understand no matter where in the world they live.
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In the 1930’s, areas of Australia had a problem with a particular insect – sugar cane beetles. Sugar cane plants were an important crop in the state of Queensland. But sugar cane beetles were damaging much of the sugar cane. Other countries had faced similar problems with these beetles. In some countries, farmers used toads to eat the insects. Toads are similar to frogs. These small four legged animals live in wet places. And they can eat many insects.
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After several years, the farmers convinced the government to use the toads. In 1935 a box of cane toads arrived in Queensland. Soon after, about three thousand toads were released into a few sugar cane fields in Queensland.
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But there was a problem. The cane beetles stayed on high leaves of the sugar cane. The toads could not reach the beetles. In the spring, the toads would have a better chance. Then, the young beetles are leaving the ground. But in the spring, the toads are not around. So the toads did not solve the cane beetle problems. And then, the toads became a problem themselves.
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The toads were not eating the cane beetles. But they were eating other things. They ate native insects, small animals, and birds. But this was not the end of the problem. Native predator animals tried to eat the toads. But the toad’s skin contains poison. So in eating the toads, the native animals die. And then, the toads began to spread to other areas in Queensland.
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The cane toads continued to breed and grow in number. Soon, the toads were more of a problem than the beetles. Today, the Australian government still works to kill all the cane toads in the country. The Australian government declares the toads to be one of the most invasive species on the continent.
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Invasive species are plants or animals that are not native to particular areas. These species compete with the native plants and animals. And the invasive species may also carry diseases that will kill the native plants and animals. This causes the natural balance in nature to become unbalanced.
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The cane toads were not the first invasive species in Australia. For thousands of years, Australia was separated from all other continents. Only birds could travel to the island. New kinds of animals from other continents did not travel to Australia. And the animals in Australia existed nowhere else in the world. The native people of Australia lived in balance with these animals. But when European explorers arrived, they brought new plants and animals with them. These new people did not understand the effect outside animals would have on Australia.
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Today, Australia has over fifty–six different invasive species. Some of the animals are large like camels. Others are very small, such as fire ants, a kind of insect. The country also struggles against many invasive plants. These plants compete with native plants for resources.
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But Australia is not the only country fighting invasive species. Every natural area in the world is special. Each area has particular plants and animals that call it home. These natural areas can easily become unbalanced by invasive species. Invasive species usually spread to new areas because people bring them.
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For example, freshwater lakes in North America and Europe are in danger from many foreign species of animals. Many of these animals came to America and Europe in large boats. These large boats carry many products across the ocean. Most of them have large tanks inside that hold water. These tanks help the boats stay balanced on the water. The boat collects the water at the beginning of the journey and then releases it at the end. But sometimes, animals enter the boat along with the water – then, the water is released, so are the animals. This is what causes problems.
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Boats have carried fish, insects, and other water animals from Asia to lakes and coastal areas in Europe and America. The animals in these areas cannot defend themselves against these new species. Today, many foreign water animals are becoming a problem in Europe and America.
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Invasive species travel in many ways. Insects can travel inside packages of fruit, wood, or any other product. And sometimes people release invasive species on purpose. This was the case with cane toads in Australia. People sometimes choose to grow invasive plants. These plants then spread into the wild. For many years, people did not understand the terrible effects of invasive plants and animals. But today, more governments and groups are trying to protect against invasive species.
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Governments use machines and chemicals to control invasive species. They inspect containers at country borders to prevent invasive species from entering. They use native species to fight against invasive species. These government programs are very important. But governments cannot fight invasive species alone. We can also help to prevent the spread of non–native plants and animals.
Here are seven easy ways that you can help fight against invasive species.
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Use native plants. If you grow flowers and plants at home, use only plants that are natural to your area. Native plants use less water and need less care. These plants will also help native animals and insects who use the plants for food.
Remove plants correctly. When you no longer want a plant, be sure that it does not grow in a place where it should not grow. Many water plants can spread to new areas and become a problem. When you remove a plant, kill it or give it to a friend.
Help remove invasive species. If you see non–native plants in your community, pull them out and throw them out. This will help protect the native species.
Do not transport water, animals, or plants. When you are in a boat, do not carry water, animals or plants from one lake to another. Clean the boat carefully.
Do not release pets into the wild. If you own an animal, do not release it into the wild. Animals such as cats, dogs, and fish can cause problems to native species. If you no longer want the animal, give it to another person or give it to a store.
Be careful what you move. When you travel, do not transport fruit or plants from one environment to another. These items can carry insects or disease that may damage natural areas.
And finally, tell others. More people need to know about the problem of invasive species. Together we can work to protect the natural balance.
