The figures in a 2/10/15 Associated Press report give the sad news that the 2014 Monarch migration numbers were, along with those of 2013, the lowest in at least 20 years–down 90%. According to a report in the New York Times ( 3/14/13) by Michael Wines there are multiple explanations. The details are shocking.

Where the wintering-over forest of the Monarchs was once as large as 50 acres, it now has been reduced to 2.94 acres, down 59% from the 2011 figure of 7.14 acres, presumably from illegal logging.

Climate change has played a part as well. The record heat in North America this year dried the butterflies’ eggs and reduced the nectar content of the milkweed. Equally devastating has been the development of herbicide-resistant corn and soybeans, which has allowed farmers to wipe out the milkweed which was once prolific between the rows of crops in the American Midwest. “The habitat is virtually gone. We’ve lost well over 120 million acres., and probably closer to 150 million acres,” said Chip Taylor, director of Monarch Watch.

All hope is not lost. The Mexican government has stepped up its protection of the forests and conservationists and state an local governments may yet be able to replenish some of the milkweed. Insect populations often can recover from devastating episode, but there is a tipping point which will make the butterflies too vulnerable to unusual climate events to bounce back. Mr. Taylor was quoted as saying that any drop in the wintering over ground below 2.5 acres may be that tipping point.

topics: nature