All International Biological Programme themes were developed in Canada, but this paper deals with section « CT » (Conservation Terrestrial) only north of 50°00' lat. N. . The author makes a short analysis of the Canadian approach within the actual economic situation. The Québec Ecological Reserves Act passed in 1974 takes place while large development projects occur on Québec northern lands. Eleven candidate reserves were proposed by IBP for a total of 650 000 ha, of which mining potential is discussed. Two examples are given : Povungnituk and Richmond Gulf. Environmental monitoring is also discussed for some proposals within a national system as defined by SCOPE, and the eventual arctic gas pipeline, from the northern arctic archipelago. The author concludes in stressing the importance of the Ecological Reserves Act and the role played by the Québec scientific community.