Ecosystem state shifts during long-term development of an Amazonian peatland

Swindles, G. T. et al. (2018) Ecosystem state shifts during long-term development of an Amazonian peatland. Global Change Biology, 24(2), pp. 738-757. (doi: 10.1111/gcb.13950)

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Abstract

The most carbon (C) dense ecosystems of Amazonia are areas characterised 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 c. 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 c. 3.9 ka BP). Local burning occurred at least three times in the past 4,500 years. Two phases of particularly rapid C accumulation (c. 6.6-6.1 and c. 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 c. 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.

Item Type:Articles
Additional Information:This work was funded by a Royal Society research grant to GTS (grant no. 481831). GTS also acknowledges NERC Radiocarbon Analysis Allocation 1800.0414. DJC and AGS acknowledge the MILLIPEAT project grant from NERC (NE/I012915/1) and NERC Radiocarbon Analysis Allocation 1681.1012. RFI is funded by NERC grant NE/K008536/1.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Parry, Dr Lauren
Authors: Swindles, G. T., Morris, P. J., Whitney, B., Galloway, J. M., Gałka, M., Gallego-Sala, A., Macumber, A. L., Mullan, D., Smith, M. W., Amesbury, M. J., Roland, T. P., Sanei, H., Patterson, R.T., Sanderson, N., Parry, L., Charman, D. J., Lopez, O., Valderamma, E., Watson, E. J., Ivanovic, R. F., Valdes, P. J., Turner, T. E., and Lähteenoja, O.
College/School:College of Social Sciences > School of Interdisciplinary Studies
Journal Name:Global Change Biology
Publisher:Wiley
ISSN:1354-1013
ISSN (Online):1365-2486
Published Online:20 October 2017
Copyright Holders:Copyright © 2017 John Wiley and Sons Ltd
First Published:First published in Global Change Biology 24(2):738-757
Publisher Policy:Reproduced under a Creative Commons License

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