填空题

Everglades National Park
A. When many people think of Florida, images of sandy coastlines or theme park rides come to mind. But about an hour south of Miami lies a natural wilderness different from anywhere else in the United States. Everglades National Park is the largest subtropical wilderness in the country. The park is home to several rare and endangered species. It is also the third largest national park in the lower forty-eight states, after Death Valley and Yellowstone. More than one million people visit the Everglades each year.
B. The Everglades is considered one of the great biological wonders of the world. The expansive wetlands stretch across more than six hundred thousand hectares (公顷). It is a place where plants and animals from the Caribbean Sea share an ecosystem with native North American species. Unlike most other national parks, Everglades National Park was created to protect an ecosystem from damage. The Everglades is home to thirty-six species that are considered threatened or protected. They include the Florida panther, the American crocodile and the West Indian manatee. In addition, more than three hundred fifty bird species and three hundred species of fresh and saltwater fish live within the park. The Everglades is also home to forty species of mammals (哺乳动物) and fifty reptile (爬行动物) species.
C. Exotic plants can also be found in the Everglades. They include what is said to be the largest growth of mangrove trees in the western half of the world. Gumbo-limbo trees, known for their peeling red skin, strangler figs and royal palms are also among the area’s plant life. The Everglades is also home to the country’s largest living mahogany tree. Sawgrass grows in some areas of the park. Be careful—it is very sharp, with teeth just like a saw. It can grow up to four meters tall. With about one and one-half meters of rainfall each year, plants and trees never stop growing in the Everglades.
D. The dry, winter season is the favorite of most visitors, when insects like mosquitoes are less of a problem. The rainy season lasts from June to November. There are many ways to explore the Everglades. Visitors could see American crocodiles while hiking the Anhinga Trail. The Everglades is the only place on Earth where fresh water crocodiles and saltwater crocodiles live in the same area. Visitors using canoes or airboats are likely to see large groups of wading birds like the wood stork or great blue heron. It is even possible to see flamingos in the Everglades. This spring, Everglades National Park launched a visitation program to what was once a highly restricted military base. Park officials are working to recover a missile base used in the 1960s. The base played a Part In the nuclear tensions between the United States and the Soviet Union.
E. The government built the Florida base shortly after the discovery of Soviet missiles about three hundred kilometers away, on the island of Cuba. Tensions were high during the Cuban missile crisis. But missiles stored at the American base were never fired. The base was closed and all missile equipment was removed in the 1970s. Today only the buildings remain. This year, the historic area had many visitors, including former American service members who remember the missile crisis. The park hopes to offer more trips next spring, to help support the history for those who lived through it and for future generations.
F. 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 1880s developers began digging drain 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.
G. Even larger efforts to drain the wetlands continued between 1905 and 1910. 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 1948, 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. Today, fifty percent of south Florida’s early wetland areas no longer exist. Populations of wading birds have been reduced by ninety percent. Whole populations of animals are in danger of disappearing. The endangered creatures include the manatee, the Miami blackhead snake, the wood stork and the Florida panther.
H. In recent years, environmental experts have learned about the damage to the Everglades. They say the natural balance of plants and animals has been destroyed. Recently, the Obama administration promised three hundred sixty million dollars to pay for Everglades restoration this year. The administration is also asking that Congress approve an additional two hundred seventy-eight million dollars for next year. The money will help to support projects approved by the government nine years ago. The projects include improving wetlands in the Picayune Strand in Southwest Florida and repairs to Lake Okeechobee’s dam. Until now, the state of Florida has spent the most money on the project.
I. Another threat biologists have been battling for years in the Everglades is the area’s population of Burmese pythons (large snakes). Officials believe there are as many as one hundred fifty thousand of these large snakes in the Everglades. But the snakes are a foreign species, native to Southeast Asia. Owners of pythons left their unwanted snakes in the Everglades years ago. Biologists say adult pythons are able to eat small deer and bobcats. When pythons are found in the Everglades, they are often killed. Scientists are now experimenting with other ways to remove the snakes, including trapping methods and offering payments to hunters. The future of the Everglades is not clear. However, efforts to protect the area are continuing so that people from all over the world may continue visiting this biological treasure.
The Soviet Union placed missiles on the island of Cuba during the Cuban missile crisis.