RESIST has produced, and will continue to generate, a multitude of individual results on degradation and recovery processes in streams. All A-projects test specific hypotheses that are related to three Main Hypotheses (MH) with eight sub-hypotheses. Project Z03 is responsible for testing these in an overarching way, using RESIST results complemented by external data. This process started in Year 3 of Phase I and has already led to three synthesis papers / preprints and a conceptual paper, with three more synthesis papers under preparation. In Phase II, Project Z03 will continue to serve as an overall synthesis project and aims to derive generic principles on the mechanisms of multiple stressors affecting freshwater ecosystem degradation and recovery. While in Phase I the focus was on degradation patterns and processes, it will transition to recovery processes in Phase II. A synthesis committee composed of the PIs of Z03, selected PIs of other RESIST projects and external advisors will guide the project and contribute to the synthesis work, together with personnel employed by Z03. For each of RESIST’s MHs, including their sub-hypotheses, strategies for testing have been defined and will be executed by Z03. This involves variance partitioning of proxies for the ARC processes (tolerance, dispersal and biotic interactions) to the biological response in phases of degradation and recovery (MH1); comparing the response of individual micro- and macroorganism groups to stressors and their release (MH2); and analysis of the rate of change for functions and communities (MH3). Additional research questions may emerge based on preliminary results, discussions within the synthesis committee and within the consortium. The synthesis committee will regularly review these and initiate work on additional research questions.