This manual introduces the concept of using light aircraft for ecological monitoring, and briefly discusses various techniques other than that of the systematic low—level reconnaissance flight (SRF), whose description and criticism form the basis of the rest of the document. A discussion of the use of the SRF for monitoring animal populations, especially Sahelian livestock, is followed by a description of methods used to monitor vegetation and soils. The technical capacity of the aircraft, the navigational equipment and the expertise of the crew necessary for the success of the SRF are given considerable attention. The analysis of the resulting data is briefly discussed. The manual ends with an exhaustive checklist for the various members of the crew and ground staff associated with the SRF. The analyses of the results obtained during four flights over the test zone of the Project and over a more wooded zone to the south are presented and discussed in some detail