The shaping of landscapes by livestock farming systems, or the difficuU appraisal of quality aspects. The authors discuss the difficulties that a multidisciplinary research group investigating the impact of pastoral farming on land planning and development encountered in attempting to define common criteria on the basis of which individual researchers might then appraise qualitatively their own specifie research abject. This assessment may relate bath to the unfolding of agricultural processes over time, to the means implemented and 1or to the results of these processes. The appreciation derives from individual perception of the usefulness of a "thing" in relation to the desired end. It also expresses several different viewpoints, that of the author 1actor of a process as well as that of other individuals legitimately entitled to voicing an opinion. This question is first posed in a land-use planning situation: which appraisable quality should be put forward when there are only few situations in which one can identify a single "manager" and detectable actions that have produced the landscape being considered? Yet the results evoke a variety of opinions, each of which arises from a different viewpoint: an attractive landscape (but which esthetic culture is being referred to?), a cynegetic landscape (but for which type of game?). The second part addresses pastoral farming and its role in scrub clearance. The authors focus successively on the food resource (to be considered bath at a given moment and over time), on the herd (managed bath for a specifie output and also for its impact on vegetation), on the farm (its operation secures the farmer's income but the way it is organised, including the practices being implemented, partly shape the landscape). At each stage, different and at times contradictory criteria may be proposed by different scientific disciplines. To evaluate a system accepted as being complex, a set of similarly complex criteria must be developed. How then is this set to be organised and ordered?