Centuries of compounding human influence on Amazonian forests

Area of Science:

• Ecology
• Environmental History
• Amazonian Studies

Background:

• Persistent ecological footprints of pre-Columbian Indigenous peoples in Amazonia are increasingly recognized.
• Ecological impacts from European colonization and the Amazonian Rubber Boom remain under-explored.
• Human activities can significantly alter forest structure and tree species composition over long timescales.

Purpose of the Study:

• To investigate the unexplored ecological impacts of European colonization and the Amazonian Rubber Boom.
• To determine if pre-Columbian and colonial human influences add to existing ecological legacies in Amazonian forests.
• To assess the spatial and temporal overlap of past human occupation sites and their potential ecological influences.

Main Methods:

• Utilized environmental niche models to predict probabilities of pre-Columbian and colonial occupation sites.
• Analyzed spatial and temporal distributions of predicted human occupation sites.
• Compared model outputs with relative abundances of Amazonian tree species to infer ecological legacies.

Main Results:

• Highest probabilities for pre-Columbian and colonial occupation sites were found in forests along rivers.
• Significant spatial overlap exists between predicted pre-Columbian and colonial human influences.
• Environmental gradients, known to structure vegetation, also predict past human influence.

Conclusions:

• Both pre-Columbian and colonial-period ecological legacies are associated with modern Amazonian forest composition.
• Past human activities, spanning millennia, have left enduring marks on Amazonian ecosystems.
• Understanding historical human-environment interactions is crucial for comprehending current forest dynamics.