The key issue in the assessment system for radiation protection of wildlife is the establishment of dose-effects relationships for reference representatives of natural biota. Within the frame of the EC Project EPIC “Environmental Protection from Ionizing Contaminants" (2000-2003), a database has been created, which includes about 1600 records from 440 publications in Russian on the dose-effects relationships in wildlife from northern-temperate climatic zones. The EPIC database “Radiation effects on biota" is based on Russian/FSU experimental and field studies; chronic/lifetime exposures are the focus of the data collection. The database information covers a very wide range of radiation dose rates to biota: from below 1E(-5) Gy d-1 up to more than 1 Gy d-1. A great variety of radiation effects are registered in the EPIC database, from stimulation at low doses up to death from acute radiation syndrome at high doses. The paper presents the dose-effects relationships for northern wildlife in the conditions of low-LET chronic irradiation. The system of dose-effects relationships forms the scale of severity of radiation effects at increasing levels of chronic radiation exposure. The system can be used as a basis for establishing criteria for radiation protection of the Northern wildlife.