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Community Science Powers New Western Monarch Studies

By Emma Pelton on 30. July 2019
Emma Pelton

Newly published papers shed light on western monarch conservation needs.

Western monarch researchers and community scientists have been busy, contributing information vital to understanding the situation facing this imperiled population of America’s most well-known butterfly.

Four new studies on western monarchs were recently published as part of the special issue of Frontiers in Ecology and Evolution titled North American Monarch Butterfly Ecology and Conservation (the online issue has been gradually published since May 2019, and these papers are each available for free). A fifth study on western monarchs is also about to be published—more details below. All of these studies draw, at least in part, on the findings of community science projects like the Western Monarch Milkweed Mapper—which has collected 53,097 records of monarchs and milkweeds in total, including nearly 500 sightings in 2019 alone.

Together, these studies contribute to our understanding of the western monarch population, including where monarchs and milkweeds occur, the habitats they rely on, and what actions are most likely to help the population recover. These papers also underscore the importance of community science efforts, which have provided key information. At the end of this blog post, we provide a list of ways in which community members can contribute to monarch research efforts—in the western United States and beyond.


Two monarchs' wings overlap, as they stand, back end to back end, mating.
Monarchs mating in Nevada in July. Submitting observations of monarch butterflies, milkweed, and monarchs breeding to community science efforts, including the Western Monarch Milkweed Mapper, help to support important research efforts. (Photo: Xerces Society / Stephanie McKnight)


Summaries of New Western Monarch Studies


An orange monarch with a partially torn wing clutches a bright pink cluster of milkweed flowers, with an arid landscape and blue sky in the background.
Monarch nectaring on swamp milkweed (A. incarnata) in Idaho. Community science has supported a variety of western monarch research, including determining which geographic areas are most suitable for the species. (Photo: Xerces Society / Stephanie McKnight)


Additional Studies of Note

  • Coming soon, in the journal Ecological ApplicationsWhy are monarch butterflies declining in the west? Understanding the importance of multiple correlated drivers by Crone et al. This study examines how the size of the western monarch’s overwintering population may be affected by different land use (e.g., coastal development, pesticide use) and climate stressors. The authors conclude that we need to simultaneously work now on protecting and restoring monarch breeding and overwintering habitat and also call for more studies to untangle which stressors are the most responsible for the population’s current status.
  • Finally, while not focused on western monarchs specifically, a noteworthy new study discusses monarch rearing. Contemporary loss of migration in monarch butterflies by Tenger-Trolander et al. in Proceedings of the National Academy of Sciences suggests that rearing and releasing monarchs obtained from commercial breeders—as well as rearing wild-collected monarchs in a controlled indoor environment—may have negative impacts on monarch migration and genetics. (Note: The full text can only be viewed with purchase; the summary, abstract, and footnotes can be viewed for free at the link above.) While more research is needed, this study provides support for recommendation by Xerces and many monarch researchers that rearing monarchs is not an appropriate conservation strategy for the species and carries risks. See Keep Monarchs Wild: Why Captive Rearing Isn’t the Way to Help Monarchs to learn more.


A monarch caterpillar (with yellow, black, and white stripes) crawls on a plant with pale green leaves and pink flowers, with an arid landscape in the background.
Monarch larvae on showy milkweed (A. speciosa) in the Great Basin. New research further supports the Xerces Society’s assertion that monarchs fare better when left to develop naturally, outdoors. (Photo: Xerces Society / Stephanie McKnight)


The Value of Community Science

The research papers above all relied on data collected by people like you, as part of community science projects. Community science is invaluable to contributing to our understanding of the western monarch and helps the conservation community to focus on the most important ways to conserve this beloved butterfly.

You can participate in community science projects which are vital to monarch research by joining people all over Canada, the U.S., and Mexico in collecting data on monarchs and milkweeds as part of the 2019 International Monarch Monitoring Blitz, from July 27 to August 4. If you live in the U.S. and are west of the Rocky Mountains, contribute your observations to the Western Monarch Milkweed Mapper; if you live east of the Rocky Mountains, contribute to Monarch Joint Venture’s Monarch Larva Monitoring Project; in Canada, check out Mission Monarch; if you’re in Mexico, we encourage you to contribute to Naturalista. We also recommend reporting first sightings of monarchs throughout these three countries to Journey North.

Already a user of iNaturalist? Check out the new Western Monarch Milkweed Mapper project to make contributing western records even easier on this popular platform.


A woman takes a photo of a monarch perched on a tree trunk, using her smartphone.
Community members across North America can make a big difference for monarch conservation, by participating in data collection efforts including the 2019 International Monarch Blitz. (Photo: Lisa Hupp / USFWS)


Looking for More Ways to Help?

Check out our Western Monarch Call to Action for more information, including what native milkweeds and nectar resources to plant, why it’s important to go pesticide-free in your garden, the importance of overwintering habitat protection, and more.

If you’re a grower in California, check out Xerces’ and the U.S. Fish and Wildlife Service’s A quick guide to monarch habitat on farms in California’s Central Valley, which provides guidance to helping monarchs in a part of the country where they need it the most.


Additional Resources

Learn more about the Xerces Society’s monarch conservation work.

Read about the Xerces Society’s Endangered Species Program.



As the Xerces Society's western monarch lead, Emma works on the western population of monarch butterflies, including adaptive management of overwintering habitat in California and breeding habitat throughout the western U.S. Emma completed a master's degree in agroecology and entomology at the University of Wisconsin–Madison where her research focused on landscape ecology and an invasive fly that affects fruit crops.

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