Netherlands butterfly population declined 40 percent since 1992

Butterflies are still struggling in the Netherlands, according to butterfly foundation Vlinderstichting's annual report. Half of the 47 species the foundation keeps track of is in decline. Since 1992, the number of butterflies in the country dropped by around 40 percent, ANP reports.

Volunteers keep track of butterfly populations on a weekly basis on hundreds of routes in the country. Their observations show that 2017 was a very good year for some species, but dramatic for others.

The number of Grayling- and Pieridae butterflies spotted in the Netherlands last year was worryingly low. According to the researchers, the Grayling butterfly is less prevalent because heathlands are closing up as a result of too high concentrations of nitrogen and its habitat is being destroyed.

On the other hand, there are 11 butterfly species that are doing remarkably well. The most seen butterfly last year was the Meadow Brown. The researchers describe the state of this species as "extremely stable". Silver-studded blue butterflies were the second most seen in the Netherlands in 2017.