Ecosystem state shifts during long‐term development of an Amazonian peatland |
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Authors: | Graeme T Swindles Paul J Morris Bronwen Whitney Jennifer M Galloway Mariusz Ga?ka Angela Gallego‐Sala Andrew L Macumber Donal Mullan Mark W Smith Matthew J Amesbury Thomas P Roland Hamed Sanei R Timothy Patterson Nicole Sanderson Lauren Parry Dan J Charman Omar Lopez Elvis Valderamma Elizabeth J Watson Ruza F Ivanovic Paul J Valdes T Edward Turner Outi Lähteenoja |
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Institution: | 1. School of Geography, University of Leeds, Leeds, UK;2. Department of Geography and Environmental Science, Northumbria University, Newcastle upon Tyne, UK;3. Geological Survey of Canada / Commission géologique du Canada, Calgary, Canada & Department of Geoscience, University of Calgary, Calgary, AB, Canada;4. Department of Biogeography and Palaeoecology, Adam Mickiewicz University, Poznań, Poland;5. Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK;6. School of Natural and Built Environment, Queen's University Belfast, Belfast, UK;7. Ottawa‐Carleton Geoscience Center and Department of Earth Sciences, Carleton University, Ottawa, ON, Canada;8. School of Interdisciplinary Studies, University of Glasgow, Glasgow, UK;9. Panama Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Panamá & Smithsonian Tropical Research Institute, Panama City, Panama;10. Facultad de Biologia, Universidad Nacional de la Amazonia Peruana, Pevas 5ta cdra, Iquitos, Peru;11. School of Earth and Environment, University of Leeds, Leeds, UK;12. School of Geographical Sciences, University of Bristol, Bristol, UK;13. School of Life Sciences, Arizona State University, Tempe, AZ, USA |
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Abstract: | The most carbon (C)‐dense ecosystems of Amazonia are areas characterized by the presence of peatlands. However, Amazonian peatland ecosystems are poorly understood and are threatened by human activities. Here, we present an investigation into long‐term ecohydrological controls on C accumulation in an Amazonian peat dome. This site is the oldest peatland yet discovered in Amazonia (peat initiation ca. 8.9 ka BP), and developed in three stages: (i) peat initiated in an abandoned river channel with open water and aquatic plants; (ii) inundated forest swamp; and (iii) raised peat dome (since ca. 3.9 ka BP). Local burning occurred at least three times in the past 4,500 years. Two phases of particularly rapid C accumulation (ca. 6.6–6.1 and ca. 4.9–3.9 ka BP), potentially resulting from increased net primary productivity, were seemingly driven by drier conditions associated with widespread drought events. The association of drought phases with major ecosystem state shifts (open water wetland–forest swamp–peat dome) suggests a potential climatic control on the developmental trajectory of this tropical peatland. A third drought phase centred on ca. 1.8–1.1 ka BP led to markedly reduced C accumulation and potentially a hiatus during the peat dome stage. Our results suggest that future droughts may lead to phases of rapid C accumulation in some inundated tropical peat swamps, although this can lead ultimately to a shift to ombrotrophy and a subsequent return to slower C accumulation. Conversely, in ombrotrophic peat domes, droughts may lead to reduced C accumulation or even net loss of peat. Increased surface wetness at our site in recent decades may reflect a shift towards a wetter climate in western Amazonia. Amazonian peatlands represent important carbon stores and habitats, and are important archives of past climatic and ecological information. They should form key foci for conservation efforts. |
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Keywords: | Amazon rainforest carbon accumulation climate Holocene palaeoecology peat Peru swamp tropical peatland |
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