Predicting pre-Columbian anthropogenic soils in Amazonia

In the paper

“Less is known of terra preta occurrence in the westernmost and interfluvial forests, though most soil surveys in these areas contain no evidence of terra pretas [10,33-38] (figure 1).”

What the sources say

• ?Not checked — no full text of the sourcecites [10] 10. McMichael C, Piperno DR, Bush MB, Silman MR, Zimmerman AR, Raczka MF, Lobato LC. 2012 Sparse pre-Columbian human habitation in western Amazonia. Science 336 , 1429-1431. (doi:10.1126/ science.1219982) source
• Not checked yetcites [33] 33. Brazil MdMeE, Departamento Nacional de Produca ˜o Mineral (DNPM). 1973-1983 Projeto RADAMBRASIL: 1973-1983, Levantamento de Recursos Naturais. DNPM, Rio de Janeiro.
• ?Not checked — no full text of the sourcecites [34] 34. Cooper M, Mendes LMS, Silva WLC, Sparovek G. 2005 A national soil profile database for Brazil available to international scientists. Soil Sci. Soc. Am. J. 69 , 649-652. (doi:10.2136/sssaj2004.0140) source
• Not checked yetcites [35] 35. McMichael C, Bush MB, Piperno D, Silman MR, Zimmerman AR, Anderson C. 2012 Scales of preColumbian disturbance associated with western Amazonian lakes. Holocene 22 , 131-141. (doi:10.1177/0959683611414932)
• ?Not checked — no full text of the sourcecites [36] 36. McMichael CH, Bush MB, Silman MR, Piperno DR, Raczka M, Lobato LC, Zimmerman M, Hagen S, Palace M. 2012 Historical fire and bamboo dynamics in western Amazonia. J. Biogeogr . 40 , 299-309. (doi:10.1111/jbi.12002) source
• ?Could not verify

  Section 3.6, “Other soils” (page not provided), says the paper excludes man-made soils, including terra preta, from its review. The Introduction discusses soil surveys but does not say whether surveys of westernmost or interfluvial forests found terra preta. Searches for terra preta and its absence in those surveys found no passage addressing the claim. (LLM, conf=0.76)

  cites [37] 37. Quesada C, Lloyd J, Anderson L, Fyllas N, Schwarz M, Czimczik C. 2011 Soils of Amazonia with particular reference to the RAINFOR sites. Biogeosciences 8 , 1415-1440. (doi:10.5194/ bg-8-1415-2011) sourceExperimental — accuracy not yet measured
• ?Could not verify

  The Study sites section describes Amazonian forest plots with soil data, but does not report whether those surveys found terra preta. Searches for “terra preta,” “westernmost,” and “interfluvial” found no passage in our copy addressing the claimed absence of evidence. (LLM, conf=0.73)

  cites [38] 38. Quesada C et al . 2009 Regional and large-scale patterns in Amazon forest structure and function are mediated by variations in soil physical and chemical properties. Biogeosci. Discuss. 6 , 3993-4057. (doi:10.5194/bgd-6-3993-2009) sourceExperimental — accuracy not yet measured

In the paper

“The older and highly weathered cratonic soils of eastern Amazonia were particularly nutrientpoor [37,56], and terra preta formation increased fertility in soils and afforded repeatable harvests in nutrient-poor areas at higher population densities.”

What the sources say

• Partly supported

  The Introduction (page unavailable) describes low soil fertility in central Amazonia and links it to ancient, deeply weathered and leached material. It does not establish that the cratonic soils of eastern Amazonia were particularly nutrient-poor; it also notes that soils on the ancient Guyana and Brazilian shields can sometimes have unexpectedly high fertility. The terra preta clause is not attributed to this source by the citation placement. (LLM, conf=0.84)

  cites [37] 37. Quesada C, Lloyd J, Anderson L, Fyllas N, Schwarz M, Czimczik C. 2011 Soils of Amazonia with particular reference to the RAINFOR sites. Biogeosciences 8 , 1415-1440. (doi:10.5194/ bg-8-1415-2011) sourceExperimental — accuracy not yet measured
• Partly supported

  The biodiversity section (p. 4) describes soils on the Eastern Amazonian craton as generally nutrient-poor, contrasting them with soils on younger Andean sediments. It also calls the craton old, but does not describe its soils as highly weathered. The terra preta clause is not attributed specifically to this source. (LLM, conf=0.83)

  cites [56] 56. Hoorn C et al . 2010 Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity. Science 330 , 927-931. (doi:10. 1126/science.1194585) sourceExperimental — accuracy not yet measured

In the paper

“These anthropogenic soil types were usually formed between 500 and 2500 years ago and contain significantly higher nutrient levels than typical Amazonian soils [4,20,23-28].”

What the sources say

• ?Not checked — no full text of the sourcecites [4] 4. Neves E, Petersen J. 2006 Political economy and pre-Columbian landscape transformation in central Amazonia. In Time and complexity in historical ecology: studies in the neotropical lowlands (eds W Balee, CL Erickson), pp. 279-310. New York, NY: Columbia University Press. source
• Not checked yetcites [20] 20. Roosevelt AC. 1991 Moundbuilders of the Amazon: geophysical archaeology on Marajo ´ Island . San Diego, CA: Academic Press.
• ?Not checked — no full text of the sourcecites [23] 23. Neves E, Petersen J, Bartone R, Augusto Da Silva C. 2004 Historical and socio-cultural origins of Amazonian dark earth. In Amazonian dark earths: origins, properties, management (eds J Lehmann, DC Kern, B Glaser, WI Woods), pp. 29-50. The Netherlands: Kluwer Academic Publisher. source
• ?Could not verify

  The discussion of soil nutrients on p. 258 concerns how cultivation used them, not nutrient levels in terra preta. Searches for “terra preta” and anthropogenic dark-earth fertility found no passage comparing those soils with typical Amazonian soils. (LLM, conf=0.72)

  cites [24] 24. Roosevelt AC. 1993 The rise and fall of the Amazon chiefdoms . L'Homme 33 , 255-283. sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [25] 25. Roosevelt AC et al . 1996 Paleoindian cave dwellers in the Amazon: the peopling of the Americas. Science 272 , 373-384. (doi:10.1126/science. 272.5260.373) source
• Supported

  The Characteristics and Classification Criteria section reports higher exchangeable bases, calcium, and magnesium in Terra Preta soils than in nearby forest soils. It also describes plant-available phosphorus as strikingly high in Terra Preta compared with normal forest soils. Page numbers are not provided in our copy. (LLM, conf=0.92)

  cites [26] 26. Sombroek W, Kern D, Rodrigues T, Cravo MS, Jarbas TC, Woods W, Glaser B (eds). 2002 Terra preta and terra mulata : pre-Columbian Amazon kitchen middens and agricultural fields, their sustainability and their replication. In Proc. 17th World Congress of Soil Science , Bangkok, Thailand .
• ?Could not verify

  The available indexed passages contain bibliographic metadata, not the thesis text. Searches for terra preta nutrient levels and related fertility terms returned no passage addressing a comparison with typical Amazonian soils, so the claim cannot be checked against our copy. (LLM, conf=0.72)

  cites [27] 27. Sombroek WG. 1966 Amazon soils: a reconnaissance of the soils of the Brazilian Amazon region . Wageningen, The Netherlands: Centre for Agricultural Publications and Documentation. sourceExperimental — accuracy not yet measured
• Not checked yetcites [28] 28. Woods WI, McCann JM. 1999 The anthropogenic origin and persistence of Amazonian dark earths. Yearb. Conf. Latin Am. Geogr. 25 , 7-14.

In the paper

“The type of river does not seem to be as important, as areas of high terra preta probability fall along black-water (including the Rio Negro), white-water (including the Amazon) and clear-water rivers (including the Tapajos) [26,55].”

What the sources say

• Partly supported

  The Application research section identifies terra preta sites near confluences involving the Rio Negro, Amazon and Tapajós, supporting occurrence across these river settings. It does not establish high terra preta probability along each river type. The Characteristics and classification criteria section says river-water type causes major differences and that terra preta patches along the upper and middle Rio Negro are rare and small. (LLM, conf=0.85)

  cites [26] 26. Sombroek W, Kern D, Rodrigues T, Cravo MS, Jarbas TC, Woods W, Glaser B (eds). 2002 Terra preta and terra mulata : pre-Columbian Amazon kitchen middens and agricultural fields, their sustainability and their replication. In Proc. 17th World Congress of Soil Science , Bangkok, Thailand .Experimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [55] 55. Kern DC, Aquino GD, Rodrigues TE, Frazao FJL, Sombroek W, Myers TP, Neves EG. 2003 Distribution of Amazonian dark earths in the Brazilian Amazon. In Amazonian dark earths: origins, properties, management (eds J Lehmann, DC Kern, B Glaser, WI Woods), pp. 51-75. Dordrecht, The Netherlands: Kluwer Academic Publishers. source

In the paper

“Terrain, geological and hydrological characteristics were more important in shaping terra preta distributions than were climatic ones (table 1 and figures 3-5).”

In the paper

“The locations of terra preta -free sites from all of these surveys were combined to form a database of terra preta absences ( n ¼ 1962).”

In the paper

“We combined these data points with 463 georeferenced terra preta sites uncovered by E.G.N. and E.K.T. in archaeological field surveys from 2008 to 2012 to obtain a total of 917 known terra preta locations (figure 1).”

In the paper

“Model results also indicated that the probability of finding terra preta is almost zero at the major archaeological sites in Bolivia, including the Llanos de Moxos and the geoglyph-rich region (figure 2).”

In the paper

“The second most important predictor was geological province, and terra pretas are most likely to be found in the Solimo ˜es Basin, Ucayali Basin and Brazilian Shield regions (figure 3).”

In the paper

“In total, 1791 of these sites lie within Amazonia (figure 1).”

In the paper

“The combined terra preta and terra preta -free dataset contained 2879 sites.”

In the paper

“In total, 454 sites fell within lowland Amazonia (figure 1).”

In the paper

“Elevation was the most important factor in the model, and the potential distribution was constrained to areas primarily between 0 and 100 m elevation (figure 3).”

In the paper

“The average AUC value obtained from the 10-fold cross-validation of the model was 0.957, with a standard deviation of + 0.006, which was much higher than that of a random prediction (0.5), and indicated that the model fitted the data well and had a high predictive capacity.”

In the paper

“Similarly, the model predicted that terra pretas are very unlikely to be found in the forests in close proximity to the western Amazonian earthworks.”

In the paper

“No site in the database contained notes or descriptions regarding any pottery sherds or soils with the black coloration or anomalously high nutrient content of terra pretas .”

In the paper

“When considering the predicted probabilities of all known terra preta presence and absence points (figure 1), a probability threshold of 0.25 was able to correctly classify the highest percentage of known sites.”

In the paper

“Elevation was the most important factor in the model, and the potential distribution was constrained to areas primarily between 0 and 100 m elevation (figure 3).”

In the paper

“As expected, riverine settings were also important in the model.”

In the paper

“The second most important predictor was geological province, and terra pretas are most likely to be found in the Solimo ˜es Basin, Ucayali Basin and Brazilian Shield regions (figure 3).”

In the paper

“Our reasoning is owing to the fact that terra pretas are found throughout all of the major archaeological sites in the interior of the Amazon Basin, including areas near the Central Amazon Project and Santarem (figures 1 and 2).”

In the paper

“The forests surrounding both sites were also predicted to be terra preta -free.”

In the paper

“Our estimates of potential terra preta sites were significantly less than the previous estimates of 10% [6,7] and did not support the assertion that most of Amazonia was a transformed landscape or cultural parkland before European arrival.”

What the sources say

• ?Not checked — no full text of the sourcecites [6] 6. Erickson CL. 2008 Amazonia: the historical ecology of a domesticated landscape. In The handbook of South American archaeology (eds H Silverman, WH Isbell), pp. 157-183. New York, NY: Springer. source
• ?Not checked — no full text of the sourcecites [7] 7. Mann CC. 2002 The real dirt on rainforest fertility. Science 297 , 920-923. (doi:10.1126/science.297. 5583.920) source

In the paper

“We suggest that aside from the areas that lie near ecotonal boundaries, such as Marajo, Xingu and the Llanos de Moxos (figures 1 and 2), our model predicts the areas of lowland interior Amazonia that experienced the most intensive preColumbian disturbances.”

In the paper

“In the nearby geoglyph-rich regions of Acre, Brazil and northern Bolivia, our model predicts an absence of terra preta (figures 2 and 3).”

In the paper

“These predictions are concordant with archaeological surveys which report an absence of terra pretas within the region [18].”

What the sources say

• ?Not checked — no full text of the sourcecites [18] 18. Schaan D, Pa ¨rssinen M, Saunaluoma S, Ranzi A, Bueno M, Barbosa A. 2012 New radiometric dates for pre-Columbian (2000-700 BP) earthworks in western Amazonia, Brazil. J. Field Archaeol. 37 , 132-142. (doi:10.1179/0093469012Z. 00000000012) source

In the paper

“Most of the previous forest inventory research occurred in areas that most probably do not contain terra pretas , but the long-term study sites near Manaus and Santarem are particularly promising for local-scale evaluations of pre-Columbian disturbance on forest structure (sites C and S in figure 6).”

In the paper

“Our estimates of potential terra preta sites were significantly less than the previous estimates of 10% [6,7] and did not support the assertion that most of Amazonia was a transformed landscape or cultural parkland before European arrival.”

In the paper

“Terra pretas occur throughout Amazonia, but are most commonly found in the central and eastern forests [26,31], and in riverine settings, particularly along bluffs overlooking the rivers [32].”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [26] 26. Sombroek W, Kern D, Rodrigues T, Cravo MS, Jarbas TC, Woods W, Glaser B (eds). 2002 Terra preta and terra mulata : pre-Columbian Amazon kitchen middens and agricultural fields, their sustainability and their replication. In Proc. 17th World Congress of Soil Science , Bangkok, Thailand .
• ?Not checked — no full text of the sourcecites [31] 31. Glaser B, Birk JJ. 2012 State of the scientific knowledge on properties and genesis of Anthropogenic dark earths in central Amazonia (terra preta de I ´ ndio). Geochim. Cosmochim. Acta 82 , 39-51. (doi:10.1016/j.gca.2010.11.029) source

In the paper

“Legacies of prehistoric influence in Amazonia are visible from aerial surveys and satellite imagery along the southern periphery of the basin, particularly in the Llanos de Moxos of Bolivia (e.g. [1,12-14]), the geoglyph-rich region of Acre, Brazil and northern Bolivia [3,15-18], and the Upper Xingu in Brazil [2,19] (figure 1).”

What the sources say

• ?Not checked — no full text of the sourcecites [1] 1. Erickson CL. 2006 The domesticated landscapes of the Bolivian Amazon. In Time and complexity in historical ecology (eds W Balee, CL Erickson), pp. 235-278. New York, NY: Columbia University Press. source
• ?Not checked — no full text of the sourcecites [12] 12. Erickson CL. 2000 An artificial landscape-scale fishery in the Bolivian Amazon. Nature 408 , 190-193. (doi:10.1038/35041555) source
• ?Not checked — no full text of the sourcecites [13] 13. Lombardo U, Canal-Beeby E, Fehr S, Veit H. 2011 Raised fields in the Bolivian Amazonia: a prehistoric green revolution or a flood risk mitigation strategy? J. Archaeol. Sci. 38 , 502-512. (doi:10.1016/j.jas. 2010.09.022) source
• ?Not checked — no full text of the sourcecites [14] 14. Lombardo U, Pru ¨mers H. 2010 Pre-Columbian human occupation patterns in the eastern plains of the Llanos de Moxos, Bolivian Amazonia. J. Archaeol. Sci. 37 , 1875-1885. (doi:10.1016/j.jas. 2010.02.011) source
• Not checked yetcites [3] 3. Pa ¨rssinen M, Schaan D, Ranzi A. 2009 PreColumbian geometric earthworks in the upper Puru ´s: a complex society in western Amazonia. Antiquity 83 , 1084-1095.
• ?Not checked — no full text of the sourcecites [15] 15. Ranzi A, Feres R, Brown F. 2007 Internet software programs aid in search for Amazonian geoglyphs. EOS Trans. 88 , 226-229. (doi:10.1029/ 2007EO210003) source
• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [16] 16. Saunaluoma S. 2010 Pre-Columbian earthworks in the Riberalta region of the Bolivian Amazon. Amazo ˆnica-Revista de Antropologia. 2 , 104-138. source
• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [17] 17. Saunaluoma S, Schaan D. 2012 Monumentality in Western Amazonian formative societies: geometric ditched enclosures in the Brazilian state of Acre. Antiqua 2 , e1. (doi:10.4081/antiqua.2012.e1) source
• ?Not checked — no full text of the sourcecites [18] 18. Schaan D, Pa ¨rssinen M, Saunaluoma S, Ranzi A, Bueno M, Barbosa A. 2012 New radiometric dates for pre-Columbian (2000-700 BP) earthworks in western Amazonia, Brazil. J. Field Archaeol. 37 , 132-142. (doi:10.1179/0093469012Z. 00000000012) source
• ?Not checked — no full text of the sourcecites [2] 2. Heckenberger M, Russell J, Fausto C, Toney J, Schmidt M, Pereira E, Franchetto B, Kuikuro A. 2008 Pre-Columbian urbanism, anthropogenic landscapes, and the future of the Amazon. Science 321 , 1214-1217. (doi:10.1126/science.1159769) source

In the paper

“Terra pretas indicate sedentary pre-Columbian settlements and are the most widely reported archaeological feature in Amazonia.”

In the paper

“As topsoil and subsoil characteristics were highly correlated with each other, we used primarily subsoil characteristics in the predictive model ( n ¼ 6) (see the electronic supplementary material, figure S1 and table S1).”

In the paper

“Other Amazonian soil surveys [10,37,40] also report no evidence of terra preta .”

What the sources say

• ?Not checked — no full text of the sourcecites [10] 10. McMichael C, Piperno DR, Bush MB, Silman MR, Zimmerman AR, Raczka MF, Lobato LC. 2012 Sparse pre-Columbian human habitation in western Amazonia. Science 336 , 1429-1431. (doi:10.1126/ science.1219982) source
• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [37] 37. Quesada C, Lloyd J, Anderson L, Fyllas N, Schwarz M, Czimczik C. 2011 Soils of Amazonia with particular reference to the RAINFOR sites. Biogeosciences 8 , 1415-1440. (doi:10.5194/ bg-8-1415-2011) source
• Not checked yetcites [40] 40. McMichael CH, Correa Metrio A, Bush MB. 2012 PreColumbian fire regimes in lowland tropical rainforests of southeastern Peru. Palaeogeogr. Palaeoclimatol. Palaeoecol. 342-343 , 73-83. (doi:10.1016/j.palaeo.2012.05.004)

In the paper

“Second, the accuracy of locations in the RADAM dataset, which comprised the majority of points in the terra preta -free dataset, may be questionable as the points were collected prior to modern GPS technology.”

In the paper

“MAXENT v. 3.3.3 (http://www.cs.princeton.edu/~schapire/ maxent/) was used to model terra preta distributions, as it commonly outperformed other modelling techniques that use presence-only or presence-absence data, especially when dealing with small sample sizes or non-random sampling [47-49].”

What the sources say

• Not checked yet

  Checked before — its earlier verdict is held back until a new check runs.

  cites [47] 47. Phillips SJ, Dudı ´k M. 2008 Modeling of species distributions with MAXENT: new extensions and a comprehensive evaluation. Ecography 31 , 161-175. (doi:10.1111/j.0906-7590.2008.5203.x) source
• ?Not checked — no full text of the sourcecites [48] 48. Elith J, Phillips SJ, Hastie T, Dudı ´k M, Chee YE, Yates CJ. 2011 A statistical explanation of MAXENT for ecologists. Divers. Distrib. 17 , 43-57. (doi:10.1111/ j.1472-4642.2010.00725.x) source
• ?Not checked — no full text of the sourcecites [49] 49. Phillips SJ, Anderson RP, Schapire RE. 2006 Maximum entropy modeling of species geographic distributions. Ecol. Model. 190 , 231-259. (doi:10. 1016/j.ecolmodel.2005.03.026) source

In the paper

“Basin-wide soil surveys show that terra preta distributions are non-random (figure 1).”

In the paper

“The perception that the entirety of the Amazon Basin was a virgin forest or 'counterfeit paradise' before European arrival to the Americas has been refuted, as recent research has documented evidence of earthwork formation, complex societies [1-3] and modified soils [4,5].”

What the sources say

• ?Not checked — no full text of the sourcecites [1] 1. Erickson CL. 2006 The domesticated landscapes of the Bolivian Amazon. In Time and complexity in historical ecology (eds W Balee, CL Erickson), pp. 235-278. New York, NY: Columbia University Press. source
• ?Not checked — no full text of the sourcecites [2] 2. Heckenberger M, Russell J, Fausto C, Toney J, Schmidt M, Pereira E, Franchetto B, Kuikuro A. 2008 Pre-Columbian urbanism, anthropogenic landscapes, and the future of the Amazon. Science 321 , 1214-1217. (doi:10.1126/science.1159769) source
• Not checked yetcites [3] 3. Pa ¨rssinen M, Schaan D, Ranzi A. 2009 PreColumbian geometric earthworks in the upper Puru ´s: a complex society in western Amazonia. Antiquity 83 , 1084-1095.
• ?Not checked — no full text of the sourcecites [4] 4. Neves E, Petersen J. 2006 Political economy and pre-Columbian landscape transformation in central Amazonia. In Time and complexity in historical ecology: studies in the neotropical lowlands (eds W Balee, CL Erickson), pp. 279-310. New York, NY: Columbia University Press. source
• ?Not checked — no full text of the sourcecites [5] 5. Glaser B, Woods WI. 2004 Amazonian dark earths: explorations in space and time . Berlin, Germany: Springer. source

In the paper

“They occur at most of the major archaeological sites in the interior forests including the Central Amazon Project [4,23], Santarem [28], Marajo [29] and the Upper Xingu [19,30] (figure 1).”

What the sources say

• ?Not checked — no full text of the sourcecites [4] 4. Neves E, Petersen J. 2006 Political economy and pre-Columbian landscape transformation in central Amazonia. In Time and complexity in historical ecology: studies in the neotropical lowlands (eds W Balee, CL Erickson), pp. 279-310. New York, NY: Columbia University Press. source
• ?Not checked — no full text of the sourcecites [23] 23. Neves E, Petersen J, Bartone R, Augusto Da Silva C. 2004 Historical and socio-cultural origins of Amazonian dark earth. In Amazonian dark earths: origins, properties, management (eds J Lehmann, DC Kern, B Glaser, WI Woods), pp. 29-50. The Netherlands: Kluwer Academic Publisher. source
• Not checked yetcites [28] 28. Woods WI, McCann JM. 1999 The anthropogenic origin and persistence of Amazonian dark earths. Yearb. Conf. Latin Am. Geogr. 25 , 7-14.
• ?Not checked — no full text of the sourcecites [29] 29. Schaan D, Kern D, Fraza ˜o F. 2009 An assessment of the cultural practices behind the formation (or not) of Amazonian dark earths in Marajo ´ island archaeological sites . In Amazonian Dark Earths: Wim Sombroek's Vision (eds W Woods, W Teixeira, J Lehmann, C Steiner, A WinklerPrins, L Rebellato), pp. 127-141. Dordrecht, The Netherlands: Springer. source

In the paper

“However, because of the extensive chemical analyses performed on these soil samples, terra pretas most likely would have been identified through the presence of abundant artefacts, charcoal or anomalous nutrient levels.”

In the paper

“and the spatial extent of terra pretas probably expanded significantly during this time.”

In the paper

“Consistent with this view, the western, and particularly the northwestern, forests contain limited, if any, evidence of pre-Columbian human presence [10,63].”

What the sources say

• ?Not checked — no full text of the sourcecites [10] 10. McMichael C, Piperno DR, Bush MB, Silman MR, Zimmerman AR, Raczka MF, Lobato LC. 2012 Sparse pre-Columbian human habitation in western Amazonia. Science 336 , 1429-1431. (doi:10.1126/ science.1219982) source
• ?Not checked — no full text of the sourcecites [63] 63. Roucoux KH, Lawson IT, Jones TD, Baker TR, Coronado ENH, Gosling WD, La ¨hteenoja O. 2013 - Vegetation development in an Amazonian peatland. Palaeogeogr. Palaeoclimatol. Palaeoecol. 374 , 242-255. (doi:10.1016/j.palaeo.2013.01.023) source

In the paper

“Most recorded dates are from 1000 to 2000 years ago [22]”

What the sources say

• ?Not checked — no full text of the sourcecites [22] 22. Neves EG, Petersen JB, Bartone RN, Heckenberger MJ. 2004 The timing of terra preta formation in the Central Amazon: archaeological data from three sites. In Amazonian dark earths: explorations in space and time (eds B Glaser, WI Woods), pp. 125-134. Berlin, Germany: Springer. source

In the paper

“Instead, these data suggested that preColumbian Amazonia was a heterogeneous landscape, with varying degrees of human impacts across the mosaic.”

In the paper

“The Llanos de Moxos regions of Bolivia is located in seasonally inundated forests at the forest-savannah transition, and instead of terra preta formation, large societies sustained themselves by using techniques such as fish weirs and raised-field agriculture (e.g. [12]).”

What the sources say

• ?Not checked — no full text of the sourcecites [12] 12. Erickson CL. 2000 An artificial landscape-scale fishery in the Bolivian Amazon. Nature 408 , 190-193. (doi:10.1038/35041555) source

In the paper

“Cultural differences undoubtedly contributed to the distribution of terra preta formation, and these boundaries may have been just as important as environmental conditions (figure 2).”

In the paper

“Cultural differences undoubtedly contributed to the distribution of terra preta formation, and these boundaries may have been just as important as environmental conditions (figure 2).”

In the paper

“Many tree species in Amazonia live several hundred years [66], and forest burning and clearing associated with terra pretas from 2000 to 500 years ago, and in many cases again at the turn of the twentieth century, may have significantly contributed to patterns and dynamics documented in the modern forests.”

In the paper

“Also, our model probably overestimates the areas where terra pretas will be found at any given time because it predicts the summed distribution taken across all ages.”

In the paper

“Ourmodelcontradicts recent assertionsthat pre-Columbian human disturbance increased Amazonian biodiversity through promoting preferred species [11].”

What the sources say

• Not checked yetcites [11] 11. Bale ´e W. 1993 Indigenous transformation of Amazonian forests: an example from Maranhao, Brazil . L'Homme 33 , 231-254.

In the paper

“Wedonote,however, that because most terra preta and terra preta -free sites lie in Brazil, our most confident predictions are for this country.”