Predicting pre-Columbian anthropogenic soils in Amazonia

Area of Science:

• Archaeology
• Environmental Science
• Soil Science

Background:

• The extent of pre-Columbian human impact in Amazonia is debated.
• Nutrient-enriched terra preta soils indicate long-term settlement.
• Previous research has not fully clarified factors influencing terra preta distribution.

Purpose of the Study:

• To determine the influence of environmental conditions on terra preta soil formation in lowland Amazonia.
• To model the potential distribution of terra preta soils.
• To identify areas for future archaeological research.

Main Methods:

• Utilized known and newly discovered terra preta sites.
• Employed maximum entropy algorithms (Maxent) for predictive modeling.
• Analyzed terrain, hydrologic, soil, and climatic data.

Main Results:

• Terra preta soils are concentrated in central and eastern Amazonia along major rivers.
• Terrain, hydrology, and soil characteristics were key predictors, more so than climate.
• Predicted terra preta distribution covers approximately 154,063 km² (3.2% of the forest).
• Terra preta formation was likely limited in western Amazonia.

Conclusions:

• Terra preta distribution is highly predictable based on environmental parameters.
• The study provides targets for future archaeological surveys in Amazonia.
• Highlights limitations of current forest inventory sites in capturing historical disturbance effects.