Peberholm

Øresund Bridge from Denmark to Sweden. On the right is the artificial Peberholm island, and on the left Saltholm.

Peberholm (Pepper Islet, Swedish: Pepparholm), is a small artificial island in the Danish part of the Øresund strait, created as part of the Øresund Bridge connecting Denmark with Sweden. Peberholm is close to the small natural island of Saltholm (Salt Islet), and was named to complement it.

Reasons for construction

The main reason for constructing the island was to have a crossover point between the tunnel and the bridge.

The tunnel was built since a bridge spanning the entire link between Malmö and Copenhagen would have interfered with obstacle-free zones around Kastrup Airport. Another reason was to provide an opportunity for large ships to pass the Öresund without worrying about the height of the bridge. To make the Øresund Bridge higher would interfere with the freight train traffic.

The other main reason was that the Øresund had to be dug deeper in order to not decrease the flow of the water because of the bridge. The material was used to create this island. The area was so shallow, and the amount of material so large, that it was chosen to make the island as long as 4 km.

Built to preserve ecology

View from north-west

The original designs for a bridge across the Øresund required extensive use of Saltholm as a stepping-stone for the bridge. They required either the construction of both a motorway and railway across Saltholm or an expansion of the existing island to serve the same purpose.

Both of these options were ultimately abandoned in order to protect the island's ecology; Danish and Swedish politicians decided instead to construct an artificial island immediately south of Saltholm to achieve that goal. The location was chosen in the belief that it would ensure the freest flow of water through the sound, a key element in the debate about whether or not the bridge should be constructed.

Peberholm is protected by strict laws. Only biologists are allowed one annual visit to the areas of the island outside of the railroad and highway to which the island owes its creation. The island is part of Natura 2000 area 142, comprising Saltholm and surrounding waters with a total area of 7,218 ha. The same area is also under two birdprotections as habitats H110 and H126.[1]

Development

Peberholm is considered to be a biological experiment. Scientists predicted that nature would colonize it and make the island flourish on its own, without any human interaction whatsoever. As of June 2007, scientists from the Biological Society of Lund had registered 454 species of plants on the island.[2] Also resident to the island as of 2005 were about 20 species of spiders, and approximately 12 species of birds.[3]

Since 2008, both the amount and number of bird species has seen an increase, and now between 20-30 species breed on Peberholm regularly. The island is largely inhabited by severals kinds of breeding gulls, and some locally threatened species have also found a home here as breeders, including Mediterranean gull and Eurasian rock pipit in some years. Many geese, ducks, Great cormorants and waders rest on the small island and White-tailed eagle is often observed here in the winter. The European green toad, which is rare and to be protected in Denmark,[4] was found living in several ditches. In 2007-8 the toads were counted to be c. 2,500 individuals, which is among the largest populations in Scandinavia. It is assumed that toads from Saltholm have swum across. Three species of mice have also populated Peberholm, from very early on, and since 2010, hares crossed the ice from Saltholm as well and are now breeding on Peberholm. It is important to surveil these populations, as mice in particular are known to be potentially dangerous to the rails stability.[5]

In the years 2004-2008 surveys focussing on insects registered a total of 345 beetle species, 421 species of butterflies and 18 species of bees. This is, however, considered a relatively low diversity compared to similar habitats of Denmark and Sweden, but some of the species found on the island are rare or threatened in the region. The population of butterflies seems peculiarly skewed towards regionally uncommon or rare species, including Epiblema grandaevana (a species of moth) and Bath White (Pontia daplidice). In 2005 the poisonous Hobo spider was discovered here, a spider that is only regionally known from a certain spot in Jutland. It is thought of as having migrated here by trains from abroad. And in 2006, the beetle species of Ceutorhynchus resedae was also discovered, a unique find in Denmark.[5]

References

  1. ↑ "142 Saltholm and surrounding sea"
  2. ↑ Nye plante- og fuglearter på Peberholm 2770 Tårnby, week 25, 2007. (Danish)
  3. ↑ http://www.birds-of-denmark.dk/peberholm.htm, Accessed 21 January 2012
  4. ↑ "European green toad" (in Danish). The Danish Nature Agency. Retrieved 2 January 2016.
  5. 1 2 "Peberholm - an artificial gem of nature"

Sources

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Coordinates: 55°36′N 12°45′E / 55.600°N 12.750°E / 55.600; 12.750

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