A regional study of Holocene climate change and human occupation in Peruvian Amazonia

Bush, Mark B.; Silman, Miles R.; Listopad, Claudia M.C.S.

doi:10.1111/j.1365-2699.2007.01704.x

Cited by 95 publications

(87 citation statements)

References 41 publications

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“…The Lake Chonita record has documented a similar, well-dated increase in fire frequency at the end of the YD. The sudden fire increase around Lake Chonita might be caused by climate, but human presence cannot be dismissed, even in the absence of land-use changes (Bush et al, 2007), as was tentatively proposed in the nearby Mapaurí area (Rull, 2009a). The onset of regional fire incidence around Lake Chonita has been dated to $12.4 k cal a BP, the oldest fire evidence in the GS so far (Fig.…”

Section: On the Origin Of The Gran Sabanamentioning

confidence: 84%

Vegetation changes in the Neotropical Gran Sabana (Venezuela) around the Younger Dryas chron

Montoya

Rull

Stansell

et al. 2011

J Quaternary Science

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The occurrence of the Younger Dryas cold reversal in northern South America midlands and lowlands remains controversial. We present a palaeoecological analysis of a Late Glacial lacustrine section from a midland lake (Lake Chonita, 4.6501 8N, 61.0157 8W, 884 m elevation) located in the Venezuelan Gran Sabana, based on physical and biological proxies. The sediments were mostly barren from $15.3 to 12.7 k cal a BP, probably due to poor preservation. A ligneous community with no clear modern analogues was dominant from 12.7 to 11.7 k cal a BP (Younger Dryas chronozone). At present, similar shrublands are situated around 200 m elevation above the lake, suggesting a cooling-driven downward shift in vegetation during that period. The interval from 11.7 to 10.6 k cal a BP is marked by a dramatic replacement of the shrubland by savannas and a conspicuous increase in fire incidence. The intensification of local and regional fires at this interval could have played a role in the vegetation shift. A change to wetter, and probably warmer, conditions is deduced after 11.7 k cal a BP, coinciding with the early Holocene warming. These results support the hypothesis of a mixed origin (climate and fire) of the Gran Sabana savannas, and highlight the climatic instability of the Neotropics during the Late Glacial.

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Section: On the Origin Of The Gran Sabanamentioning

confidence: 84%

Vegetation changes in the Neotropical Gran Sabana (Venezuela) around the Younger Dryas chron

Montoya

Rull

Stansell

et al. 2011

J Quaternary Science

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“…Pollen data indicate vegetation was dominated by moist, fire-adverse, fire-intolerant vegetation (Figure 5). Drought conditions are a key factor in increased forest flammability in modern Amazon vegetation (Brando et al, 2014;Aragão et al, 2018) thus, natural wildfire is expected to be low during wetter than average periods (Bush et al, 2007b). Thus, the anomalously wet conditions associated with the onset in increased biomass burning ∼4,500 cal yr B.P.…”

Section: Pre-columbian Fire Management In the Eastern Amazonmentioning

confidence: 99%

New Insights From Pre-Columbian Land Use and Fire Management in Amazonian Dark Earth Forests

et al. 2018

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Anthropogenic climate change driven by increased carbon emissions is leading to more severe fire seasons and increasing the frequency of mega-fires in the Amazon. This has the potential to convert Amazon forests from net carbon sinks to net carbon sources. Although modern human influence over the Earth is substantial, debate remains over when humans began to dominate Earth's natural systems. To date, little is known about the history of human land use in key regions like the Amazon. Here, we examine the history of human occupation from a ∼8,500 year-old sediment core record from Lake Caranã (LC) in the eastern Amazon. The onset of pre-Columbian activity at LC (∼4,500 cal yr B.P.) is associated with the beginning of fire management and crop cultivation, later followed by the formation of Amazonian Dark Earth soils (ADEs) ∼2,000 cal yr B.P. Selective forest enrichment of edible plants and low-severity fire activity altered the composition and structure of forests growing on ADEs (ADE forests) making them more drought susceptible and fire-prone. Following European colonization (1661 A.D.), the Amazon rubber boom (mid-1800s to 1920 A.D.) is associated with record-low fire activity despite drier regional climate, indicating fire exclusion. The formation of FLONA Reserve in 1974 A.D. is accompanied by the relocation of traditional populations and a fire suppression policy. Despite suppression efforts, biomass burning and fire severity in the past decade is higher than any other period in the record. This is attributed to combined climate and human factors which create optimal conditions for mega-fires in ADE forests and threatens to transform the Amazon from a net carbon sink to a net carbon source. To help mitigate the occurrence of mega-fires, a fire management policy reducing fire-use and careful fire management for farming may help to reduce fuel loads and the occurrence of mega-fires in fire-prone ADE forests. As both natural and anthropogenic pressures are projected to increase in the Amazon, this study provides valuable insights into the legacy of past human land use on modern ADE forest composition, structure, and flammability that can inform ecological benchmarks and future management efforts in the eastern Amazon.

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“…7,200 cal years BP until ca. 3,300 cal years BP (Bush et al 2007). This drier period have also been reported in eastern Amazonia (Cordeiro et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Paleohydrological changes in an Amazonian floodplain lake: Santa Ninha Lake

et al. 2012

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Holocene environments have been reconstructed by sedimentological, mineralogical and organic geochemical analysis of a 270-cm core from Santa Ninha Lake, a floodplain lake in lower Amazonia. Dated by fourteen AMS-radiocarbon dates, the sediment core has a basal age of 5,600 cal years BP and different sedimentary units were identified. These units document various hydrologic phases in the evolution of this lake. Reduced Amazon River influence, with reduced high-water levels of the river, characterized the period between 5,600 and 5,100 cal years BP. Comparison with other Amazonian and Andean paleoclimate studies point to a dryer climate during this phase. After 5,100 cal years BP coarse sediments and quartz increase which suggest a higher inflow of the Amazon River. Between 5,000 and 2,300 cal years BP the coarse sediments and quartz remain high but the organic carbon showed the lowest values. The riverine inflow caused dilution of the organic material produced in the lake and consequently low rates of carbon flux in these phases were recorded. These results show that the hydrodynamics of the Amazon River strongly influence the behavior, productivity and consequently the sedimentation process in the floodplain lakes.

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A regional study of Holocene climate change and human occupation in Peruvian Amazonia

Cited by 95 publications

References 41 publications

Vegetation changes in the Neotropical Gran Sabana (Venezuela) around the Younger Dryas chron

Vegetation changes in the Neotropical Gran Sabana (Venezuela) around the Younger Dryas chron

New Insights From Pre-Columbian Land Use and Fire Management in Amazonian Dark Earth Forests

Paleohydrological changes in an Amazonian floodplain lake: Santa Ninha Lake

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