The location, nature, and magnitude of some environmental changes associated with the introduction of a road across a muskeg in the discontinuous permafrost zone are identified from examination of near-infrared Landsat images. Impedance of natural surface drainage by the presence of a roadbed is hypothesized to transmit upstream hydro-thermal changes through the muskeg terrain, which in turn cause change in the muskeg vegetation community. Differences among the near-infrared spectral reflectances of fen, black spruce bog, and Sphagnum bog communities are found sufficiently large for use as indices of differences in the actual biophysical natures of the muskegs.Key words: environmental impact, northern Canada, muskegs, hydrology, Landsat interpretation, permafrost, road designMots clés: impact sur l'environnement, le nord du Canada, marécage, hydrologie, interprétation de Landsat, pergélisol, conception de route