Climate change driving butterfly range shifts worldwide

A global study of nearly 2,000 butterfly species found that climate change and extreme weather are driving widespread shifts in butterfly ranges around the world, while researchers warn that major gaps in biodiversity monitoring remain in many regions.(CN) — Here is a butterfly effect that scientists can actually measure.The geographical ranges of the colorful winged insects appear to be shifting all around the world, likely as a result of climate change and extreme weather, according to a study published in Nature Ecology & Evolution on Wednesday.The shifts potentially signal broader environmental changes across ecosystems, researchers from Australia’s Monash University, the German Centre for Integrative Biodiversity Research, the Friedrich Schiller University Jena and the Helmholtz Centre for Environmental Research say.“The main message is that butterfly redistribution is already happening, and it is more complex than a simple story of species moving poleward or uphill,” co-author Shawan Chowdhury, a global change biologist at Monash University, said in an email to Courthouse News. “Climate change and extreme weather are major drivers, but they are not acting alone. Land-use change, habitat degradation, agriculture, urban development and invasive species also shape where butterflies can survive. In many cases, climate change may push species to move, while land-use change blocks the route.”The global analysis of the range-shift records for almost 2,000 butterfly species examined 6,182 range shifts across more than 100 countries.Due to their short life cycles and sensitive environmental needs, butterflies can be seen as an early-change indicator for the environment, Chowdhury said.“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.”Researchers documented evidence of range shift for 1,758 butterfly species, representing about 10% of all known butterfly species worldwide based on published studies going back to 1991.Among the species with documented range shifts, 80% had expanded their range, 27% had experienced range contractions, and 22% had shifted along elevational gradients.Because many species exhibited multiple types of range shift, those percentages exceed 100%. For instance, butterflies may expand in one area and decline in another, Chowdhury explained.Horizontal expansions — or shifts from one area to another — were recorded on every continent, with particularly high numbers in tropical countries, while range contractions were more common in temperate regions such as Europe and North America. Elevational shifts were found almost exclusively in the Northern Hemisphere.The study also showed that there were major disparities in how well butterfly range shifts were documented among the 105 countries that were analyzed.In some European countries, such as the Czech Republic, Finland, Luxembourg, Spain and Sweden, records exist for more than half of the countries’ butterfly species, the researchers found. But in most other countries, range shifts have been documented for less than 10% of butterfly species.Researchers were able to include non-English scientific literature in their study as well as 68 expert assessments. This allowed them to create a more comprehensive dataset, they said.“Recording contributions from butterfly experts from society and efforts of natural history societies [was] hugely important to understand global butterfly biodiversity patterns,” Aletta Bonn, a professor of ecology at the Friedrich Schiller University in Jena, Germany, said.However, major geographic analysis gaps remain in Central Africa, Southeast Asia, New Guinea and the Amazon, despite being significant global hotspots for biodiversity, the researchers said.“The study helps balance the picture, but it also demonstrates an urgent need of concerted action to expand monitoring efforts globally,” co-author Guy Pe’er, a biologist with the the German Centre for Integrative Biodiversity Research and the Helmholtz Centre for Environmental Research, both in Leipzig, Germany, said in a statement.Without equitable, standardized and multilingual biodiversity monitoring, conservation efforts could be guided by incomplete evidence, the researchers cautioned.Subscribe to our free newslettersOur weekly newsletter Closing Arguments offers the latest about ongoing trials, major litigation and rulings in courthouses around the U.S. and the world, while the monthly Under the Lights dishes the legal dirt from Hollywood, sports, Big Tech and the arts.Additional Reads