LETTER LETTER REPLY TO ELIAS ET AL.: Multiproxy evidence of widespread landscape disturbance in multiple Azorean lakes before the Portuguese arrival Pedro M. Raposeiroa,b,1 , Armand Herna ndezc, Sergi Pla-Rabesd,e , Vıtor Gonçalvesa,b , Roberto Baoc , aez , Timothy Shanahan , Mario Benaventeh , Erik J. de Boerf, Nora Richteri,j, Ver Alberto S f g onica Gordonj, Helena Marquesa,b , Pedro M. Sousak,l, Martın Soutoa,b , Miguel G. Matiasm,n , Nicole Aguiarb, tia Pereiram,n, Catarina Rittera,b , Marıa Jes Ca us Rubioh , Marina Salcedob , David Va zquez-Loureiroc , Olga Margalefd,f,o , Linda A. Amaral-Zettleri,j,p , Ana Cristina Costaa,b , Yongsong Huangj , Jacqueline F. N. van Leeuwenq, Pere Masqu er,s,t,u , Ricardo Pregov , Ana Carolina Ruiz-Fern andezw , Joan-Albert Sanchez-Cabezaw , Ricardo Trigol,x, and Santiago Giralth Despite the multidisciplinary and comprehensive contamination. Previous work in the Azores has approach taken in ref. 1, we acknowledge that there shown that dating aquatic macrophytes can result in are still open questions that require further research. “old” carbon contamination (3); however, our pollen We emphasize that our study relies on multiple concentrates are almost entirely composed of terres- records that show the synchronous arrival of humans trial pollen grains, not aquatic macrophytes. Terres- on multiple islands before ca. 1400 CE. Elias et al. trial pollen grains are not affected by volcanic carbon (2) raise specific concerns about the record from emissions (4). The age model from Peixinho (figure Peixinho Lake, one of the five lakes included in the S6C of ref. 1) included two tephra layers at 650 and study, while ignoring the other multiproxy lake sedi- 700 CE, which correspond to the dates of the tephra ment records. The arguments presented by Elias layers found in the record of Pico Bog (see figure 2 of et al. (2) do not undermine in any way the main con- ref. 5). For this reason, we are puzzled by the figure clusions of our paper, but still we would like to presented by Elias et al. (figure 1 of ref. 2), where the explicitly address the main criticisms with regard to authors seem to artificially wiggle-match the two pol- the only record in question. len curves without taking into account two key strati- Elias et al. (2) question the age model developed graphic layers and ignoring the two tephra layers for Peixinho due to possible “old” volcanic carbon (Pico-4 and Pico-5) published in ref. 5. a Centro de Investigaç~ ao em Biodiversidade e Recursos Gen eticos, Rede de Investigaç~ao em Biodiversidade e Biologia Evolutiva – Laborat orio Associado, 9500-321 Ponta Delgada, Portugal; bFaculdade de Ci^ encias e Tecnologia, Universidade dos Açores, 9500-321 Ponta Delgada, Portugal; cCentro de Investigaci ons Cientıficas Avanzadas, Facultade de Ciencias, Universidade da Coru~ na, 15071 A Coru~na, Spain; dCenter for Ecological Research and Forestry Applications, Cerdanyola del Valles 08193, Spain; eDepartament de Biologia Animal, de Biologia Vegetal i d'Ecologia (BAVBE), Universitat Autonoma de Barcelona, Bellaterra 08193 Barcelona, Spain; fDepartment de Din amica de la Terra i de l’Oce a, Facultat de Ciencies de la Terra, Universitat de Barcelona, 08028 Barcelona, Spain; gDepartment of Geosciences, University of Texas at Austin, h Austin, TX 78712; Geosciences Barcelona (Geo3BCN-CSIC), Consejo Superior de Investigaciones Cientıficas, 08028 Barcelona, Spain; i Department of Marine Microbiology & Biogeochemistry, Royal Netherlands Institute for Sea Research, 1790 AB Den Burg, The Netherlands; j Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912; kInstituto Portugu^ es do Mar e da Atmosfera, 1749-077 Lisboa, Portugal; lInstituto Dom Luiz, Faculdade de Ci^ encias, Universidade de Lisboa, 1749-016 Lisboa, Portugal; m Departmento of Biogegrafıa y Cambio Global, Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Cientıficas, 28006 Madrid, Spain; nBiodiversity Research Chair, Mediterranean Institute for Agriculture, Environment and Development, Universidade de Evora,   7000-890 Evora, Portugal; oGlobal Ecology Unit Centre de Recerca Ecol ogica i Aplicacions Forestals–Consejo Superior de Investigaciones Cientıficas–Universitat Aut p onoma de Barcelona, 08193 Catalonia, Spain; Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam 1090 GE, The Netherlands; qInstitute of Plant Sciences and Oeschger Center for Climate Change Research, University of Bern, 3013 Bern, Switzerland; rInternational Atomic Energy Agency 98000 Principality of Monaco, Monaco; sInstitute of Environmental Science and Technology, Universitat Aut onoma de Barcelona, 08193 Bellaterra, Spain; tPhysics Department, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain; uSchool of Natural Sciences, Centre for Marine Ecosystems Research, Edith Cowan University, Joondalup, WA 6027, Australia; vDepartment of Oceanography, Marine Research Institute, Consejo Superior de Investigaciones Cientıficas, 36208 Vigo, Spain; wUnidad Acad emica Mazatlan, Instituto de Ciencias del Mar y Limnologıa, Universidad Nacional Aut onoma de M an 82040, Mexico; and xDepartamento de Meteorologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-919, Brazil exico, Mazatl Author contributions: P.M.R., A.H., S.P.-R., V.G., R.B., A.S., and S.G. designed research; P.M.R., A.H., S.P.-R., V.G., R.B., A.S., T.S., M.B., E.J.d.B., N.R., V.G., H.M., P.M.S., M. Souto, M.G.M., N.A., C.P., C.R., M.J.R., M. Salcedo, D.V.-L., O.M., L.A.A.-Z., A.C.C., Y.H., J.F.N.v.L., P.M., R.P., A.C.R.-F., J.-A.S.-C., R.T., and S.G. performed research; P.M.R., A.H., S.P.-R., V.G., R.B., A.S., E.D., R.T., and S.G. analyzed data; and P.M.R., A.H., S.P.-R., V.G., R.B., A.S., T.S., N.R., M.G.M., C.P., A.C.C., R.T., and S.G. wrote the paper. The authors declare no competing interest. This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND). 1 To whom correspondence may be addressed. Email: pedro.mv.raposeiro@uac.pt. Published January 19, 2022. PNAS 2022 Vol. 119 No. 4 e2120107119 https://doi.org/10.1073/pnas.2120107119 j 1 of 2 Common key indicators of human impacts on islands reflect lanceolata is an introduced species (5) and is an indicator of multiple and synchronous changes in the landscape, e.g., fire, pastures (8). This evidence clearly demonstrates changes in the deforestation, the presence of cereal grains, and fecal biomarkers Azorean landscape resulting from human arrival before the 15th (6, 7). In the record from Peixinho and the lake records from the century. The early decrease in arboreal pollen is also observed in other islands, we observed an increase in macrocharcoal and figure 5 of ref. 5, although this was not highlighted in the original polycyclic aromatic hydrocarbons, the presence of Secale cere- paper. ale, 5β-stigmastanol, coprostanol, and coprophilous spores, as As stated in ref. 1, we acknowledge the point raised by Elias well as a decrease in arboreal pollen. These signals are followed et al. (2) that the Portuguese arrival led to more extensive by increases in lake trophic states. The grains of Secale were changes in the landscape. Our multiproxy, multisite datasets counted in subsequent pollen slides indicating a local source and strongly suggest that people had already occupied the Azores not erratic long-distance dispersal. Plantago spp. were identified Archipelago and altered the pristine landscape before the offi- to Plantago lanceolata and Plantago coronopus, of which P. cial arrival of the Portuguese. 1 P. M. Raposeiro et al., Climate change facilitated the early colonization of the Azores Archipelago during medieval times. Proc. Natl. Acad. Sci. U.S.A. 118, e2108236118 (2021). 2 R. B. Elias et al., Is there solid evidence of widespread landscape disturbance in the Azores before the arrival of the Portuguese? Proc. Natl. Acad. Sci. U.S.A., 10. 1073/pnas.2119218119 (2022). 3 S. Bj€ orck et al., A Holocene lacustrine record in the central North Atlantic: Proxies for volcanic activity, short-term NAO mode variability, and long-term precipita- tion changes. Quat. Sci. Rev. 25, 9–32 (2006). 4 N. Piotrowska, A. Bluszcz, D. Demske, W. Granoszewski, G. Heumann, Extraction and AMS radiocarbon dating of pollen from Lake Baikal sediments. Radiocar- bon 46, 181–187 (2004). 5 S. E. Connor et al., The ecological impact of oceanic island colonization—A palaeoecological perspective from the Azores. J. Biogeogr. 39, 1007–1023 (2012). 6 N. Dubois et al., First human impacts and responses of aquatic systems: A review of palaeolimnological records from around the world. Anthr. Rev. 5, 28–68 (2017). 7 D. A. Sear et al., Human settlement of East Polynesia earlier, incremental, and coincident with prolonged South Pacific drought. Proc. Natl. Acad. Sci. U.S.A. 117, 8813–8819 (2020). 8 K. Behre, The interpretation of anthropogenic indicators in pollen diagrams. Pollen Spores 23, 225–245 (1981). 2 of 2 j PNAS Raposeiro et al. https://doi.org/10.1073/pnas.2120107119 Reply to Elias et al.: Multiproxy evidence of widespread landscape disturbance in multiple Azorean lakes before the Portuguese arrival