This publication reviews what is known about the effects of radiation upon such biotic types (or of similar organisms, where more precise data are lacking) with regard to the effects of mortality, morbidity, reduced reproductive success, and chromosomal damage. Drawing on this information, the report derives a set of derived consideration reference levels for each biotic type in order to help optimise the level of effort that might be expended on its environmental protection, or that of similar types of organisms, and thus serve as points of reference in any wider consideration of what authorities may wish to do under different exposure situations. The various factors that should be taken into account when considering what to do if the derived consideration reference levels are likely to be attained are also discussed. Some broader background information on the types of animals and plants used is also given. Additional information is provided on advice with regard to extrapolating and interpolating the limited set of dosimetric models to other shapes and sizes of animals and plants.