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A survey was conducted between October 2010 and June 2011 to determine the diversity, distribution, and abundance of plants in 4 sites of the Lebialem highlands and to relate species diversity and abundance to altitude and soil types. Twelve (12) plots, each of 1 ha (250 × 40 m), were surveyed at the submontane and montane altitudes of the sites. One hundred (100) species belonging to 82 genera were identified with the genera Cola and Psychotria being the most represented. Vulnerable species included Guarea thompsonii, Schefflera hierniana, Allanblackia gabonensis, Cyclomorpha solmsii, Vepris trifoliolata, and Xylopia africana. Species such as Xymalos monospora, Tricalysia atherura, and Piptostigma oyemense present in the study area were endemic to Cameroon. Diversity and distribution of plants were affected by parameters such as the altitude and the soil type. Soil analysis revealed that diversity in the study area was affected by the organic carbon, nitrogen, calcium, and the cation exchange capacity of the soil.

Municipal solid waste generated in our cities, with an unprecedented population growth, has resulted in degrading environmental quality, thus a major problem for policy makers. The extent of Pb, Cu, Zn, Cd, Hg and Zn contamination in soils of the studied area, where vegetables were grown, using metal contamination factor (CF) and pollution load index were assessed. The concentrations of heavy metals studied were in the order Cu > Zn > Cd > Hg > Pb > Ni, with the highest value (in mg/kg) for Zn (14.15±0.73), Cu (14.15±1.59), Cd (6.57±1.71) and Hg (6.29±0.97) recorded in site SS1. The geoaccumulation index (Igeo) indicated that sites SS3, SS4 and SS5 were uncontaminated, moderately contaminated (1< Igeo<3) for Zn, landfill was moderately to heavily contaminated (1< Igeo<3) for Cu, Cd and for swamp only Hg. Contamination factor (CF) for soils indicated that site SS1 had a very high degree of contamination (CF > 6) for Cu and Cd while the swamp, old dumpsite and downstream had a low contamination (CF<1). The landfill area is moderately contaminated and considering the age and other anthropogenic factors, this environment may become highly polluted in future. This present work could serve as a landmark for contemporary research in ecotoxicology .

Background The Orchidaceae are noted for their floral diversity. In the Mount Cameroon Region (MCR), the genus Bulbophyllum is the most represented genus of the entire flora of this region. Despite the large number of different species in Orchidaceae, very little is known and documented about the orchids in Cameroon at large, in the MCR in particular. Orchids are widely used in flower gardens and trade. The aim of this study was to assess the floristic value of the orchids compared with those of other parts of the world and equally assess species which are used in herbal medicines. Methods This research was carried out in the MCR and the main flower market in Cameroon. Semi-structured questionnaires were administered to vendors, buyers, and cultivators at a ratio of 1:1:1, as well as to herbalists and cultural use indices computed. A total of 107 flower gardens in all gardening localities (07) of the region were sampled. Results A total of 66 out of 107 gardens had at least one orchid species. Five orchids which are hybrids cultivated by vegetative propagation are traded as ornamental plants in the MCR. A total of 23 species were used for herbal treatment of certain ailments. The ethnobotanical richness of orchids was scored at 6.86. Ansellia africana had the highest cultural importance index (CI), relative importance index (RI), and the relative use index (RNU) while tradactyle tridactylites had the lowest. It was also found that most orchids were used for clairvoyance that is highly associated with myths or folklore and also for external application. Conclusion The level of awareness on uses of orchids in the MCR is low. Many people consume orchids mixed with different species of plants for herbal treatment. Orchid trade is used as a part of subsistence by orchid cultivators and vendors.

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