A Study of a Vegetation Catena in Guinea Savanna at Mole Game Reserve (Ghana)

Though a fairly extensive literature relating to the Guinea savanna zone in Africa exists, practically nothing has been written about this vegetation type in Ghana, with the exception of a few general accounts (e.g. Vigne 1936; Taylor 1952; Baker 1962) and a study on the effects of fire by Ramsay & Rose-Innes (1963). This paper is an attempt to provide factual data of species composition, structure and environment of vegetation from Mole Game Reserve, which represents a relatively well-preserved area of Guinea savanna in Ghana. During 1966-67 three visits were made to Mole Game Reserve by a group of senior members of the Department of Botany, University of Ghana: at the end of the rainy season (early November 1966), in the peak of the dry season (late December 1966, during the Harmattan weather) and at the very end of the dry season (March and April 1967). The bulk of the work was accomplished during the last expedition, organized as a field course for university students. Mole Game Reserve is the largest and most 'developed' of Ghana's few nature reserves. It lies in the Gonja region, occupying a roughly rectangular area of about 900 miles2 (2300 kM2) (Fig. 1). The terrain is rather varied for savanna country, and includes a number of hills, scarps and plateaux which, however, never rise to more than 900 ft (275 m) above sea level. Several fairly large rivers, all of which cease flowing in the dry season, run through the reserve. The large scale map of the area (1: 125000), which is devoid of contours, is notoriously inaccurate about the situation and direction of flow of the rivers and streams, but aerial photographs are available for the whole area. The sample plots were placed in a soil-vegetation catena near Lovi Camp (Fig. 1), which lies in a central position in the reserve. The surrounding soils and plant communities represent a good sample of the whole reserve. The following is a brief identification of sites and terms used in connection with further descriptions (see Fig. 2).