What If Gone

Species → African savanna elephant

African savanna elephant

Loxodonta africana

311,000 individuals
Extinction risk Endangered
MegaherbivoreEcosystem engineerSavanna
African savanna elephant (Loxodonta africana)
Photo: Diego Delso, Wikimedia Commons (CC BY-SA 4.0)

What if it disappeared?

Impact High
Years to decades

Without elephants preferentially knocking down and uprooting trees not defended by symbiotic ants, the boundary between open savanna and wooded areas would no longer be shaped the same way.

Documented
Detail

Goheen, J.R. et Palmer, T.M. (2010). Defensive Plant-Ants Stabilize Megaherbivore-Driven Landscape Change in an African Savanna. Current Biology, 20(19), 1768–1772.

The authors show that an acacia species protected by symbiotic ants withstands elephant damage far better than a closely related, unprotected species — a survival difference that, at the landscape scale, determines whether an area stays wooded or opens into savanna.

Over the long term

Without this browsing pressure, savanna would tend to close in into continuous woody cover — a mechanism documented across several African ecosystems, though its exact magnitude varies with rainfall and fire.

Extrapolated
Detail

Extrapolation à partir de plusieurs études de terrain sur la suppression de couvert ligneux par l'éléphant, dont Goheen & Palmer (2010).

Fire and climate act alongside elephants to maintain the savanna/open-woodland mosaic; disentangling the share attributable specifically to elephants from that of these other factors remains difficult and varies from site to site.

What's missing to confirm it: The relative contribution of elephants, compared to fire and rainfall, to the long-term maintenance of the savanna/open-woodland mosaic is not consistently isolated from one ecosystem to another.

Documentation

Last verified: August 7, 2026

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