Semi-natural grasslands/heathlands provide important ecosystem services like biodiversity, carbon and nutrient storage/buffering and human recreation. The short vegetation and the co-existence of many different plant and animal species and/or functional types make these ecosystems particularly valuable “model ecosystems”, in which key ecosystem processes, such as species interactions/competition and ecosystem-level biogeochemical cycling may be investigated. The Brandbjerg site builds upon the former CLIMAITE experiment (VKR-Centre of Excellence, 2005-2015), where the three major climate change factors CO2, warming and summer drought, were manipulated simultaneously. Since 2016, the new experimental setup provides a response surface across 24 plots (each 7 m2) of three treatment levels of drought (removing up to 66% of ambient precipitation). The greenhouse gas exchange is continuously monitored using ECO2fluX automatic chambers.