A contribution to the concept and the classification of the bioclimatic unit in Sub-Saharan Africa

Abstract

A bioclimatic unit is an integration of climatic factors (e.g. radiation, humidity complexes) and features modified by physiography and vegetation (biotic communities and associated habitats, i.e. wherever possible, ecosystems).

Unit implies an entity irrespective of ecological status and dimensions: these are otherwise differentiated.

It often must suffice to use vegetation communities, because information regarding biotic communities or ecosystems is unavailable.

Increasingly, disturbance of ‘natural’ conditions makes it imperative to involve man in the classification, demarcation and policy for the development of bioclimatic units.

Ignorance regarding the nature and distribution of a climax necessitates using pro- (pre- or post-) climaxes.This is based upon the differentiation in these criteria: climatic (radiation and humidity complexes); vegetation (physiognomy and ecological status) . . . and as these are further modified by physiography and edaphic features (physiognomic differentiation ranges from specific faciations of forest or thicket); wooded savanna (facies ofwoodland, shrubland); facies or faciations of grassland; climatic differentiation ranges from highly humid toarid . . . and further to subdesert and desert.

Recommendations respecting policy and practice in pastoral, crop production and forestry development based on this concept have been used in various sectors of Africa. South East Asia and Latin America. Detailed experience has been gained in Natal and elsewhere.

Several maps illustrate the application of the concept.