Evidence That Large Civilisations Lived In Amazon Basin? Have They Sig Transformed Most Pristine Tropical Forests?

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Terra Preta de Indio

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- Fertile dark earth soils- edge of dryland forests along rivers, patches of nutrient-rich black soils overly deep strongly weathered infertile soils. Terra Preta de Indio. Can be as much as 2m deep, cover 1ha- several. Soils improved by adding crumbled charcoal, ash, green manure, fish meal. Often contain broken ceramics and bone fragments- human origin. Sites often associated w fruit trees and other useful spp. Charred woody material- good nutrient holding characteristics- allow near permanent cultivation and supported high pop densities. Still used for agriculture by modern farmers.

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Heckenberger 2003

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both pristine forests and cultural parkland existed

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Barlow et al 2012

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cannot necessarily extrapolate findings to other regions- archaeological sampling NOT random. Pre-columbian activities- focused spatial distribution. Non-terra preta soils probably make up >99.9% of land. Not uncommon to find ADE in vicinity of river communities, they are localised and limited in extent, rarely found far from rivers. Tree monodominance- variety of explanations, doesn’t necessarily mean human dispersal. E.g. Muaritia palms- clear indicator of wetlands, doesn’t necessarily indicated enrichment planting. Biodiversity higher in lightly disturbed forest- intermediate disturbance hypothesis. Short term increases in total spp richness typically followed by loss of forest dependent spp. Larger settlements less sustainable than smaller ones in terms of hunting pressure. Even sparsely settled human pops deplete game stocks in Amazonian indigenous territories and extractive reserves.

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Levis 2012

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If ecological conditions were sole determinants of plant distributions in the infterfluve, we should find roughly same useful tree and palm communities on paleo-varzeas, pre-holocene floodplains, similar geomorphological and hydrological conditions- instead found unusual species-environment associations Bertholletia excels, Attalea speciose, which are natural associated with upland forests, found as dominants in a site on paleo-varzeas of madeira river.

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Glaser 2001

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terra preta soils may derived from oxisols by enrichment with black carbon from residues of incomplete burning produce by early Amerindian population. Due to highly aromatic structure, assumed to be chemically and microbially stable and persists in environment over centuries or millennia. Oxidation during this time produced carboxylic groups on the edges of the aromatic core, which increased the cation exchange capacity and reactivity of black carbon in the soil. Human excrement and biomass accumulated from surrounding land, together with residues from hunting and fishing, are responsible for nutrient richness and the high base saturation of terra preta soils. May still result in larger carbon inputs in the topsoil.

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Upper xingu region, southern Amazon

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LT presence of Xinguano peoples in this region over more than 1000 years indicated by archaeological work on several interconnected settlements AD1250-1650 and from substantially altered forests and wetlands. Settlements covered residential area of 40-80ha in area of 400km2, population of 2500-5000 people. Areas were intensively managed, included formally arranged transportation network and agricultural areas, as well as patches of secondary regrowth and managed forests. They have a distinctly different forest cover type (Heckenberger 2003), which contain tree spp associated w terra preta anthosols. The buriti palm, widely used by Xinguanos, closely associated with ancient settlement areas, as is Acrocomia aculeate, may date to time of ancient communities. Fruit trees common near abandoned settlements

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pre columbian settlements

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, although widespread, scattered, concentrated at main river channels. Human impact on forest hinterland low. Concentric zones of anthropogenically-altered environments around village sites more likely, consistent w distribution of anthropogenic soils. However, recognition of rock paintings, circular or square areas, ranging 100-350m across, outlined by trenches 1-7m deep, and other major earthworks spread across south-west amazon, indicate sophisticated human agrarian society may have been extended over much larger area than previously suspected.

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archaeological evidence- hunter gatherers and large scale food production

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(ceramics and human-modified soils), indicates first Neotropical hunter-gatherers living at localised sites 11,000-10,000BP. Horticulture using native tubers and seed plants, and tending and deliberate planting of trees increased btw 10,000 and 8,600BP and by 7,000BP large-scale food production in Central America- cultivation of fields away from houses.

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Rodonia, brazil

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evidence of occupation by hunter gatherers dates to 9000BP. Agricultural activity around 4500BP. Native fruit trees domesticated by prehistoric people.

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how big were pre columbian communities

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Evidence suggests that typical pop densities of Amazonian pre-Columbian communities were at least an order of magnitude greater than current indigenous communities.- Recent studies have documented areas of dense interconnected settlements, representing complex societies which converted forests into patchy, managed landscape mosaics. This mgmt. dates from late Pleistocene and often lasted several centuries, changed subsequent forest composition and transformed soils.

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charcoal

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- Fire used for land management. Buried charcoal in soil profile. 300 soil profiles, 60,000ha in Guyana recorded charcoal in all of them. Radiocarbon dating of charcoal layers across amazon basin, shows expansion of agricultural activity at AD 250, series of peaks between AD 700- 1550, little activity after AD1600. Pattern matches archaeological estimates of settlement expansion. - Charcoal-based evidence, ceramic artefacts in Las Cruces reserve, Costa Rica, inhabited for at least 3000 years.

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Laguna Zoncho

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- Sedimentation of charcoal and maize pollen in Laguna Zoncho indicates intensity of forest clearing and burning increased over 2500 year period, leading up to AD1500. Cultivation abandoned- forms costa rica’s largest remaining tract of lower montane RF.

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abandonment of indigenous managed landscape after european invasion

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- Abandonment of indigenous managed landscape after European contact resulted in these landscapes regenerating into dense forest. Some studies suggest an enrichment of local floras in areas used by pre-Columbian Amerindians.