https://www.tbo.com/news/environment...2005_173359609
Every year thousands of monarch butterflies dance through the air over North Florida, migrating between their breeding ground in Mexico and their regular homes along the U.S. Atlantic coastline.
Every year, there have been fewer and fewer of them.
A new University of Florida study — at 37 years, the longest of its kind — has found that the number of caterpillars and butterflies in North Florida have been declining steadily since 1985.
Since 2005, the numbers have dropped by 80 percent.
"It’s alarming," said associate professor Jaret Daniels, a co-author of the study. "Before 2005, there was more fluctuation in the data. Since 2005, the rate of decline has been steady."
The scientists involved in the study say the causes of the decline are not entirely clear, but they believe there are two major factors at work.
One is the development of areas that had been planted with native milkweed, the favorite food of young monarchs. The other is the widespread use of a herbicide called glyphosate, often applied to farmers’ fields to kill weeds. One of the weeds it kills is milkweed.