The last glacial maximum climatic conditions on Easter Island

Ghasem, Azizi; Flenley, J. R.

doi:10.1016/j.quaint.2007.09.027

Cited by 43 publications

(47 citation statements)

References 35 publications

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“…Coupled stratigraphic variations in the pollen of these forest elements and of grasses allowed these authors to infer a cool and dry phase between 26 and 12 14 C kyr BP, followed by an increase in precipitation and an expansion of forests that persisted throughout the Holocene until the recent deforestation. A recent, more detailed pollen analysis of sediments representing the Last Glacial Maximum (LGM) used the alternation of palm and grass pollen to infer a phase cooler and probably drier than the present (Azizi and Flenley, 2008). Minimum values of palm pollen coinciding with maximum grass values around 22 and 17 14 C kyr BP were interpreted in terms of the coldest and driest phase of this interval.…”

Section: Background and Current Hypothesesmentioning

confidence: 99%

“…The total annual precipitation is highly variable, ranging between 500 and 1800 mm (average 1130 mm); the maximum rainfall occurs from April to June, and the driest moth is October with 70 mm (Azizi and Flenley, 2008).…”

Section: Geography Hydrology and Climatementioning

confidence: 99%

“…Pollen analyses are mostly based on the sediments inside the three volcanic craters ( Flenley et al, 1991;Butler and Flenley, 2001;Peteet et al, 2003;Gossen, 2007;Azizi and Flenley, 2008;Mann et al, 2008). Microscopic charcoal, a proxy for fire, was reported in Rano Aroi, Rano Raraku 9 and Rano Kao Mann et al, 2008).…”

Section: Study Sites and Proxiesmentioning

confidence: 99%

“…Additional data on the potential palm forests were provided by a further core obtained in Rano Raraku (RRA5) covering between 28 and 11 14 C kyr BP (Azizi and Flenley, 2008). In this case, the resolution was 680 years per sample interval.…”

Section: The Evidence and Its Current Interpretationmentioning

confidence: 99%

“…The magnitude of ecological and cultural inferences about Easter Island's history contrasts with the limited number of cores studied, their fragmentary nature and the low resolution of the analyses, the few proxies used (mostly pollen), and the existence of a sedimentary hiatus within which important information 4 about the environmental shift is still hidden (Mann et al, 2008). At present, studies about the paleoecology of the island seem to have spring up again and new cores have been obtained and are being analyzed (Gossen, 2007;Azizi and Flenley, 2008;Mann et al, 2008;Sáez et al, 2009). We consider it appropriate to accurately review the existing evidence at this point, to provide a neutral perspective on the proposals erected so far.…”

Section: Introductionmentioning

confidence: 99%

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Paleoecology of Easter Island: Evidence and uncertainties

Rull

Cañellas-Boltà

Sáez

et al. 2010

Earth-Science Reviews

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The existence of palm-dominated forests covering the island since the last glaciation and the recent deforestation by humans are paradigmatic in Easter Island's paleoecological reconstructions. The timing and mode of the deforestation are controversial, but there is general agreement that it actually occurred, and it is often given as an example of a human-induced environmental catastrophe with philosophical implications for the future of the whole planet. To evaluate whether this is the only well-supported hypothesis or if there might be other scenarios compatible with the paleoecological data, this paper reviews all the available evidence on past vegetation changes on Easter Island. The discussion is centered on three main points: 1) the alleged nature and extension of the former forests, 2) the taxonomic identity of the dominant palms, and 3) the nature of the recent ecological changes leading to a treeless island.The potential causes of the assumed deforestation are beyond the scope of this study.Concerning the first point, palynological and anthracological results obtained so far are not only compatible with a forested island, but also with other scenarios, for example a mosaic vegetation pattern with forests restricted to sites with a high freshwater table (gallery forests), which are mostly around the permanent lakes and along the coasts.With regard to palm identity, some extant species have been proposed as potential candidates, but the palms that dominated these forests seem to have become extinct and their identity remains unknown. The existence of a sedimentary hiatus around the dates of forest decline complicates the picture and reinforce the possibility of climatic changes. It is concluded that the hypothesis of a previously forested island has yet to be demonstrated. Therefore, the recent ecological disaster, human-induced or not, is still speculative. Several types of future studies are proposed for a better understanding of Easter Island's ecological history, including: modern analog studies from similar situations, pollen dispersal modeling, high-resolution multi-proxy studies along the cores obtained so far, more coring campaigns in the search for older sediments, and DNA and isotopic analyses of plant remains for taxonomic identification purposes.3

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Section: Background and Current Hypothesesmentioning

confidence: 99%

Section: Geography Hydrology and Climatementioning

confidence: 99%

Section: Study Sites and Proxiesmentioning

confidence: 99%

Section: The Evidence and Its Current Interpretationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Paleoecology of Easter Island: Evidence and uncertainties

Rull

Cañellas-Boltà

Sáez

et al. 2010

Earth-Science Reviews

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A stable isotope (δ¹³C and δ¹⁵N) perspective on human diet on rapa nui (Easter Island) ca. AD 1400–1900

Commendador

Dudgeon

Finney

et al. 2013

American J Phys Anthropol

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Ecological and environmental evidence suggests that Rapa Nui was among the most marginally habitable islands in Eastern Polynesia, with only a fraction of the biotic diversity found on archipelagos to the west, and capable of sustaining many fewer cultigens traditionally transported by Polynesian colonizers. However, archaeological evidence for human dietary adaptations under such restrictions is limited. Little is known about the particulars of the subsistence base and dietary changes on Rapa Nui that may be associated with a hypothesized late prehistoric decline in the quality and diversity of food sources. To better understand prehistoric Rapa Nui diet we examined stable carbon and nitrogen isotope compositions of human teeth along with archaeological faunal material thought to comprise the Rapa Nui food web. Our results indicate that contrary to previous zooarchaeological studies diet was predominantly terrestrial throughout the entire sequence of occupation, with reliance on rats, chickens and C3 plants. While a few individuals may have had access to higher trophic level marine resources, this is evident only later in time (generally post-AD 1600). A decline in (15)N through time was observed, and may be attributed to declines in available terrestrial proteins; however, presently we cannot rule out the effect of changing soil and plant baseline δ(15)N. Our results also suggest differential access to higher trophic level marine resources among contemporaneous populations, but more research is required to clarify this observation.

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Diet, Geography and Drinking Water in Polynesia: Microfossil Research from Archaeological Human Dental Calculus, Rapa Nui (Easter Island)

Dudgeon

Tromp

2012

Intl J of Osteoarchaeology

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Microfossil analysis of human dental calculus provides consumption‐specific and archaeologically relevant data for evaluating diet and subsistence in past populations. Calculus was extracted from 114 teeth representing 104 unique individuals from a late 16th to early 18th century skeletal series on Rapa Nui (Easter Island) to address questions of human–environment interactions and possible dietary preference. Scanning electron microscopy was used in lieu of optical microscopy for its superior depth of field and resolution of surface detail. The calculus microfossil recovery produced 16,377 total biogenic silica microfossils: 4733 phytoliths and 11,644 diatoms. The majority of phytoliths correspond with the Arecaceae or palm family (n = 4,456) and the minority corresponds to the Poaceae or grass family (n = 277). Because of the relatively large sample size, we were able to test hypotheses related to age cohort, sex, dental element and geographic region. Results indicate no significant difference in phytolith or diatom recovery based on age cohort or sex. The high frequency and proportion of Arecaceae phytoliths found in calculus extracted from the anterior dentition suggests consumption of soft or cooked foods containing palm phytoliths and the high frequency of diatoms recovered from the southern part of the island argue for different sources of drinking water. Copyright © 2012 John Wiley & Sons, Ltd.

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The last glacial maximum climatic conditions on Easter Island

Cited by 43 publications

References 35 publications

Paleoecology of Easter Island: Evidence and uncertainties

Paleoecology of Easter Island: Evidence and uncertainties

A stable isotope (δ¹³C and δ¹⁵N) perspective on human diet on rapa nui (Easter Island) ca. AD 1400–1900

Diet, Geography and Drinking Water in Polynesia: Microfossil Research from Archaeological Human Dental Calculus, Rapa Nui (Easter Island)

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The last glacial maximum climatic conditions on Easter Island

Cited by 43 publications

References 35 publications

Paleoecology of Easter Island: Evidence and uncertainties

Paleoecology of Easter Island: Evidence and uncertainties

A stable isotope (δ13C and δ15N) perspective on human diet on rapa nui (Easter Island) ca. AD 1400–1900

Diet, Geography and Drinking Water in Polynesia: Microfossil Research from Archaeological Human Dental Calculus, Rapa Nui (Easter Island)

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A stable isotope (δ¹³C and δ¹⁵N) perspective on human diet on rapa nui (Easter Island) ca. AD 1400–1900