Population levels of more than 700 North American bee species are declining as habitat loss and pesticide use continue at a breakneck pace, according to a new report.

The report from the Center for Biological Diversity relies on an evaluation of more than 1,400 bee species with sufficient data for the assessment. More than half of those species are on the decline and nearly a quarter is at risk of extinction, according to the report.

“We’re on the verge of losing hundreds of native bee species in the United States if we don’t act to save them,” said study author Kelsey Kopec, a pollinator researcher, in a statement. “If we don’t act to save these remarkable creatures, our world will be a less colorful and more lonesome place.”

The study joins a growing body of research sounding the alarm on the threats facing bees. A 2015 report from a United Nations group found that populations are declining for 37% of bee species, with 9% of butterfly and bee populations facing extinction.

The insects play an important economic role as pollinators helping sustain agricultural production. In the United States, that value reaches billions of dollars annually, according to a 2015 White House report.