The Butterflies They are disappearing in USA Due to insecticides, to Climate change Already the loss of habitat, and its population has decreased by 22% since 2000, according to a new study.
The first national systematic analysis of the abundance of butterflies revealed that the number of specimens in the 48 continental statements has been reduced an average of 1.3% per year since the change of the century, with 114 species showing significant decreases and only nine increasing, according to a study published in the journal Science on Thursday.
“Butterflies have been decreasing in the last 20 years,” Nick Haddad, co -author of the study and entomologist at Michigan State University said. “And we see no sign that this will end.”
A team of scientists combined 76,957 surveys of 35 tracking programs and combined them to make an equitable comparison, and ended up telling 12.6 million butterflies over the decades. Last month, an annual study focused only on monarch butterflies – which federal officials plan to include threatened species – counted an almost historical figure of less than 10, 000, 000, compared to 1.2 million copies of 1997.
Many of the decline species fell 40% or more.
The United States has 650 species of butterflies, but 96 of them were so scarce that they did not appear in the data and another 212 were not found sufficient specimens to calculate trends, said Collin Edwards, main author of the study, ecologist and data scientist from the Washington Fishing and Wildlife Department.
Some known species suffered important falls. The population of Red Admiral, which is so quiet that it perds over people, has decreased 44% and that of American lady, with two large eye spots on its rear wings, 58% were reducedEdwards said.
Even the white butterfly of the cabbage, which according to Haddad is “A species that is well adapted to invade the world,” fell 50%.
Anurag Agrawal, an expert in butterflies at Cornell University, said that what worries him most is the future of another species: humans.
“The loss of butterflies, parrots and marsopas is undoubtedly a bad sign for us, for the ecosystems we need and for the nature we enjoy”said Agrawal, who was not part of the study, in an email. “They are telling us that the health of our continent is not so good (…) Butterflies are ambassadors of the beauty of nature, its fragility and interdependence of species. They have something to teach us. ”
What is happening with the butterflies in the United States probably also happens with other insects less studied throughout the continent and the world, said David Wagner, an entomologist at the University of Connecticut who also did not participate in the study.