Biodiversity hotspots and conservation priorities in the Campo-Ma’an rain forests, Cameroon

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’Eléphant 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.