New research shows early-warning species is on the move, expanding or contracting geographic range and changing altitude<\/p>\n
Butterflies, often considered a \u201csentinel of change\u201d, are on the move across every continent they inhabit, shifting to survive as global heating reshapes their environment.<\/p>\n
About one in 10 species have already expanded or contracted their geographic range, or shifted in altitude, according to a global study published in Nature Ecology & Evolution.<\/p>\n
Lead author Dr Shawan Chowdhury, head of Monash University\u2019s Global Change Ecology Lab, said the study, which analysed shifts in 1,758 species across 105 countries, revealed the \u201castonishing\u201d scale of change, largely driven by climate change and extreme weather.<\/p>\n
\u201cButterflies are early\u2011warning indicators and are signalling a warning across the entire planet. If their ranges shift this dramatically, it signals profound changes across ecosystems.,\u201d he said.<\/p>\n
About 80% of butterflies that shifted expanded their ranges, often moving into newly suitable areas as temperatures rise.<\/p>\n
Some moved surprisingly fast, he said. The tawny coster butterfly \u2013 originally native to India, Bangladesh and Sri Lanka \u2013 entered Australia in 2012 and has moved at a rate of 135km per year since. An expanding range wasn\u2019t necessarily good news, he said, particularly if the insect was moving into less suitable habitat and populations were low.<\/p>\n
About 27% of species \u2013 including Cupido minimus, the United Kingdom\u2019s smallest butterfly \u2013 saw their ranges shrink, disappearing from areas they used to occupy. Others moved altitude, shifting to higher or lower elevations.<\/p>\n
Range expansions occurred across all continents, particularly in the tropics, while contractions were mainly in Europe and North America, the paper said. Shifts in elevation were almost exclusively in the northern hemisphere.<\/p>\n
Climate change and severe weather were the main drivers, although other factors played a role, such as habitat loss and agriculture. In Germany, a species known as the cranberry fritillary (Boloria aquilonaris) has lost much of its original habitat due to bog drainage. In Romania, agricultural intensification drove a contraction for the Danube clouded yellow butterfly (Colias myrmidone). In Brazil, the blue butterfly Godartiana byses has expanded from the states of Rio de Janeiro and Bahia to S\u00e3o Paulo in response to climate warming.<\/p>\n
Some species experienced range expansion in one part of their distribution and contraction in another, Chowdhury said, which was \u201cquite concerning\u201d. \u201cYou don\u2019t really know what\u2019s going to happen for that species, whether they\u2019re going to be endangered or whether they are going to be least concern in the long term.\u201d<\/p>\n
Globally, butterfly conservation plans would need to respond to species on the move, particularly in response to climate change, Chowdhury said.<\/p>\n
\u201cWe urgently need coordinated global monitoring, especially in the tropics, to understand what species are doing, where they\u2019re going, and how we can protect them,\u201d he said.<\/p>\n
In Melbourne, one endangered butterfly has shown promising signs of recovery.<\/p>\n
Before its rediscovery in 1986, the Eltham copper butterfly \u2013 small, burnished and roughly the size of a coat button \u2013 was thought extinct. Its survival depends on an intricate three-way relationship with a native shrub known as sweet bursaria and the Notoncus ant, which lives in the root of the plant.<\/p>\n