Ecological restoration, civic engagement, and people working for the common good will be components of a successful monarch recovery strategy
The annual monarch migration is one of the most magnificent and intriguing of all natural phenomena but this natural spectacle is at risk, risk of vanishing as monarch populations continue to decline. This is because the monarch population of the central U.S. flyway is in decline.
We know from on-site monitoring that monarch numbers on their overwintering sites are decreasing. For the third year in a row the forest areas occupied by the overwintering adult monarch butterfly population in Mexico has declined, according to a report from the World Wildlife Fund (WWF), which conducts the monitoring.
In December of 2017, 9 colonies in Mexico covered a forest area of 2.48 hectares, “an area that represents a decrease of 14.77 percent with respect to the previous season (2.91 ha).”, according to the report released on March 5, 2018. By comparison the forest area occupied by adult monarchs in 2015-16 was 4.01 hectares.
Habitat Loss in the Eastern United States
In the Midswest, research and monitoring of monarchs has provided strong evidence that the primary threat to monarchs in the eastern U.S. is due to loss of breeding habitat (Pleasants and Oberhauser 2012, Pleasants 2015, Monarch Joint Venture). Breeding habitat includes milkweed (Asclepias species) host plants for monarch eggs and caterpillars, and nectar plants for the adult butterflies.
The Biology and Migration of the Monarch Butterfly
Monarch Joint Venture provides a description of the monarch life cycle and a video of a monarch emerging from its chrysalis here. An overview of monarch migration from Monarch Joint Venture is found here.
There is Urgency.
What can you do? Plant milkweed species, lots of them, and then add nectar plants.
Experts estimate that an additional 1.8 billion milkweed stems are needed in the central U.S. monarch flyway (Billions more milkweeds needed to restore monarch) to support monarch reproduction and migration. This many milkweed stems (Asclepias species) are required for the caterpillars (monarch caterpillars can eat only milkweed leaves), as well as plentiful nectar plants like asters, goldenrods, and blazingstars, for the adults butterflies.
The 2018 Monarch Conservation Implementation Plan calls for: “an approach that engages “all hands” and “all regions” to most effectively support the eastern population. The South Central region plays a significant role in supporting both the spring and fall migrations.”
It will take a big, united effort to accomplish this feat. Everyone needs to get involved in the effort to save the monarch. Every nook and cranny of unused land; every plot of waste space, every backyard garden, every restoration project needs to be devoted to plants that support the monarchs.
Vacant lots, bike path rights-of-way, and community gardens are ideal spaces in which to create butterfly gardens—with both milkweed stems for the caterpillars, and nectar sources for the adults.
Every interested person has to help. If you have not yet ordered your milkweed plants or seeds, do so soon to have them ready for planting in just a few weeks. Look to native plant sales, or native plant nurseries as reliable sources of plants, seeds, and information and tips about growing butterfly gardens.
Pleasants, J.M., and Oberhauser, K.S.. 2012. Milkweed loss in agricultural fields because of herbicide use: effect on the monarch butterfly population. Insect Conservation and Diversity. 6:135–144
Pleasants, J.M. 2015. Monarch butterflies and agriculture in Monarchs in a changing world: biology and conservation of an iconic butterfly. Ed: KS Oberhauser, Kelly R Nail, Sonia Alitzer. Cornell University Press, Ithaca.