Study Finds That Climate Change Could Lead Monarchs to Overwinter in New Places

Monarchs overwintering in Pacific Grove, California.

Jessica Weinberg McClsoky

February 2019 - A recent study uses a climatic niche model to predict where monarch butterflies might overwinter in the future. The study focuses on California’s Santa Barbara County, in part for its wide range of elevations. To establish where monarchs overwinter now, it uses the locations of groves surveyed during Western Monarch Counts. With a niche model that predicts these locations well, the researchers changed variables to test what might happen under different climate conditions. They find that current overwintering sites are not likely to remain the same. Rather, their model suggests a shift to higher elevations under a modest greenhouse gas emissions scenario. Under a more extreme scenario, they find that only the County's highest elevation ridges would qualify as suitable overwintering habitat.

The study’s authors also suggest several implications of their results for scientists and land managers. For example, if the butterflies start overwintering in new places, Western Monarch Count accuracy will suffer unless it can find a way to compensate. Similarly, the results suggest that protecting the groves where monarchs overwinter today may not be enough. Land managers may need to also find and conserve the possible overwintering sites of tomorrow. Check out the full study, published in the journal Insects, to learn more.

See more from the Bay Area Nature & Science Blog