“This is the first time we have the data that we can analyze statistically that shows there’s a downward trend [in monarch butterfly populations],” said Professor of Biology Ernest H. Williams in a July 11 New York Times article titled “In Midwest, Flutters May Be Far Fewer.” Williams, the Christian A. Johnson Excellence in Teaching Professor of Biology, is the co-author of “Decline of monarch butterflies overwintering in Mexico: is the migratory phenomenon at risk?” recently published in the journal Insect Conservation and Diversity.
The article presents the results of a study showing that the number of monarchs overwintering on the mountains in Mexico - representing the population of monarchs east of the Rocky Mountains - has declined significantly over the past 17 years. The researchers attribute the decrease in monarchs to the loss of milkweed from use of “Roundup Ready” crops, land development, illegal logging at the wintering sites in Mexico and severe weather.
