Denmark has lost huge areas of rare butterfly habitat

Butterflies are considered as much of a Danish summer sight as strawberries and bowls of 'koldskål' dessert, but their numbers have regressed significantly and efforts by authorities to protect endangered species have not had the desired effect, researchers from the University of Copenhagen have concluded.

Denmark has lost huge areas of rare butterfly habitat
Denmark's butterfly habitats are shrinking and conservation measures are not having the desired effect, researchers have concluded. Illustration photo by Gary Bendig on Unsplash

Areas in which rare breeds of butterfly can thrive in eastern Denmark have shrunk by almost three-quarters in the last 26 years, according to a University of Copenhagen study. 

The decline of their habitats means that several species are endangered, the study found.

Meanwhile, researchers concluded that sate efforts to protect wildlife areas had failed and that the conditions are worse in Denmark than in comparable neighbouring countries.

Research led by biologist Emil Blicher Bjerregård tracked six endangered butterfly species over six years, the university said in a press statement.

“For the 22 butterfly species which we have been keeping an eye on, their distribution on Zealand, Lolland, Falster and Møn has shrunk by 72 percent overall since 1993,” Bjerregård said in the statement.

Only one of the species increased its numbers in that time and several are now only present in small local areas, he said.

The 22 species could be found in 565 localities in Denmark in 1993, compared to 158 localities in 2019 – a decline of 72 percent.

“This is solid data showing some dramatic figures which actually seem to be worse than in our neighbouring countries. Many of the species that were previously common and widespread in Denmark have become very rare,” associate professor Hans Henrik Bruun, a senior researcher on the study, said in the statement.

“And once they’re gone, they don’t come back,” he said.

Forest, marsh and grass butterfly habitats are all affected by the trend.

“Butterflies are a good indicator of nature quality,” Bjerregård noted.

Efforts by nature agencies in Denmark and the EU to protect the species maybe ineffective, the two researchers said.

“Most of the areas with butterflies have now been formally protected for decades. But we can see no signs that nature conservation – neither national nor EU-regulated – has made any positive difference to the rare species of butterflies in the last 30 years,” Bruun said.

“Butterfly habitats are too poorly protected from human activities. For example, you can find [nature] areas and national parks where there are supermarkets with hundreds of parking spaces,” Bjerregård noted.

Less human leisure activity – such as mountain biking, riding or trail running – in wild habitats would also increase their protection, he said in the statement.

“Protected natural areas in Denmark are small isolated patches, when what the species need are larger, continuous natural areas, so that the populations are not as vulnerable to fluctuations in weather and climate as they are now,” he explained.

There are currently 66 different species of butterflies in Denmark. Of these, some 37 are “red-listed”, meaning they are endangered or vulnerable. 12 species of butterfly have disappeared from Denmark since the 1960s.

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Denmark’s library of ancient ice tells tales of climate’s past

How was the air breathed by Caesar, the Prophet Mohammed or Christopher Columbus? A giant freezer in Copenhagen holds the answers, storing blocks of ice with atmospheric tales thousands of years old.

Denmark's library of ancient ice tells tales of climate's past

The Ice Core Archive, housing 25 kilometres (15 miles) of ice collected primarily from Greenland, is helping scientists understand changes in the climate.

“What we have in this archive is prehistoric climate change, a record of man’s activities in the last 10,000 years,” glaciology professor Jorgen Peder Steffensen of the University of Copenhagen told AFP.

Blocks of ice have been his passion for 43 years — and it was while drilling into Greenland’s ice sheet that he met his wife Dorthe Dahl-Jensen, also a top expert in the field of paleoclimatology.

Steffensen has since 1991 managed the repository, one of the biggest in the world, with 40,000 blocks of ice stacked on long rows of shelves in large boxes.

The frozen samples are unique, made up of compressed snow and not frozen water.

“All the airspace between the snowflakes is trapped as bubbles inside (and) the air inside these bubbles is the same age as the ice,” Steffensen explained.

The repository’s antechamber is similar to a library’s reading room: this is where scientists can examine the ice they have withdrawn from the main “library”, or storage room.

But they must be quick: the temperature in the antechamber is kept at -18 degrees Celsius (-0.4F) — decidedly balmy compared to the -30C (-22F) in the storage room.

Here, Steffensen removes a block of ice from a box. Its air bubbles are visible to the naked eye: it’s snow that fell during the winter of year zero.

“So we have the Christmas stuff, the real Christmas snow,” says Steffensen with a big grin, his head covered in a warm winter bonnet with furry ear flaps.


A team of researchers brought the first ice cores to Denmark in the 1960s from Camp Century, a secret US military base on Greenland.

The most recent ones date from this summer, when scientists hit the bedrock on eastern Greenland at a depth of 2.6 kilometres, gathering the oldest ice possible.

Those samples contain extracts from 120,000 years ago, during the most recent interglacial period when air temperatures in Greenland were 5C higher than today.

“The globe has easily been much warmer than it is today. But that’s before humans were there,” Steffensen said.

This recently acquired ice should help scientists’ understanding of risingsea levels, which can only be partly explained by the shrinking ice cap.

Another part of the explanation comes from ice streams, fast-moving ice on the ice sheet that is melting at an alarming rate.

“If we understand the ice streams better, we can get a better idea of how much the contribution will be (to rising sea levels) from Greenland and Antarctica in the future,” Steffensen said.

He hopes they’ll be able to predict the sea level rise in 100 years with a margin of error of 15 centimetres — a big improvement over today’s 70 centimetres.


Ice cores are the only way of determining the state of the atmosphere prior to man-made pollution.

“With ice cores we have mapped out how greenhouse gases, carbon dioxide and methane vary over time,” Steffensen said. “And we can also see the impact of the burning of fossil fuels in modern times.”

This project is separate from the Ice Memory foundation, which has collected ice cores from 20 sites worldwide to preserve them for future researchers at the French-Italian Concordia research station in Antarctica,before they disappear forever due to climate change.

“Storing Greenland’s ice memory is very good,” said the head of the foundation, Jerome Chappellaz.

But, he noted, the storage of samples in an industrial freezer is susceptible to technical glitches, funding woes, attacks, or even wars. In 2017, a freezer that broke down at the University of Alberta in Canada exposed 13 percent of its precious samples thousands of years old to undesirably warm temperatures.

At Concordia Station, the average annual temperature is -55C, providing optimal storage conditions for centuries to come.

“They have a treasure,” said Chappellaz, appealing to the Danes to join Concordia’s project.

“We must protect this treasure and, as far as possible, ensure that it joins mankind’s world heritage.”