The hominy blue, Polyommatus icarus, is one of 189 species of butterflies found in Germany. Photo by Jan Christian Habel / TUM
March 20 (UPI) -- Pollinators are on the decline. Bee numbers are steadily decreasing, and as new research out of Germany confirms, butterfly numbers are down, too.
Scientists found the number of butterfly species in meadows next to commercial agriculture are two-thirds less than the number of butterfly species found in nature preserves.
Researchers surveyed butterfly species in 21 meadow sites outside of Munich. Four of the sites were situated in nature preserves, while the remaining 17 were adjacent to areas featuring high-intensity agriculture.
In total, scientists counted 864 individual butterflies, comprising 24 different species. Butterfly species considered generalists were found in both nature preserves and farm-adjacent meadows. Specialist species were less likely to be found near commercial farms.
"In the meadows that are surrounded by agriculturally used areas we encountered an average of 2.7 butterfly species per visit; in the four study sites within the protected areas 'Dietersheimer Brenne' and 'Garchinger Heide' near Munich we found an average of 6.6 species," Werner Ulrich, professor of ecology at Copernicus University in Poland, said in a news release.
The findings -- published in the journal Insect Conservation and Diversity -- echo the results of previous studies that showed pesticides used in commercial farming have deleterious effects on local pollinators.
"Our results show an obvious trend: in the vicinity of intensively cultivated fields that are regularly sprayed with pesticides, the diversity and numbers of butterflies are significantly lower than in meadows near less used or unused areas," said Jan Christian Habel, a professor of conservation biology and ecology at the Technical University of Munich.
Authors of the new study argue more eco-friendly cultivation measures are needed to protect pollinators. The researchers also said more field studies could help identify the specific ways in which commercial farming techniques negatively impact specific butterfly species and their preferred habitats.