Faecal sterols reveal human colonization of the planet
The chemical compounds accumulated in human faeces in sediments and soil can tell a part of our evolution on Earth.
Thanks to these findings, researchers from Ca’ Foscari University of Venice and IDPA-CNR have demonstrated the presence of individuals who colonized the oceanic islands and the resulting environmental transformation.
In this international study, the results of which were published in Scientific Reports, the researchers analysed the faecal remains found in the sediments of Lake Diamond and Lake Kirkpatrick, proving the presence of the Maori people who, starting from around 1280, colonized the two islands, clearing them of forests in just a few decades to make space for fields and pastures.
Microparticles of coal and pollen were found in the sediment cores analysed, which are evidence of forest fires as well as of sudden and unprecedented change.
Archaeological and palaeoecological evidence attributes the deforestation to the Maori people. The new study confirms their arrival in the area and the impact they had on the native forest, which also demonstrates the validity of the method used by the Italian researchers to reconstruct the history of human presence in a given region.
“Lakes collect traces of the faeces of populations that have lived in surrounding areas, and these are deposited on the lake floors”, explained Elena Argiriadis, one of the authors of the study.
“Traces of human excrement also tell of the Europeans’ arrival on the southern island of New Zealand starting in the 1800s. The exponential growth in the concentration of faecal sterols demonstrates the rapid increase in the population of the area from the beginning of the nineteenth century to the present day”, said Carlo Barbante, Professor at Ca’ Foscari University and Director of CNR-IDPA.