Egyptian Artifacts Reveal Ecological Collapse and Mammal Extinctions Over 6000 Years of History

Scientists have learned a bit more about Egypt's ancient ecological past by examining depictions of animals in ancient Egyptian artifacts. Now, researchers have announced that species extinctions probably made the ecosystem progressively less stable over time.

About six millennia ago, there was about 37 species of large-bodied mammals in Egypt, including lions, wild dogs, elephants, oryx, hartebeest and giraffe. Today, though, only eight of these species remain.

"What was once a rich and diverse mammalian community is very different now," said Justin Yeakel, one of the researchers, in a news release. "As the number of species declined, one of the primary things that was lost was the ecological redundancy of the system. There were multiple species of gazelles and other small herbivores, which are important because so many different predators prey on them. When there are fewer of those small herbivores, the loss of any one species has a much greater effect on the stability of the system and can lead to additional extinctions."

The researchers examined paleontological and archaeological evidence in the region, as well as historical records. They identified five episodes over the past 6,000 years when dramatic changes occurred in Egypt's mammalian community. Three of these episodes coincided with extreme environmental changes as the climate became hotter and dryer. These drying periods also corresponded with upheaval in human societies, such as the collapse of the Old Kingdom about 4,000 years ago.

"There were three large pulses of aridification as Egypt went from a wetter to a drier climate, starting with the end of the African Humid Period 5,500 years ago when the monsoons shifted to the south," said Yeakel. "At the same time, human population densities were increasing, and competition for space along the Nile Valley would have had a large impact on animal populations."

The findings reveal a bit more about these shifting climate patterns. In fact, the most recent shift occurred just 100 years ago. The fact that these shifts had huge impacts on ecosystem stability means that there are implications for understanding the modern ecosystems of today.

The findings are published in the journal Proceedings of the National Academy of Sciences.