The role of peat decomposition in patterned mires: a case study from the central Swiss Alps.

Brigitta Ammann 1 , Herbert E. Wright 2 , Vania Stefanova 2 , Jacqueline F. N. van Leeuwen 1 , Willem O. van der Knaap 1 , Daniele Colombaroli 1 & Willy Tinner 1

Affiliations

  1. University of Bern, Switzerland, Institute of Plant Sciences and Oeschger Centre for Climate Change Research
  2. University of Minnesota, Limnological Research Center, 310 Pillsbury Drive SE, Minneapolis, MN 55455, USA

Published: 15 August 2013

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Abstract

A number of hydrological, botanical, macro- and micro-climatological processes are involved in the formation of patterned peatlands. La Grande Tsa at 2336 m a.s.l. is probably the highest bog in the central Swiss Alps and is unique in its pattern. In two of five pools there is in the contact zone between the basal peat and the overlying gyttja an unconformity in the depth-age models based on radiocarbon dates. Palynostratigraphies of cores from a ridge and a pool confirm the occurrence of an unconformity in the contact zone. We conclude that deepening of the pools results from decomposition of peat. The fact that the dated unconformities in the two pools and the unconformity in the ridge-core all fall within the Bronze Age suggest they were caused by events external to the bog. We hypothesize that early transhumance resulted in anthropogenic lowering of the timberline, which resulted in a reduction in the leaf-area index and evapotranspiration, and in higher water levels and thus pool formation.

Keywords

deepening of pools, mires, patterned peatlands, peat decomposition, pool formation

How to cite

Ammann B., Wright H. E., Stefanova V., van Leeuwen J. F. N., van der KnaapW. O., Colombaroli D. & Tinner W. (2013) The role of peat decomposition in patterned mires: a case study from the central Swiss Alps. – Preslia 85: 317–332