Answer :

Final answer:

The passenger pigeon was a keystone species due to its large population and significant impact on the ecosystem. They influenced seed dispersal and forest regeneration, playing a vital role in shaping the dynamics of their habitat.

Explanation:

The passenger pigeon was a keystone species due to its large population and its impact on the ecosystem. Keystone species play a vital role in their community, and major changes in their numbers can affect the populations of many other species.

The passenger pigeon was once the most numerous bird on Earth, forming enormous flocks that darkened the skies during migrations. Their presence had significant effects on the environment. For example, they influenced seed dispersal and forest regeneration. As they fed on fruits and nuts, they helped spread plant seeds over large areas, promoting the growth of diverse plant communities.

Unfortunately, due to market hunting on a massive scale and habitat destruction, the passenger pigeon became extinct in the early twentieth century. With their extinction, the ecosystem lost an essential player that had shaped the dynamics of forests and other components of their habitat.