Abstract

Tropical rainforests are home to a high level of biodiversity and are of global importance in the development of conservation strategies. To make effective and accurate modelling of the composition of forest ecosystems, it is necessary to study the composition, diversity and structure of these ecosystems. The aim of this study is to make an inventory, investigate the biodiversity and conservation status of woody species between mixed forests (F.mx) and Gilbertiodendron dewevrei monodominant forests (F. mono). The methodological approach adopted was inventories of woody species with diameters ≥10cm in 8 permanent plots (5 of F. mono and 3 of F. mono) in the Dja Biosphere Reserve. The diversity indices between the two types of forest, the chorology and the IUCN status of the species were determined from the inventory data. Overall, 196±6 species from 43 families and 144 genera were identified in the F.mx, compared with 84±7 species in 32 families and 72 genera in the F. mono. Total species richness, Shannon Simpson diversity index and Piélou equitability were significantly higher in the F.mx than in the F. mono. The average stem density was higher in F.mx than in F. mono. In the F.mx, the family value index shows that the Annonaceae family (FIV=10.54%) was the most represented, whereas in the F. mono, it was the Fabaceae family (FIV=71.61%). Tabernaemontana crassa (13.63%) and Gilbertiodendron dewevrei (127.71%) were the most important species in terms of importance value index in F.mx and F.mono respectively. According to the IUCN classification, 5% and 2% of species in F.mx and F.mono respectively were vulnerable. Dialium guineense, endemic to south-west Cameroon, was identified in F.mx. In both types of forest, around 58% belong to the Guinean-Congolese region.

Keywords:Conservation status; Congo basin; Diversity; Species richness; Tropical rainforest