Biodiversity Hotspots and Conservation Priorities in the Campo-Ma’an Rain Forests, Cameroon

Abstract

Abstract. Until recently, patterns of species richness and endemism were based on an intuitive interpretation of distribution maps with very limited numerical analyses. Such maps based solely on taxonomic collections tend to concentrate on collecting efforts more than biodiversity hotspots, since often the highest diversity is found in well-collected areas. During the last decades, there has been an overwhelming concern about the loss of tropical forest biological diversity, and an emphasis on the identification of biodiversity hotspots in an attempt to optimise conservation strategies. Furthermore, the concept of sites of high diversity, or hotspots, has attracted the attention of conservationists as a tool for conservation priority settings. With the development of GIS tools, geostatistics, phytosociological and multivariate analysis software packages, more rigorous numerical analyses of distributional and inventory data can be used for assessing conservation priorities. In the Campo-Ma'an rain forest, inventory data from 147 plots of 0.1 ha each and 7137 taxonomic collections were used to examine the distribution and convergence patterns of strict and narrow endemic species. We analysed the trends in endemic and rare species recorded, using quantitative conservation indices such as Genetic Heat Index (GHI) and Pioneer Index (PI), together with geostatistic techniques that help to evaluate and identify potential areas of high conservation priority. The results showed that the Campo-Ma'an area is characterised by a rich and diverse flora with 114 endemic plant species, of which 29 are restricted to the area, 29 also occur in southwestern Cameroon, and 56 others that are also found in other parts of Cameroon. Although most of the forest types rich in strict and narrow endemic species occur in the National Park, there are other biodiversity hotspots in the coastal zone and in areas such as Mont d'Ele´phant and Massif des Mamelles that are located outside the National Park. Unfortunately, these areas, supporting 17 strict endemic species that are not found in the park, are under serious threat and do not have any conservation status for the moment. Taking into consideration that with the growing human population density, pressure on these hotspots will increase in the near future, it is suggested that priority be given to the conservation of these areas and that a separate management strategy be developed to ensure their protection.Biodiversity and Conservation (2005) 00:00-00 Ó Springer 2005

Tree diversity and conservation value of Ngovayang’s lowland forests, Cameroon

“…The Southern Ngovayang is among the most species-rich sites of the range of small mountains bordering the gulf of Guinea, with a mean of 110 tree species ha -1 ( (White 1983;Davis et al, 1994;van Gemerden et al 2003;Tchouto et al 2006Tchouto et al , 2009. Furthermore, the Fisher's a value for Ngovayang is significantly higher (KruskalWallis test, P = 0.039) than that for forests of Korup National Park (mean of 30.5), widely known for its high diversity and endemism.…”

“…The proportion of Lower-Guinea species in different sites is highest near the coast (23% for Dja and central Gabon forests to 43% for Monte Alen, Ngovayang and Korup). In Campo-Ma'an National Park, identified as a biodiversity hotspot due to its high levels of species richness and endemism (Tchouto et al 2006(Tchouto et al , 2009, the proportion of Lower Guinea endemics (including Cameroonian endemics) is lower (29%), but this apparent difference may Table 4 Comparison of Ngovayang tree diversity with that of other forest sites in Central Africa and the Neotropics, based on 1-ha (100 m 9 100 m) plots, by decreasing values of Fisher's a simply reflect the inclusion in the inventory for this site of secondary-forest and swampy environments, which harbor numerous species with large geographic ranges. Additional indications of high endemism in the Massif come from studies focusing on the distribution of particular taxonomic groups.…”

“…A taxonomic search of potential taxa of high conservation value, such as those endemic to Cameroon and other rare and threatened species according to Tchouto et al (2006), was conducted using the literature (Keay andHepper 1954-1972;Aubréville andLeroy (1961-1992;1963-1978, supplemented by the CJB (2010) data base (Conservatoire du Jardin Botanique de Genève: http://www.villege.ch/musinfo/bd/cjb/ africa/recherche.php) and the IUCN (2010) red list. In this study, the notion of rarity was defined following three criteria which describe different ways in which a plant species can be rare: (1) abundant somewhere or scarce everywhere (2) restricted to a single habitat type or not, and (3) geographically widespread or restricted (Pitman et al 1999).…”

Geographic distribution patterns and status assessment of threatened plants in China

“…These records, however, suffer spatial and temporal shortcomings when mapping the geographic range of species, mainly due to uneven historical sampling techniques (Townsend Peterson and Watson 1998). Some studies have shown that maps based solely on taxonomic collections tend to focus on concentrated areas where data was collected more than on biodiversity hotspots since the greatest diversity is usually found in well-collected areas (Tchouto et al 2006). In this study, a combination of herbarium specimens and various relevant references was used to avoid this problem and to ensure the scope and precision of the distribution data was reliable.…”

Are there habitats that contribute best to plant species diversity in coastal dunes?

“…Comparable measurements of species richness along the coastal dune gradient, which evidence rare and endangered species, can help answering crucial questions for ecosystem management such as which community best contributes to total species diversity or which are the priority habitats to propose for conservation planning. (Metzger et al 2005;Tchouto et al 2006). While rare and endangered species may contribute little to ecosystem function, they constitute the keystone of many conservation programs such as those promoted by EU Directive 92/43.…”