The number of monarch butterflies hibernating in Mexico reached an all-time low last year, according to a recent study led in part by a University of Minnesota professor — compelling experts to call for immediate action to conserve the species’ migration.

The total area occupied by monarchs in Mexico — the butterfly’s main destination when migrating from the north — declined by more than 90 percent from 2003-04 to 2013-14, according to an annual census of winter monarch colonies in Mexico.

Now, an international group of scientists, including Fisheries, Wildlife and Conservation Biology professor Karen Oberhauser, is calling on the governments of the U.S. and Canada to boost conservation efforts for the insect’s habitat.

Oberhauser is the director of the University’s Monarch Larva Monitoring Project and was a leader in the recent study.

The area the butterflies occupy in Mexico is an “indirect indicator” of how many monarchs are migrating from North America to Central America each winter, according to a University news release.

Experts, including Oberhauser, say monarchs aren’t at risk of extinction. But Carl Stenoien, an ecology, evolution and behavior graduate student, said they serve as a “good indicator species,” signaling to scientists that other species are experiencing the same problem.

“If something bad is happening to monarchs, something bad is happening to a lot of other species,” Stenoien said.

Robert Blair, a fisheries, wildlife and conservation biology professor, said he thinks the research on monarch butterfly migration may shed light on the migrations of other animals, including birds, mammals and insects.

“In the field of conservation biology, lots of people are concerned with losing the phenomenon of migration because habitats are being chopped up,” Blair said.

Monarch populations have been in sharp decline in recent years due to changes in land use, extreme climate conditions and deforestation across North America, according to a University press release.

Oberhauser made a major discovery of a decline in the monarch’s summer habitat a decade ago. Blair said he remembers the research, which showed a significant loss in monarch habitat.

“[Oberhauser] said, ‘This might be the new normal. We don’t have nearly as much habitat as we had 20 years ago,’” he said.

Oberhauser said she encourages people to plant milkweed, monarch butterflies’ primary food source, to help combat this habitat loss.

Later this month, monarch advocates will travel to the North American Leaders’ Summit in Mexico to push government leaders to conserve monarch migration.