The critically endangered monarch butterfly grew its presence in Mexico last year, a study showed on Tuesday, giving a glimmer of hope to researchers who track the fluttering orange and black migrants despite a decades-long population collapse.
In one of the planet's most epic wildlife migrations, the slow-moving monarch butterflies travel south as many as 2,800 miles (4,500 km) from spots in Canada and the United States to hunker down for the winter in warmer Mexico, where millions cover entire trees that tourists flock to see.
Last winter, the pockets of Mexican forest where the intrepid insects end up each year saw 35% more butterflies than in 2020, according to the study led by the local office of the environmental organization World Wildlife Fund (WWF).
Biologists documented the presence of the species in 7.02 acres last December in the two central Mexican states where they spend the winter, Michoacan and the State of Mexico, up from the 5.19 acres in December 2020.
But that compares to nearly 45 acres of Mexican forest covered with monarch butterflies in the mid-1990s.
The race to help the species recover is also tied to the crucial role it plays in the health of interconnected species.
Specifically, monarch butterflies boost ecosystems as pollinators, with their migratory journey promoting a wide range of flowering plants as well as helping crops humans tend, WWF Mexico head Jorge Rickards said in a statement accompanying the study.
But dire challenges to the butterflies' future persist, including climate change, illegal logging plus the growing scarcity of the plant where they lay their eggs.
Despite the recent uptick, the monarch butterflies' "steady decline is worrisome," the WWF added.
The group recommends more scientific monitoring, sustainable tourism and forest management, as well as "alternative income-generating ventures" like mushroom production and tree nurseries to help restore the forest and boost local incomes.