Non-uniform tropical forest responses to the 'Columbian Exchange' in the Neotropics and Asia-Pacific

It has been suggested that Iberian arrival in the Americas in 1492 and subsequent dramatic depopulation led to forest regrowth that had global impacts on atmospheric CO2 concentrations and surface temperatures. Despite tropical forests representing the most important terrestrial carbon stock globally, systematic examination of historical afforestation in these habitats in the Neotropics is lacking. Additionally, there has been no assessment of similar depopulation-afforestation dynamics in other parts of the global tropics that were incorporated into the Spanish Empire. Here, we compile and semi-quantitatively analyse pollen records from the regions claimed by the Spanish in the Atlantic and Pacific to provide pan-tropical insights into European colonial impacts on forest dynamics. Our results suggest that periods of afforestation over the past millennium varied across space and time and depended on social, economic and biogeographic contexts. We argue that this reveals the unequal and divergent origins of the Anthropocene as a socio-political and biophysical process, highlighting the need for higher-resolution, targeted analyses to fully elucidate pre-colonial and colonial era human-tropical landscape interactions. The authors assess the impact of Spanish colonization on forest dynamics across the tropics, finding variable responses according to regional land use strategies, as well as other cultural, social and biophysical factors.

Automated summary

The study reveals that afforestation in tropical regions varied spatially and temporally over the past millennium, depending on social, economic, and biogeographic factors. This highlights the unequal and divergent origins of the Anthropocene as a socio-political and biophysical process, emphasizing the need for higher-resolution, targeted analyses to fully understand pre-colonial and colonial era human-tropical landscape interactions. The impact of Spanish colonization on forest dynamics across the tropics was found to be variable, influenced by regional land use strategies, cultural, social, and biophysical factors.