Milkweed Seed Supply Chains for Monarch Habitat Restoration
Summary and Statement of the Problem
The largest habitat recovery initiative in American history is needed to plant new and enhance existing populations of milkweeds and other native wildflowers for the recovery of monarch butterflies. This report offers insights—particularly for departments of transportation and other landscape managers—on how best to build collaborations to manage the milkweed seed supply chain to recover monarchs as well as crop pollinators in North America over the next decade. It highlights how governmental agencies, for-profit and non-profit organizations may work together to plant a billion new milkweeds and better manage roadside stands in monarch breeding grounds to reverse dramatic declines in monarchs and native bees.
Most of the recommendations here are derived from interviews with seed collectors, seed producers, nurserymen, landscape architects, right-of-way managers and habitat restorationists. This report underscores the need for co-management of the entire “milkweed seed supply chain” in order to avoid bottlenecks and wasteful efforts so that conservation targets can be reached in a cost-effective manner. We are optimistic that such collaborative efforts can restore healthy relationships between the species of concern and among the people who can positively impact their well-being.
Introduction and Justification
In February of 2014, the elected leaders of the United States, Mexico and Canada agreed to engage in an effort toward monarch recovery that may become the largest habitat restoration effort in the history of North America. Ironically, it will focus not just on a single imperiled species—the iconic monarch butterfly—but its relationships with milkweeds and other native plants required for its survival. The restoration and careful management of the “milkweed communities” will also benefit imperiled native bees and the domestic honeybee that are essential for crop production and food security.
The stated target of this tri-national initiative will be to plant upwards of a billion milkweed plants in the spring and summer breeding grounds of monarchs to recover migratory butterfly populations that overwinter in Mexico so that they will consistently cover 4–6 hectares (ha) of forested habitat. The US Fish and Wildlife Service has provisionally announced this target after months of data accumulation, modeling, mapping and expert review facilitated by the Monarch Conservation Science Partnership coordinated by the U.S. Geological Survey. The justification for this estimate comes from the best currently-available science, briefly outlined below.
According to several recent journal articles and government reports, the loss of several milkweed species from wild, semi-managed and cultivated landscapes in North America may be the major factor contributing to steep declines of monarch butterflies over the last 15 years. These milkweed declines impact the viability of monarch butterfly populations because monarch larvae require milkweed host plants to complete their life cycle. The first study to assess the magnitude of this dilemma, authored by John Pleasants and Karen Oberhauser, was published in Insect Conservation and Diversity in 2012. It suggested that roughly a million milkweed stems or plants may have been lost from monarch summer breeding.
With contributions from interviews with John Pleasants, Herb Knudsen, George Ball, Jr., Blake Curtis, Gail Haggard, Jim Verrier, Francesca Claverie, Peggy Olwell, Kay Havens, Laura Lopez-Hoffman, Laura Jackson, Brianna Borders, John Anderson, Victor Schaff, Bonnie Harper-Lore, Eric Lee-Mader, Mace Vaughn, David Dreeson, Steve Buckley, Mark Fishbein, George Cates, Tao Fong, and LeRoy Brady.