Global warming is leading to a population decline in northerly butterfly species and a flourishing population in subtropical species, according to a Harvard University study.

The group gathered its data from the Massachusetts Butterfly Club, an amateur naturalist group that logged nearly 20,000 trips throughout the state of Massachusetts over the past 19 years.

The findings, published by Harvard University students in Nature Climate Change on Sunday, showed that uncertain climates are changing butterfly communities.

"Over the past 19 years, a warming climate has been reshaping Massachusetts butterfly communities," said the study's lead author, Greg Breed, in a release.

There were reports of an increase in warm climate species, like the giant swallowtail and zabulon skipper, which were considered rare to the region as recently as the 1980s.

However, three quarters of species that were known to thrive in the north of Boston, Mass., have seen a rapid decline. Those that exist as eggs or larvae in winter months might have been affected by drought or a lack of snow, according to the study.

"For most butterfly species, climate change seems to be a stronger change-agent than habitat loss," Breed said. "Protecting habitat remains a key management strategy, and that may help some butterfly species. However, for many others, habitat protection will not mitigate the impacts of warming."