Conservation efforts needed to support monarch butterfly population recovery

Monarch butterfly on milkweed with field and sky in background
Monarch butterfly on common milkweed. Photo by Jacqueline Pohl, Iowa State University.

AMES, Iowa – The last year was a difficult one for the eastern monarch butterfly, according to a report just released that indicates monarchs occupying forest canopy in their wintering grounds in Mexico decreased by 22%, down from approximately 7 acres in 2021 to a little under 5 ½ acres during the winter of 2022-2023. Scientists estimate that a long-term average of 15 acres is needed to sustain the eastern monarch population and its continental migration.

The report, produced annually by the World Wildlife Fund in collaboration with the National Commission of Natural Protected Areas (CONANP), the National Autonomous University of Mexico (UNAM) and the Monarch Butterfly Biosphere Reserve (MBBR), is based on annual surveys that go back to the 1990s. The surveys provide critical data to assess status and trends of the North American Eastern monarch population and inform conservation practices in Mexico, Canada and the United States. The goal, to maintain a long-term average of 15 acres of occupied forest canopy during the winter, in turn shapes objectives for establishing breeding habitat in the Midwestern states, including Iowa through the Iowa Monarch Conservation Consortium.

Many factors contribute to the decline of monarch butterflies. In addition to habitat loss in their wintering grounds, the availability of breeding habitat with milkweed plants and blooming forbs in the Midwest is also key to the species’ long-term survival. Milkweed is the only plant that monarch butterflies will lay their eggs on, and it is also the primary food source for monarch caterpillars.

The international announcement comes at a pivotal time for monarch conservation, with the US Fish and Wildlife Service’s  re-evaluation of the monarch’s status under the Endangered Species Act slated for 2024. Conservation efforts are one aspect that will be used to inform the species status assessment by providing an estimate of the change in habitat due to conservation efforts since 2018 and anticipated change in the future. 

Fortunately, there are steps that Iowans can take to help support the monarch butterfly population. One of the most important things  is to establish appropriate habitat. This can be as simple as planting a few milkweed plants in yards or gardens, or as involved as establishing more extensive pollinator habitat. To encourage Iowans to establish habitat, consortium members have collaborated with Iowa State University Extension and Outreach to develop a Habitat How-To webpage that provides practical steps and additional resources to guide planning efforts.

An updated mobile app to track habitat establishment, HabiTally, is available as a free download for iOS and Android devices from the App Store and is designed to improve data collection about monarch habitat. “Now is a good time to remind Iowans about planting monarch friendly habitats around their homes, businesses, farms, and even ditches, and then documenting it by adding their habitat to the HabiTally app and joining their friends and neighbors in supporting monarch conservation,” said Kayla Lyon, director of the Iowa Department of Natural Resources.

There is hope for the future. In September 2022, the Iowa consortium released a Monarch Conservation Effort Report, which showed that from 2018 through 2020, Iowans added 430,000 acres of habitat in the state. A new interactive Monarch Conservation Effort Dashboards lets users see how state or county habitat establishment has changed over this time.

“As we work to protect our natural resources and improve water quality in rural, suburban and urban settings, Iowans are also ensuring that habitat is available for pollinators and wildlife in their communities,” said Iowa Secretary of Agriculture Mike Naig. “Pollinators like the monarch are important to the ongoing productivity of Iowa agriculture.  The practices pursued by the Iowa Monarch Conservation Consortium and many other partners will continue to provide long-term habitat for monarchs and other beneficial pollinators.”

A recent article in the journal BioScience integrates years of ISU monarch research showing how adding habitat will help conservation efforts. The findings estimate that the state’s monarch conservation plan has the potential to increase the size of the breeding monarch population in Iowa and the Midwest by 10-25% per generation.

“The challenges the eastern monarch butterfly population continues to endure is a cause for concern and our continued focus and energy,” said Daniel J. Robison, holder of the endowed dean’s chair in the College of Agriculture and Life Sciences. “Through Iowa State University’s research efforts and collaborative work with the Iowa Monarch Conservation Consortium, we are learning more about the species and its habits and habitat, and building habitat to help it thrive. We continue to partner with individuals and organizations at the state and national levels to inform science-based decisions toward the sustainability of this important species in Iowa and throughout our region.”

Iowa Monarch Conservation Consortium is a group of 50 organizations, including agricultural and conservation associations, agribusiness and utility companies, universities, and federal agencies. To learn more about the Iowa Monarch Conservation Consortium, visit and follow @IowaMonarchs on FacebookTwitter and YouTube.