PEATBOG: Pollution, Precipitation and Temperature Impacts on Peatland Biodiversity and Biogeochemistry

Nancy B. Dise¹, Christian Blodau², Simon Caporn¹, Per-Eric Lindgren³, Jos Verhoeven⁴, Bo Svennsson³, Luca Bragazza⁵, Richard Payne¹, Bjorn Robroek⁴, James Rowson¹, Yuanqiao Wu², Kasia Zajac², and Daphne Lai<sup>1

1</sup>Manchester Metropolitan University, Manchester UK, This e-mail address is being protected from spam bots, you need JavaScript enabled to view it ,
²University of Bayreuth, Bayreuth, Germany,
³Linköping University, Linköping, Sweden,
⁴Utrecht University, Utrecht, Netherlands,
⁵University of Ferrara, Italy

Peatlands are threatened by climate change and nitrogen pollution
Peatlands are the world’s largest soil carbon pool, support a unique biological community, and provide important ecological, economic and protective functions, such as groundwater recharge and pollutant removal. Maintaining these critical functions depends upon protecting the integrity of the whole ecosystem. Peat cutting, drainage, and land conversion are all clear threats to peatlands. But peatlands are also highly vulnerable to ‘unseen’ threats such as changes in precipitation, temperature, and nutrients.
The projected change in the climate of many northern peat-forming regions toward warmer air temperatures, drier summers and more frequent droughts, are exactly those that have been shown to cause peatlands to degrade and begin to lose, through erosion, decomposition, or fire, the carbon that they have been accumulating for hundreds or thousands of years. Peatlands are also highly sensitive to air pollution, particularly nitrogen deposition. Reactive nitrogen from fossil fuel combustion or intensive agriculture can contaminate rain and snow, causing soil acidification, nutrient enrichment, and a decline in species that are sensitive to these conditions. Even the ‘average’ levels of these pollutants in a typical rural countryside have been shown, over the long term, to lead to a significant decline in biodiversity. Finally, there is good evidence that the combined impact of elevated nitrogen deposition and a warming climate could exceed the sum of the individual stressors and lead to a dramatic decline in the biodiversity of mosses, sensitive vascular plants, and microbes, potentially leading to catastrophic peat loss.

Aims and objectives of the project
PEATBOG aims to understand how nitrogen pollution and changing climate, individually and combined, will affect the biodiversity and ecosystem properties of peatlands. We also aim to develop meaningful indicators of risk to these impacts that are of use to conservation managers and policymakers.
To address these aims, we first, through surveys, determine relationships between peatland species richness and nitrogen deposition across northern Europe and the Alps. Second, by manipulating, in the field, the water table and temperature of two peatlands in areas receiving different levels of nitrogen pollution, we investigate whether peatlands that have received historically high nitrogen loads are more sensitive to drought and warming than less polluted peatlands. Impacts on nutrient cycles and carbon accumulation are examined at various levels of detail across the survey sites, field manipulation sites and in controlled laboratory experiments. Changes in microbial community composition and function are also determined across the different scales of inquiry, and linked to changes in the vegetation and soil. Finally the survey, field, and laboratory investigations are integrated to develop models, at various scales and for a range of applications, of the response of peatlands to elevated nitrogen deposition and climate change.

Policy relevance and stakeholder involvement
The main users of the results of PEATBOG will be conservation managers, policymakers, and scientists. For conservation managers the project aims to produce simple and reliable indictors of sensitivity to nitrogen deposition and risk for biodiversity loss for raised bogs and, potentially, other peatland types in Europe. These could take the form of ecological indicator species, dichotomous decision trees, or recommendations for monitoring networks. For policymakers the project will produce national/European-scale risk assessments, GIS-based maps to highlight peat-forming regions most vulnerable to current and future changes in climate and nitrogen pollution, and an evaluation of the effectiveness of applying the critical loads concept for biodiversity protection of peatlands. For the scientific community PEATBOG will produce new information on the integrated ecological/biogeochemical impacts of N deposition on peatlands, including scientific publications, detailed process-based models for hypothesis testing, and open-access data.

The project has a seven-member Core Advisory Group encompassing the European policy and conservation arenas concerned by PEATBOG, and a wider Stakeholder/ Scientists Group with representatives from science, policy, management and the public. The core group is closely involved throughout the project to frame the research into contexts that are relevant, useful and transferable to policy. These include the UN Convention on Biological Diversity, the UN Convention on Long-Range Transboundary Air Pollution, and the IPCC. The Stakeholder/Scientists group will be registered on the website, regularly updated with all project developments and meetings, invited to comment at any stage of the project, and actively participate in the project where appropriate. Close engagement with these groups will lead to effective dissemination of the results of PEATBOG into the policy arena on matters of biodiversity protection, habitat management, water quality, air quality, and carbon sequestration.