BUTTERFLIES WITHOUT BORDERS
On a cool March day in 2010, I walked into a Gothic cathedral. Not a typical one, this one was in the High Sierra of Michoacan, Mexico.
I was reminded of the first time I entered Chartres and my eyes had been immediately drawn towards the heavens. In this case, the ceiling above was an indigo sky, the buttresses conifer trees and the glorious stained glass windows, monarch butterflies.
Here, in a protected sanctuary called El Rosario, these bright orange, black and white butterflies were clustered like hanging nests in the upper branches of the oyamel conifers. As the sun emerged and the air warmed, some began fluttering about like colorful snowflakes, a few even landing upon our heads, arms and backs. Unlike the hushed silence of a snowfall, however, there was a subtle, yet distinctive murmur. It was the sound of their delicate wings. These butterflies without borders were preparing to embark on their long and arduous trip towards El Norte.
We have all heard about the remarkable migrations the Eastern monarchs perform each year. They are the most famous migrating Lepidoptera known, traveling up to three thousand miles in each direction and faithfully returning to the same over-wintering sites in the central Mexican highlands. This phenomenon, that includes a span of three to four generations in one year, has intrigued scientists and laymen for decades. (West coast monarchs follow a different itinerary, heading to southern California/northern Mexico.)
Many theories abound. Flight patterns appear to be inherited and based upon the position of the sun as well as a circadian clock in the butterflies’ antennae. The earth’s magnetic field most probably contributes to their sense of orientation as well.
My own antennae now piqued has led me more than ever to be on the outlook for monarchs both in New England and in Mexico. Sadly, last summer, fewer monarchs appeared in my northern garden. (And this is despite encouraging the milkweed to multiply by mowing our field much later in summer.) While returning south again this fall, I wondered how the monarchs might also be faring. After all, we seemed to be following a similar path — albeit at a different tempo…
Unfortunately, their voyages spanning a few months are getting tougher. The devastating drought on their migration paths in the Southwest most certainly has had a deleterious effect on their survival rate. With little nectar from flowers and compromised sources of water, these migrants are being seriously challenged. As Monarch Watch, a prime research and conservation program based at the University of Kansas stated last fall: “The migration is just beginning to navigate a 1000 miles of hell – a nearly flowerless/nectarless and waterless expanse of central KS, OK, TX, and NE Mexico.”
Notwithstanding the effects of climate change, other major factors are affecting their numbers: loss of habitat and food sources. Beginning with roadside management practices involving herbicides and frequent mowing and ending with the worst of all culprits: industrial agriculture that uses Monsanto Round-Up Ready genetically engineered crops, the odds are stacked against them. Round-Up Ready is so selective, so “perfect”, that it was developed to ignore crops such as soy beans and corn, while killing the weeds, e.g. milkweed or Asclepias. Since monarchs lay their eggs upon this “weed” and their caterpillars rely upon it exclusively for food, much is at stake.
For the entomologist expert Lincoln P. Brower, Round Up Ready is “like absolute Armageddon for biodiversity over a huge area.” In Iowa alone, according to an agronomist expert, the amount of milkweed on farms declined 90 percent from 1999 to 2009, due to the adoption of herbicide tolerant (HT) crops.
Experts like Dr. Chip Taylor, an insect ecologist and the director of Monarch Watch, believe strongly that the explosion in genetically modified crops is threatening monarchs by depriving them of their prime larval habitat and food source. As it turns out, milkweed also acts as a protector, infusing the monarchs with what to birds is highly unpalatable, a typical miracle of nature. Indeed, other butterfly species such as the Queen and Viceroy evolved to visually mimic the monarch, thereby staving off potential predators.
Low monarch numbers implies that the integrity of the overwintering sites in Mexico is now more important than ever. Unfortunately, evidence that monarch populations are in decline has come from a recent study showing a drop of the monarchs’ geographic spread. “The amount of land occupied by the monarchs is thought to be a proxy for their population size”, according to the NY Times article. That amount is decreasing.
While the monarchs face serious ecological challenges up north, the monarch sanctuaries that have been established by the Mexican government are not without problems. The exclusive oyamel trees on which the monarchs cluster are valuable lumber sources that many local people depend upon for income. Although such logging is prohibited and ecotourism is promoted as an alternative, lumbering, at least for some, continues to be more lucrative.
Unlike in the United States and Canada where monarchs are more dispersed, one of the problems in their overwintering site is that they are clustered more densely in the state of Michoacan. This makes the possibility of habitat destruction very serious. “Conservation organizations, in particular the Mexican group Monarca, A.C., worked with governmental agencies and local people to establish land protection, sponsor research, initiate education about monarch conservation, and enhance alternative economic development in the region. Despite the establishment of five sanctuaries in 1985 and the opening of tourist trade, these efforts have not yet assured the continued survival of the overwintering monarch population,” according to Monarch Watch.
Fortunately, conservation organizations, such as the Mexican group Monarca, A.C., continues to work with governmental agencies, NGO’s and the local population to establish land protection, sponsor research, initiate education about monarch conservation, and in general enhance alternative economic development in the region.
For more information on MonarchWatch:www.monarchwatch.org/
March 4, 2012 at 2:36 pm
What a beautiful and informed article. I have been to the Monarch sites in Mexico and it is truly a miracle to hear butterflies fly. I hope we as a species wake up to our part in the destruction of these magnificent and amazing creatures.
March 5, 2012 at 10:11 am
Thanks Pinky for your comment. So many people love these creatures that I feel they have a chance to thrive. I’ve gotten some letters from people who read the article in l’Atencion too!
By the way, an interest in going to Patzcuaro with Audubon in April??? I’m going with a good friend visiting here.