BIOGEOGRAHIC TYPOLOGY

The Biogeography is the science of the plant species and plant communities distribution on the Earth and their relationships. Studying the actual and preterit areas of the taxa and syntaxa and with the knowledge and modelization coming to the other natural sciences (Physical Geography, Edaphology, Bioclimatology, etc.), the Biogeography tries to establish a global hierachical typology of the Biosphere. Its typological units in hierarchic decreasing order are: kingdom, region, province, sector, district and tesela.

The biogeographic taxonomy proposed and used by us in this work could be compared, and is related to the phyto-chorologic proposals of Drude (1897), Engler & Gilg (1919), Meusel, Jäger & Weinert (1965) Good (1974), and Takhtajan (1986). The last mentioned proposal could be called "corionomic", because it is mainly based in the area superposition and in the richness of several vascular plant taxa, particularly families and genus present in some geographic territories ("corias" or "phyto-corias").

Our proposal has more conceptual and territorial similarities with the hybrid "floristic-vegetation" approach proposed by Brockmann-Jerosch & Rübel (1912), with the biostructural approach of Udvardy (1975) and, above all, with the genuine phytosociological related approach of Schmithüsen (1968, 1976). Anyhow, we think it useful to combine the concepts and nomenclature within all the valid approaches (vg. floristic region should be similar to vegetation region, vegetation circle or plant communities circle). We must do not forget that the Biogeography as bioecological-geographic science focuses in the sectorization and systematization of the present Earth biodiversity and habitats .

In our present proposal we use several criteria for the characterization and delimitation of the biogeographic units: floristic, structural, bioclimatic, zoological, eco-functional and edaphic. With this eclectic but not ambiguous position sometimes we have needed sometimes to propose some new biogeographic great units not suggested before. Anyway, we have tried, in addition to maintaining as much as possible the traditional names and hierarchies to obtain that all the boundaries between units could be objective and enough justified, using vegetation series and geoseries as main delimitatating criteria.

Worldwide we recognize in total four kingdoms with seven subkingdoms and forty for regions. The kingdoms and subkingdoms are: I. Holarctic (13 regions), II. Paleotropical: IIa. African (7 regions), IIb. Indo-Malayan (5 regions), IIc. Polynesian (3 regions), III. Neotropical-Austroamerican: IIIa. Neotropical (9 regions), IIIb. Austroamerican (3 regions), IV. New Zealandian-Australian: IVa. New Zealandian (1 region), IVb. Australian (3 regions). By continents the number of regions are Eurasia: 15 regions, North America: 9 regions, South America: 9 regions, Africa: 9 regions, Australia and Polynesia: 7 regions (figures 5 and 6).  

Figure 5.    Biogeographic kingdoms, subkingdoms and regions of the geobiosphere. We recognize four kingdoms, seven subkingdoms and forty four regions.

We recognize as major biogeographic units of the Earth within the geobiosphere four kingdoms, seven subkingdoms and fourty four biogeographic regions (Fig. 5). Their distribution in the continents and relationships with the macrobioclimates is given in Fig. 6.

Figure 6. Correspondence among the geobiosphere biogeographic regions, the continents and the macrobioclimates in the World. As a whole we recognize 44 regions: nine in North America; nine in South America; fifteen in Eurasia; nine in Africa and seven in Australia and Polynesia.

BIOGEOGRAPHIC SYNOPSIS OF AMERICA

For America we recognize two kingdoms, three subkingdoms, four superregions, eighteen regions and eighty one provinces (Fig. 7). [Dr. G. Navarro (South America), Dr. J. Giménez de Azcárate and Dr. A. Penas (Meso-America), Dr. M. Costa and Dr. D. Sánchez-Mata (North America) have collaborated in the biogeographic synopsis of both american continents].

Figure 7.    Biogeographic synopsis of America at regional and provincial level (with collaboration of Drs. D. Sánchez-Mata and M. Costa for United States and Canada, Drs. J. Giménez de Azcárate and A. Penas for Mexico, and Dr. G. Navarro for South America). In total we recognize in America: 2 kingdoms, 2 subkingdoms, 3 superregions, 18 regions and 73 provinces.

BIOGEOGRAPHIC TYPOLOGY OF NORTH AMERICA TO SECTORIAL AND SUBSECTORIAL LEVELS

The biogeographic typology synthesis of the regions, provinces, sectors and sometimes subsectors of North America (Mexico included, with the collaboration of Dr. J. Giménez de Azcárate and Dr. A. Penas) is presented below, based chiefly in a previous synopsis (Rivas-Martínez, 1997: 13). We recognize in North America (North of Panama) 2 kingdoms, 2 subkingdoms, 2 superregions, 9 regions, 33 provinces, 87 sectors and 78 subsectors.

Figure 8. Distribution of biogeographic provinces and regions of North America (Meso-America included). 1. Circumarctic Region: 1.1. North American Arctic Province; 2. North American Boreal Region, 2.1. Canadian Boreal Province, 2.2. Yukonian-Alaskan Province; 3. North American Atlantic Region: 3.1. Appalachian Province, 3.2. Great Lakes and Central Lowlands Province, 3.3. Prairies Province, 3.4. Coastal Plains Province, 3.5. Texas Prairies Province; 4. Rocky Mountain Region: 4.1. Boreal Oceanic Province, 4.2. Cascade Province, 4.3. Northern Rocky Mountain Province, 4.4. Central-Eastern Rocky Mountain Province; 5. Californian Region: 5.1. Northern Californian Province, 5.2. Southern Californian Province; 6. Great Basin Region: 6.1. Columbia Plateau Province, 6.2. Intermountain Province, 6.3. Colorado Plateau Province, 6.4. Mohave Province, 6.5. Neomexican-Arizonian Middlands Province; 7. Mexican Xerophytic Region: 7.1. Baja California Province, 7.2. Sonoran Province, 7.3. Sinaloan Province, 7.4. Chihuahuan Province, 7.5. Taumaulipan Province; 8. Madrean Region: 8.1. Western Madrean Province, 8.2. Neovolcanic-Eastern Madrean Province, 8.3. Balsas River and Southern Madrean Province; 9. Caribbean-Mesoamerican Region: 9.1. Floridan Province, 9.2. Cuba Province, 9.3. Antilles Province, 9.4. Veracruzan-Yukatanian Province, 9.5. Chiapas-Honduras Province, 9.6. Panama and Costa Rica Province [Synthesis by S. Rivas-Martínez, with the collaboration of M. Costa, J. Giménez de Azcárate, A. Penas and D. Sánchez-Mata].