The Dutch butterfly population is continuing a marked downward trend according to figures released by Statistics Netherlands.
The butterfly population in the Netherlands declined further in 2012 and has currently reached the lowest level during the past twenty years. The number of butterflies requiring a grassland habitat has dropped dramatically in agricultural areas.
Not only many rare butterfly species, but also many common species have struggled to survive in recent years, but 2012 was an exceptionally bad year butterfly-wise. The butterfly population shrank to the lowest level since 1992.
Rare species like the large chequered skipper and the tree grayling are doing very poorly, but more common species like the peacock butterfly and the large white are not doing well either, mainly due to loss of habitat. The quality of the remaining habitat is also less good than it used to be, partly due to fragmentation, intensification of agricultural production, parched land and over-fertilisation.
Other species are thriving, e.g. the speckled wood butterfly and the orange tip. In the past, the speckled wood butterfly was only found in forests, but today they are also found in gardens and road verges and the population is growing rapidly. The orange tip benefits from the warmer weather in spring.
Dramatic decline grassland butterflies
The situation for butterfly species in the past commonly found in grasslands has deteriorated dramatically. The population of so-called ‘farmland butterflies’ was reduced to one quarter compared to 1992. The decline is predominantly caused by intensification of agricultural production methods, resulting in a reduction of flowers in grassland and road verges. The small skipper seems to have vanished from agricultural areas; the wall brown is no longer found in many parts of the Netherlands.
Farmland butterflies are doing relatively well in nature reserves, mostly grassland in former agricultural areas now often managed by nature conservation organisations. The butterfly population in these areas was nearly 60 percent in 2012 relative to 1992.
Half of butterfly species in decline compared to 1992
Just over half of all butterfly species found in the Netherlands are severely in decline compared to 1992; one quarter of species are seriously under threat. One quarter are doing well and 10 percent are doing very well.