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Plant diversity in a Central African rain forest: Implications for biodiversity conservation in Cameroon Figure 1.1 Present land use planning map of the Campo-Ma’an Technical Operational Unit (Annex 4). Physical environment Geology and soils The Campo-Ma’an area is situated on the Precambrian shield, which is the most important and extensive geological formation in Cameroon. This Precambrian basement complex consists mainly of metamorphic rocks and old volcanic intrusions (Franqueville, 1973). Metamorphic rocks such as gneisses, migmatites, schists and quartzites dominate the geology in the area. Soils that are developed on these metamorphic rocks are acid and poor in nutrients. Sedimentary rocks of the Cretaceous can also be found in the Campo basin. The topography ranges from undulating to rolling in the lowland area, to steeply dissect in the more mountainous areas. In the Campo area, altitudes are mostly low, ranging from 0 m at sea level to about 500 m. In the eastern part, which is quite mountainous, the altitude varies between 400-1100 m and the rolling and steep terrain brings about a more variable landscape. Following the FAO classification system, soils in the Campo-Ma’an area are generally classified as Ferrasols and Acrisols (Franqueville, 1973; Muller, 1979; van Gemerden & Hazeu, 1999). They are strongly weathered, deep to very deep and clayey in texture (except at the seashores and in river valleys where they are mainly sandy), acid and low in nutrients with pH (H2O) values generally around 4. Although Ferric soils are the most widespread, poorly drained as Dystric Fluviosols or Gleyic Cambisols soils are commonly found in the river valleys and adjacent swampy areas throughout the Campo-Ma’an area. The dominant soils in the coastal 6
General introduction plain are Plinthic Ferrasols, with patches of Haplic Acrisols and Acri-Xanthic Ferrasols. In the eastern part of the Campo-Ma’an area, soils are developed on ectinites including gneiss, micashist and quartzite. In the mountainous area, soils are developed on migmatites and granites and are mostly classified as Acri-Xanthic Ferrasols and Xanthic Ferrasols. Climate and hydrology The Campo-Ma’an area has a typical equatorial climate with two distinct dry seasons (November-March and July-mid-August) and two wet seasons (April-June and mid-August-October). The average annual rainfall generally decreases with an increasing distance from the coast, ranging from 2950 mm/year in Kribi and 2800 mm in Campo to 1670 mm in Nyabissan in the Ma’an area. The Ma’an forest has significantly less rainfall than other areas. This is probably due to a rain shadow effect caused by the Nkolebengue Hills (up to 1000 m) which forms a substantial upland block between Ma’an and the ocean. The average annual temperature is about 25°C and there is little variation between years. The hydrography of the area shows a dense pattern with many rivers, small river basins, fast-flowing creeks and rivers in rocky beds containing many rapids and small waterfalls. The main rivers draining the TOU are the Ntem, Lobe, Bongola, Biwome, Ndjo’o, Mvila and Nye’ete. Swamps are commonly found in the valley of these rivers. Socio-economic settings Population, ethnicity and settlements A recent census carried out by ERE Développement in April 2001 has shown that about 61,000 people live in 167 towns, villages and agro-industrial or logging camps. Generally, the area has a low population density of about 10 inhabitants per km² and is sparsely populated with most people living around Kribi, along the coast, and in HEVECAM, SOCAPALM and HFC camps (ERE Développement, 2002; de Kam et al., 2002). There are seven main ethnic groups in the area which are the Batanga, Mabea (or Mabi), Mvae, Yassa, Ntumu, Bulu and the Bagyeli (or Bakola) Pygmies. In addition to these ethnic groups, there are residents from other parts of Cameroon and Equatorial Guinea who depend on the work provided by the timber companies and agro-industrial plantations. The Bakola pygmies are mainly forest dwelling hunters and gatherers, although they seem to be in the process of sedentarisation (Annaud & Carriere, 2000). They are in small number and depend mostly on the forest for their livelihood. Their life style is seriously threatened by the ongoing logging activities. The Batanga, Mabea, and Yassa are mostly found in small fishing villages along the coast between Kribi and Campo. They rely mostly on the sea for their livelihood and have fishing as their main occupation. The Mvae, Ntumu and Bulu are mainly farmers, hunters and forest gatherers. Logging and agro-industrial enterprises There are two main logging enterprises in the Campo-Ma’an area which are “la Forestière de Campo” (HFC) and Wijma (GWZ). HFC is operational since 1966 and operates a sawmill and port facilities at Ipono near Campo. Other companies such as Wijma and CFK also have sawmill facilities. Log production is about 39,250 m³/year and more than 135,000 m³ of sawn woods are produced per year. Timber harvesting in the area provides about 115 millions FCFA/year ($ 201,754) to the 7
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Plant diversity in a Central Africa
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Chapter 4 BIO-INDICATOR SPECIES AND
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Chapter 5 BIODIVERSITY HOTSPOTS AND
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Chapter 6 GENERAL CONCLUSIONS AND I
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REFERENCES
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ANNEXES
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SUMMARY Summary The fragile ecosyst
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Summary suggest that the Campo-Ma
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RESUME Résumé La biodiversité de
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Résumé nombreux auteurs qui argum
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SAMENVATTING Gildas Peguy Tchouto M
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