An evaluation of fecal stanols as indicators of population change at Cahokia, Illinois

Fecal stanols show simultaneous flooding and seasonal precipitation change correlate with Cahokia’s population decline

“…Although other mammals, including dogs, donkeys, seals, horses, goats, and cattle, produce coprostanol, only sheep and pigs are known to generate sufficient quantities that could mask changes in human stanol concentration (20)(21)(22)(23), and neither domesticate was present in the Cahokia area before Euroamerican settlement (24). White et al (15) demonstrated the validity of this approach by producing a 1,200-y record of Cahokia region population change through fecal stanol analysis of Horseshoe Lake sediment that parallels population trends identified by previous demographic reconstructions derived from archaeological evidence (2,14). Because smaller sites contemporary with Cahokia's occupation are present in the watershed (2), and the proximity of a population to drainages and the lake may affect the amount of fecal stanols at each coring site, the Horseshoe Lake fecal stanol record (15) captures population change at the watershed level.…”

“…White et al (15) demonstrated the validity of this approach by producing a 1,200-y record of Cahokia region population change through fecal stanol analysis of Horseshoe Lake sediment that parallels population trends identified by previous demographic reconstructions derived from archaeological evidence (2,14). Because smaller sites contemporary with Cahokia's occupation are present in the watershed (2), and the proximity of a population to drainages and the lake may affect the amount of fecal stanols at each coring site, the Horseshoe Lake fecal stanol record (15) captures population change at the watershed level. However, Cahokia is the most likely candidate for controlling the lake's fecal stanol signature because HORM12 and 15HSL show parallel trends; the stanol trends in both cores closely track the Cahokia population estimates of previous demographic reconstructions (2,14); the footprint of Cahokia's inhabitants on the landscape likely expanded throughout much of the watershed through activities such as hunting, fishing, and gathering; modern hunter-gatherers (25) and rural farmers (26) without sewage systems frequently practice open defecation away from their homes, where much of their daily activities take place; archaeological surveys around Horseshoe Lake show fewer Mississippian Lohmann phase sites, c. 1050-1100 CE, compared with sites from the preceding century and a half, whereas within the watershed, the numbers of Lohmann phase sites and sites from the preceding phase are similar, which is evidence of shifting settlement locations associated with the rise of Cahokia (27,28); and Cahokia is the largest archaeological site in the watershed, followed by the East St. Louis Mound precinct near the watershed's southwest corner (29).…”

“…Fecal stanols, notably coprostanol and epicoprostanol, are organic molecules that originate in the guts of humans and may persist in sediment for hundreds to thousands of years (18). Fecal stanols deposited in sediment provide evidence of trace human waste products, and are used as a proxy for measuring population change over time (15,19). Although other mammals, including dogs, donkeys, seals, horses, goats, and cattle, produce coprostanol, only sheep and pigs are known to generate sufficient quantities that could mask changes in human stanol concentration (20)(21)(22)(23), and neither domesticate was present in the Cahokia area before Euroamerican settlement (24).…”

“…This study directly compares reconstructions of Cahokia-region population change inferred from fecal stanol concentrations (15) with changes in hydroclimate inferred from oxygen-isotopic analysis and grain size within two cores, HORM12 and 15HSL, from Horseshoe Lake, an oxbow lake on the Mississippi River floodplain in southern Illinois (Fig. 1).…”

Cahokia: Urbanization, Metabolism, and Collapse

“…Fecol stanols (organic molecules that originate in the human gut, and persist for centuries in soils) closely track reconstructed population trends in the American Bottom (White et al, 2018). The frequency of these molecules, argue White et al (2019), support the idea that massive flooding was related to the late twelfth century changes, including population contraction, catastrophic abandonment of some settlements, a decline in mound construction, and the building of the first palisade.…”