Butterflies in the U.K. experienced their fourth worst year on record in 2016 and the majority of species saw a decline in numbers, according to a new study.
The yearly U.K. Butterfly Monitoring Scheme found that out of 57 species studied, 40 recorded a decline compared to 2015, with a mild winter and cold spring creating a difficult environment.
The study was led by Butterfly Conservation, the Centre for Ecology & Hydrology, the British Trust for Ornithology and the Joint Nature Conservation Committee.
In a news release on Wednesday, Butterfly Conservation said that research indicated "increasingly mild winters" were impacting butterflies because they could lead to, among other things, increased disease and predation. It added that cold springs could reduce or delay emergence, leading to shorter lifespans.
"Worryingly, not even the pleasant summer weather of 2016 was enough to help butterflies bounce back from a run of poor years," Tom Brereton, head of monitoring at Butterfly Conservation, said in a statement.
"The results show that butterflies are failing to cope with our changing climate and how we manage the environment," Brereton added. "As butterflies are regarded as good indicators of environmental health this is hugely concerning for both wildlife and people."
Among the butterflies which saw a decline, the Heath Fritillary fell by 27 percent compared to 2015, while the Grizzled Skipper fell by 24 percent and the Gatekeeper dropped by 48 percent. The Heath Fritillary has fallen by 82 percent in the last decade.
"The weather at critical times of species development can cause dramatic changes in population numbers in the short term," Marc Botham, butterfly ecologist at the Centre for Ecology & Hydrology, said.
"What is of greatest concern is the regularity with which these short-term changes in recent years are negative, resulting in significant long-term declines for many species."