Prediction of long-term changes in ecosystem functions of a peatland site with the semi-quantitative decision support system PMDSS

For implementation of sustainable land use strategies in Europe tools for evaluating long-term changes of peatland functions are essential. Therefore a semi-quantitative peatland management decision support system for agricultural used peatlands in Europe was developed. It is called Peatland Management Decision Support System (PMDSS). The aim of the tool is to better understand and to forecast long-term processes in peatland ecosystems in order to help scientists, water boards and environmental agencies in decision making about long-term management. PMDSS is based on derived indicators of ecosystem functions of peatlands, which are: harvest of plant products, land use category, mean summer water table (MSWT), nitrogen discharge, Global Warming Potential (GWP) and conservation value of plants. PMDSS is realized as an easy to use spreadsheet program in Excel. The model is one-dimensional and applicable for a site or field, where the input parameters, particularly land use category, vegetation type and MSWT are relatively homogenous. It is running with annual intervals and for a time span of 100 years (vegetation 50 years). Results are presented as values, text and diagrams. PMDSS is accessible via internet. PMDSS was applied to sites in several European countries. A case study in the Eider Valley peatland is presented, which is typical for Weichselian landscapes of northwest Germany. The site has a deep peat layer and is mainly influenced by groundwater discharge. It was used as a meadow and pasture during the past centuries and is left abandoned since the mid 1990s. Effects of different land use and water management scenarios onto the development of the site are determined. The scenarios are typical for peatland sites in northwest Germany and northwest Europe. Results are plausible as a rough estimate of magnitude and development trend.