Eastern monarch butterfly population plunges below extinction threshold

The yearly count of monarch butterflies overwintering in Mexico, released today, shows a decrease of 53% from last year’s count and is well below the threshold at which government scientists predict the migration could collapse.

Scientists estimate that 6 hectares—about 15 acres—is the extinction threshold for the migratory butterflies’ survival in North America. The latest count, conducted by World Wildlife Fund Mexico, found overwintering monarchs occupying just 2.83 hectares, or 7 acres.

Read more from Tierra Curry, of the Center for Biological Diversity on Phys.org here.