A tiny enemy threatens the powerful king of the savannah: it is the Pheidole megacephala ant, an invasive alien species that arrived in Kenya 15 years ago, progressively turning the entire ecosystem upside down to the point of forcing the lions to change their hunting habits to survive.
This is demonstrated by 30 years of research conducted at the Ol Pejeta Conservancy reserve, published in the journal Science by the research group led by the University of Wyoming.
To reconstruct the complex network of interactions between the species that populate the African ecosystem, researchers used camera traps, collars monitored by satellites and complex statistical models.
Data collected over 30 years shows that alien ants, who arrived quietly from an island in the Indian Ocean, triggered a devastating domino effect.
It all started with the extermination of native ants, which nest in acacia trees, defending them from attacks by herbivores with bites and the production of formic acid.
With these little 'guardians' missing, the trees began to be destroyed more easily by giraffes and elephants.
In an increasingly barren landscape, lions have thus found themselves no longer having areas to hide in to ambush their favorite prey, zebras.
To remedy this, they had to change their objective to buffalo, which were decidedly more difficult to hunt.
From 2003 to 2020, the percentage of zebra kills by lions dropped from 67% to 42%, while the percentage of buffalo kills went from zero to 42%.
The alien ants are therefore "loosening the bonds that hold the African ecosystem together, determining who gets eaten where", the researchers observe.
The study therefore demonstrates that "the conservation of ecosystems does not only require saving species from extinction, but safeguarding existing interactions between species", as underlined in a commentary article Kaitlyn M. Gaynor, ecologist at the University of British Columbia.
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