In the latest issue of the journal Biodiversity and Conservation, Karl-Olof Bergman, a researcher in conservation biology, and his colleagues publish the results of a comprehensive study of 60 pasturelands in Östergötland in Sweden. They turned out to be a haven for a number of species that are growing more and more rare in countries like Germany, the U.K., and Belgium.
The heath fritillary (Melitaea athalia), for example, is found in all locales in the Swedish study, whereas it has completely disappeared from Belgian Flanders and has declined dramatically in both western Germany and the U.K. The high brown fritillary (Argynnis adippe) can be found in 65 percent of the Östergötland pastures but has virtually disappeared from the other countries.
The pasturelands under study are 3-8 hectares in size, with deciduous tree growth and surrounded by conifers. This is a type of biotope that is receding in the rest of Western Europe. If efficiency measures in Swedish agriculture continue at today’s rate, there is a danger that the same development will take place in Sweden as well. The greatest danger is the decline in small farms with grazing animals.
“Sweden has a tremendous responsibility to conserve these species and environments. If the trend is not halted, Europe runs the risk of losing some of its most diverse biotopes,” says Karl-Olof Bergman.
The study, which was carried out on five occasions from May to September 2004, found 17,153 butterflies of 64 different species.
The article “Importance of boreal grasslands in Sweden for butterfly diversity and effects of local and landscape habitat factors” by Karl-Olof Bergman, Lena Ask, John Askling, Håkan Ignell, Henrik Wahlman, and Per Milberg is published in the online version of Biodiversity and Conservation.