144 Indicators of climate change impacts on biodiversity – A concept for the national level Rainer Schliep, Robert Bartz, Rainer Dröschmeister, Frank Dziock, Silvia Dziock, Ingo Kowarik, Laura Radtke, Livia Schäffler, Stefan Siedentop, Christoph Sudfeldt, Ulrich Sukopp, Sven Trautmann and Stefan Heiland Technische Universität Berlin, Department of Landscape Planning and Development, Berlin, Germany; Technische Universität Berlin, Department of Ecosystem Science / Plant Ecology, Berlin, Germany; Federal Agency for Nature Conservation, Bonn, Germany; University of Applied Sciences, Faculty of Agriculture/ Landscape Management, Dresden, Germany; University of Stuttgart, Institute of Regional Development Planning, Stuttgart, Germany; Federation of German Avifaunists, Münster, Germany On behalf of the German Federal Agency for Nature Conservation (BfN), a research consortium is currently developing a comprehensive indicator system with the objective of monitoring the direct and indirect impacts of climate change on biodiversity in Germany and to highlight the need for further action in nature conservation and other policies. One of the main challenges in defining the indicators is to find a balance between scientific validity with the need for an easily understandable system, informing stakeholder dialogues on feasible adaptation and mitigation measures. The final indicator system should include pressure, state, impact and response indicators according to the DPSIR framework. In the first two work packages of the project, climate change effects on biological diversity and nature conservation strategies as well as measures to adapt to climate change were reviewed. Further, we analysed comparable indicator systems such as the European Biodiversity Indicators (SEBI), the Climate Change Indicators of the European Environment Agency (EEA), indicators derived from the biodiversity monitoring programs of Switzerland (BDM-CH) and Austria (MOBI-e) and the UK Climate Change Indicators. A set of six criteria to evaluate the suitability of existing indicators and concepts for the development of new indicators was extracted: Thematic relevance: The indicators must address a relevant key topic in the context of biodiversity changes caused by climate change. This includes the entirety of (direct and indirect) impacts of climate change on biodiversity. Data availability and stability of data collection: The indicators should be based on precise data from permanent monitoring programs using scientifically sound and standardised methods. Data should cover the entire area of Germany and should be updated annually. Relation to political objectives: The indicators should relate to politically agreed targets in order to inform about the (socially) desired direction of change. Relation to politically controllable subjects: In general, the indicator subject should be controllable by policy measures. However, there are indicator subjects only controllable by policy measures exceeding national jurisdiction (e. g. the 2° C climate target). Easy comprehension and clarity: Although the indicator system designed here is dedicated to serve an informed expert community, the indicators should be understandable, transparent and simple. Finally, means of statistical analysis for the determination of indicator status and trend should be elaborated.