VOA慢速英语 改善沼泽地国家公园状况

　　(MUSIC)

　　VOICE ONE:

　　Experts say changes to the Everglades are threatening several different kinds of wildlife. They say the threats are a result of actions the United States government began more than fifty years ago, and settlers began even earlier.

　　The National Park Service says early colonial settlers and land developers thought the Everglades had little value. The settlers had plans to remove water from the area and in the eighteen eighties developers began digging drainage canals. At the time, they did not understand the complexity of the Everglades' ecosystem. As a result, they were not prepared for all the work and caused environmental problems. The ecosystem, however, was able to survive.

　　VOICE TWO:

　　Even larger efforts to drain the wetlands continued between nineteen oh five and nineteen ten. Large areas were changed to farmland. This led to increased development, with more people moving to the Everglades and also more visitors.

　　More changes came in nineteen forty-eight, when Congress approved the Central and South Florida Project. As part of the plan, the Army Corps of Engineers built roads, canals and water-control systems throughout South Florida. The aim of the project was to provide water and flood protection for developed areas and agriculture. Workers built a huge system of waterways and pumping stations to control the overflow of Lake Okeechobee, north of the Everglades.

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