March 4 (UPI) — Butterfly numbers are down across the American West, even in places relatively undisturbed by human activity.
In a new study, published Thursday in the journal Science, researchers compiled butterfly numbers for a variety landscapes across the West. According to the data, butterflies have experienced an annual decline of 1.6 percent over the last several decades.
Though researchers combined a variety of datasets, most of the info was sourced from the North American Butterfly Association’s summertime butterfly counts.
“This is the summer equivalent of the Christmas bird count,” lead study author Matt Forister told UPI in an email.
“Butterfly enthusiasts go out for a day in mid summer and count all of the butterflies in a certain area that they search every year,” said Forister, a biology professor at the University of Nevada, Reno.
Researchers also utilized data from a longterm butterfly-counting project in Northern California, as well as observation data posted on the iNaturalist web platform.
The combined datasets featured information on more than 250 butterfly species and 72 locations different locations. All of the data was collected between 1977 to 2018. The majority of data was collected in relatively undeveloped places.
“Our findings suggest that the effects of climate change are quite serious, leading to losses even in what appear to be otherwise-healthy ecosystems,” Forister said.
“A number of mechanisms may be involved, including effects on plants — that in turn affect insects — as well as effects on overwintering stages of insects that might not be as successful in warmer conditions,” he said.
Because most butterflies are easier to count than much smaller insects, they are an ideal target species for researchers trying to gain insights into the health of insect communities.
“We believe that butterflies are indeed good proxies for other insects and other pollinators,” Forister said.
The butterfly declines estimated by Forister and his research partners are in agreement with the estimated declines of other kinds of insects — losses ranging between 1 and 2 percent per year.
“Insects are the glue that holds terrestrial ecosystems together. They connect plants to numerous other animals, not the least of which are birds, many of which need caterpillars to raise their young,” Forister.
“So if we want to understand the resilience of intact ecosystems, looking to insects is a great way to do that. And, of course, in crop systems insects are key to food security because of pollination, pest control and other services,” he said.
If butterflies are suffering out in the wild, researchers suggest they’re likely struggling in urban and suburban settings, too. To help, scientists suggest boosting the diversity of butterfly-friendly plants in parks and yards.
“Among other things, people need to use less pesticides in their backyards and they should be asking their local city governments about the poisons used in parks,” Forister said. “And, just as important: fight climate change at all possible levels.”