Posted on 12 September 2013.
By Ranger Steve Mueller
In September people see Monarch butterflies migrating south.
Mrs. Tacoma, a kindergarten teacher at Cedar Trails Elementary, collects Monarch caterpillars on milkweed plants and feeds them until they form a chrysalis. When the adult butterfly emerges to pump fluid into its bright orange wings, students see a miracle that most people have not witnessed. Once fluid has dried in the butterfly’s wing veins, the class releases it for a 2000-mile journey to south central Mexico.
This year fewer Monarchs will be migrating. It has been a rough year and decade for survival. Dr. Lincoln Brower predicted long ago that migrating Monarchs would become a thing of the past during the first decades of the 21st century. It is hoped his prediction will prove wrong. The predictions of Brower and other scientists are based on several factors that have been building to diminish wildlife in North America.
Dr. ‘Chip’ Taylor, of Monarch Watch, highlighted factors. He said, for monarch recovery, we need to create a lot of milkweed habitat and need to mobilize people to do it to save wildlife, by creating habitats in yards and gardens. He continued that gardeners across this country could help by planting milkweed and using native plants to stabilize native pollinator communities. People now have another purpose for creating a garden. The purpose is conservation.
Taylor identifies factors that have led to the sharp drop in the monarch population.
1. Monarch numbers seen each year in the eastern United States and Canada are determined by the amount of habitat that remains. New roads, housing developments, and agricultural expansion serving a growing human population transform a natural landscape in ways that make it impossible for Monarchs to live.
2. Month to month temperature and moisture conditions are critical factors and are affected by climate change. Climate change is well documented but the question of how much is human caused is still not precise. It is clear human activities are affecting the rate of climate change but quantifying exactly how much is exceedingly difficult.
3. Increased planting of genetically modified corn in the U.S. Midwest promotes greater use of herbicides, which in turn kills milkweed. Monarch decline is coincident with the adoption of Roundup-ready corn and soybeans. We’re basically creating a desert out there, except for the corn and the soybeans.
4. The increase of soybean and corn crops as bio-fuels has reduced wildlife habitat.
5. Extreme weather events threaten to become more common and may have a negative impact on Monarch populations and other wildlife.
6. Taylor points out that sustaining the monarch migration will be a challenge that requires support and cooperation of Canada, the United States and Mexico. This is symptomatic of issues affecting plant and animal nature niches and may impact our national wellbeing.
7. As human populations grows, lumbering, clearing land for growing food and grazing cattle reduces space essential for survival of other life forms, on which society is dependent.
8. Our own population is projected to increase by two billion people by 2040 so Taylor doesn’t see the monarch in that future world. Our population cannot continually grow and also maintain a healthy world. We are going to see a lot of changes. There are natural restrictions on how fast populations can grow based on food production, declining arable land, and limitations of water. If we don’t get with it and if we don’t start modifying our behavior, life is going to get to be pretty tough.
He says the Monarch issue is his way of introducing people to the larger issues.
9. Monarch over wintering sites are vulnerable for a number of reasons. A census taken at the monarchs’ wintering grounds found their population had declined 59 percent over the previous year and was at the lowest level ever measured.
Italics in this article are my commentary additions. To read Taylor’s complete discussion go to http://e360.yale.edu/feature/tracking_the_causes_of_sharp__decline_of_the_monarch_butterfly/2634/
Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at the firstname.lastname@example.org Ody Brook, 13010 Northland Dr, Cedar Springs, MI 49319-8433.