Suitable habitat for migrating monarch butterflies will shift southwards because of climate change, according to a study publishing February 25th in the open-access journal PLOS Climate by Francisco Botello and Carolina Ureta at the National Autonomous University of Mexico and colleagues.
One of the most dramatic and awe-inspiring phenomena in nature is the mass migration of the brightly colored monarch butterfly. Each year, millions of monarchs travel thousands of kilometers from their breeding grounds in Canada and the U.S. to overwintering sites in central Mexico. Conservationists have raised concerns over dramatic declines in the number of migrating monarchs, caused by a combination of habitat loss, parasites, and reduced availability of food plants. Monarch butterflies (Danaus plexippus) rely on milkweed plants in the genus Asclepias, which provide egg-laying sites, food, and toxic compounds that help to protect caterpillars and adult butterflies from predators. Climate change could affect the availability of milkweed plants, as well as altering cues that trigger migration, such as temperature. However, few studies have investigated how climate change will impact monarch migration.
Researchers used computer modelling to predict the location of suitable habitat across Mexico for monarch eggs and caterpillars and for tropical milkweed plants in 2030, 2050 and 2070. The results show a decline in suitable habitat of between 8% and 40% by 2070. Monarch habitat shifted southwards, driven by changes in climate and the geographic distribution of milkweed plants. This caused egg-laying sites and food plant availability to become more concentrated in southern Mexico, fracturing existing migrating routes.
The study highlights significant changes in available habitat for migrating monarch butterflies as the climate warms. The disruption of monarch migration routes may cause the butterflies to establish resident populations in northeastern and central Mexico, instead of continuing their route to the north. For long-distance migratory species like monarch butterflies, international collaboration will be essential to conserve their migration in the face of climate and environmental change, the authors say.
The authors add, "Although the monarch butterfly species itself may not be directly threatened under climate change scenarios, its migratory process is. Under future climate change scenarios, areas of highest climatic, biological, and environmental suitability for monarch butterflies are projected to shift farther away from the Mexico–U.S. border, making migration energetically more demanding and potentially promoting population residency rather than long-distance migration."
In your coverage, please use this URL to provide access to the freely available paper in PLOS Climate: https://plos.io/4ruNBEQ
Citation: Sánchez-Cordero V, Castañeda S, Mendoza-Ponce A, Juárez-Jaimes BV, Botello F, Ureta C (2026) Regional risk shifts to monarch butterfly migration due to climate change. PLOS Clim 5(2): e0000802. https://doi.org/10.1371/journal.pclm.0000802
Author countries: Mexico
Funding: The author(s) received no specific funding for this work.
