Contents - Previous - Next

This is the old United Nations University website. Visit the new site at http://unu.edu

9: Floral and faunal diversity

Materials and methods
Results and other observations
Other observations
Discussion
Conclusion
References

Lewis Enu-Kwesi

This paper presents the results of a preliminary inventory of floral diversity and, to a lesser extent, faunal diversity in selected sites within the southern sector of the forest-savanna transition zone in Ghana (see fig. 5.1, p. 39).

Materials and methods

Using principally the rapid multidisciplinary integrated transect survey method described in chapter 6, the following sites were surveyed:

• the area centred on Yensiso (Yensiso, Adenya, Gyamfiase and Kokormu);
• the area centred on Amanase (Amanase and Whanabenya); and
• the area centred on Sekesua (Sekesua and Osonson; see figs. 6.1-6.3, pp. 44, 45, 46). Other methods were group discussion and interview by questionnaire.

A 30 m traverse chain was dragged along each selected traverse farm footpath extending 1.7 to 2.0 km in distance in each of the study areas. The 30 m chain drag along the footpath was used for the rough-and-ready measurement of the 30 x 30 m² quadrats within which the plant species (including trees, shrubs, herbs, climbers and geophytes) were rapidly surveyed, identified and recorded as far as one could see on the right-hand side of the transect direction.

Results and other observations

Over 102 plant species belonging to approximately 51 plant families were encountered in the three study areas (tables 9.1, 9.2). Twenty-three families out of the 51 possessed tree species. Eighteen of these 23 families were dicotyledonous and consisted of 34 genera, whereas there were 5 monocotyledonous families that comprised 8 genera. Twenty-eight families out of the 51 also contained herbs, climbers and shrubs, and 23 out of these 28 families were dicotyledonous, whereas the remaining 5 were monocotyledonous. The 28 families consisted of 60 genera, 48 of which were dicotyledonous and 12 monocotyledonous.

Table 9.1 List of Tree Families Encountered in the Three Study Sites

T = large tree capable of exceeding s = shrub or pygmy tree
30 m height (megaphanerophyte) H = herb
t = small tree

Table 9.2 List of Families Eneountered in the Three Study Sites That Contained Shrubs and Herbs

T = large tree capable of exceeding c = small understorey climber
30 m ht. (megaphanerophyte) s = shrub or pygmy tree
t = small tree H = herb

Further analysis of tables 9.1 and 9.2 indicated that when the three study areas were considered together, there was a predominance of herbaceous and shrub species over tree species; and that tall trees (T) that are above 30 m in height constituted the life-form that was least prevalent in the entire study area.

Table 9.3 indicates that there were relatively very few tall trees or megaphanerophytes in the three study areas. These included Bombax buanopozense found at Yensiso, Osonson and Sekesua; Ceiba pentandra also found in all the study areas (Yensiso, Kokormu, Adenya, Osonson, Sekesua and Whanabenya except Amanase). This observation may only indicate that Ceiba pentandra occurs less frequently at Amanase when compared to the other sites and not necessarily that it is totally absent from there. Also Terminalia ivorensis, a good timber species, was found at both Yensiso and Amanase. Antiaris toxicaria/africana was another tree species which was present in all the study areas except at Kokormu and Adenya in the Yensiso area and Whanabenya in the Amanase area. This observation may also simply be an indication of the relative abundance of the species in the three study areas of the transition zone. However, borne as it is out of a preliminary rapid survey, this conclusion must be accepted only as a tentative one to be subjected to verification through more detailed studies.

Other tall tree species that were found included the following very important class one timber species:

• Chlorophora/Milicia excelsa, which was found only at Yensiso;
• Triplochiton scleroxylon, which was found in all three study areas; and
• Cola gigantea (a non-timber species), which was found in all three study areas.

Continue

Contents - Previous - Next