Big Data Palaeoecology reveals significant variation in Black Death mortality in Europe

Abstract The Black Death is the most reknown pandemic in human history, believed by many to have killed half of Europe's population. However, despite the advances in ancient DNA research that allowed for the successful identification of the pandemic's causative agent (bacterium Yersinia pestis), our knowledge of the Black Death is still limited, based primarily on medieval texts available for single areas of Western Europe. In our study we remedy this situation and we focus in particular on the scale of the Black Death mortality. We collected data on landscape change from 261 coring sites (lakes and wetlands) located in 19 European countries. We used two independent methods of analysis to evaluate whether the changes we see in the landscape at the time of the Black Death agree with the hypothesis that half of the population died within a single year in each of the 21 regions we studied. We discovered that while the Black Death had devastating impact in some regions, it had negligible or no impact in others. The inter-regional differences in the Black Death mortality across Europe demonstrate the significance of cultural, ecological, economic and climatic factors that mediate the dissemination and impact of the disease. The complex interplay of these factors, along with the identification of the pathogen that caused disease outbreaks, should be the focus of future research on historical pandemics.