User blog comment:Jho5689/Fairy Tail 337 and onwards/@comment-11232389-20130625163146/@comment-1776824-20130625163858

Okay, for starters, Future Rogue's timeline won't collapse. It will continue as is, just without him there to witness it. Timelines don't ever collapse, they infinitesimally split. The Dragons actually should stay, as destroying the Gate was never mentioned to remove the Dragons in the first place, as they came from the past (and Future Lucy didn't know they came from the Eclipse Gate anyway). However, Zirconis MUST return to the past for time to flow correctly, just like a certain someone had to dance for time to continue to flowing normally as well. =P

This all means one of two things: Zirconis will die in a new Dragon King Festival (highly unlikely) or they will all be transported back to the past by the Eclipse Gate's destruction and Zirconis will die by Acnologia's hand (the preferred course of action).