The island of Pepparholm was built during construction of the Öresund Bridge
On the four-kilometer-long artificial island of Pepparholm, the Öresund Bridge turns into a tunnel towards Copenhagen.
Limestone bedstraw (hedmåra in Swedish) grows abundantly on Pepparholm, but nowhere else within a radius of 200 kilometers.
Spoonbills are very rare in these areas. But in 2024 they suddenly appeared on Pepparholm.
Wild specimens of the early marsh-orchid grow on Pepparholm.
Fact box
Rich birdlife
Around 30 bird species have been observed on Pepparholm, including:
- Black-headed gull
- Eurasian curlew
- Northern lapwing
- Seagull
- Lesser black-backed gull
- Grey heron
- Northern shoveler
- Pied avocet
- Eurasian spoonbill
Source: natursidan.se
The construction of Pepparholm
Where the tunnel into Copenhagen and the bridge meet, we created an artificial island from dredged material from the seabed. The island also became a kind of biological experiment where nature could take its course without human intervention.
Pepparholm is today protected by legislation. Only biologists and Öresund Link’s own staff are allowed to visit the island.
Construction began in 1995 and was completed in 1999.
Limestone bedstraw (hedmåra in Swedish) is an inconspicuous little plant with white flowers that grows abundantly on the island of Pepparholm just outside Copenhagen. And that is odd. Because the plant doesn’t really belong in the Öresund region, between Copenhagen and the southern tip of Sweden. It doesn’t grow in Sweden at all, and in Denmark you find it in western Jutland – 200 kilometers from Pepparholm.
But Pepparholm is no ordinary islet. It is a 4-kilometer long artificial island where the Öresund Bridge turns into a tunnel that leads towards Copenhagen.
Originally, the Öresund Bridge was to be built straight over the existing island of Saltholm. But when the planners realized that the bridge and its traffic would disturb Saltholm’s delicate nature too much, they decided instead to build an artificial island. This meant yet another challenge for the Skanska-led consortium that had been commissioned to build the bridge.
The island was designed by Swedish bridge and landscape architect Inger Berglund and was built from blasted rock and 240,000 cubic meters of limestone-rich soil dredged from the bottom of the Öresund strait. After a naming competition in Denmark, the island was named Pepparholm (also known as Pepparholmen).
Nature took control
When the bridge and island were completed, the land surface of Pepparholm was left untouched and raw. It looked almost like a desert. But nature was allowed to take over. What would happen?
Now we know. New species appear. Life finds a way.
Today, Pepparholm is a lush island with extensive grass and shrub vegetation. There are around 600 plant species, around 1,000 insect species and a rich birdlife with around 30 breeding species. In addition, you can find frogs and other small animals who have made the island their home.
“It is a very special place,” says Staffan Nilsson, a biologist and active member of the Lund Botanical Society, which makes him one of the few people who have access to Pepparholm a few times each year. Otherwise people are forbidden from visiting the island.
Since the Öresund link was completed, the society has been keeping a close eye on the nature on the island.
“A lot happened in the first five years. Then it became more stable. But new species are appearing quite continuously. It is interesting to follow as it goes along,” Staffan says.
Brought by the wind
Nothing has been planned or planted on Pepparholm. So how did all the greenery get there? Staffan explains that the plants came to the island in three main ways.
Many of the first to establish themselves came with the wind.
“Think dandelions and similar species,” he says.
Other species have most likely come to Pepparholm with excavation materials and other materials used when the island, the bridge connection and the tunnel were built.
Some seeds have probably been on or in the machines used on the project – that is how Staffan believes limestone bedstraw came to Pepparholm. Finally, many species have come with birds and their droppings.
“It is berry-eating birds that carry the seeds out. After a while, berry bushes started to appear here and there – blackcurrants, blackberries and the like,” says Staffan.
He explains what he finds so fascinating about Pepparholm: “It's that the plants have had to find their way here on their own, making it a strange environment and combination of species that you don't see anywhere else.”
Exciting environment for research
Our own ecologist Tim Schnoor did not work at Skanska when the island was built, but today he finds the environment on Pepparholm to be fascinating:
“It is exciting to have environments, new ecosystems, that are allowed to self-colonize. For example, it means opportunities for research under unusually controlled forms for ecology.”
Tim has studied how a certain type of soil fungus has colonized Pepparholm, and compared it with other islands in the region.
“It gave us a picture of what types of fungi colonize new ecosystems. You can simply study the shifts in ecosystems over time. It’s exciting.”
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