Are there ecological effects of ionizing radiation?

Concerns of environmental effects of ionizing radiation has increased, and has also shifted from being centred on only humans, towards including also effects on ecosystems. Knowledge of radiation effects on wild populations and ecosystems is however limited and methods for assessing ecological risks of such effects are still in their infancy. For example, development of better methods for extrapolating effects on individual organisms to estimates of negative effects on populations would greatly improve risk assessments, since populations often constitute what we wish to protect. In this paper, possible ecological effects of ionizing radiation from radionuclides are discussed and evaluated in terms of how individual level effects are translated to risks at the level of the population and higher. We conclude that ecological effects of ionizing radiation at the level of the population and above can be caused by two different mechanistic routes: Firstly, the detrimental effects of radiation to individuals such as increased mortality, morbidity, and decreased fertility and fecundity can, depending on their magnitude have implications on population dynamics and thereby also potentially on community and ecosystem properties. Secondly, ionizing radiation may cause genetic damage, which can have effects at the population level by affecting the genetic structure, and genetic diversity of populations. (author)