The monarch butterfly is one step closer to extinction: the collapse of its population prompted a group of researchers on Thursday to place the famous insect with orange and black wings on its list of endangered species.
“It’s not just a devastating decline,” said Stuart Pimm, a Duke University ecologist who was not involved in the decision. “We are talking about one of the most recognizable butterflies on the planet. »
The International Union for Conservation of Nature (IUCN) has added the migratory butterfly to its “red list” of endangered species for the first time. She now considers it to be “in danger” ― two steps from extinction. The group estimates that the butterfly’s population in North America has collapsed by 22% to 72% over the past 10 years, depending on the method of measurement used.
The scientific community is “mainly concerned about the rate of decline” of the species, says Nick Haddad, a biologist at Michigan State University. “It’s very easy to imagine how quickly this butterfly could become even more endangered. Haddad, who was also not involved in the IUCN decision, calculates that the number of monarch butterflies he studies in the eastern United States has plunged 85% to 95% since the 1990s.
In North America, millions of monarch butterflies make the longest known migration of any insect. After spending the winter in the mountains of central Mexico, the butterfly migrates north and gives birth to multiple generations during a journey of several thousand kilometers. The descendants that go as far as southern Ontario and Quebec return to Mexico at the end of the summer.
“It’s quite a show. It’s breathtaking,” said Anna Walker, a New Mexico BioPark Society biologist who helped reclassify the butterfly.
A smaller population overwinters along the California coast, then scatters to several states west of the Rocky Mountains in spring and summer. It has collapsed even more severely than that of the eastern continent, although there was a slight improvement last winter.
Emma Pelton, from the non-profit company Xerces, which studies this western population, explained that these butterflies are threatened by habitat loss, the ever-increasing use of pesticides in agriculture and climate change. “There are things people can do to help,” she said, like planting the milkweed the caterpillars need.
Central and South American monarch butterflies, which do not migrate, have not been designated as “endangered”.
The tigers are getting back on their feet
The IUCN also announced that the most recent estimates of the world’s tiger population are 40% higher than the last calculations, made in 2015. The new data, which shows between 3,726 and 5,578 tigers in the wild around the world , reflect a more accurate count of individuals and, potentially, an actual increase in populations, notes Dale Miquelle, tiger specialist for the Wildlife Conservation Society.
Over the past decade, tiger populations have recovered in Nepal, northern China and possibly India, but the big cats have disappeared entirely from Cambodia, Laos and Vietnam, Miquelle says. They are still considered “in danger”.