One in Ten Butterfly Species Has Shifted Its Range as Climate Warms, Largest Global Study Finds

The largest study of its kind — 6,182 range-shift records for 1,758 butterfly species across 105 countries — finds roughly one in ten species has moved, with climate change and extreme weather behind nearly 80% of documented shifts. Most shifting species expanded their ranges, but the tropics remain a critical blind spot.

Key Takeaways

The largest study of its kind — 6,182 range-shift records for 1,758 butterfly species across 105 countries — finds roughly one in ten species has moved, with climate change and extreme weather behind nearly 80% of documented shifts.
Most shifting species expanded their ranges, but the tropics remain a critical blind spot.

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Roughly one in ten butterfly species worldwide has shifted its distribution range, with climate change and extreme weather behind nearly 80% of the documented moves, according to the largest study of its kind, published in Nature Ecology & Evolution and led by Dr. Shawan Chowdhury of Monash University.

The team compiled 6,182 range-shift records for 1,758 butterfly species across 105 countries, drawing on scientific literature in English and other languages plus 68 expert assessments. "We found butterfly species shifting their ranges on every continent where they occur," Chowdhury said. "The scale is astonishing, and it's happening far beyond the well-studied regions of Europe and North America."

Among species that moved, 80% expanded their ranges, often tracking newly suitable conditions as temperatures rise; 27% contracted; and 22% shifted along elevational gradients — though elevational shifts were rarely documented in the tropics, a major concern given that tropical species live close to their thermal limits.

The study also exposes severe blind spots: Central Africa, Southeast Asia, New Guinea and the Amazon remain critically under-represented despite being global biodiversity hotspots. "Without non-English studies and expert knowledge, we would have dramatically underestimated the global patterns," Chowdhury said. Five European countries — the Czech Republic, Finland, Luxembourg, Spain and Sweden — have documented shifts for more than half of their butterfly species.

The authors argue that butterflies are early-warning indicators: if their ranges are shifting this dramatically, it signals profound changes across ecosystems. They call for equitable, standardized, multilingual monitoring, especially in the tropics, to meet the targets of the Kunming-Montreal Global Biodiversity Framework. "Climate-driven redistribution is not a future scenario but a current, accelerating reality," Chowdhury said, one that demands conservation strategies capable of responding to species on the move.