Final answer:
The overpopulation of zebras and antelopes without their predator, the lions, can lead to ecosystem imbalance due to excessive grazing. Lions serve as keystone species, and their presence is crucial for maintaining biodiversity.
Step-by-step explanation:
No, having more antelope and zebras will not necessarily help trees and shrubs to flourish, and it does not necessarily mean it will be helpful for the ecosystem. The absence of a main predator like lions can lead to overpopulation of herbivores such as zebras and antelopes.
This imbalance can cause excessive grazing, leading to degradation of vegetation, which negatively affects the biodiversity of the ecosystem. Rather, predators like lions play a crucial role as keystone species, maintaining the balance by keeping the herbivore populations in check. For instance, the reintroduction of wolves in Yellowstone National Park greatly enhanced the ecosystem's biodiversity, demonstrating the importance of such predators in habitat restoration and ecosystem balance.