A restoration case study called “Beaver re-introduction” is the Swedish contribution to the new EU Green Deal project MERLIN. The case study will have a before-after design, which means experimental construction as well as removal of 60 beaver dams in Sweden, of which 10 will be located in the Vindeln Catchment including Krycklan (Svartberget Research Station). It is a four-year project and aims to sample two years before the measures (dam construction/removal) and two years of sampling after the measures. The studied parameters will be similar in all case studies within the MERLIN project; the focus on beavers as a case study will only be conducted in Sweden. A variety of biota are planned to be sampled as the focus is on biodiversity aspects with elements of potential ecosystem services. Likely parameters to be studied are e.g. fish migration, mitigation of climate change effects (flood and drought resilience, formation of greenhouse gases), methylation of mercury and pathogens (especially Francisella tularensis causing tularemia [Swedish harpest] and Sindbis virus causing Sindbis fever [Swedish Ockelbosjukan] in humans) in beaver systems.