The biogeographical typology of continental Portugal is approached as a hierarchical model of ecological regions based mostly on the analysis of taxa and vegetation-types present-day distribution. The system establishes an hierarchical typology of natural regions fully included in the worldwide biogeographical classifications of Braun-Blanquet, Mensel, Takhtajan, Axelrod, Cronquist, Mensel & Jaeger, Ehrendorfer and Rivas-Martínez. The units in the portuguese territory are briefly characterized down to the level of Superdistrict and also the criteria supporting their definition and circumscription. Two main methodological approaches were followed. The first, put emphasis on the diagnostic importance of actual distribution of taxa of several ranks and their phylogenetic relationships, taxa areals and vicariance. The model took on account the available data on paleo-ecological studies and also knowledge obtained by the comparative study of present-day taxa distribution (cladistical inference) in relation to floral migratory pathways and past climate change. The second approach deals with present-day distribution of vegetation units in several levels of ecological complexity (communities, successional units and vegetation catenae). The later, aims to synthesize the actual dominant ecological conditions in actual and potential terms. The comparison of the distributions of actual vegetation units was found to have high diagnostic value in establishing the frontiers between biogeographical units. Also, the authors found that cladistic reasoning applied to present-day vegetation units is useful for the sake of interpreting recent Quaternary climate and ecological changes of paramount importance for the biogeographical model. The two main methodological approaches were found to be highly consistent among them and yielding a similar classification of the territory. Incidentally, in a passive fashion, the typology has been compared to patterns issued from other sciences (bioclimate, zoology, human geography, archeology, river ecology and forestry) and found to be highly congruent.

A map of the biogeographical units in the 1: 1000.000 scale is presented.

regressar à página inicial