Observations on Microclimate and Vegetation Interrelationships on the Accra Plains (Ghana)

Abstract

The main relationships between macroclimate and broad vegetation zones are well known for most parts of West Africa. For Ghana, meteorological conditions are summarized by Walker (1962) and a clear correlation can be made by comparing his maps of annual rainfall distribution with vegetation zones. But as Hopkins (1965, p. 50) has stated, little is known about microclimatic factors, especially in savanna areas. The present paper is a small contribution towards a better understanding of microclimate and its interrelationships with the vegetation of the southern savanna zone in Ghana, known as the Accra Plains (see White 1954 for definition and maps). Though the vegetation of the Accra Plains is referred to above as 'savanna' it does not fit with any of the main savanna types found in West Africa and might be better referred to as a kind of steppe (cf. Boughey 1957) since the grasses in this very dry area (less than 30 in. (75 cm) rainfall) rarely exceed 80 cm in height. It is an almost unique type of vegetation consisting essentially of a matrix of low grassland in which are embedded slightly raised islands of woody vegetation occupying the sites of old termite mounds. Brief accounts of this vegetation and its possible origin are given by Aubreville (1959) and Lawson (1966).