[by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:12.67]This week on our national parks journey, [00:17.00]we explore a remote island near Michigan's border with Canada. [00:25.20]It sits within a huge freshwater lake. [00:30.76]It is one of the least-visited national parks in America. [00:36.92]Welcome to Isle Royale National Park! [00:41.44]Isle Royale is surrounded by the deep blue waters of Lake Superior, [00:50.20]the largest freshwater lake on Earth by area. [00:55.96]The park's quiet forests and rocky shores offer a kind of solitude and peace [01:05.76]not found in some of the more popular national parks. [01:10.76]No cars or other wheeled vehicles are permitted on Isle Royale. [01:19.04]There are no real roads on the island. [01:23.24]The only way to get to the park is by boat or sea plane. [01:29.40]The National Park Service operates shuttle boats that take visitors to Isle Royale. [01:38.00]The boats leave from two Michigan ports. [01:42.20]A boat trip to Isle Royale takes three to five hours. [01:48.36]Waters are often extremely rough. [01:52.68]Isle Royale is the largest of the islands within the national park. [01:59.04]It is 72 kilometers long. [02:03.84]The entire national park protects a total area of 230,000 hectares, [02:14.20]including some 450 islands that surround Isle Royale. [02:21.36]Fifty-two-thousand hectares is land. The rest is water. [02:27.96]Isle Royale became a national park in 1940. [02:34.40]In 1980, officials named it an International Biosphere Reserve [02:42.64]because of its unique ecosystem. [02:46.76]Its remote location is part of what makes it among the least-visited national parks. [02:56.08]But, once they arrive, most visitors stay a while. [03:02.64]The average stay for visitors to Isle Royale National Park is 3.5 days. [03:11.24]The average stay for visitors to most other national parks is just four hours. [03:19.80]Isle Royale offers hiking, camping, boating, and even scuba diving. [03:29.36]The extremely cold waters of Lake Superior help keep shipwrecks in excellent condition. [03:39.12]The National Park Service protects 11 sunken boats for divers to explore. [03:47.68]They are reminders of Lake Superior's commercial shipping history. [03:54.68]The sunken wooden ship called The America is one of the most popular dive sites. [04:02.56]The America carried passengers, mail, [04:06.52]and supplies to many towns along the shores of Lake Superior. [04:13.68]It first launched in 1898, and was used until 1928, when it was damaged. [04:24.60]It sank to the bottom of the lake soon after. [04:28.96]Today, divers can swim through the ship's ballroom, bedrooms and engine room. [04:37.84]Painted on the ship's engine is an American flag. [04:42.69]Many divers take pictures of this sight. [04:47.40]The Rock Harbor lighthouse is another reminder of the former shipping industry. [04:55.68]Workers built the lighthouse in the 1850s to help guide ships safely to the island's copper mines. [05:06.56]The mining industry was short-lived, however. [05:11.68]The lighthouse itself lit the way for ships for just 24 years. [05:19.24]But, it still stands today. [05:22.20]Inside, exhibits and information help visitors understand Isle Royale's maritime history. [05:32.36]A short hiking trail leads visitors to the lighthouse. [05:37.76]Visitors to Isle Royale share the trails with a well-studied population of moose and wolves. [05:47.76]Both species migrated to the island sometime in the early to mid-1900s. [05:56.33]Scientists believe that moose swam to the island. [06:01.72]They think wolves walked there during a freeze of the lake sometime in the 1940s. [06:10.49]Scientists have closely studied the relationship [06:14.56]between Isle Royale's wolves and moose since the late 1950s. [06:21.84]It is one of the best-studied predatory-prey relationships in the world. [06:30.00]Researchers closely record their population numbers. [06:36.12]Much of the research takes place during the winter, when the trees are bare. [06:43.20]The researchers fly over the island to observe the animals from above. [06:51.00]In early 2016, researchers from Michigan Tech University [06:57.52]observed just two remaining wolves on Isle Royale. [07:03.36]The moose population, however, is growing. [07:07.92]Scientists observed about 1,300 moose on the island this winter. [07:16.68]Animal research is the only winter activity going on at Isle Royale. [07:23.96]The national park is closed each year beginning in late October [07:30.60]because of the harsh weather conditions. [07:34.52]It reopens in spring time the next year. [07:38.64]But for the other months of the year, [07:42.92]Isle Royale offers refreshing lake breezes, [07:47.40]green forests, and clear blue waters. [07:52.20]Its stunning scenery and unusual solitude [07:57.20]keep visitors returning year after year. [08:01.52]I'm Ashley Thompson. [08:03.84]And I'm Caty Weaver. [08:06.00]更多听力请访问51VOA.COM