Fifteen to 34-year-olds have spent more time listening to streaming music services than all of BBC radio for the first time.
The broadcaster has outlined the challenges it faces as competition increases, in its annual plan.
In radio, it said that from October to December 2017 – for the first time, it is estimated that “15 to 34-year-olds listened more to streaming music services (five hours a week) than all BBC radio (four hours 30 minutes).”
In TV, 16 to 24-year-olds spend more time with Netflix than all of BBC TV (including iPlayer).
While 16 to 34-year-olds spent similar amounts of time with BBC1, ITV and Netflix – around two hours a week each.
The BBC said changes to the TV market increased the risk of an “imminent threat” to British content.
And it said: “As our income has fallen in real terms, our ability to fund original British content has diminished.”
It added: “The volume and breadth of British content that British audiences rely upon is now under serious threat.”
It also said that under-35s are spending less time with BBC News.
It said BBC News would take the lead on challenging “fake news”.
It will also “challenge misleading accusations and engage more openly with critics on social media as well as address and correct errors in real-time”.
The plan also said there would be further changes to iPlayer to create more “live content” and “personalisation”.