The news that Koalas are functionally extinct are from a press release that was issued in May, before the fires, from a group that has been saying they're extinct for years. Koalas ARE IN TROUBLE but there is still hope for conservation.
Update on the koalas: Scientists say there's no way to know how bad the situation is. "It's incredibly difficult for scientists to get a full grasp on koala numbers across Australia, so categorizing the species as 'functionally extinct' is difficult."
I thought this, from the excellent , was very helpful.
There is no way the fires in their current form are going to cause national extinction. Here, the claim is 1000 koalas have died, and I have not seen a higher number