Conflicting research, listings and delistings of the monarch butterfly as endangered, and historic heat converged to ring in a new year that left monarch butterfly followers’ heads spinning in efforts to make sense of the news.

The hottest year in history set the stage for testy debates, given an increase of the average worldwide temperature of 1.48 degrees Celsius/2.66 degrees Fahrenheit. That increase is a frightening 2/10 of a Celsius degree from the Intergovernmental Panel on Climate Change goal of limiting a warming world to a maximum of 1.5 Celsius, set in 2016.

The extremely hot 2023 seemed to foreshadow that future. Severe drought, wildfires, record heat, the mis-timed emergence of milkweed in the spring and a lack of nectar plants in the fall. It also delayed or even cancelled departures for fall migrating monarchs since the warm autumn encouraged late season lingering and even winter breeding. 

In an interesting twist, Canada added the monarch butterfly to its endangered species list under Canada’s Species at Risk Act (SARA) in December. The SARA, enacted in 2002, aims to protect at-risk species of Canadian wildlife.

The move by Canada came on the heels of the highly respected International Union for the Conservation of Nature’s  (IUCN), reversal of listing the monarch as  “endangered” in September. The Sweden-based IUCN downgraded the monarchs to “vulnerable,” a less severe designation.

Commenting on the seemingly conflicting narratives, Andrew Holland, a spokesperson for the Nature Conservancy of Canada, told Global News that monarchs are having “a tougher time” in Canada than elsewhere around the world.

The Canadian listing, unlike the IUCN designation, comes with regulatory authority. Canada will establish recovery strategies, actions for protecting monarchs and make it an offense to kill, harm or damage a species or its residence.

Meanwhile, an optimistic new study published in the journal Insects by monarch researcher David James, who focuses on the the western population at Washington State University, clashed with the narrative of some monarch butterfly researchers who focus mostly on the eastern populaion.

drought dead trees

Drought and prolonged extreme heat took a toll on the ecosystem in 2023. –Photo by Monika Maeckle

In the study, published January 7 and titled “Monarch Butterflies in Western North America: A Holistic Review of Population Trends, Ecology, Stressors, Resilience and Adaptation,” James provides an overview of the impacts and consequences of climate change, pesticides, predators and other threats to the western monarch butterfly population. Ultimately, he concludes that monarch butterflies are amazingly resilient and have bounced back in recent years thanks, in part, to the the planting of non-native milkweeds in mostly urban settings.

Migration studies expert Andy Davis was not having it. Davis labeled the study “bombastic” in a post on his Thoughtful Monarch Facebook page, and took James to task for selective science.

“I referred to this paper as bombastic, because much of the conclusions David comes to are in contrast to those from other research, including some of my own, and many of my colleagues’,” Davis wrote in the post. He proceeded to challenge James for arguing that “things are different in the west than the east, and conclusions reached from eastern monarchs are not applicable (though he has no trouble drawing conclusions from work done in Australia).”

Weighing in from Emory University, monarch scientist Jaap de Roode, not a frequent presence on Davis’ Thoughtful Monarch page, also challenged James. “This paper is called a ‘Review,'” de Roode commented. “It is not. It is a speculative opinion piece that draws selectively on a subset of science that aligns with the author’s views.”

If you are confused about what to think about the future of monarch butterflies, you are not alone.

TOP PHOTO: Western monarchs overwintering on a conifer tree on the California coast. –Photo by Joanna Gilkeson/US Fish and Wildlife Service.

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