Paleoecological orthodoxies long maintained that pre-Columbian Amazonian forests were essentially unaltered wildernesses, pointing to nutrient-poor, heavily leached oxisols as insurmountable barriers to sustained agriculture and dense settlement. Recent sediment core analyses, however, reveal localized soil horizons known as terra preta, which contain persistent pyrogenic biochar, elevated phosphorus levels, and high concentrations of edible palm phytoliths rather than climax canopy tree pollen. In contrast, adjacent forest tracts lacking terra preta display continuous arboreal succession and negligible microcharcoal deposits across the Holocene.
Based on the passage, which of the following statements about pre-Columbian Amazonian forests is most strongly supported?
- ASediment core analysis from regions containing terra preta indicates that climax canopy trees were completely eradicated across Amazonian habitats during the Holocene.
- BPre-Columbian populations relied on widespread slash-and-burn clearing that depleted soil nutrients throughout the broader river basin.
- Pre-Columbian anthropogenic modifications of forest vegetation and soil composition were geographically localized rather than uniformly distributed throughout the Amazon basin.Cevap
- DNaturally occurring oxisols across the Amazon basin spontaneously developed into terra preta via recurring natural wildfire cycles without human cultivation.
- EThe natural, unamended oxisols in the Amazon basin were sufficiently fertile to sustain large, permanent agrarian societies without artificial nutrient enrichment.