環(huán)球英語 — 414：Island Environments
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Welcome to Spotlight. I’m Ruby Jones
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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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High up in the tree tops, a small insect eats the leaves of a palm tree. This beetle is called the picudo rojo. Its body is red. Its nose is long and bent. The beetle lives on the island of Tenerife, one of the Canary Islands. It is eating one tree in particular – the Canary Palm Tree. This tree is special to this area. It has always grown on the island. But the beetle has not always lived on the island. The beetle is not supposed to be here. It was brought here by humans. The picudo rojo is damaging the Canary Palm trees. It is causing problems for other animals who call the Canary Islands home.
Today’s Spotlight is on the special ecology of islands.
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Islands are very special places. They are different in many ways from mainland areas. Different islands form in different ways. Some islands grow out of the ocean floor, from volcanoes. Hot liquid rock moves up from deep inside the earth. When it cools in the ocean, over many years, it can create a volcanic island. Only particular animals can travel to volcanic islands. Birds can fly to the islands. Some animals swim to the islands. But many animals cannot swim the long distances through the ocean to reach the island. So the animal life is limited.
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Other islands form as areas of land move away from each other. Over many years, pieces of land can separate from larger areas of land. These are called continental islands. Often, as the island moves away from larger areas of land, the animals living there stay on the island. They move too. And they are part of the environment of the new island.
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Island plants and animals are very special for this reason. They are not affected by new species of plants or animals. They can grow, develop, and change without being influenced by outside species. The plants and animals on an island form a special balance. This is the island’s ecosystem. But island ecosystems are very delicate. They can become unbalanced easily. This is what is happening on the Canary Islands.
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The Canary Islands are off the Northwest edge of Africa near Morocco. They are volcanic islands. Tenerife is the largest island in the group. It is very dry on this island. But in one area, the clouds push against the mountain. Water collects here in a valley. And where there is water, there is life. The Canary Islands are home to many plants and animals. Many of those are endemic species. Endemic species are plants and animals that only exist in one place. The Canary Islands have over 4,000 endemic species. Places such as Great Britain only have 100.
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The Canary Islands are home to many birds including the Canary, a small yellow bird named after the islands. Only a few mammals, animals with hair on their bodies, live on the islands. Most are small and eat only plants. The islands also have great biodiversity. There are many different kinds of plants and animals, more than many other areas in the world. About every six days, scientists find a new species on the islands. But invasive species are threatening these animals and plants.
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You may have heard an earlier Spotlight program on invasive species. In that program, we talked about the problems foreign species can have on an ecosystem. This is particularly true on islands.
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In 1985, a government agreement removed restrictions on people entering the Canary Islands. These rules limited who, what and when things entered the Canary Islands. This included people. Before, these restrictions helped reduce the number of foreign plants and animals people brought to the islands.
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European governments seriously control what comes into Europe. But the governments do not restrict what moves around Europe. Since the Canary Islands are part of Spain, the government treats the islands like any other part of Europe. But the Canary Islands are at risk much more than other areas. Today, government officials say that a foreign species enters the islands about once every seventeen days. And about every six months one of those species turns into a problem species.
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One of these problem species is the Picudo Rojo. We described this insect at the beginning of the program. The insect probably travelled to the island on foreign palm trees, brought to the island by people. But it has caused serious damage to the native Canary Palms. And there are many other examples too. Today, one of every two plants on the island is a foreign species.
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Domingo Berriel works for the Canary Island’s environmental protection agency. He thinks that the government needs more control over what plants and animals enter the Canary Islands. He says that if this does not happen, the effects could be very bad.
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“If we do not act soon, the effects on our endemic species could be very serious.”
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Mr. Berriel understands that humans are the largest threat to the Canary Island’s ecosystem. Humans bring the foreign plants and animals that threaten the native species. But the Canary Islands are not the only place facing this problem.
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You may have heard of the Galapagos Islands, in Ecuador. They are found off the northwest coast of South America. The islands are named after the large tortoises that exist only on the islands. These islands are known for having many special animals.
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Charles Darwin, a famous nature scientist explored the Galapagos Islands in 1835. He was amazed at the animals on the islands. He saw that the animals on each island were different. They all had an important part in keeping the balance of life on the islands. He knew this was a special place.
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But there were many other visitors than Charles Darwin. And most of them did not care about the special ecological balance there. Before humans arrived, the native animals on the islands had no natural predators. Nothing hunted them or ate them. But when humans arrived, the native species became threatened. Humans brought predator animals. The people also ate the animals on the islands.
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Today, there are over 700 foreign species of plants on the islands, and only 500 native plants. Foreign species of animals threaten many native species. Even the famous Galapagos Tortoise is threatened. And some people illegally kill some of the island animals for money.
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But there is hope. In 1959 the government of Ecuador made most areas of the islands a protected national park. In 1986, the waters around the islands were also protected. The islands are now also a UNESCO world heritage site. People are working to protect the delicate ecology of this area.
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Private groups, governments, and citizens need to work together to help protect these special natural areas, like the Galapagos and Canary Islands. Humans have caused much of the damage that affects these islands, but humans can also help to stop this damage.
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