Peatland Rewetting In Nitrogen-Contaminated Environments: Synergies and trade-offs between biodiversity, climate, water quality and Society

PRINCESS will investigate the potential of alternative land uses on rewetted peatlands to tackle the major environmental challenges of Europe: greenhouse gas emissions, nitrogen pollution and biodiversity loss. All relevant EU policy objectives include rewetting drained peatlands as an essential ecosystem-based solution. To the date obvious synergies and trade-offs both within (e.g. between carbon dioxide and methane emissions) and between the policy objectives (e.g. between emissions, biodiversity and economic returns) remain unquantified. Such quantification is crucial for optimizing between alternative land use options for rewetted peatlands, i.e. high-intensity paludiculture, low-intensity paludiculture, and wilderness. PRINCESS will • evaluate the synergies and trade-offs between (1) restoring biodiversity and healthy ecosystems, (2) keeping global warming below 2°C, (3) clean water and (4) fair income to farmers • explore to what extent atmospheric N loads can guide decision-making on which land use option – under given circumstances – optimally contributes to the policy objectives • identify tipping points where switching from one land use option to another would maximise policy objectives. To achieve these objectives, PRINCESS will • focus on the peatlands which are the largest sources of GHG and affected most by nitrogen loads, i.e. temperate fens. Results, however, are relevant across drained-and-to-be-rewetted peatlands in the temperate and boreal zones. • bring together complementary skills from six peatland-rich countries, including those with little (FI, NO, PL) and strong peatland degradation and N loading (AT, BE, DE), the latter being also front-running in rewetting and paludicultures • analyse crucial processes under highly controlled conditions in the laboratory and in mesocosms, test them under more realistic conditions in the field, and model and upscale them to catchment and EU scale • use these different scales of study to maximize internal (sound interpretation of causal effects) and external (their relevance) validity • apply the most advanced techniques and methods from biogeochemistry, microbial ecology, plant ecology, socio-economic modeling on and across scales, using measurable and quantifiable indicators. PRINCESS is organized in seven work packages (WP), one each for coordination and outreach, and five to cover each of the relevant scales. Each WP considers all three land use options but has a different focus within or between the indicators. PRINCESS will provide vital scientific information for agricultural land use policies for peatlands in the EU by evaluating which land use option after rewetting complies best - under high nitrogen loads - with key policy objectives such as healthy ecosystems, climate change mitigation and adaptation, clean water, fair income to farmers, or, taken together, a greener and more sustainable Europe.