On the Problems of Biogeography
Authors: Raušer Jaroslav 
Published: January 2024

The question of occurrence of organisms upon the Earth has been many times treated of by geographers as well as biologists. Some consider biogeography and independent scientific branch of geography, others think it part of biology. Both tendencies according to the subject of one's studies may be considered either biological or geographical branches. Subject of biological studies is organism (or organic associations) with its biotic manifestations. Geographers study geographical areas whose typical and very often characteristic phenomena are organisms (or organic associations). In spite of the endeavour of several geographers, the geographical substance of the study of phyto- and zoogeography has remained rather obscure. Therefore the author suggested the Czech term "geografie rostlin" and "geografie živočišstva" which corresponds to the English "plant geography" and "animal geography", the Russian "geografija rastěnij" and "geografija životnych", and to the German "Vegetationsgeographie" and "Tiergeographie". The new Czech expressions are to distinguish geographical branches from biological branches since the former in their conception and subject of their study are different from the latter (e. g. from geobotany and geozoology). Both branches have been divided into three groups. In plant geography, the author accepted Schmithüsen's conception (1957). Since area is the subject of the study, geographical branches must be sorted from the areal point of view. Plant and animal geography treats of the two organic elements of the biosphere more or less separately. This fact is also reflected in textbooks on geography. Em. de Martonne (1920, 721) mentioned for the first time the impossibility of any sharp distinguishing the two branches from each other. If geographical works are to contain some complete knowledge of the Earth's phenomena, a separate study of flora and fauna becomes out of question. Only in this way we may achieve the right view of the function of this element of the geographical area. Consequently we may consider biogeography an independent branch of science treating of the occurrence of organic associations and making use of the knowledge and the results of the plant and animal geography. As fundamental biogeographical unit may be considered the geographical biogeocoenosis (after Sukačev 1940). It represents an unit of organic associations (phytocoenoses and zoocoenoses) as seen from the areal point of view, and definite parts of the surface of the Eearth (biocoenosis + topographically defined ecotop = natural biogeocoenosis). Biogeography studies the biogeocoenoses of the Earth, treats of their characteristic features and resemblances. Biogeography - similarly as plant and animal geography - may be divided into three basic branches: a) Biogeographical investigation occupies itself with the occurrence of biogeocoenoses taking note - at the same time - of particularly characteristic biots of plants as well as animals and their relation to the environment. It makes use of the knowledge of the biological branches, phytocoenology and zoocoenology. It is concerned with taxons of these associations of outstanding physiognomy for the areal division. b) The areal-topographical biogeography studies the geobioms, i. e. a plant occurrence and a corresponding animal association which - as a firmly fixed phase in a certain stage of historical development depends closely upon the geographical conditions of the place of occurrence, especially topographical, edaphic and climatic ones. It only changes if the place of its occurrence itself is through a change, e. g. a change of climatic conditions. Consequently, it is concerned with the consequence of the geobioms in the place of occurrence, and with their features characteristic of the geographical area. c) Chorological biogeography makes use of the knowledge on geobioms and studies the areal division of the biosphere.