This is an article about the fact that some endangered species have unique and irreplaceable ecological niches is not taken into consideration when prioritizing conservation. It does not mention parrots BUT we do know, from other studies, that the canopy feeders behavior of throwing most of their food to the floor, not only disperses plant species but also feeds lots and lots ground animal species. Eliminate them and you are killing off plants and other animals.
https://phys.org/news/2020-02-threatene ... roles.html