How could the death of large animals affect the stability of biogeocenoses?

Large animals occupy several ecological niches in the biocenosis at once, for example, predators (wolves, bears) or some herbivores (deer, moose). If they die, several links will disappear in the power supply chains at once.

1) If these are predators, then there will be no one to regulate the number of herbivores. Due to increased competition for food and the spread of disease, they will begin to die.

2) Due to the lack of large herbivores, predators will also have nothing to eat.

The ecosystem will begin to collapse, its sustainability will decline. Nevertheless, the vacated ecological niches can be occupied by other organisms, and then the ecosystem will survive.