Here's why:
* Keystone species have a disproportionately large impact on their ecosystem relative to their abundance. They play a crucial role in maintaining the structure and function of the ecosystem.
* Giraffes are herbivores with a wide diet, but they don't significantly influence the distribution or abundance of other species. Their impact is more of a consumer, not a manipulator of the ecosystem's structure.
* Other species, like elephants or acacia trees, have a more pronounced effect on the African savanna. Elephants create clearings and disrupt vegetation, while acacia trees are a critical food source and habitat for many animals.
Examples of keystone species in Africa:
* Elephants: Their feeding and trampling activities create open areas and maintain grassland habitats.
* Lions: They regulate prey populations, influencing the distribution and abundance of herbivores.
* Acacia trees: Provide food and shelter for a wide range of species, creating a diverse and complex ecosystem.
While giraffes are important members of the African savanna ecosystem, their impact on its structure and function is not considered to be significantly disproportionate to their abundance. Therefore, they are not classified as a keystone species.