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T9
Long-term vegetation development in an Amazonian peatland
* 1 K.H. Roucoux, 1 I.T. Lawson, 2 T.D. Jones, 1 T.R. Baker, 1,3 E.N. Honorio Coronado, 4
W.D. Gosling, 5 O. Lähteenoja
1 School of Geography, University of Leeds, Leeds, LS2 9JT
2 Lancaster University, Bailrigg, Lancaster, LA1 4YW
3 Instituto de Investigaciones de la Amazonía Peruana, Av. José A. Quiñones km 2.5, Iquitos, Peru.
4 Department of Environment, Earth and Ecosystems, The Open University, Walton Hall, Milton Keynes,
MK7 6AA
5 Department of Biology, University of Turku, FI-20014 Turku, Finland
The existence of widespread peat-forming ecosystems in western Amazonia has recently
been reported (Lähteenoja et al., 2009, 2012). The contribution these peatlands make to
Amazonian biodiversity and below-ground carbon storage (Lähteenoja et al., 2012) make
it imperative that we understand their potential responses to future climatic and land use
change. Of the complex ecohydrological factors which interact to determine peatland
distribution and function, vegetation composition is pivotal and an understanding of longterm
peatland vegetation history is central to predicting their sensitivity to environmental
change. We present results of the first attempt to establish the long-term (millennial-scale)
vegetation history of one of these peatland sites: Quistococha, close to the city of Iquitos
in northern Peru (Roucoux et al., 2013). Pollen and sedimentological analyses show that
peat formation began at the core site under sedge fen or floating mat vegetation c. 2200
calendar years before present (cal yr BP). This was followed by the development of a
seasonally flooded woodland c. 1880 cal yr BP. The permanently water-logged palm
swamp which persists today began to form c. 1000 cal yr BP, with the present vegetation
community established by c. 400 years ago. Our results show that the vegetation has
undergone continuous change throughout the period of peat formation, with several abrupt
transitions, and reversals and repetitions in the apparent trajectory of change. The pollen
data, combined with sedimentary evidence, suggest that the dominant control on
ecosystem functioning and development is the flooding regime and there appears to have
been a decrease in fluvial influence over time. There is no clear evidence of direct climatic
or anthropogenic influence although we cannot rule the possibility of climatically driven
hydrological changes. Our results caution against adoption a simple model of peatland
vegetation succession in the region. Further work at this site and at other sites in the
region will enable us to test the possible drivers of change.
Keywords: Amazonia; Peru; peat; pollen; succession; aguajal
Lähteenoja, O., Ruokolainen, K., Schulman, L., Alvarez, J. (2009) Amazonian floodplains harbour
minerotrophic and ombrotrophic peatlands. Catena 79, 140-145.
Lähteenoja, O., Rojas Reátegui, Y., Rasanen, M.E., Del Castillio Torres, D., Oinonen, M., Page, S.E.
(2012) The large Amazonian peatland carbon sink in the subsiding Pastaza-Marañon foreland basin,
Peru. Global Change Biology 18, 164-178.
Roucoux, K.H., Lawson, I.T., Jones, T.D., Baker, T.R., Honorio Coronado, E.N., Gosling, W.D.,
Lähteenoja, O. (2013) Vegetation development in an Amazonian peatland. Palaeogeography,
Palaeoclimatology, Palaeoecology 372, 242-255.