As well as royal affairs and the exploits of the gods, ancient Egyptian artefacts depict lions, giraffes, hartebeests and elephants – all of which are extinct in modern Egypt. Using ancient art such as the ceremonial slate palette in Oxford’s Ashmolean museum, scientists writing in the journal PNAS paint a dismal picture of ecological destabilisation in the Nile Valley since the first pharaohs. The research concludes that the region is more vulnerable to environmental perturbations today than at any previous time in recorded history.
Egypt was once home to 37 species of large mammals; today there are eight. A team led by Justin Yeakel of the Santa Fe Institute in New Mexico assembled a detailed timeline of this ecological collapse that shows striking coincidences between local extinctions and environmental shifts to drier conditions. Of the five separate episodes of dramatic change since the unification of Egypt 5,000 years ago, three occurred during drying events and coincided with upheavals to Egyptian dynasties.
“Understanding how ecosystems functioned in the recent past – and even the distant past – can have a huge impact on how we understand them today,” Yeakel says.
The steady erosion of species diversity over time selectively eliminated herbivores, leading to an increasingly predator-heavy ecosystem. Today, the predator-prey networks in Egypt rely on a small number of pivotal species, including critically endangered rhim gazelles, so that extinctions now have a disproportionately large impact on mammalian communities.
“The system has lost redundancy; 6,000 years ago it was very diverse,” says Yeakel. “There were many different smaller-bodied herbivores but their elimination unravels the food base, pulling the rug out from under the food web.”
The most recent shift in mammalian communities began about 100 years ago with the local extinction of animals including leopards and wild boars. This still continues, and a number of the remaining mammal species are considered critically endangered.
“This might be a modern phenomenon,” warns Yeakel. “It’s important to know if this is a more general pattern in ecological systems because if it is, it means that perturbations that happened in the past may have different impacts today.”
Photograph: Ashmolean Museum, University of Oxford