In many areas of science, scientists need to find distinct common characterizations of the same objects and, vice versa, to identify sets of objects that admit multiple shared descriptions. For example, in biology, an important task is to identify the bioclimatic constraints that allow some species to survive, that is, to describe geographical regions both in terms of the fauna that inhabits th...

Université d'Aix-Marseille III, Centre de Saint-Jérôme, Laboratoire de Botanique et d'Ecologie Méditerranéenne, 13397 MARSEILLE/CEDEX 4. Abstract: Methods of classifying ecosystems have developed differently in Europe and America. Individualization of bioclimatic zones and of altitudinal levels proved most valuable, particularly the role of edaphic factors. This methodology can be associated wi...