ANALYSE DE LA DIVERSITE ET DE LA STRUCTURE DEMOGRAPHIQUE DES PEUPLEMENTS DE ANNONA SENEGALENSIS AU CENTRE-SUD DU NIGER

Annonasenegalensis Pers. is a woody species characteristic of Sudano-Sahelian ecosystems and of considerable importance to rural populations in Niger. This study assessed floristic diversity, biological and phytogeographical types, and the demographic structure of stands associated with A. senegalensis in the Maradi and Zinder regions. Data were collected in 2023 and 2024 in 14 villages using 142 plots of 2,500 m2. Regeneration was assessed in 25 m2 subplots. Shannon, Pielou and Sorensen indices, the Importance Value Index (IVI), and diameter- and height-class distributions fitted to the Weibull distribution were used. The inventories recorded 26 woody species belonging to 14 families in Maradi and 38 species belonging to 18 families in Zinder. The biological and phytogeographical spectra, established for 34 species, were dominated by microphanerophytes (55.9%) and nanophanerophytes (35.3%), and by Sudano-Zambezian species (55.9%), respectively. Annonasenegalensis was classified as a Sudano Zambesiannanophanerophyte. Shannon diversity was 2.33 in Maradi and 2.67 in Zinder, with Pielou evenness values of 0.74 and 0.76, respectively.