BioND — Dynamics of Biological Networks

Collapse of an ecological network in Ancient Egypt

Justin D. Yeakel, Mathias M. Pires, Lars Rudolf, Nathaniel J. Dominy, Paul L. Koch, Paulo L. Guimaraes, and Thilo Gross
Proceedings of the National Academy of Sciences 111(40), 14472–14477, 2014.



The dynamics of ecosystem collapse are fundamental to determining how and why biological communities change through time, as well as the potential effects of extinctions on ecosystems. Here, we integrate depictions of mammals from Egyptian antiquity with direct lines of paleontological and archeological evidence to infer local extinctions and community dynamics over a 6,000-y span. The unprecedented temporal resolution of this dataset enables examination of how the tandem effects of human population growth and climate change can disrupt mammalian communities. We show that the extinctions of mammals in Egypt were nonrandom and that destabilizing changes in community composition coincided with abrupt aridification events and the attendant collapses of some complex societies. We also show that the roles of species in a community can change over time and that persistence is predicted by measures of species sensitivity, a function of local dynamic stability. To our knowledge, our study is the first high-resolution analysis of the ecological impacts of environmental change on predator–prey networks over millennial timescales and sheds light on the historical events that have shaped modern animal communities.

Media Coverage

American Scientist, 2015-05-15
From the Cambrian Burgess Shale to ancient Egypt, food webs share surprising structural attributes. When redundancy is lost, the threat of extinction grows.

Clive Cookson and Tyler Shendruk, Financial Times Weekend Magazine, 2014-10-03
Research concludes that the region is more vulnerable to environmental perturbations today than at any previous time in recorded history

Tajirul Hague, New Historian, 2014-09-15
According to a new study that was published in the Proceedings of the National Academy of Sciences, a number of creatures that have been depicted in Ancient Egyptian artifacts have helped scientists to create a record of mammal extinctions that date back to 6000 years. The study might not offer comprehensive proof that population pressures and droughts forced these animals away, but they do depict an interesting pattern.

Archeology, 2014-09-14
Ancient Egyptian images of the natural world have helped quantitative ecologist Justin Yeakel of the University of California, Santa Cruz, determine that the drying climate and growing human population have probably made Egypt’s ecosystem progressively less stable.

Robert Czepel, Austrian Broadcasting, 2014-09-09
Vor 6.000 Jahren lebten in Ägypten noch Löwen, Elefanten und Giraffen. Heute sind sie längst aus dem Niltal verschwunden. Forscher haben die Wellen des Aussterbens mit Hilfe von Tierdarstellungen auf Kunstwerken rekonstruiert. Ihr Fazit: Verantwortlich dafür waren der Klimawandel - und der Mensch.

Sarah Griffith, Daily Mail, 2014-09-09
Rock inscriptions and tomb carvings have shed light on the large beasts that thrived in Egypt before they were wiped out around 6,000 years ago.

Popular Archaeology, 2014-09-08
Ancient Egyptian artworks help scientists reconstruct how animal communities changed as climate became drier and human populations grew.

Sarah Zielinski, Smithsonian Magazine, 2014-09-08
Ancient Egypt’s highly decorated tombs and funerary objects—meant to ensure a safe trip into the afterlife—also hold a rich record of the region’s wildlife. Now scientists have used that art, along with other paleontological, archaeological and historical evidence, to map out the rise and fall of Egypt’s large mammals and match those patterns to changes in climate and human interactions.

Jessica Ruvinsky, Science, 2014-09-08
Six thousand years ago, Egyptian lions hunted wildebeests and zebras in a landscape that resembled the Serengeti more than the Sahara. Since then, the number of large mammal species has decreased from 37 to eight, says quantitative ecologist Justin Yeakel of the Santa Fe Institute. New research using ancient animal depictions tracks the collapse of Egypt’s ecological networks one extinction at a time, offering a glimpse into how climate change and human impacts have altered the structure and stability of ecosystems over millennia.

John Roach, NBC News, 2014-09-08
Images of lions, giraffes, wildebeests and other creatures depicted on ancient Egyptian artifacts have helped scientists create a 6,000-year record of local mammal extinctions, according to a new study. Several of the extinction episodes correlate with known periods of drought and rapid human population growth.

Virginia Gewin, nature, 2013-08-08
Ancient Egyptian rock inscriptions and carvings on pharaonic tombs chronicle hartebeest and oryx — horned beasts that thrived in the region more than 6,000 years ago. Researchers have now shown that those mammal populations became unstable in concert with significant shifts in Egypt’s climate.