Comparison of plant communities on the Ibity and Itremo massifs, Madagascar, with contrasting conservation histories and current status

Abstract

Background: Deforestation processes and species extinction on islands have made them the focus of substantial efforts to create and strengthen local environmental organisations, establish new protected areas and improve natural resource management. In Madagascar, despite promising new policies, the flora and fauna are under serious threat. More than 80% of the island shows a significant loss of natural plant cover. Current levels of diversity reflect natural disturbance regimes, with fire representing one of the more important factors.Aims: We compared two new protected areas (Ibity and Itremo) with different environmental and management contexts to identify the roles and impacts of the environmental conditions and the different types of management applied by their respective local communities on vegetation. Both areas have extensive stands of tapia (Uapaca bojeri) woodland.Methods: Herbaceous vegetation surveys were carried out enumerating 16 1-m² quadrats in each of 10 sites on Ibity and seven on Itremo to characterise plant community composition and structure, complemented by tree and shrub surveys within three 40 × 40 m quadrats at each site.Results: Floristic richness was higher at Ibity. Populations of U. bojeri were better conserved at Itremo.Conclusions: While the total exclusion of fire is impracticable, careful management should enable the maintenance of natural conditions and at least lead to a reduction in the impacts on the structure of tapia woodland vegetation.