European Butterfly Populations Down Nearly 50 Percent in Past Two Decades
Grassland butterfly populations in Europe have declined dramatically over the last two decades, largely because of increased agriculture and and a failure to properly manage grassland ecosystems, according to a report by the European Environmental Agency (EEA).
The EEA reported that grassland butterflies across Europe have declined in number by nearly 50 percent. Because butterflies are considered to be representative indicators of trends observed in other terrestrial insects, the find is particularly worrying, the EEA stated, adding that as many as two-thirds of the word's insect populations could be at risk.
"This dramatic decline in grassland butterflies should ring alarm bells -- in general Europe's grassland habitats are shrinking," said EEA executive director Hans Bruyninckx. "If we fail to maintain these habitats we could lose many of these species forever. We must recognize the importance of butterflies and other insects -- the pollination they carry out is essential for both natural ecosystems and agriculture."
Seventeen butterfly species were examined in the recently published report "The European Grassland Butterfly Indicator: 1990-2011."
The report indicated that of the 17 species studied, populations of eight have declined in number across Europe and two have remained stable. Results for the remaining seven species in the study were inconclusive. Butterflies examined in the report include the Common Blue (Polyommatus icarus), which has declined significantly, the Orangetip (Anthocharis cardamines), which seems to be stable since 1990, and the Lulworth Skipper (Thymelicus acteon), which shows an uncertain trend over the last two decades.
Grassland butterflies' habitat is being lost due to two primary factors: the intensification of of agriculture and the abandonment of grasslands in mountainous and wet regions. Agricultural operations on flat, easy-to-manage land has increased across Europe, expanding the area of land where a lack of biodiversity and high pesticide concentration is detrimental to butterfly populations. Meanwhile, large areas of mountainous grassland in eastern and southern Europe have been abandoned by farmers. The abandoned land becomes overgrown and is replaced by scrub land and woodland, which butterflies are not suited to live in.
"While the report is based on data from 1990 to 2011, it should be noted that in many areas of Europe the current changes in land use began before 1990. The report therefore suggests that the recent halving of butterfly numbers may be the most recent development in a much bigger long-term decline," the EEA stated.
A full version of the report can be read here.