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Cited by 98Pacific and Southeast Asian StudiesArchaeology and ancient environmental studiesAmazonian Archaeology and Ethnohistory

Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

Open access
Stevenson, Christopher M., Puleston, Cedric O., Vitousek, Peter M., Chadwick, Oliver A., Haoa, Sonia, Ladefoged, Thegn N.·2015·Proceedings of the National Academy of Sciences
DOI 10.1073/pnas.1420712112PMC PMC4313829
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Abstract

Significance: Our paper evaluates a long-standing debate and examines whether the prehistoric population of Rapa Nui experienced a significant demographic collapse prior to European contact in AD 1722. We have used dates from hydrated obsidian artifacts recovered from habitation sites as a proxy for land use over time. The analysis suggests region-specific dynamics that include the abandonment of leeward and interior locations. These temporal land-use patterns correlate with rainfall variation and soil quality. This analysis demonstrates that the concept of “collapse” is a misleading characterization of prehistoric human population dynamics. As a result, we see our approach as useful in the study of other prehistoric societies for which a sudden demographic collapse has been proposed in prehistory.

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Crossref · 10.1073/pnas.1420712112

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Claims the paper makes

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  • Findingown data
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    The analysis supports a substantial decrease in land-use intensity in certain parts of the island prior to European contact.

    “This analysis confirms that the intensity of land use decreased substantially in some areas of the island before European contact.”
    Quote in the paperSubstantial claim
  • Findingown data

    New chronometric evidence from three study areas reveals spatial and temporal variation in Rapa Nui land use.

    “New chronometric evidence from three study areas reveals spatial and temporal variation in Rapa Nui land use.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
  • Findingown data

    Only 0.64% of SA1 iterations placed the decline start after AD 1720.

    “Only 0.64% of iterations resulted in the decline beginning after AD 1720.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.
    • Rests on an assumption: The bootstrap resampling adequately captures uncertainty in the decline dates.
  • Findingown data

    The best-fit curve method suggests SA3's land-use decline most likely began around AD 1850 or later, well after European contact.

    “The best-fit curve methodology suggests the most likely date for the initiation of land-use decline was ca.AD 1850 or later, well after European contact (Fig. 3C).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.
    • Rests on an assumption: The best-fit curve methodology correctly identifies the initiation of land-use decline.
  • Findingown data

    The authors' information demonstrates that some regions of Rapa Nui experienced declines in land-use intensity before European contact.

    “Our information demonstrates that some regions of Rapa Nui experienced declines in the intensity of land use before European contact.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
  • May combine two claims. 32
  • Classified as probably not a substantial claim. 11

  • May combine two claims.

    Findingown data
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    The study's analysis indicates that land-use dynamics differed by region, with some near-coastal and upland areas declining before European contact while other coastal areas increased and then declined after contact.

    “The analysis suggests region-specific dynamics including precontact land use decline in some nearcoastal and upland areas and postcontact increases and subsequent declines in other coastal locations.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    The temporal patterns of land use are associated with variation in rainfall and soil quality, and locations with poorer environmental conditions declined earlier.

    “These temporal landuse patterns correlate with rainfall variation and soil quality, with poorer environmental locations declining earlier.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    SA3 has adequate rainfall and relatively fertile soils.

    “In contrast, SA3 represents a region with adequate rainfall and relatively fertile soils (Table 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    SA1 stood at 53.7% of its AD 1618 maximum, and SA2 stood at 60% of its post-AD 1600 maximum, which occurred in AD 1667.

    “SA1 was at 53.7% of its AD 1618 maximum, and SA2 was at 60% of the post-AD 1600 maximum, which occurred in AD 1667.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.

  • May combine two claims.

    Findingown data

    In SA2, land use began after AD 1200, increased rapidly through the AD 1300s, and then increased more slowly until about AD 1480.

    “In the interior study area (SA2), land use initiated after AD 1200 with a rapid increase through the AD 1300s and a lower rate of increase until ca.AD 1480 (Fig. 2B).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The authors' climatic data show that near-surface annual soil temperatures depend on elevation, averaging 22-24 °C on the coastal plain and 19 °C just below the Maunga Terevaka summit.

    “Our climatic data show that near-surface annual soil temperatures also are elevation dependent and average 22-24 °C on the coastal plain and 19 °C just below the summit of M. Terevaka (SI Appendix, Fig. S1 and Table S2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The SA1 curve suggests land use peaked around AD 1650 and then dropped rapidly.

    “The curve suggests land use peaked around AD 1650 and dropped rapidly thereafter.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.

  • May combine two claims.

    Findingown data

    Initial settlement and expansion occurred from about AD 1200, and the interior was rapidly developed for agriculture beginning in the early AD 1300s.

    “Initial settlement and expansion occurred from ca.AD 1200, with the rapid development of the interior for agricultural activities beginning in the early AD 1300s.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.

  • May combine two claims.

    Findingown data

    In SA3, land use was relatively high during the late AD 1600s and remained so until after AD 1800.

    “In this area, land use was relatively high during the late AD 1600s until after AD 1800.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.

  • May combine two claims.

    Findingown data

    SA1 has relatively high soil nutrient availability but low rainfall; SA2 has the lowest nutrient supply and highest rainfall; SA3 has intermediate rainfall and relatively high soil nutrient levels.

    “SA1 has relatively high soil nutrient availability as indexed by plant-available phosphorus, calcium, and base saturation but low rainfall; SA2 has the lowest nutrient supply and highest rainfall; and SA3 is characterized by intermediate amounts of rainfall and relatively high soil nutrient levels (Table 1).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.

  • May combine two claims.

    Findingown data

    In SA3, near the northeast coast, land use increased more slowly from about AD 1240 to AD 1500, then rose more steeply during the AD 1600s to an initial peak around AD 1690.

    “In contrast to SA1 and SA2, in the near coastal northeastern study area (SA3) land use increased at a relatively slower rate from ca.AD 1240 to ca.AD 1500, with a steeper increase during the AD 1600s to an initial peak around AD 1690 (Fig. 2C).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: The three primary study areas represent the island's environmental and land-use diversity.

  • May combine two claims.

    Premisecitation
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    Archaeological evidence documents societal changes on Rapa Nui, such as obsidian spear point manufacture, destruction of elite dwellings, refuge cave habitation, cannibalism, altered burial practices, and a shift from ahu structures to the Birdman cult.

    “There is archaeological evidence for societal change on Rapa Nui, including the manufacture of obsidian spear points, the destruction of elite dwellings, habitation in refuge caves, cannibalism, a change in burial practice, and a marked ideological shift away from ceremonial platform (ahu) structures to the formation of the Birdman (tangata manu) cult centered at Orongo (see ref. 23 for a summary)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] 23. Kirch PV (2000) On the Road of the Winds. An Archaeological History of the Pacific Islands before European Contact (Univ of California Press, Berkeley, CA).

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    Evidence for precontact societal collapse, extensive environmental degradation beyond deforestation, or warfare capable of causing such a collapse is minimal.

    “Empirical evidence for societal collapse, extensive environmental degradation (other than deforestation), or warfare that could have caused such a collapse before European contact is minimal (20).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [20] 20. Mulrooney MA, Ladefoged TN, Stevenson CM, Haoa S (2010) Empirical assessment of a pre-European societal collapse on Rapa Nui (Easter Island). The Gotland Papers: Selected Papers from the VII International Conference on Easter Island and the Pacific: Migration, Identity, and Cultural Heritage, eds Wallin P, Martinsson-Wallin H (Got- land Univ Press, Gotland, Sweden), pp 141-154.

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    A recent island-wide radiocarbon analysis concluded that demographic continuity persisted into the postcontact era rather than population decline in the late precontact period.

    “A recent analysis of radiocarbon dates from throughout Rapa Nui noted the inherent (and severe) ambiguities in radiocarbon calibrations in the time period of interest but concluded that there was demographic continuity into the postcontact era as opposed to population decline during the late precontact period (19).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [19] 19. Mulrooney MA (2013) An island-wide assessment of the chronology of settlement and land use on Rapa Nui (Easter Island) based on radiocarbon data. J Archaeol Sci 40(12):4377-4399. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    There is strong evidence for deforestation on Rapa Nui, but the timing and causes of deforestation remain debated.

    “For environmental degradation, there is substantial evidence for deforestation (26)(27)(28)(29)(30) but its timing and causes have been debated (2,(31)(32)(33)(34).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [26] 26. Flenley JR (1993) The palaeoecology of Easter Island, and its ecological disaster. Easter Island Studies: Contributions to the History of Rapanui in Memory of William T. Mulloy, ed Fischer SR (Oxbow Books, Oxford, UK), pp 27-45.

      Not checked in the free run.

    • cites [27] 27. Flenley JR (1996) Further evidence of vegetational change on Easter Island. South Pacific Study 16(2):135-141.

      Not checked in the free run.

    • cites [28] 28. Flenley JR (1998) New data and new thoughts about Rapa Nui, in Easter Island. Pacific Context South Seas Symposium: Proceedings of the Fourth International Conference on Easter Island and East Polynesia, eds Stevenson CM, Lee G, Morin FJ (Easter Island Foundation, Los Osos, CA), pp 125-128.

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The authors propose that precontact declines in land-use intensity, and presumably population, in dry and infertile regions better reflect environmental constraint than environmental degradation, though constraint and degradation can intergrade.

    “We propose that precontact declines in the intensity of land use (and presumably population) in dry and infertile regions of Rapa Nui better reflect a framework of environmental constraint than of environmental degradationalthough constraint and degradation can intergrade, as in the case of infertile soils that are suitable for shifting cultivation being degraded through overuse.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: Land-use intensity is a valid proxy for regional population size.

  • May combine two claims.

    Premisecitation
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    Soil erosion was limited to specific areas-the older Poike peninsula, a small northwest coastal section, and slopes of some smaller volcanic cones-and there is no evidence of widespread erosion that would have disrupted agriculture.

    “Soil erosion occurred in limited areas (i.e., on the older Poike peninsula (35)(36)(37), along a small section of the northwest coast, and on the slopes of some of the smaller volcanic cones); however, there is no evidence of widespread soil erosion that could have interfered with agricultural production (38).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [35] 35. Rull V, et al. (2010) Paleoecology of Easter Island: Evidence and uncertainties. Earth Sci Rev 99(1-2):50-60. source

      Not checked in the free run.

    • cites [36] 36. Mieth A, Bork H-R (2004) Easter Island -Rapa Nui: Scientific Pathways to Secrets of the Past (Christian-Albrechts-Universitat zu Kiel, Kiel, Germany).

      Not checked in the free run.

    • cites [37] 37. Mann D, et al. (2008) Drought, vegetation change, and human history on Rapa Nui (Isla de Pascua, Easter Island). Quat Res 69(1):16-28. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The authors suggest SA1 would have been highly vulnerable to periodic droughts and therefore among the earliest areas abandoned.

    “We suggest that this area would have been highly vulnerable to periodic droughts and therefore would have been one of the earliest areas to be abandoned.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Modern rainfall and soil data reflect past conditions relevant to precontact agriculture.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Rapa Nui was formed by multiple volcanic events.

    “The island of Rapa Nui was created by multiple volcanic events (43).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [43] 43. Vezzoli L, Acocella V (2009) Easter Island, SE Pacific: An end-member type of hotspot volcanism. Geol Soc Am Bull 121(5-6):869-886. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    To test robustness, the authors resampled the distributions of mean OHD dates in each study area 2,500 times with replacement.

    “To assess the robustness of the findings, we bootstrapped (resampled with replacement) the distributions of mean OHD dates in each study area 2,500 times.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The bootstrap resampling adequately captures uncertainty in the decline dates.

  • May combine two claims.

    Interpretationreasoning

    Precontact reductions in land-use intensity in the dry northwest and nutrient-leached upland areas would have increased land pressure elsewhere and may have led to periods of conflict as land use was renegotiated.

    “Reductions in the intensity of land use before European contact in the dry northwest section of Rapa Nui and the region of nutrient-leached soils in upland areas would have contributed to increasing land pressure in other parts of the island and may have led to periods of conflict as land use was renegotiated.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given
    § Variation in Rapa Nui (Easter Island) land use indicates production and population peaks prior to European contact

    The number of hydration dates is treated as a measure of discarded material over time and as a proxy for land-use intensity.

    “We use the quantity of hydration dates as a measure of the amount of discarded material over time and as a proxy for landuse intensity.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The main cultigens on Rapa Nui were sweet potato, dryland taro, yam, and ti, with sweet potato possibly a secondary introduction.

    “On Rapa Nui, the primary cultigens were sweet potato (Ipomoea batatas), dryland taro (Colocasia esculenta), yam (Dioscorea spp.), and ti (Cordyline) (49), of which sweet potato was perhaps a secondary introduction (50).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [49] 49. Stevenson CM, Jackson T, Mieth A, Ladefoged TN (2006) Prehistoric agriculture at Maunga Orito, Easter Island (Rapa Nui), Chile. Antiquity 80(310):919-936. source

      Not checked in the free run.

    • cites [50] 50. Wallin P, Stevenson CM, Ladefoged TN (2005) Sweet Potato Production on Rapa Nui. The Sweet Potato in the Oceania: A Reappraisal, eds Ballard C, Brown P, Bourke RM, Harwood T (Ethnology Monographs, Pittsburgh, and Oceania Monographs, Sydney), pp 85-88.

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Obsidian hydration dating yields a mean date with a standard error of 30 years for each datable object.

    “OHD produces results that consist of a mean date with an SE of 30 y for each dateable object.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [41] 41. Stevenson CM, Novak SW (2011) Obsidian hydration dating by infrared spectroscopy: Method and calibration. J Archaeol Sci 38(7):1716-1726. source

      Not checked in the free run.

    • cites [42] 42. Stevenson CM, Ladefoged TN, Novak SW (2013) Prehistoric settlement on Rapa Nui, Chile: Obsidian hydration dating using infrared photoacoustic spectroscopy. J Archaeol Sci 40(7):3021-3030. source

      Not checked in the free run.

    • Rests on an assumption: The revised obsidian hydration dating calibrations and protocols produce accurate dates.

  • May combine two claims.

    Study design and conductreasoning

    The authors' approach provides a robust method for determining when island regions were occupied and used and when the initial post-AD 1600 decline began, while quantifying uncertainty.

    “Our approach provides a robust means of determining when regions of the island were occupied and used and when the initial period of decline after AD 1600 began, including quantification of the uncertainty associated with these results.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The authors suggest that farming these poor soils could only be sustained through long-fallow shifting cultivation, and that a shorter fallow cycle would have degraded the already low fertility.

    “We suggest that cultivation of these poor soils could be sustained only through long-fallow shifting cultivation, and that attempting to farm the area with a shorter fallow cycle would have degraded the already very low fertility of this area.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Modern rainfall and soil data reflect past conditions relevant to precontact agriculture.

  • May combine two claims.

    Premisecitation

    Rainfall differences have caused substantial variation in Rapa Nui soil nutrients, similar to volcanic substrates of comparable age in Hawai'i, and older substrates are generally more nutrient-depleted than younger ones.

    “Differential rainfall has caused substantial variation in Rapa Nui soil nutrients, as it does in volcanic substrates of similar age in Hawai'i (46,47), and older substrates generally are depleted in soil nutrients compared with younger ones.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [46] 46. Vitousek PM, et al. (2014) Farming the Rock: A biogeochemical perspective on in- tensive agriculture in Polynesia. Journal of the Pacific Archaeology 5(2):51-61. source

      Not checked in the free run.

    • cites [47] 47. Chadwick OA, et al. (2003) The impact of climate on the biogeochemical functioning of volcanic soils. Chem Geol 202(3-4):195-223. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    If past climatic conditions resembled modern ones, periodic droughts would have affected crop production, with taro most vulnerable and sweet potato more resilient to fluctuating rainfall.

    “Recent analysis of modern rainfall data documents periodic droughts, and if similar conditions existed earlier in time (52), such climatic events would have affected crop production, with taro being most vulnerable and sweet potato being more resilient to the parameters of the island's fluctuating rainfall (17).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [52] 52. Junk C, Claussen M (2011) Simulated climate variability in the region of Rapa Nui during the last millennium. Climate of the Past 7(2):579-586. source

      Not checked in the free run.

    • cites [17] 17. Hunt TL, Lipo CP (2011) The Statues that Walked: Unraveling the Mystery of Easter Island (Free, New York).

      Not checked in the free run.

    • Rests on an assumption: Modern rainfall and soil data reflect past conditions relevant to precontact agriculture.

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationnone given

    Land-use change information is directly related to regional food production, though different behavioral strategies across study areas would affect the strength of that relationship.

    “This information on land-use change is related directly to regional food production, although differential behavioral strategies (e.g., horticultural, residential, and religious activities) in different study areas would influence the strength of the correlation.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The relationship between land-use intensity and food production is direct enough to infer changes in food supply.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    Land-use changes should also be connected to regional population, though that connection may be further modulated by differential behaviors.

    “Changes in land use also should be connected to regional population, although that connection could be modulated further by differential behaviors.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Land-use intensity is a valid proxy for regional population size.

  • May combine two claims.

    Interpretationreasoning

    If the decrease in land use and associated food production was not offset by increased production elsewhere, the results are consistent with a decline in overall food supply before European contact.

    “If that decrease in land use and associated food production was not offset by increased food production elsewhere on the island, then the results are consistent with a decrease in overall food supply before European contact.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The relationship between land-use intensity and food production is direct enough to infer changes in food supply.

  • May combine two claims.

    Interpretationown data

    The results indicate that island-wide landscape use was shaped by an underlying climatic and biogeochemical matrix and by responses to dynamic variations in those factors.

    “These results indicate that island-wide landscape use was modulated by an underlying climatic and biogeochemical matrix as well as by response to dynamic variations in climatic and biogeochemical factors.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.

  • May combine two claims.

    Study design and conductreasoning

    The summed probability fractions in the curve indicate when obsidian artifacts were most likely created and, by proxy, the intensity of land use in different island regions from initial occupation through after European contact.

    “The summed probability fractions that form the curve indicate the periods when the obsidian artifacts most likely were created and, by proxy, the intensity of land use in different regions of the island from the first occupation until after European contact.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.

  • May combine two claims.

    Premisecitation

    Although lowland soils with moderate rainfall are richer in available nutrients than wetter high-elevation soils, nearly all Rapa Nui soils are nutrient-depleted compared with soils where precontact Hawaiian farmers intensified production.

    “Although soils of the lowland areas with moderate rainfall are richer in biologically available nutrients than are wetter, higher elevation soils (45), all but the richest Rapa Nui soils are nutrient depleted in comparison with the soils where precontact Hawaiian farmers intensified agricultural production (48).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [45] 45. Ladefoged TN, et al. (2010) Soil nutrient analysis of Rapa Nui gardening. Archaeology in Oceania 45(2):80-85. source

      Not checked in the free run.

    • cites [48] 48. Vitousek PM, et al. (2004) Agriculture, soils, and society in precontact Hawai'i. Science 304(5677):1665-1669. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Modern rainfall records from 1958 to 1997 show substantial year-to-year variation and periodic droughts.

    “Analysis of modern rainfall data from 1958-1997 shows considerable year-to-year variation, with droughts occurring (17).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [17] 17. Hunt TL, Lipo CP (2011) The Statues that Walked: Unraveling the Mystery of Easter Island (Free, New York).

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The central upland portion of Rapa Nui, including SA2, is wet but has strikingly low soil fertility compared with the island's lowlands.

    “In contrast, the central, upland portion of Rapa Nui (SA2 and surrounds) is wet but strikingly low in soil fertility in comparison with the lowlands of Rapa Nui (43).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [43] 43. Vezzoli L, Acocella V (2009) Easter Island, SE Pacific: An end-member type of hotspot volcanism. Geol Soc Am Bull 121(5-6):869-886. source

      Not checked in the free run.

    • Rests on an assumption: Modern rainfall and soil data reflect past conditions relevant to precontact agriculture.

  • May combine two claims.

    Interpretationown data

    This land-use reconstruction argues against an island-wide precontact collapse as a useful explanatory concept for Rapa Nui, though it supports a real precontact decline in land use probably associated with food production declines.

    “This temporal reconstruction of land-use history associated with food production argues against the notion of an island-wide precontact collapse as a useful explanatory concept for Rapa Nui-although it does support the reality of a precontact decline in land use that probably was associated with declines in food production.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The number of obsidian hydration dates is a valid proxy for land-use intensity.
    • Rests on an assumption: Land-use intensity is a valid proxy for regional population size.
37 of 37

  • The paper relies on this without support.

    The number of obsidian hydration dates is a valid proxy for land-use intensity.

    “We use the quantity of hydration dates as a measure of the amount of discarded material over time and as a proxy for landuse intensity.”

  • The paper relies on this without support.

    Land-use intensity is a valid proxy for regional population size.

    “Changes in land use also should be connected to regional population, although that connection could be modulated further by differential behaviors.”

  • The paper relies on this without support.

    The revised obsidian hydration dating calibrations and protocols produce accurate dates.

    “using 428 obsidian hydration dates developed under revised calibrations and protocols”

  • The paper relies on this without support.

    The three primary study areas represent the island's environmental and land-use diversity.

    “The three intensive study areas were situated to sample diverse environmental settings.”

  • The paper relies on this without support.

    The best-fit curve methodology correctly identifies the initiation of land-use decline.

    “we used a curve-fitting method and compared the observed OHD SPDs with hypothetical distributions derived from land-use intensities and determined the best fits.”

  • The paper relies on this without support.

    The bootstrap resampling adequately captures uncertainty in the decline dates.

    “we bootstrapped (resampled with replacement) the distributions of mean OHD dates in each study area 2,500 times.”

  • The paper relies on this without support.

    Modern rainfall and soil data reflect past conditions relevant to precontact agriculture.

    “if similar conditions existed earlier in time”

  • The paper relies on this without support.

    The relationship between land-use intensity and food production is direct enough to infer changes in food supply.

    “This information on land-use change is related directly to regional food production”
8 of 8

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Recent studies challenge the predominant causal explanations for large-scale demographic downfall and emphasize the potential roles of climate, anthropogenic pressures and the climate-human relationship.

    “Recent studies [ 21 – 23 ] challenge the predominant causal explanations for large-scale demographic downfall and emphasize the potential roles of climate, anthropogenic pressures and the climate–human relationship.”

    From Ecology of the collapse of Rapa Nui society (2020) · cites this paper as [23]

  • Pressure for farming land was the main driver of the deforestation process.

    “Furthermore, palm tree pollen % dynamics in Rapa Nui are best explained by the negative effect of the human population, supporting the idea that pressure for farming land was the main driver of the deforestation process [ 23 , 41 , 44 , 48 ] (electronic supplementary material, table S3).”

    From Ecology of the collapse of Rapa Nui society (2020) · cites this paper as [23]

  • The patterns of an increase in charcoal influx values for the period 1400-1700 CE, probably associated with an intensification of fire disturbance by humans, combined with the evidence of changes in the intensity of land use previous to the European contact, are consistent with the increase/decrease SPD dynamic.

    “Moreover, the patterns of an increase in charcoal influx values for the period 1400–1700 CE, probably associated with an intensification of fire disturbance by humans [ 21 ], combined with the evidence of changes in the intensity of land use previous to the European contact [ 23 ], are consistent with the increase/decrease SPD dynamic.”

    From Ecology of the collapse of Rapa Nui society (2020) · cites this paper as [23]

  • SPD curves derived from OHD data reproduce consistent variations in land use for food production, with an overall expansion in intensity starting at 1240 CE and spatially heterogeneous slowdowns at approximately 1380-1430 CE and then since approximately 1660 CE.

    “Precisely, SPD curves derived from OHD data reproduce consistent variations in land use for food production, with an overall expansion in intensity starting at 1240 CE and spatially heterogeneous slowdowns at approximately 1380–1430 CE and then since approximately 1660 CE [ 23 ].”

    From Ecology of the collapse of Rapa Nui society (2020) · cites this paper as [23]

  • Land use varied considerably after 1240 CE, driven by environmental constraints and variation in agricultural production.

    “More importantly, land use varied considerably after 1240 CE, driven by environmental constraints and variation in agricultural production [ 23 ].”

    From Ecology of the collapse of Rapa Nui society (2020) · cites this paper as [23]

Cites

Flagged first, then by citations

Research works printed but not linked: 9

  1. G Lee Easter Island rock art: Ideological symbols as evidence for socio-political change. PhD dissertation (University of California Los Angeles CA). (1986).
  2. J Van Tilburg Power and symbol: The stylistic analysis of Easter Island monolithic sculpture. PhD dissertation (University of California Los Angeles CA). (1986).
  3. CM Stevenson Corporate descent group structure in Easter Island prehistory. PhD dissertation (Pennsylvania State University State College PA). (1984).
  4. CM Stevenson, The socio-political structure of the southern coastal area of Easter Island. The Evolution of Island Societies, ed PV Kirch (Cambridge Univ Press, Cambridge, UK), pp. 69–77 (1986).
  5. CM Stevenson, S Haoa Prehistoric Rapa Nui. Easter Island Foundation (Bearsville, Los Osos, CA, 2008).
  6. CM Stevenson Archaeological Investigations on Easter Island, Maunga Tari: An Upland Agricultural Complex (Easter Island Foundation, Bearsville and Cloudmountain, Los Osos, CA, 1997).
  7. JR Flenley, New data and new thoughts about Rapa Nui, in Easter Island. Pacific Context South Seas Symposium: Proceedings of the Fourth International Conference on Easter Island and East Polynesia, eds CM Stevenson, G Lee, FJ Morin (Easter Island Foundation, Los Osos, CA), pp. 125–128 (1998).
  8. JR Flenley, PG Bahn, Ratted out. Am Sci 95, 4–5 (2007).
  9. A Mieth, H-R Bork Easter Island - Rapa Nui: Scientific Pathways to Secrets of the Past (Christian-Albrechts-Universitat zu Kiel, Kiel, Germany, 2004).

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Related

Authors
Stevenson, C. M., Puleston, C. O., Vitousek, P. M., Chadwick, O. A., Haoa, S., & Ladefoged, T. N.
Affiliations
  • Virginia Commonwealth University (US)
  • University of California, Davis (US)
  • Stanford University (US)
  • University of California, Santa Barbara (US)
  • Fundación Mata Ki Te Rangi, Hanga Roa, Rapa Nui, Chile; and
  • University of Auckland (NZ)
ORCID
Venue
Proceedings of the National Academy of Sciences
Publisher
National Academy of Sciences
Published
2015-01-05
Volume
112
Issue
4
Pages
1025-1030
ISSN
  • 0027-8424 (ISSN-L)
  • 1091-6490
DOI
10.1073/pnas.1420712112
PMC
PMC4313829
OpenAlex
W2049769897
Semantic Scholar
2985a7647169518ad93563d6bc573a3feee82bff
Cited by
98
References
50
Citations by year
2026: 1 · 2025: 5 · 2024: 2 · 2023: 3 · 2022: 13 · 2021: 5 · 2020: 10 · 2019: 34 · 2018: 8 · 2017: 9 · 2016: 6 · 2015: 2
FWCI
43.63
Type
journal article
Language
en
Open access
Licence
www.pnas.org/site/misc/userlicense.xhtml (vor, 181 d)
Locations
  • Proceedings of the National Academy of Sciences (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
Funders
National Science Foundation (0911056)
Topics
  • Social Sciences › Geography, Planning and Development › Pacific and Southeast Asian Studies
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Archaeology and ancient environmental studies
  • Social Sciences › Arts and Humanities › History › Amazonian Archaeology and Ethnohistory
Keywords
Easter Island, prehistoric land use, societal collapse, population growth, demographic dynamics, obsidian hydration dating, habitation sites, rainfall variability, soil quality, European contact, prehistoric agriculture
MeSH terms
Agriculture, Anthropology, Cultural, Female, Glass, Humans, Male, Polynesia, Population Dynamics, History, 15th Century, History, 16th Century, History, 17th Century, History, 18th Century

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