REstoration and prognosis of PEAT formation in fens – linking diversity in plant functional traits to soil biological and biogeochemical processes

(Research question) Belowground biodiversity is formed by fungi, bacteria, archaea, animals and plants that altogether affect soil functioning, particularly by controlling rates of production and decomposition of organic matter. Peat soils, being the most concentrated stores of soil carbon, are formed by a long-term net exceedance of production over decomposition. In Europe most peatlands, especially fens, are severely degraded. Rewetting is a well-established method for peatland restoration but surprisingly little is known about the drivers and pathways that determine whether ecosystem services such as carbon storage or restoration of biodiversity are truly reinstated. Previous research on peatland carbon cycling has focused almost exclusively on rainwater-fed bogs with upward growing peatmoss. In contrast, in groundwater-fed fens roots of sedges and grasses grow into the older peat to form ‘displacement peat’. REPEAT aims to clarify the mechanisms of peat formation in fens by linking biogeochemical processes to soil community structure and biodiversity, as well as to plant belowground litter quality, with special focus on the prospects of restoring peat formation. Paludiculture (sustainable biomass harvest in wet and rewetted fens) and restoration prospects of fens providing vital ecosystem services for mitigation of climate change, regional hydrology, nutrient retention and biodiversity conservation will receive special attention. The main research question is: How do environmental factors and human management interact with soil biodiversity in determining rates of peat accumulation in undrained and rewetted fens? Eight hypotheses will be tested.
(Novelty) This project is the first to systematically address sedge and grass ('displacement') peat formation, the predominant peat formation mechanism of the temperate zone, using an interdisciplinary, multi-method and multi-site approach. It focuses on both the least disturbed and the most disturbed fens and investigates the restorability of the latter ones, while covering all major fen regions in the European Union.
(Themes of the call) REPEAT addresses theme 1 with all three sub-themes 1-3.
(Links) REPEAT builds on the Biodiversa PEATBOG project, will deliver guidance for ERANET projects FACCE CAOS and CINDERELLA, and it underpins various LIFE+ projects.
(Study areas) The study spans four countries covering both the least and the most disturbed sites of all major fen regions in the EU.
(Work plan) In order to compare undrained, drained and rewetted fens, we will analyse ecosystem processes at four study areas, supplemented by an ex-situ mesocosm and laboratory experiments. The project will be organised in 8 work packages. WP2 combines all site measurements, which will be used as factors and indicators in other WPs. WP3 measures peat formation in all sites, both by direct methods and by calculating balance between production and decomposition of organic matter. This information will be analysed in reference to the results of WP4/WP5, which analyse the diversity of producer and decomposer communities in functional terms. Modelling (WP6), along with the scientific integration package (WP7) translate project results into ecosystem processes and provide input to terrestrial climate models. WP8 will then communicate the main results to stakeholders.
(Relevance) In the EU, peatland emissions mainly derive from drained fens. GHG fluxes from most drained fens must be mandatorily accounted from 2021 onwards, which will boost peatland rewetting as the most important emission reduction option from the land sector. Peatland restoration responds also to the EU Biodiversity Strategy 2020, the CBD Aichi Goals, and the EU Water Framework Directive. Guidance on biodiversity-driven mechanisms of carbon sequestration and ecosystem resilience is urgently needed.
(Stakeholder engagement) REPEAT addresses stakeholders at various levels. A key stakeholder (Wetlands International) is involved as a consortium partner. Stakeholders in participating countries will be integrated through workshops, side events, and field days. Endusers at the EU, national, and regional level are identified.
(Exploitation of results) Data and project results will be shared within the consortium and also with the scientific community (via a website, publications, conference contributions, and a scientific conference.
(Knowledge transfer) The project will advance the knowledge base for process-oriented restoration of fens and will directly impact the application of related policy. The most important endusers are land managers, regional/national conservation and agricultural agencies, conservation NGOs, and the LIFE+ programme.
(European added value) REPEAT will consolidate the peatland ecology expertise of five geographically dispersed institutions covering the most important European fen regions in order to obtain the best state-of-the-art knowledge of processes that contribute to fen peat accumulation.