Monarch butterflies work better than previously thought | National Geography

‘Always uncertain’

No matter how important the NABA database is, it is not a sanjivi. According to Kathleen Brodick, a wildlife biologist at the University of Arizona who is not involved in new research, a scientific counting platform is divided into sections to ensure that each section is numbered uniformly.

Another way to calculate the number of animals in a particular area is to do ‘Point-Transcend Counts’ (PTTs), in which researchers follow a specific path and calculate the number of animals with points at constant points along the way. In contrast, NABA censuses are not so strictly organized, so volunteers do not follow the same path every year.

“The new study reflects the data we have and analyzes that data accurately,” says Brodick. But when it comes to a complex and widespread species like the monarch butterfly, the use of data collected by civilian scientists always creates “uncertainties,” he says.

Emma Pelton, head of defense biology at the Xerces Society for Invertebrate Conservation, makes similar comments. The Xerces Society was one of the organizations that asked the U.S. Fish and Wildlife Service in 2014 to add the monarch butterfly to its list of protected species.

“We work with a lot of citizen scientists, and this research is a great example of the amazing analysis we can do when people go out of nature and count insects,” said Belton, who is not involved in the new research. ‘But you have to point out the limitations of this approach.’ (Read more about monarch butterfly threats, including pesticides.)

Belton points out that these types of figures can have small variations because they are usually made by people who only do one day a year, i.e. at the peak of summer and in places called real butterfly sites. According to him, the figures were “not taken at random places and times, nor are they representative of a particular landscape.”

“It’s very important for a migratory insect, it’s really all over the United States,” Belton said. For example, monarch butterflies can occur in urban areas and crop fields, usually in areas not covered by NABA PTTs.

“In general, these are highly respected authors and they have addressed this broader issue with a strong data set,” says Belton. “But I do not think this is the right set of data for the question they are trying to answer.”

Therefore, neither Brodick nor Belton believe that new research will change the outcome of the U.S. Fish and Wildlife Service’s, especially as many populations, including those in western North America, are still declining, and the species deserves to be added to the official endangered species list. Numbers.

Matt Forister, an entomologist at the University of Nevada in Reno, says, “Despite the findings of the new study, we should not jump to conclusions, especially when you consider that this species shows a sharp decline in numbers in other categories. Its life cycle.” . ‘

“If that decline continues, you have the situation where you can see all the remaining monarch butterflies on a tree in Mexico,” he says. “At that point, it will only take a storm for them to disappear.”

Georgia Burham, spokeswoman for the U.S. Fish and Wildlife Service, wrote in an email that the monarch butterfly is being evaluated each year for its need to be included in the list of protected species. If the species still meets the conditions by 2024, it will be protected under the Endangered Species Act.