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Variation of Biodiversity in Sacred Groves and Fallows in the Western Highlands of Cameroon
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97 Variation of Biodiversity in Sacred Groves and Fallows in the Western Highlands of Cameroon C.M. Tankou1* , G.R. de Snoo2 , G. Persoon3 and H.H. de Iongh2 Published in the African Journal of Ecology 1 Faculty of Agronomy and Agricultural Sciences, University of Dschang, P.O. Box 222 Dschang, Cameroon. 2 Institute of Environmental Sciences, Leiden University, P.O. Box 9518, 2300 RA Leiden, The Netherlands 3 Department of Anthropology, Leiden University, P.O. Box 9518, 2300 RA Leiden, The Netherlands . * Corresponding author. cmtankou@yahoo.com; tel: (237) 77 66 03 04; fax: (237) 33 45 15 66 4 98 4 Variation of Biodiversity in Sacred Groves and Fallows Abstract This study was conducted in order to estimate species richness and diversity in different ecosystems and understand the floristic changes resulting from variation in abiotic factors in sacred groves. Vegetative assessment in quadrats revealed that the sacred groves were rich in plant genetic diversity composed of a total of 42, 65 and 82 ethno-botanical species of herbs, shrubs and trees respectively, of varied ecological and economic importance. The herbaceous ̝-diversity was significantly higher in the fallows than the sacred groves at low altitudes. The tree species richness was higher at low altitudes compared to high altitudes with tree ß-diversity increasing with altitude. Varying combinations of soil pH, total P, total K, CEC and slope percent were related to herbaceous species richness, herbaceous Shannon index and shrub species richness. Intensive land-use has completely changed the structure of the native vegetation and caused severe plant diversity losses, though some useful forage species have been introduced in the area. Habitat changes in the sacred groves may be driven by biophysical while a combination of human and biophysical factors could be considered in the case of rotational fallow vegetation. Key words Biodiversity, Western Highlands of Cameroon, sacred groves, rotational fallows, abiotic factors. 4.1 Introduction Loss of biodiversity in the tropics is principally due to the destruction of habitat by anthropogenic activities (Wilson, 2000) especially the clearing of natural vegetation and conversion into agricultural cropland, harvesting non-timber forest products, selective extraction of plants and animals, biological invasion, and monoculture (Swamy et al., 2000; Mishra et al. 2004; Sundarapandian et al., 2005). Biodiversity strongly influences the provision of ecosystem services and therefore human wellbeing (Ma, 2005). Cameroon has a complex mosaic of diverse habitats, with moist, tropical forest dominating in the south and covering 54% of the country (UNEP-WCMC, 2003), montane forest and alpine savannah in the highlands, and sub-Sahelian savannah in the far north (Letouzey, 1968, 1985; White, 1983). These diverse habitats harbour more than 9,000 species of plants, 160 of which are endemic (UNEP-WCMC, 2003). In the Western Highlands of Cameroon (WHC) there is however a preponderance of patches of land still preserved as sacred groves because of strong religious beliefs held by the indigenous people. These sacred groves, rich in medicinal, rare, and endemic plants, are refugia for the relic flora of the region [54.234.184.8] Project MUSE (2024-03-29 10:57 GMT) 99 4.1 Introduction (Whittaker, 1975; Jeeva et al., 2007). The WHC is considered one of the major agricultural zones of Cameroon. Intensive land-use due to demographic pressure has led to major changes in the agro-ecosystem in the WHC including the reduction in biodiversity. Most of the research on biodiversity has been concentrated in the humid rainforest agro-ecological zone of Cameroon (Comiskey et al., 2003) and virtually little or no attention paid to the species richness and diversity in the WHC. This paper aims at highlighting the biodiversity situation of this hitherto neglected zone with emphasis on the potential of the sacred groves and their differences with fallowed lands. The primary determinants of change in species composition and community structure in undisturbed ecosystems are abiotic factors that vary with altitude (Whittaker, 1975). The establishment and management of a modified and simplified plant community, influences the composition and activities of the associated herbivore, predator, symbiont and decomposer sub-communities (Swift & Anderson, 1993). Timber exploitation and shifting cultivation have accounted for the destruction of biodiversity in the humid south of Cameroon (Zapfack et al., 2002), while demographic pressure and human mobility have provoked fragmentation of large natural areas into small pockets in the WHC. This has resulted in increased intensity of land use over time and space and the permanent destruction of natural habitats that have greatly influenced plant species richness and diversity in the area...