The ME5 project aimed to analyze the effects of climate-related changes in hydrology (water input and water levels) in peat polders on water quality change, GHG fluxes and carbon storage.  GHG fluxes in different vegetation types and water bodies across gradients of land use intensity were quantified in situ at the smaller, plot scale using chambers. Water and nutrient budgets were compiled for a range of peat polders and set to populate a dynamic water balance and surface water quality model formulated in SOBEK.  The model was calibrated and verified and then used to deduce climate change effects on surface and ground water level, water quality, and GHG-fluxes. Climate scenarios W+ and G, developed by KNMI, have been used.

Highlights

(1)    plot-scale terrestrial methane fluxes from wetlands with different land use intensity can be predicted well from present vegetation composition, and this relation holds when aggregate, higher-order vegetaiton tpyes are used.

(2)    Methane fluxes from water bodies in these peatlands are linked to adjacent land use: ditches draining intensively used, fertilized pastureland emit substantially more methane than those in less-productive wetlands, such as fens, sedge beds and reedland.

(3)    Present nutrient budgets of peat polders are dominated by agricultural land use rather than variable water management.

(4)    Based on the SOBEK modelling, we conclude that climate change over the coming decades will have considerable effect on late summer groundwater level, peat soil mineralisation, subsidence, GHG fluxes and nutrient dynamics, but only of the extreme W+ climate scenario. Still, dairy farming, as the predominant current land use practice appears not hampered by these effects. The more moderate G-scenario, however, did not differ from the current situation.

Key Papers

Dias. A.T.C., Hoorens, B., Van Logtestijn, R.S.P., Vermaat, J.E., & Aerts R., 2010. Plant species composition can be used as a proxy to predict methane emissions in peatlands after land-use changes. Ecosystems 13: 526–538

Hellmann, F. & Vermaat, J.E., 2011. Impact of climate change on water management in Dutch peat polders. Ecological Modelling (submitted)

Vermaat, J.E. & Hellmann, F., 2010. Covariance in water- and nutrient budgets of Dutch peat polders: what governs nutrient retention? Biogeochemistry 99:109-126

Vermaat, J.E., Hellmann, F., Dias, A.T.C., Hoorens B, Van Logtestijn, R.S.P. &  Aerts R. (accepted) Greenhouse gas fluxes from Dutch peatland water bodies: are they affected by land use? Wetlands