In several previous posts in this blog I’ve detailed the amazing migration that monarch butterflies undertake each year and described their life cycle. Right now there are six fresh inches of snow on the ground and the temperature is 8 degrees, so I’m thinking about my summer garden and hoping I see more monarchs this coming season than I did last year, when I spotted just a single one. In past years my garden hosted monarchs routinely. They would lay eggs on my milkweed in July during their flight north and nectar on the asters and boltonia during their September flight south. Sometimes, in September especially, there would be a dozen or more on the same plant at the same time.
Over the past decade, monarch populations have declined precipitously because of a number of factors, primarily habitat loss. In the Mexican mountains where the midwestern and east coast monarch populations go for the winter, logging has removed much of the forest. And in the American midwest, because corn prices are way up due to ethanol production, farmers are now plowing under every last bit of land, including remaining bits of prairie that held–you guessed it–milkweed plants. Add to that the use of genetically modified seed that grows herbicide-resistant corn (so farmers can use lots and lots of herbicides to kill all the weeds, including, once again, all the milkweed), and you’ve got an almost extinct butterfly species. In normal years, 450 million monarchs used to spend the winter in Mexico. Last year it was 60 million. This year, it’s 3 million.
Some people are replanting milkweed, as a recent article in the NY Times details. In the Midwest, a large-scale citizen-science project is underway to plant milkweed in backyards. We can all help–monarchs fly along the east coast as well, or used to. Contact Monarch Watch to order a Monarch Waystation seed kit. Or easier still, plant a couple of milkweeds (Asclepias incarnata for wet sites and Asclepias tuberosa for dry sites) and a couple of New England asters (Aster nova-angliae) in a sunny place in the spring. Soon you’ll see gorgeous flowers like these:
You can get another take on this issue in Barbara Kingsolver’s novel Flight Behavior. Kingsolver was a biologist before she began writing novels, and this book is a thinly disguised excuse for setting out the results of climate change and habitat loss in fictional form. It describes the social and economic consequences in a small rural community when, for unknown reasons, the entire monarch population overwinters in the Tennessee mountains rather than in Mexico. An entertaining way to get a good overview of just a few effects of climate change and how scientists study them.
And an in-the-garden-this-week note: once the weather warms up a bit, now is the time to prune woody plants. Believe it or not, they’ll begin to break dormancy by around mid-February, so the next six weeks or so are prime pruning season. Check back soon for more about winter pruning.