A federally endangered bumblebee — a single male of the species — has been discovered at the Pine Bend Bluffs Natural Area in Inver Grove Heights, a positive sign for ecologists who have worked on restoring the area.

A rusty patched bumblebee was identified recently in the 256-acre bluffland area along the Mississippi River on acreage owned by Flint Hills Resources, the company that owns Pine Bend refinery, according to a news release from Friends of the Mississippi River.

Just one bee represents approximately 0.2% of the species' known world population. Minnesota hosts the largest population of the bee in the world, with about 35% of the species buzzing about in the Twin Cities metro area, the release said.

The bee, also known by its Latin name Bombus affinis, was named Minnesota's state bee this summer by Gov. Tim Walz.

"The Pine Bend Bluffs Natural Area is a beautiful bluffland along the Mississippi River filled with unique hidden treasures," said Karen Schik, an ecologist at Friends of the Mississippi River, in a statement. She added that she's thrilled that the bee has made the area its home.

The Pine Bend Bluffs area — which is owned by Flint Hills Resources, the Minnesota Department of Natural Resources and Macalester College — is one of the largest natural areas in the Twin Cities, the news release said. It's located across the highway from the Pine Bend refinery.

The bee, which became a federally endangered species in 2017, also was spotted elsewhere in Dakota County this summer, in several Burnsville parks. The largest population was located in the city's restored Civic Center Prairie.

Once common across the Midwest and East Coast, the rusty patched bumblebee has played a critical role as a pollinator of crops and wildflowers. But its population has plunged 87% in the last 20 years, leaving small, scattered populations in 13 states.

It's on the brink of extinction due to single-crop farming, pesticides, loss of food and habitat, and climate change, according to the U.S. Fish and Wildlife Service.

Erin Adler • 612-673-1781