A rusty patched bumble bee, which the U.S. Fish and Wildlife Service proposed listing for federal protection as an endangered species, is pictured in Madison, Wis., on Aug. 7, 2015. (Courtesy of Rich Hatfield via Reuters)

The U.S. Fish and Wildlife Service on Thursday delayed listing the rusty patched bumble bee as endangered, a result of a regulatory freeze White House chief of staff Reince Priebus imposed on President Trump’s first day in office.

The previous administration announced Jan. 11 that the rusty patched bumble bee, whose numbers have declined 87 percent since the mid-1990s, was so imperiled that it should become the first bee species to be listed as endangered. But a day before the new protections were set to take effect, the Fish and Wildlife Service said they would not take effect before March 21.

The striped black and yellow pollinator with a long black tail used to be so abundant in the Midwest that it was considered a nuisance by some residents. It now only exists in parts of Wisconsin, Illinois and Minnesota. A parasitic fungus carried by commercial bees, along with habitat destruction and pesticide exposure has contributed to such a severe decline that the Fish and Wildlife Service has determined it will go extinct within 40 years without federal intervention.

“The change in the effective date from February 10 to March 21, 2017, is not expected to have an impact on the conservation of the species,” Gary Frazer, the agency’s assistant director of ecological services, said in a statement. “FWS is developing a recovery plan to guide efforts to bring this species back to a healthy and secure condition.”

Previous administrations — dating back to Ronald Reagan — have enacted a 60-day freeze on pending regulations upon taking office, though they have allowed many of those measures to go through without delay. The memo stated that a pause in regulatory action was needed for “reviewing questions of fact, law, and policy they raise.”

“The Department is working as expeditiously as possible on this and expects to issue further guidance on the effective date of the listing shortly,” Heather Swift, a spokeswoman for the Interior Department, said in an email.

An endangered species listing would force the Fish and Wildlife Service to outline steps to recover the bumble bee and designate protected habitat for it. Farm groups, as well as oil and gas firms, opposed the endangered designation on the grounds that it could interfere with their industries’ operations.

Rich Hatfield, senior endangered species conservation biologist for the Xerces Society for Invertebrate Conservation, said in an interview that he remained optimistic that the bee would win new federal safeguards.

“This species is critically imperiled and needs protection,” he said. “I’m hopeful that the administration will recognize the importance that pollinators play for food security in this country.”

Hatfield added that the Fish and Wildlife Service established a committee of experts in November to help stave off the bee’s extinction, and the working groups are scheduled to reconvene by phone next week. “Those meetings have not been canceled,” he said.