Danish butterflies are in sharp decline

According to new research from Aarhus University, twelve species of butterflies have been lost for ever during the last fifty years, and the decline is continuing. This is the first mapping of the decline of butterflies in Denmark since 1900. Read the entire story in the latest edition of Rømer – Aarhus University’s free online magazine.

2015.05.21 | Rasmus Rørbæk Christensen

The Pearl-bordered Fritillary lives in warm flowery clearings and is a species in sharp decline. The species was previously widespread in Denmark, but is now only found in a few locations in Central Zealand and on the islands of Lolland and Falster. (Photo: Emil Brandtoft)

Denmark’s butterflies have undergone an accelerating negative trend since the mid-twentieth century. Within just fifty years, a total of twelve species – corresponding to approximately 10% of the overall number of Danish butterflies – have disappeared from the Danish countryside.

This decline in the number of butterflies shows no immediate sign of abating. A number of species are so critically endangered today that they run the risk of extinction within a short period of years unless targeted management efforts are implemented to save their habitats. These are the results of a new research project from Aarhus University, which have just been published in the scientific journal Diversity and Distributions.

Hard conditions for specialised butterflies
There is a significant difference between which species are extinct or endangered, and which ones are still doing relatively well in the Danish countryside.

“The greatest losses have mainly been suffered by the butterfly species that live in the woods. Out of the twelve species of butterflies that have been lost, ten had woodland habitats. The species that have died out include attractive and colourful butterflies such as the Cryptic Wood White, Duke of Burgundy Fritillary and Clouded Apollo,” says Anne Eskildsen, Department of Bioscience, Aarhus University.

Anne Eskildsen is behind the research project, which is part of her PhD degree programme. The research was carried out in collaboration with international colleagues.

Conditions are hard not only for species with woodland habitats such as clearings, but also for species that are associated with rare host plants. The species that do much better on the whole are those that to a greater extent are generalists and can thrive in a number of different habitats.

A signal that nature is suffering
According to Anne Eskildsen, the decline of the butterflies is not just a loss of colourful biodiversity, but also a signal from nature that should be taken seriously.

“The great sensitivity of the butterflies and their rapid response time to even small changes in their surroundings are helping to provide us with an early warning when changes take place in nature. They’re therefore considered to be a kind of ‘nature thermometer’ that can give us an indication of nature’s general state of health. The considerable decline we’ve seen among butterflies is thus one of the clearest examples right now that nature is suffering in Denmark,” says Anne Eskildsen.

The reasons for the enormous decline in the species of Danish butterflies are mainly found in the intensification of forestry and agriculture, which has resulted in limited space in the modern landscape for wildernesses and butterflies.

Read the entire story in RØMER
You can read much more (in Danish only) and find a number of other popular science articles about new research results from Aarhus University here.

Read the entire article Danish butterflies are in sharp decline via this link.

RØMER is published electronically eight times a year in the form of a newsletter that comes directly to your inbox. It is free to subscribe, and you can sign up on the website.

Read more (in Danish only) below.

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