出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/10/10 09:31:24」(JST)
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The Frisian Islands
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| Geography | |
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| Area | 1,047.49 km2 (404.44 sq mi) |
| Country | |
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Netherlands, Germany, Denmark
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| Demographics | |
| Population | 81,341 |
The Frisian Islands, also known as the Wadden Islands or Wadden Sea Islands, form an archipelago at the eastern edge of the North Sea in northwestern Europe, stretching from the north-west of the Netherlands through Germany to the west of Denmark. The islands shield the mudflat region of the Wadden Sea (large parts of which fall dry during low tide) from the North Sea.
The Frisian Islands, along with the mainland coast in the German Bight, form the region of Frisia, traditional homeland of the Frisian people. Generally, the term Frisian Islands is used for the islands where Frisian is spoken and the population is ethnically Frisian. In contrast, the term Wadden Islands is used for the entire archipelago, including the Danish-speaking Danish Wadden Sea Islands slightly further to the north on the western coast of Jutland.
Most of the Frisian Islands are protected areas, and an international wildlife nature reserve is being coordinated between the countries of Netherlands, Germany and Denmark. Natural gas and oil drilling continue, however, and the presence of the Ems, Weser and Elbe estuaries; while ship traffic causes tension between wildlife protection and economic influences.
During the last ice age, which ended approximately 12,000 years ago, the sea level was about 60 meters lower and what is now the North Sea was dry land. With the melting of the ice caps, the level rose to form the North Sea, reaching the current coast line around the beginning of the Holocene era, approximately 7,000 years ago. Tidal action transported large quantities of sand to form a line of dunes extending over 500 km from the Netherlands to the mouth of the river Elbe in Germany. The sea broke through the dunes in many places to form the Wadden Islands, with the low-lying country behind becoming the tidal Wadden mudflats.
The Dutch West Frisian and the German East Frisian Islands are barrier islands.[1] They arose along the breakers' edge where the water surge piled up sediment, and behind which sediment was carried away by the breaking waves. Over time, shoals arose, which finally were only covered by infrequent storm floods.[1] Once plants began to colonise the sandbanks, the land began to stabilise.[2]
On the other hand, the North Frisian Islands arose from the remains of old Geestland islands, where the land was partially removed by storm floods and water action and then separated from the mainland. They are, therefore, often higher and their cores are less exposed to changes than the islands to the south. Beyond the core, however, the same processes are at work, particularly evident on Sylt, where the south of the island threatens to be broken away, while the harbour at List in the north silts up.[3] The Danish Islands, the next in the chain to the north, arose from sandbanks. Right up into the 20th century, the silting up of the islands was a serious problem. To protect the islands, small woods were planted.
Long before the beginning of the modern era, there were already humans inhabiting the Wadden area. Up to 800 AD, most inhabitants lived on terpen (man-made hills). The living conditions were bad, as this quote from Roman Pliny shows:
... what is nature and characterizations of living by people who live without trees or shrubs. We have indeed said that in the east, to the coasts of the ocean, a number of races in such needy conditions exist; but this also applies to the races of peoples which are called the large and small Ghaucen, which we have seen in the north. There, two times in each period of a day and a night, the ocean with a fast tide submerges an immense plain, thereby the hiding the secular fight of the Nature whether the area is sea or land. There this miserable race inhabits raised pieces ground or platforms, which they have moored by hand above the level of the highest known tide. Living in huts built on the chosen spots, they seem like sailors in ships if water covers the surrounding country, but like shipwrecked people when the tide has withdrawn itself, and around their huts they catch fish which tries to escape with the expiring tide. It is for them not possible to keep herds and live on milk such as the surrounding tribes, they cannot even fight with wild animals, because all the bush country lies too far away. They braid ropes of sedges and rushes from the marshes with which they make nets to be able to catch fish, and they dig up mud with their hands and dry it more in wind than in the sun, and with soil as fuel they heat their food and their own bodies, frozen in northern wind. Their only drink comes from storing rain water in tanks front of their houses. And these are the races which, if they were now conquered by the Roman nation, say that they will fall into slavery! It is only too true: Destiny saves people as a punishment.[4]
Around 1000, dike construction began. Monks were instrumental in this activity, among others those of the monastery of Aduard. But earlier attempts had been undertaken to dam the sea. At the Frisian Peins (in the municipality Franeker), a 40-meter section of dike has been discovered that is thought to date from the 1st or 2nd century BCE.
In the late Middle Ages the dike system was gradually strengthened and flooding diminished. Beginning in the 17th century, dikes were built further out to reclaim more land. This activity peaked in the 19th and 20th centuries.
The dunes south of the Wadden Sea were also liable to this process, but man’s intervention prevented the many storm surges from changing the coast of the provinces North Holland and South Holland into separate islands with Wadden mudflats behind them. However, around 1200, storm surges did break up the northern coast of Western Friesland into five islands. Around 1600, four of these along the West coast had been again recovered, but Wieringen, to the south-east of Texel, remained an island up to the 20th century.
In Friesland and Groningen plans were made to embank and drain the Wadden Sea. As a result, the islands would have become part of the mainland. As of today, nature and environmental movements have been able to prevent this.
The only plan ever to be carried out was the construction of a causeway from the Frisian Holwerd to Ameland, in 1872, which was not very successful. Shortly after construction, the causeway had already suffered so much storm damage that the dam was abandoned in 1882. The dam has been almost entirely eroded since then.
In the northern Wadden Sea building dams proved to be considerably simpler. Nordstrand is now so much linked to the rampart by dikes that one can't really call it an island anymore, and also Langeness, Oland, Nordstrandischmoor, Hamburger Hallig, Sylt, and Rømø are all reachable by dams. Mandø is even reachable without a dam by means of tidal road.
The Wadden Islands are in continuous movement. The most important movement is the 'migration': the islands themselves are slowly but certainly moving from West to East. On the West side most of the islands disappear slowly into the sea and on the East side even larger sand-banks arise. This movement is also the reason that most of the villages themselves are on the West side of their island. When they were founded they were situated in the center. Over the course of the last few centuries, many houses and even entire villages disappeared into the sea.
The second movement is the development of a hook shape. Along the sea breaches hook-shaped sand ridges arise, which change form with the moving of the sea arm. By growth of these hooks new shoals arise such as the Noorder and Zuiderhaaks. Sometimes such a shoal grows, originating where an island has been 'walking', and the island recovers its lost area.
(from West to East)
The Dutch islands have a surface of 405.2 km² and a total of 23,872 inhabitants.
The names of all these places suggest this is the transition area between island and shoal (plaat in Dutch). Griend and Rottumeroog are generally considered to be an island, the others are considered to disappear from time to time into the waves. The former island of Wieringen can be found at the top of Noord-Holland, against the Afsluitdijk.
(from West to East and south to North)
The German islands have a surface of 448.52 km² and a total of 53,296 inhabitants. It is possible to make a boat excursion from several German Wadden Islands to the small rock island of Helgoland which is situated 70 kilometres off the coast line in the German Bight. Although it is no Wadden Island, there are strong cultural links with the Wadden area, for example a dialect of North Frisian is spoken here.
Not all aforementioned islands are officially considered to be Wadden Islands. For the definition of an island, a minimum of 160 hectares must no longer be submerged during average high water by the North Sea.
(from South to North)
In the 20th century, south of Rømø lay the only Danish hallig, Jordsand. However, in 1999 the last remains proved to be gone. North of Fanø the sand coast has been opened and closed numerous times in the course of history, but at the moment the coast line is closed, and forms a whole again save for two west coast fjords. The Danish islands have a total surface of 193.8 km² and a total of 4,173 inhabitants.
Satellite image of the Dutch islands
Sand dunes and beach on Amrum
De Slufter, a nature reserve on Texel
Fortified coast line on Wangerooge
Sheep grazing on Mandø
Lighthouse on Schiermonnikoog
View from the lighthouse of Borkum
Beach on Juist
Beach on Sylt
Bird's-eye view of Baltrum
The island Trischen with the mouth of the river Elbe
| Wikisource has the text of the 1911 Encyclopædia Britannica article Frisian Islands. |
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Coordinates: 53°57′N 8°30′E / 53.950°N 8.500°E / 53.950; 8.500
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