The poor fens of the Laforge region, northeastern Canada, have developed under subarctic conditions. They are characterized by a microtopography of large pools and low, narrow strings. Paleorecords suggest some of these systems were once ombrotrophic and relatively dry. Taking account of their current bioclimatic position, we aimed to explore the possible pathways towards the current wet state, a process referred to as “aqualysis”. We combined paleoecological methods applied to a peat core with conceptual modelling to identify factors that might plausibly explain aqualysis. Reconstructions showed the Abeille peatland became minerotrophic with high water tables between 2400 and 2100 cal yr BP. Conceptual modelling, supported by simulations using the numerical DigiBog model, allowed us to identify the effects of cooling and increased precipitation on productivity, decay, peat hydraulic conductivity and vertical peat accumulation. Both cooling and increased precipitation were required for aqualysis to occur and for wet surface conditions to persist to the present day. Increased recharge from the catchment, which also restricted drainage from the peatland center laterally, was likely critical for the development of minerotrophic conditions. The scenario of cooling and wetting in these peatlands is supported by available paleoclimate records for eastern Canada.

Drained coastal peatlands are a source of greenhouse gas (GHG) through abundant CO2 release caused by aerobic peat degradation. Published rates of CO2 fixation and CH4 release for natural peatlands suggest that areas of peat formation are a (small) net source of GHG emission because the radiative effect of emitted CH4 exceeds the CO2 uptake by the vegetation. It is shown here that wetland restoration of reclaimed peat areas in the western Netherlands leads to a reduction of GHG emission because the expected increase in anaerobically generated CH4 release is much smaller than the decrease in aerobically produced CO2.

Assessment of land use related greenhouse gas (GHG) emissions on larger spatial scales is usually achieved by modelling. Surface flux measurements are expensive and measurement locations too widely scattered to serve as spatially reliable flux estimates. Here we assess CO2 and CH4 fluxes from wetland nature reserves in the Dutch province of Drenthe, using the PEATLAND-VU model. Since surface flux observations in the province are absent and cannot be obtained in a short (<1 year) time frame, we extrapolated model validation from elsewhere to the research area. In this way a cost-effective methodology is developed for landuse-related greenhouse gas emission assessments, which can be applied by local governments at a subnational scale.

Nature development and restoration in the Netherlands involves usually the restoration of high water tables in former agricultural areas and extensivation or abandonment of agricultural activities. Wet peat soils are known to emit considerable quantities of CH4, while drained agricultural soils emit CO2 from decomposition of the soil organic matter. Therefore, these landuse changes may affect GHG emissions and an assessment of their effects is useful for environmental policy.

The PEATLAND-VU Model was used to simulate the CH4 and CO2 emissions for the years 2005-2007 and for May/June 2008. Previous field validation of the model elsewhere was checked for local validity with CH4 and CO2 flux measurements in short field campaigns in May/June 2008, at two locations, Visvliet and Balloërveld. These sites represent respectively eutrophic and oligotrophic peat and peaty soils, and showed large differences in fluxes. These flux differences were simulated correctly by the model by adapting the vegetation net primary production and methane oxidation parameters. Next, model simulations were run for eight combinations of vegetation and soil type. Using the simulated fluxes and the areal extent of the soil combinations, a GIS-based upscaling over all nature reserves was made.

This study shows that river valley floors with mesotrophic and eutrophic peat soils dominate the greenhouse fluxes of the area. CH4 fluxes are high in wet terrain, while the CO2 fluxes are high when water table is lower. The fluxes from oligotrophic peat soils are comparatively low. Nature development can contribute to a decrease of the total greenhouse gas flux from peat soils and to conservation of soil organic matter.