Faecal records show Maya population affected by climate change

A McGill-led study has shown that the size of the Maya population in the lowland city of Itzan (in present-day Guatemala) varied over time in response to climate change. The findings, published recently in Quaternary Science Reviews , show that both droughts and very wet periods led to important population declines. These results are based on using a relatively new technique involving looking at stanols (organic molecules found in human and animal faecal matter) taken from the bottom of a nearby lake. Measurements of stanols were used to estimate changes in population size and to examine how they align with information about climate variability and changes in vegetation drawn from other biological and archaeological sources. By using the technique, the researchers were able to chart major Maya population changes in the area over a period starting 3,300 years before the present (BP). They were also able to identify shifts in settlement patterns that took place over the course of hundreds of years that are associated with changes in land use and agricultural practices. They discovered, moreover, that the land had been settled earlier than previously suggested by archaeological evidence.