Utilization de donnees de teledetection pour la caracterization d'un ecotone en region tropicale de montagne: Exemple dans la Sierra de la Laguna, basse Californie Sud Mexique

This study aims to identify and quantify the spatial distribution of the boundaries (ecotone) between the tropical deciduous forest and the oak forests of the Sierra de la Laguna mountain range (Baja California Sur, Mexico). The methodology was based on field data organized on transects, on high-resolution remotely sensed data and on a Digital Elevation Model. The latter was used to improve land cover classification, which was limited by the effect of topography in rugged areas. Result show that the radiometric existence of the ecotone can be identified on February images, when the contrast between leaves phenology of the studied forest systems is the most pronounced. A difference of distribution and amplitude of the ecotone according to abiotic factors was also found. The need to support landcover classification with field data to obtain reliable characterization is discussed. The possibility of using former images to study transition environments, evaluate vegetation changes, and make suggestions to managers of this natural area are discussed also.