I remember the warm summer day when, during our regular walk, my family and I discovered the monarchs. Now, when I say monarchs, I’m talking thousands of them, all fluttering in their orange and black glory. It was an indelible moment that I will never forget. That moment may never happen again.
Today the winter monarch colonies, which are found west of Mexico City, in an area of about 60 miles by 60 miles, are a pitiful remnant of their former splendor. The aggregate area covered by the colonies dwindled from an average of 22 acres between 1994 and 2003 to 12 acres between 2003 and 2012. This year’s area, which was reported on Wednesday, hit a record low of 2.9 acres.
Why is this happening?
Reasons for the decline are multiple, including: out-of-control ecotourism, extreme weather and diversion of water. Two threats loom above all others: the destruction of breeding habitat in the United States because of the widespread use of powerful herbicides and genetically engineered crops, and illegal logging in Mexico’s high-elevation Oyamel fir forests.
Deforestation has always been a dark shadow lurking in these beautiful mountains, and it has never been adequately dealt with by the Mexican government. In the 1980s, horrified television viewers watched footage of loggers armed with chain saws felling trees covered with butterflies and log-laden trucks crushing butterflies as they drove down the mountains. That led to the establishment, in 1986, of the Monarch Butterfly Special Biosphere Reserve, within which logging was outlawed. But still it continued.
How could ecotourism hurt them?
Ecotourism is an important part of the local economy, but we must make sure that its costs in habitat degradation and increased butterfly mortality don’t kill the goose that lays the golden egg. The Mexican government has made strides in reducing much — but not all — illegal logging, and needs to do more. The United States, for its part, should re-examine the extent to which industrialized herbicide-based agriculture is destroying the flora in the Midwestern United States that monarchs depend on in the spring and summer. In addition to all of this, we simply need better data on the butterflies.
We are fortunate to have experienced the magnificent overwintering phenomenon over more than three decades. We hope that better stewardship will allow the monarch butterflies to continue to festoon the Oyamel forests of Mexico for generations to come.