Main determinants of forest and savanna distribution

Present distribution of forest and savanna can be interpreted by looking for parallels with environmental conditions at various spatial scales. Among them, climate and edaphic conditions determine water availability and are of paramount importance in the competition between the two vegetation types. The outcome of competition is modified by disturbances such as fire and shifting cultivation. In the following paragraphs we discuss these main environmental factors, and how they operate at...

Leguminosae Caes

Life form small tree Max. height 10 m (herbarium) Max. diameter data unavailable Leaf alternate, paripinnately compound, 10-16 leaflets, ovate to asymmetric, nanophyll (0.9-1.2 x 2-3 cm), entire, coriaceous, rachis with small scalelike glands close to and above leaflets, and with hairs red brown and curly Inflorescence axillary, unbranched (raceme), densely pubescent, branching racemes from the axils of very young and small leaves Flower small corolla dark-red fragrant Fruit dry dehiscent...

Diospyros liberiensis

Max. diameter 5 cm (Hawthorne & Jongkind Leaf alternate, simple, elliptic to ovate, mesophyll (3-11 x 7-22 cm), entire, herbaceous, pubescent beneath, large glandular spots Inflorescence axillary, unbranched Flower small unisexual flowers male flower with 4 lobes female flower unknown Fruit fleshy (berry) (3.3 x 4 cm), velvet, yellow to orange or black containing two parallel seeds in colourless pulp Seed long, very large (2.6 x 1.8 x 0.9 cm), brownish black Continent Upper Guinea endemic...

Methods

Study area, plot- and data selection The area covered in this analysis is confined to the forest zone of Sierra Leone, Liberia, C te d'Ivoire and Ghana. These countries contain most of the forest in Upper Guinea and are relatively well studied. The data we have used are collected by various organisations. For Sierra Leone we used the data from Small (1953), Savill & Fox (1967) and Davies (1987). For Liberia we used data from the German Forestry Mission to Liberia (GFML 1967a, 1967b, Sachtler...

Forest cover changes in Cte dIvoire and Upper Guinea

Of the forest that covered West Africa at the beginning of the 20th century, the large majority has disappeared and the Ta National Park forest in C te d'Ivoire is now the last important one. Notwithstanding this rampant deforestation, it is necessary to remember that the forest was not always present throughout the centuries forests took over savanna zones, and vice versa (Guillaumet & Adjanohoun 1971, Maley 1996, van Rompaey 1993). More recently, extensive savanna zones got forested during...

And management

Need for effective conservation and sustainable use Forests are important as a habitat for plants and animals, for their role in the maintenance of cycles of rainfall and biogeochemical substances like carbon and nitrogen, and as a source of all kinds of forest products (e.g. timber, fuelwood, bushmeat, medicines, lianas for construction) satisfying the needs of human beings. Forests are commonly used for recreation and religious ceremonies (e.g. sacred forests). In short, tropical forests are...

Checklist of Upper Guinea forest species CCH Jongkind

Appendix 1 Colour figures Chapter 2 Forest cover changes in C te d'Ivoire and Upper Guinea 481 Appendix 2 Forest sites in Upper Guinea 493 Appendix 3 Forest reserves in Upper Guinea 499 Appendix 4 Hotspots of plant biodiversity in Upper Guinean forests 501 Appendix 5 Geographical map of West Africa 503 Authors, photographers and illustrators Index

Discussion

What determines the main vegetation gradient in Upper Guinea Our results show that rainfall is the single most important parameter determining the vegetation gradient for the Upper Guinean forests. However, several other factors are closely correlated with rainfall, notably soil characteristics like cation availability and soil water holding capacity. Also latitude and longitude are strongly correlated to rainfall and these geographical factors, more than soil parameters, account for the rest...

Map Symbol For Evergreen Forest

Ds ms me we1 we2 we 3 hw forest type Figure 4.6 Comparison of forest types with respect to (A) rainfall, (B) water holding capacity and (C) cation availability. Comparison with existing national and local vegetation maps We compared our forest types with other ones that were made for the separate countries Ghana, C te d'Ivoire, Liberia and Sierra Leone (Table 4.5). Our vegetation map is comparable to the map for Ghana (Hall & Swaine 1981). Their gradient from wet evergreen via moist...

What explains the distribution of rare and endemic West African plants

Understanding species distribution patterns is a crucial step for the conservation and management of plant communities and ecosystems. This is particularly true for species with small distribution ranges that grow and reproduce under a very particular set of environmental conditions. West African forests, although less species rich than some other tropical forests, seem to be relatively rich in endemic species (e.g. Myers et al. 2000, White 2001). About 22 of the forest species in Upper Guinea...

Study sites and methods

The study sites comprise thirteen forests in the centreeast, the southeast, the southern coast, the centre-west, and the southwest of C te d'Ivoire. The choice of these different forests was based on the intactness of the forest cover and the availability of species lists. The forests vary from semi-deciduous to evergreen (Figure 5.2), they are of various sizes (2590 to 300,000 ha), and have different soil and climatic conditions (Table 5.1). Three soil types can be distinguished tertiary...

Literature

Abbadie L, Lepage M, Le Roux X (1992) Soil fauna at the forest-savanna boundary role of termite mounds in nutrient cycling. In Furley PA, Proctor J, Ratter JA (eds) Nature and Dynamics of Forest-savanna Boundaries. Chapman & Hall, London pp 473-484 Abbiw DK (1990) Useful plants of Ghana. Intermediate Technology Publications and Royal Botanical Gardens, Kew Achard F, Eva HD, Stibig HJ, Mayaux P, Gallego J, Richards T, Malingreau JP (2002) Determination of deforestation rates of the world's...

Project On Drynaria Laurentii

This list contains all names of all the vascular plant species from the forests of Upper Guinea. In total c. 2800 names of different species are included, some with subspecies and varieties. For each of the species a taxonomic publication is given, mostly recent publications with detailed information about the species distribution and ecology. In the case that a species is not cited for Upper Guinea in the literature, a herbarium specimen is cited instead. In the list the herbarium citations...