Collapse of an ecological network in Ancient Egypt

TL;DR

This study reconstructs 6000 years of Egyptian mammal community changes, revealing nonrandom extinctions linked to climate and societal collapse, and highlights how species roles evolve over time due to environmental pressures.

Contribution

It provides the first high-resolution analysis of millennial-scale ecological impacts of climate and human activity on predator-prey networks in Egypt.

Findings

Extinctions were nonrandom and associated with aridification events.

Community stability was linked to species sensitivity and dynamic stability.

Environmental and societal collapses coincided with community destabilization.

Abstract

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 6000-year span. The unprecedented temporal resolution of this data set 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. 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.