The main aim is to evaluate the consequences of ionizing radiation and radioactive contamination on non-human biota on a higher level of organization, i.e. how do effects of radiation manifest themselves at the community/ecosystem level. The knowledge of radiation effects in radioecology today is mainly based on direct effects on single species in the laboratory or field. The key challenge is to translate this knowledge to cover multiple species ecosystems together with the abiotic part of the environment. Our overarching hypothesis is that ecosystem interactions and processes (e.g. food chain interactions, competition between and within species, changes in biodiversity) can result in indirect effects from exposure to ionizing radiation.