The Mbam and Djerem National Park (MDNP) is threatened by bush fires and particularly by uncontrolled late fires which compromise all of its biodiversity of the park. This study aims to assess the impact of fires on the plant diversity. To do this, plots were demarcated on the basis of the distribution of active fires, burned areas and ground measurements. A total of 56 herbaceous species have been identified. It also appears that the heights of grass after the early fires are higher than those observed after the late fire (ANOVA, p = 0.005). In regularly burned areas over two successive seasons, decomposing biomass is rare, herbaceous recolonization is mainly done by spreading. On the other hand, at the plots excluded from fire, the dead biomass accumulates from season to season and is relatively more abundant on the soil surface and this congestion would induce the vertical growth of herbaceous plants to the detriment of spreading on the ground. We observe the active and early regrowth of grasses after the passage of fire (in less than 3 months) as well as their fruiting (six months later). Thus, to conserve biodiversity and meet the high demand for plant biomass, better knowledge of the impact of fires on ecosystems becomes essential in the planning of Park activities.

Keywords: Active fire, herbaceous, burnt area, savannah, protected area, Cameroon