Rare bee species makes a comebackin San Francisco's Presidio

SAN FRANCISCO - A rare species of sand-loving bees is making a comeback in San Francisco's Presidio for the first time in about a century.

The San Francisco Chronicle reports Friday ecologists spotted hundreds of silver digger bees in the park last week while surveying a dune restoration project in the park.

Experts believe the removal of invasive plants and the restoration of dunes and grasses at the former military base helped bring back the bees. They said the bees were common in San Francisco as late as the 1920s but began to disappear when the coastal prairie on the western side of the city was paved over for development.

Their habitat has been slowly restored since the military in 1994 turned the land over to the National Park Service.

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Information from: San Francisco Chronicle, http://www.sfgate.com