jackscarab:

Functional extinction is when a population becomes so limited that they no longer play a significant role in their ecosystem and the population becomes no longer viable. While some individuals could produce, the limited number of koalas makes the long-term viability of the species unlikely and highly susceptible to disease.

I mean.

I knew that Australia was on fire, but I didn’t take the next step in logic to realize that the species that lived in some of the trees of the continental brushfire would take such a severe hit from it.

At least some polar bears have wandered south and crossed with grizzlies as an alternative to starving and drowning in the increasingly iceless Arctic. Koalas have no such luck. Their survival needs are too specific. They’re done for.