Bus-powered devices will lose power, so will not function. (Valve actuators should automatically adopt a safe position.) On return of power, they should restart automatically, with or without operator intervention as desired by the user.
Communication will be lost (even to non-bus-powered devices). On removal of the short circuit, the network will recover automatically.
The power supply should include current limiting, so it would not be damaged, and will recover when the short is removed.