Functional Extinction refers to a species whose population has declined to the point where it can no longer play a significant role in their ecosystem. 

As of March 2021, the Australian Government listed an extra 13 species as extinct under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). 

That brings the total number to 100 of Australia's endemic species validly listed as extinct (or extinct in the wild) since the colonisation by Europeans in 1788. 

Sadly, more mammal species have become extinct in Australia than any other country.

natureaustralia.org