Assessing the impact and legacy of swidden farming in neotropical interfiuvial environments through exploratory modelling of post-contact Piaroa land use (Upper Orinoco, Venezuela)

摘要

Humans are increasingly viewed as active agents of environmental and land-cover change in the moist Neotropics. While the scale and extent of pre-Columbian anthropic impacts are actively debated, the effects of post-Contact patterns of land use are rarely examined over the long term, defined here as centennial timescales. This article examines a putative area of historical low human impact located in the western Guiana Shield, the upper Cuao River, using an exploratory agent-based modelling approach. Based on an extensive ethnographic literature on the Piaroa, who have inhabited the region for at least four centuries, the model investigates the legacy effects of ethnographic patterns of land use in the interval between European Contact and the present. Model outcomes indicate that the potential range of anthropic changes to the environment of the study area is significantly greater in scale than previously assumed. Interpretative discrepancies between present vegetation conditions and the model are likely the product of sparse palaeoecological and archaeological research in the upper Cuao. More broadly, the results imply that small-scale agriculture and agroforestry can lead to extensive and persistent structural changes to ecosystems in relatively short timescales. The experiment bolsters existing cautions against assuming the 'natural' baseline of Neotropic forests based on present appearance. As a form of middle-range theory, the model demonstrates how computational approaches can promote closer integrations between ecological, archaeological, and ethnohistorical data, as well as frame the expectations of future research.