Does hydrological restoration affect greenhouse gases emission and plant dynamics in sphagnum peatlands?

Fatima Laggoun-Défarge (1) , Sébastien Gogo (1) , Léonard Bernard-Jannin (1) , Christophe Guimbaud (2) , Renata Zocatelli (3) , J Rousseau (4) , Stéphane Binet (1) , Benoît D’angelo (1) , Fabien Leroy (1) , Nevila Jozja (3) , Franck Le Moing (1) , Christian Défarge (1, 3)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
3 CETRAHE
4 SNE

The C-sink function of peatlands is mainly controlled by soil waterlogging and Sphagnum moss dominance. La Guette peatland (Sologne, France) was drained for decades by a road ditch resulting in vascular plant (Molinia caerulea) invasion. Hydrological restoration was undertaken in 2014 and vegetation experiments were set up. In both downstream and upstream stations, three treatments (n=4) were conducted: " control " with intact vegetation, " bare peat " , and " Sphagnum " (bare peat seeded with Sphagnum). Our aim was to assess the effect of such actions on plant community diversity and CO 2 /CH 4 fluxes. In each plot, gas fluxes and plant cover were measured. 18 months after the restoration work, " bare peat " and " Sphagnum " plots were quickly colonised by Eriophorum angustifolium (up to 90%), Rynchospora alba (up to 10%), Trichophorum cespitosum (up to 60%). In both stations, control plots functioned as C sinks with lower CH 4 emissions and higher ecosystem respiration compared to the other treatments. However, at peak biomass the latter treatments tended to act as sinks for CO 2 in 2015 than in 2014 suggesting that plant cover, higher in 2015 than in 2014, is a crucial determinant for CO 2 fluxes. Although vegetation colonisation is proceeding fast, two years do not appear to be sufficient to trigger a C sink function in restored peatlands.

Keywords: plant removal experiments; peat organic matter; CO2 and CH4 fluxes; Molinia caerulea; water table

Domains: Ecosystems; Hydrology; Environmental Engineering

Fatima Laggoun-Défarge, Sébastien Gogo, Léonard Bernard-Jannin, Christophe Guimbaud, Renata Zocatelli, et al.. Does hydrological restoration affect greenhouse gases emission and plant dynamics in sphagnum peatlands?. Proceedings of the 15th International Peat Congress, Aug 2016, Sarawak, Malaysia. ⟨insu-01381659⟩