As part of the Care-Peat project, one of the objectives is to promote practices that enhance carbon storing capacity of peatlands. However, before tackling this topic, the first step consists in evaluating if the ecosystem functions as a carbon sink or source. Moreover, one must be able to estimate whether or not the actions undertaken indeed stimulate the C sink capacity of the restored site.
Furthermore, to disseminate to a large extent the need to take into account the C sink capacity in management practices among the managers community, it is pertinent to produce a toolkit to assess the C sink restoration actions. To do so, GHG fluxes must be measured using the same methodology and a model must be developed to produce a decision support tool (DST). In order to produce comparable data between sites and run a model applicable to all sites, a protocol must be written to obtain a coherent data set within the Care-Peat project. This report synthesizes the methodologies and the numerical tool developed during this project.
Measuring GHG fluxes
First, among the different techniques to measure GHG fluxes, it was decided in this project to use the closed chamber method. Common, cheap and easy to implement, it consists in inserting a collar in the peat and then placing a chamber on the collars in a way that the system is airtight. Many collars can be installed within a specific plot and the fluxes can be measured one after the other with the same chamber-sensor. Moreover, we assessed the amount of CO2 absorbed by the peatland by studying additional plots that were composed of different vegetation. Thus, spatial variation can be easily assessed with a relatively low cost and easy maintenance. At last, to estimate the benefit of restoration works, the C balance before restoration should be ideally compared to the one after restoration works. Because of the duration of the project, instead of comparing C fluxes before and after restoration, C fluxes between a non-restored zone of the site (CONTROL area) have been compared to an area of the site that had been restored (RESTORED area). In such a way, it may be possible to assess the effect of restoration activities on C fluxes.
Model to predict GHG fluxes
In parallel to field measurements, numerical models can be useful tools to improve understanding of the interaction between hydrology, weather conditions, vegetation and greenhouse gas emissions in peatlands. Many models exist and each function differently to calculate GHG fluxes. In this report, we present the numerical model developed during the Care-Peat project. It uses conceptual and mathematical equations to estimate GHG fluxes at the interface between peatland and atmosphere. The developed model is based on the estimation of GHG emissions due both to ecosystem respiration and vegetation uptake. The ecosystem respiration is estimated from the water table depth whereas the estimation of the Gross Primary Production includes a dependency in air temperature conditions, solar energy and vegetation types. This model can calculate GHG budgets per day, month or annum. This model was integrated in a user-friendly Decision Support Tool that sites managers/owners can use to estimate GHG fluxes before and after restorations works.
