MATTERS ARISING https://doi.org/10.1038/s41467-022-31064-2 OPEN Evidence confirms an anthropic origin of Amazonian Dark Earths Umberto Lombardo 1,2 ✉, Manuel Arroyo-Kalin 3 ✉, Morgan Schmidt 4, Hans Huisman5, Helena P. Lima 6, Claide de Paula Moraes 7, Eduardo G. Neves8, Charles R. Clement9, João Aires da Fonseca10, Fernando Ozorio de Almeida 11, Carlos Francisco Brazão Vieira Alho 12, Christopher Bronk Ramsey 13, George G. Brown 14, Marta S. Cavallini8, Marcondes Lima da Costa 15, Luís Cunha 16, Lúcia Helena C. dos Anjos17, William M. Denevan18, Carlos Fausto19,20, 1234567890():,; Caroline Fernandes Caromano 21, Ademir Fontana22, Bruna Franchetto19, Bruno Glaser23, Michael J. Heckenberger24, Susanna Hecht25,26, Vinicius Honorato7, Klaus A. Jarosch 2, André Braga Junqueira 1, Thiago Kater 8, Eduardo K. Tamanaha27, Thomas W. Kuyper 12, Johannes Lehmann 28, Marco Madella 29,30, S. Yoshi Maezumi 31,32, Leandro Matthews Cascon33, Francis E. Mayle 34, Doyle McKey 35, Bruno Moraes 36, Gaspar Morcote-Ríos37, Carlos A. Palheta Barbosa38, Marcos Pereira Magalhães 6, Gabriela Prestes-Carneiro7, Francisco Pugliese8, Fabiano N. Pupim39, Marco F. Raczka 34, Anne Rapp Py-Daniel7, Philip Riris40, Bruna Cigaran da Rocha 7, Leonor Rodrigues41, Stéphen Rostain42, Rodrigo Santana Macedo43, Myrtle P. Shock 7, Tobias Sprafke2,44, Filippo Stampanoni Bassi45, Raoni Valle7, Pablo Vidal-Torrado 46, Ximena S. Villagrán8, Jennifer Watling 8, Sadie L. Weber8 & Wenceslau Geraldes Teixeira 22 ARISING FROM Silva et al. Nature Communications https://doi.org/10.1038/s41467-020-20184-2 (2021) F irst described over 120 years ago in Brazil, Amazonian Dark (Caldeirão, see maps in Silva et al.5), is too limited to distinguish Earths (ADEs) are expanses of dark soil that are excep- among the multiple possible mechanisms for ADE formation. tionally fertile and contain large quantities of archaeological Moreover, it disregards or misreads a wealth of evidence pro- artefacts. The elevated fertility of the dark and often deep A duced by archaeologists, soil scientists, geographers and anthro- horizon of ADEs is widely regarded as an outcome of pre- pologists, showing that ADEs are anthropic soils formed on land Columbian human influence1. Archaeological research provides surfaces enriched by inputs associated with pre-Columbian clear evidence that their widespread formation in lowland South sedentary settlement6–9. To be accepted, and be pertinent at a America was concentrated in the Late Holocene, an outcome of regional level, Silva et al.’s hypothesis5 would need to be sup- sharp human population growth that peaked towards 1000 BP2–4. ported by solid evidence (from numerous ADE sites), which we In their recent paper Silva et al.5 argue that the higher fertility of demonstrate is lacking. ADEs is principally a result of fluvial deposition and, as a cor- ollary, that pre-Columbian peoples just made use of these locales, contributing little to their enhanced nutrient status. Geomorphological and pedological considerations Soil formation is inherently complex and often difficult to There are several problems with reviving the argument10 that interpret, requiring a combination of geochemical data, strati- ADE fertility originates from deposited alluvium. First, the graphy, and dating. Although Silva et al. use this combination of Caldeirão ADE site is located on a Miocene plateau ~20 m methods to make their case5, their hypothesis, based on the above the Solimões River floodplain (~40 m asl), which in itself analysis of a single ADE site and its immediate surroundings precludes significant flooding during the Holocene11. Second, A full list of author affiliations appears at the end of the paper. NATURE COMMUNICATIONS | (2022)13:3444 | https://doi.org/10.1038/s41467-022-31064-2 | www.nature.com/naturecommunications 1 MATTERS ARISING NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-022-31064-2 Fig. 1 Caldeirão’s soil compositional data compared with published data of Solimões River sediments and anthropic materials. Data is in Supplementary Table 1; the wood ash and bone/dung fields in (C, D) are offset to compensate for soil (Ulti) background concentrations. ADE = Amazonian Dark Earth, Ulti = Ultisol soil profile. A Geogenic elements Al and Fe are similar in ADE and Ultisols, but different from Solimoes sediments. B, C Anthropogenic elements K, Ca, and P fall in the range of anthropogenic materials. Solimões sediments have much lower Ca/K ratios and far higher K concentrations. Black continuous and broken lines give the 1:2 and 1:2.13 Ca:P ratios quoted by Silva et al.5 for human faeces and freshwater fish, respectively, corrected for 500 mg/kg soil (Ulti) background. D Ca and Sr show strong correlations in ADE. The Ca/Sr ratio in ADE is close to that of wood ash, suggesting an anthropogenic origin for Sr, while Solimões sediments have overall much higher values. the parent material of the ADE and adjacent Ultisol shows Archaeological considerations analogous clay mineralogy and geogenic composition: both Research conducted at numerous archaeological sites in the Central sites are characterised by the same 1:1 clays (as shown by Silva Amazon17 has shown that the largest ADE expanses record multi- et al.’s Supplementary Fig. 35) and both lack the 2:1 clay component occupations that date to the period 1200–800 BP and minerals expected from fluvial origin12. Moreover, no differ- are often underlain by remains of older (<2500 BP) ceramic ence is observed in the geogenic elements (Al, Ti, Cr, V, Fe, As) occupations2–4,6. This also applies in the case of the Caldeirão site, (Fig. 1A). Third, the overall mineral assemblage of the Cal- where coring and excavations clearly show that the ADE is a deirão ADE is incompatible with the geochemistry of the pottery-rich archaeological deposit characterised by a pre- sedimentary load of the Solimões River (Fig. 1A, B, D). Fourth, dominantly human-made assemblage of mounds and pits the lower clay content in the anthropic ADE horizons at Cal- (Fig. 2A–E). Silva et al.’s sampling transects and elemental/isotopic deirão (erroneously described by Silva et al. as “sandy clay measurements neither take into consideration nor detect this loam”5) is not evidence of fluvial deposition but a partial out- demonstrable anthropic conditioning of pre-Columbian origin (see come of argilluviation9. Fifth, other well-studied ADE sites Inset II in Fig. 2E)5. Furthermore, Silva et al. misunderstand stra- nearby contradict Silva et al.’s inference5: at the Hatahara ADE tigraphic associations when suggesting that >7.6 ky 14C BP char- site, located 4 km from Caldeirão on the same Miocene bluff, coal collected from −90 cm in their Ultisol transect provides an the similarity in quartz sand grain morphology between the accurate age marker for the beginning of ADE formation5. Middle ADE A and B horizons excludes the inference of fluvial inputs Holocene charcoal fragments are commonly found stratified in into the A horizon13. Further afield, a large number of ADE Amazonian soil profiles18, including the B horizons of ADE sites are found along blackwater (non alluvial) rivers, associated profiles14. However, the relevant age to understand ADE formation with small headwater streams and springs, or found at eleva- (and whether it is consistent with human occupation) is that of the tions exceeding 90 m above the maximum flood level14–16, silt-sized charcoal making up the dark horizon of an ADE. At the demonstrating that alluvial deposition is irrelevant to the for- nearby ADE site of Hatahara, the age of this charcoal pool is mation of many ADE expanses. Indeed, if ADE were the result consistent with a late first millennium AD Paredão phase settle- of alluvial processes, their spatial distribution along rivers ment, albeit with older occupations starting around 500 BC19,20. would be continuous rather than patchy. For Caldeirão, similar ages have been reported21. 2 NATURE COMMUNICATIONS | (2022)13:3444 | https://doi.org/10.1038/s41467-022-31064-2 | www.nature.com/naturecommunications NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-022-31064-2 MATTERS ARISING Demographic considerations assumption does not account for decades of research on the subject. Silva et al. argue that a late Holocene onset for incipient agriculture For instance, ethnoarchaeological research with the Kuikuro com- in the Central Amazon region would preclude populations large munity, who are fisher-cultivators that live in the Upper Xingu enough to produce the levels of elemental enrichment recorded at region, has demonstrated that the greatest enrichment in P, Ca, and Caldeirão5. This argument presupposes that indigenous land use Sr, as well as high organic carbon and nearly neutral pH, occurs in regimes relying on incipient agriculture, aquatic wildlife, and mounded refuse middens. Once enriched soil horizons form in the hunting could not have created areas of persistent high fertility. This middens, typically within a few years, they are often used for NATURE COMMUNICATIONS | (2022)13:3444 | https://doi.org/10.1038/s41467-022-31064-2 | www.nature.com/naturecommunications 3 MATTERS ARISING NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-022-31064-2 Fig. 2 Archaeological fieldwork—excavations and mapping—carried out at the Caldeirão site in 2011. A, B, C, and D Vertical profiles exposed by multiple archaeological excavations at the Caldeirão ADE. E Google Earth image of the Caldeirão ADE (see location of profiles A–D within insets I and II). 2a and 2b are ~25 m apart and show the stratigraphy of archaeological deposits in mound (2a) and flat (2b) areas. 2c and 2d are ~12 m apart and show the stratigraphy of archaeological deposits at an Embrapa reference profile (C) and nearby archaeological excavation (D). Note clearly defined archaeological matrix features infilled with ADE sediment (C), and infilled pit feature with well-preserved ceramic vessels, suggesting intentional deposition by ancient indigenous Amazonians (D). E Yellow shaded area shows the spatial distribution of mounds and archaeological pottery ascertained through archaeological survey and excavation. Insets I, II, II show details of the topography and/or archaeological excavations, as well as sampling location for profiles depicted in (A–D). Inset II: Note the close proximity between identified mounded areas (black arrows), archaeological excavations, and the area of the ADE sampled by Silva5 (blue rectangle). Inset III: Survey has also identified mounded areas (black arrows) near the area Silva et al.5 sampled for Ultisols (red rectangle). cultivating crops such as maize, sweet potato, and manioc22. Soil ratio in ADEs is the result of differential preservation coupled with enrichment and ADE formation, therefore, are consistently asso- the specific tropical soil dynamics of Ca, which is easily leached, and ciated with domestic activities in indigenous villages and, contrary P, which binds with soil Fe and Al oxides28. to Silva et al.’s claim5, it is this elemental enrichment accumulating By way of conclusion: the geogenic model for ADE formation, in settlements that is used for cultivation (and not the other way which famously argued that ADEs are dark soils of natural fer- around). More broadly, measurements of elemental enrichment tility resulting from the deposition of alluvial horizons10, was laid with P and Ca constitute a poor demographic proxy and, on their to rest over 40 years ago29. Silva et al.’s hypothesis5 reiterates this own, do not reveal agricultural activity: virtually any long human geogenic position but, as we have shown here, it does not stand occupation can result in soil enrichment23. ADE sites, like Cal- up to scrutiny. deirão, are very rich in nutrients because they concentrate human debris and waste associated with resources gathered or produced in large areas. It is the concentration of resources in settlements that Data availability produce ADEs over hundreds or thousands of years. Put another All relevant data are provided with the paper. way, a thousand people could extract resources produced from a 50 hectares’ catchment but concentrate debris and waste in a village of Received: 21 January 2021; Accepted: 27 May 2022; 0.1 hectares. Silva et al.’s5 reference to improbably large agricultural populations, which implicitly suggests that ADEs were initially established for agricultural purposes, does not constitute evidence of fluvial deposition and disregards the association between ADE and middens that is supported by current research. References 1. Clement, C. R. et al. The domestication of Amazonia before European conquest. Proc. R. Soc. Lond. B Biol. Sci. 282 https://doi.org/10.1098/rspb.2015.0813 (2015). Elemental enrichment and isotopic ratios of ADE vs. Ultisols 2. Neves, E. G., Guapindaia, V. L. C., Lima, P. H., Costa, B. L. S. & Gomes, J. in (Acrisols) Amazonía. Memorias de las Conferencias Magistrales del 3er Encuentro Internacional de Arqueología Amazónica (ed. Rostain, S.) 137–157 (Ministerio Most of the co-authors of Silva et al.5 have elsewhere argued that the Coordinador de Conocimiento y Talento Humano/IKIAM, 2014). elemental composition of Caldeirão site “…can be used to unveil 3. Moraes, Cd. P. & Neves, E. G. O ano 1000: Adensamento populacional, ADE sites and differentiate them from Amazonian soils without interação e conflito na Amazônia Central. Amazonica 4, 122–148 (2012). anthropic influence”24. We agree with their earlier assessment: 4. Arroyo-Kalin, M. & Riris, P. Did pre-Columbian populations of the enrichment of the ADE compared to the Ultisols is consistent with Amazonian biome reach carrying capacity during the Late Holocene? Philos. Trans. R. Soc. Lond. B Biol. Sci. 376, 20190715 (2021). inputs associated with human settlement. Among the latter are those 5. Silva, L. C. R. et al. A new hypothesis for the origin of Amazonian Dark related to burning, including K, Rb, Ba, Ca, Sr, P (from ash and Earths. Nat. Commun. 12, 127 (2021). charcoal); P, Ca, Sr, K, Zn, Cu (human waste); and Ca, P, Sr, Zn 6. Schmidt, M. J. et al. Dark earths and the human built landscape in Amazonia: (bone debris) (Fig. 1B, C)25. Most of these, along with pyrogenic C, a widespread pattern of anthrosol formation. J. Archaeological Sci. 42, 152–165 have been reported in ADEs8. The most logical explanation for such (2014). 7. Arroyo-Kalin, M. In Archaeological Soil and Sediment Micromorphology (eds an assemblage is anthropic inputs associated with settlement activity. Georges Stoops & Cristiano Nicosia) 345–357 (Wiley and sons, 2017). Indeed, research at the Hatahara site shows that the dark ADE 8. Glaser, B. & Birk, J. J. State of the scientific knowledge on properties and sediments are bulked up by sand and silt-sized particulate material genesis of Anthropogenic Dark Earths in Central Amazonia (terra preta de resulting from anthropic activity (fragmented charcoal and bone, Índio). Geochim. Cosmochim. Acta 82, 39–51 (2012). pottery fragments, sponge spicules, etc.)13. Bioturbation can then 9. Macedo, R. S., Teixeira, W. G., Corrêa, M. M., Martins, G. C. & Vidal-Torrado, P. Pedogenetic processes in anthrosols with pretic horizon (Amazonian Dark mix these added materials in soil over time throughout the profile. Earth) in Central Amazon, Brazil. PLoS ONE 12, e0178038 (2017). How, then, can a fluvial input be surmised? The core of Silva et al.’s 10. Falesi, I. C. In Man in the Amazon (ed. Wagley, C.) 201–229 (The University argument is that differences in Sr and Nd isotope ratios between Presses of Florida, 1974). ADE and Ultisols are best explained by fluvial inputs5. However, 11. Pupim, F. N. et al. Chronology of Terra Firme formation in Amazonian both Sr and Nd are found in plants26 and terrestrial and aquatic lowlands reveals a dynamic Quaternary landscape. Quat. Sci. Rev. 210, 154–163 (2019). vertebrates27, as well as in mineral matter and Silva et al. admit that 12. Guyot, J. L. et al. Clay mineral composition of river sediments in the Amazon their methods cannot discriminate these sources5. As there are no Basin. Catena 71, 340–356 (2007). independent indications of sediment input in ADE’s bulk chemical 13. Arroyo-Kalin, M., Neves, E. & Woods, W. I. In Amazonian Dark Earths: Wim composition, but ample evidence for non-mineral anthropogenic Sombroek’s Vision (eds Woods, W. I. et al.) 99–125 (Springer Netherlands, inputs, it is most likely that isotopic signature in the studied ADE 2009). 14. Heckenberger, M. J., Petersen, J. B. & Neves, E. G. Village size and resulted from the deposition of food debris. Silva et al. regard the permanence in Amazonia: two archaeological examples from Brazil. Lat. Am. difference in elemental stoichiometries of freshwater fish (Ca:P Antiquity 10, 353–376 (1999). ~2.13) and human faeces (Ca:P ~2) compared with ADEs as further 15. Guapindaia, V. & Aires Da Fonseca, J. Metodologia de delimitação no sítio evidence of ADE being of fluvial origin5. However, while the Ca:P arqueológico Cipoal do Araticum na região do rio Trombetas, Pará, Brasil. ratio is highly variable in Caldeirão ADE (Fig. 1C), the modern Ca:P Bol. Mus. Para. Emílio Goeldi Ciênc. Humanas 8, 657–673 (2013). 4 NATURE COMMUNICATIONS | (2022)13:3444 | https://doi.org/10.1038/s41467-022-31064-2 | www.nature.com/naturecommunications NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-022-31064-2 MATTERS ARISING 16. Eden, M. J., Bray, W., Herrera, L. & McEwan, C. Terra Preta Soils and Their T.W.K., J.L., M.M., S.Y.M., L.M.C., F.E.M., D.M., B.M., G.M.R., C.A.P.B., M.P.M., G.P.C., Archaeological Context in the Caqueta Basin of Southeast Colombia. Am. F.P., F.N.P., M.F.R., A.R.P.D., P.R., B.R., L.R., S.R., R.S.M., M.P.S., T.S., F.S.B., R.V., Antiquity 49, 125–140 (1984). P.V.T., X.S.V., J.W., and S.L.W. H.H. prepared Fig. 1. H.P.L. and M.J.S. prepared 17. Neves, E. G. In Ethnicity in ancient Amazonian: reconstructing past identities Fig. 2A–D. M.A.K., M.J.S., and W.T. prepared Fig. 2E with input from H.P.L., E.G.N., from Archaeology, Linguistic and Etnohistory 1–27 (University Press of C.M., and U.L. H.P.L., B.M., E.G.N., M.J.S., C.F.C., G.P.C., F.S.B., M.S.C. and R.V. carried Colorado, 2011). out archaeological fieldwork at Caldeirão. 18. Pessenda, L. C. R. et al. 14C Dating and stable carbon isotopes of soil organic matter in forest–Savanna Boundary Areas in the Southern Brazilian Amazon Region. Radiocarbon 40, 1013–1022 (1997). Competing interests The authors declare no competing interests. 19. Arroyo-Kalin, M. Slash-burn-and-churn: landscape history and crop cultivation in pre-Columbian Amazonia. Quat. Int. 249, 4–18 (2012). 20. Neves, E. G., Petersen, J. B., Bartone, R. N. & Heckenberger, M. J. In Additional information Amazonian Dark Earths: Explorations in Space and Time (eds Glaser, B. & Supplementary information The online version contains supplementary material Woods, W. I.) 125–134 (Springer Berlin Heidelberg, 2004). available at https://doi.org/10.1038/s41467-022-31064-2. 21. Schellekens, J. et al. Molecular composition of several soil organic matter fractions from anthropogenic black soils (Terra Preta de Índio) in Amazonia Correspondence and requests for materials should be addressed to Umberto Lombardo —a pyrolysis-GC/MS study. Geoderma 288, 154–165 (2017). or Manuel Arroyo-Kalin. 22. Schmidt, M. Amazonian Dark Earths: pathways to sustainable development in tropical rainforests? Bol. do Mus. Para. Emílio Goeldi. Ciências Humanas 8, Peer review information Nature Communications thanks William Balée, Talitha Santini 11–38 (2013). and the other, anonymous, reviewer(s) for their contribution to the peer review of 23. Canti, M. & Huisman, D. J. Scientific advances in geoarchaeology during the this work. last twenty years. J. Archaeol. Sci. 56, 96–108 (2015). 24. Barbosa, J. Z. et al. Elemental signatures of an Amazonian Dark Earth as result Reprints and permission information is available at http://www.nature.com/reprints of its formation process. Geoderma 361, 114085 (2020). 25. Oonk, S., Slomp, C. P. & Huisman, D. J. Geochemistry as an aid in Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in archaeological prospection and site interpretation: current issues and research published maps and institutional affiliations. directions. Archaeol. Prospection 16, 35–51 (2009). 26. Tyler, G. Rare earth elements in soil and plant systems—a review. Plant Soil 267, 191–206 (2004). Open Access This article is licensed under a Creative Commons 27. Tütken, T., Vennemann, T. W. & Pfretzschner, H.-U. Nd and Sr isotope Attribution 4.0 International License, which permits use, sharing, compositions in modern and fossil bones – Proxies for vertebrate provenance adaptation, distribution and reproduction in any medium or format, as long as you give and taphonomy. Geochim. Cosmochim. Acta 75, 5951–5970 (2011). appropriate credit to the original author(s) and the source, provide a link to the Creative 28. Sato, S., Neves, E. G., Solomon, D., Liang, B. Q. & Lehmann, J. Biogenic Commons license, and indicate if changes were made. The images or other third party calcium phosphate transformation in soils over millennial time scales. J. Soils material in this article are included in the article’s Creative Commons license, unless Sediment. 9, 194–205 (2009). indicated otherwise in a credit line to the material. If material is not included in the 29. Smith, N. J. H. Anthrosols and human carrying capacity in Amazonia. 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Author contributions U.L., M.A.K., M.J.S., H.H., H.P.L., C.P.M., E.G.N., W.T., and C.R.C. co-wrote the paper with inputs from J.A.F., F.O.A., C.B.V.A., C.B.R., G.G.B., M.S.C., M.L.C., L.C., L.H.C.A., © The Author(s) 2022 W.M.D., C.F., C.F.C., A.F., B.F., B.G., M.H., S.H., V.H., K.A.J., A.B.J., T.K., E.K.T., 1 Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona (ICTA-UAB), Bellaterra, Barcelona, Spain. 2Geographical Institute, University of Bern, Bern, Switzerland. 3Institute of Archaeology, University College London, London, UK. 4Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA. 5Groningen Institute of Archaeology, University of Groningen, Groningen, Netherlands. 6Museu Paraense Emílio Goeldi, Belém, Brazil. 7Instituto de Ciências da Sociedade, Universidade Federal do Oeste do Pará, Santarém, Brazil. 8Museum of Archaeology and Ethnology, University of São Paulo, São Paulo, Brazil. 9Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil. 10ArqueoMaquina, Belém, Brazil. 11Departamento de Arqueologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. 12Wageningen University & Research, Wageningen, Netherlands. 13School of Archaeology, University of Oxford, Oxford, UK. 14 Embrapa Forestry, Colombo, Brazil. 15Geosciences Institute, Federal University of Pará, Belem, Brazil. 16Centro de Ecologia Funcional, Universidade de Coimbra, Coimbra, Portugal. 17Soils Department, Federal Rural University of Rio de Janeiro, Seropédica, Brazil. 18Department of Geography, University of Wisconsin-Madison, Gualala, CA, USA. 19Museu Nacional, Universidade Federal do Rio de Janeiro, São Cristóvão, Brazil. 20 Princeton Institute for International and Regional Studies, Princeton University, Princeton, NJ, USA. 21Naturalis Biodiversity Center, Leiden, Netherlands. 22Embrapa Solos, Rio de Janeiro, Brazil. 23Department of Soil Biogeochemistry, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany. 24Department of Anthropology, University of Florida, Gainesville, FL, USA. 25School of Public Affairs, UCLA, Los Angeles, CA, USA. 26Graduate Institute for International Development Research, Geneva, Switzerland. 27Instituto de Desenvolvimento Sustentável Mamirauá, Tefé, Brazil. 28School of Integrative Plant Science, Department of Global Development, Cornell University, Ithaca, NY, USA. 29Culture and Socio- Ecological Dynamics Research Group, Department of Humanities, Universitat Pompeu Fabra, Barcelona, Spain. 30Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain. 31Department of Ecosystem and Landscape Dynamics, University of Amsterdam, NATURE COMMUNICATIONS | (2022)13:3444 | https://doi.org/10.1038/s41467-022-31064-2 | www.nature.com/naturecommunications 5 MATTERS ARISING NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-022-31064-2 Amsterdam, Netherlands. 32Department of Archaeology, Max Planck Institute for the Science of Human History, Jena, Germany. 33Faculty of Archaeology, Leiden University, Leiden, Netherlands. 34Department of Geography and Environmental Science, University of Reading, Reading, UK. 35 CEFE, Univ Montpellier, CNRS, EPHE, IRD, Univ Paul-Valéry Montpellier, Montpellier, France. 36Amazon Hopes Collective, Belém, Brazil. 37 Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia. 38Institute of National Historic and Artistic Heritage, Belém, Brazil. 39Departamento de Ciências Ambientais, Universidade Federal de São Paulo, Diadema, Brazil. 40Institute for Modelling Socio- Environmental Transitions, Bournemouth University, Poole, UK. 41Climate and Agriculture Group, Agroscope, Zurich, Switzerland. 42French National Centre for Scientific Research, Paris, France. 43Instituto Nacional do Semiárido (INSA), Campina Grande, Brazil. 44Center of Competence for Soils, BFH-HAFL, Zollikofen, Switzerland. 45Museu da Amazônia, Manaus, Brazil. 46Soil Science Department, University of São Paulo, Piracicaba, Brazil. ✉email: Umberto.Lombardo@uab.cat; m.arroyo-kalin@ucl.ac.uk 6 NATURE COMMUNICATIONS | (2022)13:3444 | https://doi.org/10.1038/s41467-022-31064-2 | www.nature.com/naturecommunications