For decades, WBAI-FM has remained a proudly scrappy alternative in New York’s radio market, a bastion of left-wing political commentary and community voices rarely heard elsewhere on the dial.

That identity was cast into doubt on Monday when the station’s owner, the nonprofit Pacifica Foundation, abruptly laid off most of WBAI’s staff and replaced its local programming with shows drawn from Pacifica’s four other stations.

Ten of WBAI’s 12 employees were laid off, according to John Vernile, Pacifica’s interim executive director.

Employees and volunteer hosts at the station said they were blindsided by Pacifica’s decision. “We are in disbelief,” said Alexander J. Urbelis, a host of “Off the Hook,” a weekly show about computer hacking. “Nobody was given any notice of this or any opportunity to be heard.”