Invasion of a Sphagnum-peatland by Betula spp and Molinia caerulea impacts organic matter biochemistry. Implication for carbon and nutrient cycling.
Abstract
Peatland act as a sink of carbon (C) through the conservation of dead remains of plants. Under global changes triggered by human activities, it is not only the sink capacity of peatland that is in danger, but also the C already stored. Invasion of Sphagnum peatlands, mainly by Molinia caerulea and Betula spp, is a growing preoccupation. This study aims to assess the extent of the influence of such invasion on the biochemical characteristics of the peat. Elemental analysis and Rock Eval pyrolysis parameters were measured in 50 cm profiles collected in invaded and intact plots. The results showed that Oxygen Index (OI) can be used to detect new C substrate injection as such new materials have a lower OI than Sphagnum spp and Sphagnum peat. Differences in terms of water table level and nutrient status are suggested to be of great importance to determine the fate of surface and deep new C input. This study stimulates new investigation testing a possible priming effect triggered by the invading vegetation and using stochiomeric constrain as a theoretical framework.
Origin : Files produced by the author(s)