The past year was a difficult one for the eastern monarch butterfly. According to a report released in April, monarchs occupying forest canopy in their wintering grounds in Mexico decreased by 22%, down from approximately 7 acres in 2021 to a little under 5½ 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, the National Autonomous University of Mexico and the Monarch Butterfly Biosphere Reserve, is based on annual surveys that go back to the 1990s. The surveys provide critical data to assess the status and trends of the North American Eastern monarch population and inform conservation practices in Mexico, Canada and the U.S. The goal is to maintain a long-term average of 15 acres of occupied forest canopy during the winter, which 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 critical 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 U.S. Fish and Wildlife Service’s re-evaluation of the monarch’s status under the Endangered Species Act slated for 2024.
Fortunately, there are steps that Iowans can take to help support the monarch butterfly population. One of the most important things is establishing appropriate habitat around homes, businesses, farms and even ditches. This can be as simple as planting a few milkweed plants in yards and gardens or as involved as establishing more extensive pollinator habitat.
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.
“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,” says Iowa Secretary of Agriculture Mike Naig. “Pollinators like the monarch are important to the ongoing productivity of Iowa agriculture.”
A recent article in the journal BioScience integrates years of Iowa State University monarch research, showing how adding habitat will help conservation efforts. The findings estimate that the state’s monarch conservation plan can potentially increase the size of the breeding monarch population in Iowa and the Midwest by 10-25% per generation.
To learn more about the Iowa Monarch Conservation Consortium, visit iowamonarchs.info and follow @IowaMonarchs on Facebook, Twitter and YouTube.
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