Pre-Columbian fire management and control of climate-driven floodwaters over 3,500 years in southwestern Amazonia

In landscapes that support economic and cultural activities, human communities actively manage environments and environmental change at a variety of spatial scales that complicate the effects of continental-scale climate. Here, we demonstrate how hydrological conditions were modified by humans against the backdrop of Holocene climate change in southwestern Amazonia. Paleoecological investigations (phytoliths, charcoal, pollen, diatoms) of two sediment cores extracted from within the same permanent wetland, ∼22 km apart, show a 1,500-y difference in when the intensification of land use and management occurred, including raised field agriculture, fire regime, and agroforestry. Although rising precipitation is well known during the mid to late Holocene, human actions manipulated climate-driven hydrological changes on the landscape, revealing differing histories of human landscape domestication. Environmental factors are unable to account for local differences without the mediation of human communities that transformed the region to its current savanna/forest/wetland mosaic beginning at least 3,500 y ago. Regional environmental variables did not drive the choices made by farmers and fishers, who shaped these local contexts to better manage resource extraction. The savannas we observe today were created in the post-European period, where their fire regime and structural diversity were shaped by cattle ranching.

Participatory Mapping of Mid-Holocene Anthropogenic Landscapes in Guyana with Kite Aerial Photography

The nature and degree of human modifications of humid tropical forests in Amazonia have been widely debated over the past two decades. Many regions provide significant evidence of late Holocene anthropogenic influence by settled populations, but the antiquity of human interventions is still poorly understood due to a lack of earlier archaeological sites across the broad region, particularly pertaining to the mid-Holocene. Here we report on Amerindian occupations spanning the period from ca. 6000-3000 BP along the middle Berbice River, Guyana, including early evidence in Amazonia of cultural practices widely considered indicative of settled villages, notably terra preta or “black earth” soils, mound construction, and ceramic technology. These more settled occupations of the mid-Holocene initiated a trajectory of landscape domestication extending into historical times, including larger-scale late Holocene social formations. Collaborative research with local indigenous communities, including archaeological excavations, landscape mapping using kite based aerial photography, and three-dimensional photogrammetry, was designed to promote the decolonization of archaeological knowledge production and encourage indigenous ownership of Amerindian history and cultural heritage in Guyana.

Local varieties of Araucaria angustifolia (Bertol.) Kuntze (Pinales: Araucariaceae) in southern Brazil: A brief discussion about landscape domestication

A Araucária é uma espécie emblemática da Floresta Ombrófila Mista – FOM. O comércio do “pinhão”, sua semente, é economicamente relevante para grupos regionais, influenciando no manejo e uso da espécie. As populações da espécie foram historicamente manipuladas pela ação humana, que identificam variedades locais, caracterizando certo grau de domesticação da espécie e da paisagem. Assim, o objetivo desse estudo foi identificar essas variedades, caracterizar o uso e manejo do “pinhão” em comunidades locais circundantes ao Parque Nacional de São Joaquim – PNSJ, e discutir interações homem-plantas que possam ser relevantes na estruturação de paisagens culturais domesticadas. Aplicamos questionários semi-estruturados a quinze agricultores-extratores no entorno do PNSJ. Realizando turnês guiadas, montamos nove parcelas de 1600 m2 para coleta de dados populacionais da Araucária. Nos questionários, quatro variedades foram citadas: “Cajuvá”, “Macaco”, “Do cedo” e “Do tarde” além de duas variedades identificadas nas turnês-guiadas (N=52). Todos entrevistados afirmaram usar, direta/indiretamente, o “pinhão”, além de citarem variedades que conhecem e/ou manejam na FOM, evidenciando processo de domesticação. A conservação da Araucária pode ser favorecida ao considerar populações humanas locais que usam e manejam os recursos dessa espécie, fortalecendo sua conservação ao nível de paisagens manejadas junto às Unidades de Conservação do estado.