Swiss authorities have temporarily shut the airspace over a small part of southwestern Switzerland because recreational gliders have endangered the work of emergency teams battling a persistent forest fire in the area. The Federal Office of Civil Aviation said Friday that the restriction in an airspace of up to about 2,400 meters, over a wooded mountainside near the town of Bitsch, will last a week. The measure affects civil aircraft and drones and is aimed “to protect the ongoing activities of response teams on the ground and in the air,” the office said. Office spokesman Christian Schubert said the closure affects about 40-50 square kilometers in an area that is popular with recreational gliders. The heads of local helicopter crews and firefighting squads requested the closure because of the dangers presented by the gliders to what was already risky work, Schubert said.