Legacies of Indigenous land use and cultural burning in the Bolivian Amazon rainforest ecotone

Abstract

The southwestern Amazon Rainforest Ecotone (ARE) is the transitional landscape between the tropical forest and seasonally flooded savannahs of the Bolivian Llanos de Moxos. These heterogeneous landscapes harbour high levels of biodiversity and some of the earliest records of human occupation and plant domestication in Amazonia. While persistent Indigenous legacies have been demonstrated elsewhere in the Amazon, it is unclear how past human–environment interactions may have shaped vegetation composition and structure in the ARE. Here, we examine 6000 years of archaeological and palaeoecological data from Laguna Versalles (LV), Bolivia. LV was dominated by stable rainforest vegetation throughout the Holocene. Maize cultivation and cultural burning are present after ca 5700 cal yr BP. Polyculture cultivation of maize, manioc and leren after ca 3400 cal yr BP predates the formation of Amazonian Dark/Brown Earth (ADE/ABE) soils (approx. 2400 cal yr BP). ADE/ABE formation is associated with agroforestry indicated by increased edible palms, including Mauritia flexuosa and Attalea sp., and record levels of burning, suggesting that fire played an important role in agroforestry practices. The frequent use of fire altered ADE/ABD forest composition and structure by controlling ignitions, decreasing fuel loads and increasing the abundance of plants preferred by humans. Cultural burning and polyculture agroforestry provided a stable subsistence strategy that persisted despite pronounced climate change and cultural transformations and has an enduring legacy in ADE/ABE forests in the ARE. This article is part of the theme issue ‘Tropical forests in the deep human past’.

Tropical forests in the deep human past

“…Maezumi et al . [ 21 ] examine the role of land use, cultural burning and soil enrichment in shaping the composition and structure of the Amazon forest ecotone. They integrate 6000 years of archaeological and palaeoecological data from Laguna Versalles, Bolivia which was dominated by stable forest vegetation throughout the last 10 000 years.…”

“…The dry forest-savannah zone seems to have been particularly favoured; as in Africa, this mosaic landscape provides a wide range of resources, and also the possibility of working with and enhancing natural fire regimes to aid vegetation clearance and ecosystem transformation. Maezumi et al [21] examine the role of land use, cultural burning and soil enrichment in shaping the composition and structure of the Amazon forest ecotone. They integrate 6000 years of archaeological and palaeoecological data from Laguna Versalles, Bolivia which was dominated by stable forest vegetation throughout the last 10 000 years.…”

“…Furthermore, despite assumptions that tropical forests have been relatively unchanged, there is ample evidence that past fluctuations in precipitation, temperature and CO 2 concentration have impacted forest form and extent in different parts of the tropics throughout the Miocene, Pliocene, Pleistocene and Holocene [16–18]. As we will also see in this volume, the arrival of hominins, particularly Homo sapiens , into these forests may also have introduced further changes to fire dynamics [19–21], species composition [22] and structure [21]. Thus, while tropical forests can be defined as sitting between the latitudes of 23.5° N (the Tropic of Cancer) and 23.5° S (the Tropic of Capricorn), covering the tropics of Central and South America, western and central Africa, western India, Southeast Asia and Oceania, they are far from being homogeneous and, in the case of Australia and China [13], local edaphic and hydrological regimes have led to similar biomes straying beyond the astronomically defined tropics, as they have also done in the past [16].…”

Influence of flooding variability on the development of an Amazonian peatland

“…Other archaeological sites have been reported by Coomes et al (2021) in the proximity of the San Roque peatland, although their age is unknown. Given the definitive archaeological evidence for human occupation in Amazonia by 10 000 cal a BP in Colombia, Bolivia and Brazil (Cavelier et al, 1995;Gnecco and Mora, 1997;Lombardo et al, 2013Lombardo et al, , 2020Roosevelt, 2013;Watling et al, 2018;Maezumi et al, 2022), the possibility that humans have occupied this area of Amazonia during this period is very likely, even if archaeological evidence has not yet been found in the immediate vicinity of the core site. According to Denevan's (1996) 'bluff model' of human settlement in Amazonia, in which prehistoric communities (and their fires) were situated along the course of rivers, the attribution of anthropogenic origin to the abundant microcharcoal recorded in this fluvially dominated part of the sequence between 4330 and 3180 cal a BP seems plausible.…”

Pre‐contact and post‐colonial ecological legacies shape Surinamese rainforests

“…Fire can cause severe and persistent ecological consequences (Åkesson et al, 2023; Barlow & Peres, 2008; Bodin et al, 2020; Bush et al, 2016; Maezumi et al, 2018; McMichael et al, 2022). Such ecological legacies from fire, or cultivation, plant domestication, and agroforestry primarily occur within a few kilometers of archaeological sites (Bodin et al, 2020; Maezumi et al, 2018, 2022). They have been reported, however, up to 5 km (Levis et al, 2018, 2020) and 20 km (Franco‐Moraes et al, 2019; Levis et al, 2017) of archaeological sites.…”