The new numbers are still way below the average from the first 10 years of monitoring (about 21 acres) and what scientists consider sustainable (about 15 acres). But they still amount to good news, said Karen Oberhauser, a professor emeritus at the University of Wisconsin-Madison, and one of the nation’s leading monarch experts.
“We are in a period of relative stability where the population has stopped declining,” Oberhauser, who was not involved in the new WWF Mexico report, told me.