Ph. D. defense of Mr Jean Didier T. Akpona, CEBioS collaborator in Benin

Thesis Jury

President of Jury: Prof. Dr. Ir. Jean Cossi GANGLO, Full Professor in Forestry, Université d’Abomey-Calavi

Members

• Prof. Dr. Ir. Kouami KOKOU, Full Professor in Ecology and Management of Natural resources Université de Lomé (Togo), Reporter
• Dr. Amadé OUEDRAOGO, Associate Professor, Université de Ouagadougou Joseph KIZERBO (Burkina Faso), Reporter
• Prof. Dr. Ir. Achille Ephrem ASSOGBADJO, Full Professor of Forestry and Ethnobotany, Université d’Abomey-Calavi (Bénin), Examiner
• Prof. Dr. Ir. Romain GLELE KAKAÏ, Full Professor of Biometry and Forestry, Université d’Abomey-Calavi (Bénin), Thesis Promotor

Abstract :

Even if several studies exist on the flora and vegetations in Africa, several woody species remain little or partially studied. However, most of these species are of high socioeconomic importance and there is a high relationship between their derived products and their uses by local communities. The Republic of Benin has three biogeographical zones characterized by three specific climatic conditions.

This study is a contribution to the sustainable management of woody plant species populations in Benin. It combines different approaches: ethnobotanical surveys, prioritization approach, ecology, geographical information system and germination to (i) assess the ethnobotanical knowledge and factors supporting the choice  of woody species, (ii) identify priority timber species, (iii) assess effects of habitat disturbance on Pterocarpus erinaceus populations, (iv) identify factors affecting P. erinaceus seeds germination and seedlings growth, and (v) evaluate the effect of soil types and age plantation on Khaya senegalensis growth in plantations. Findings showed that thirty three woody species were currently logged for diverse purposes (timber, firewood, charcoal, etc.) in Benin.

The Sudano-Guinean zone appears to hold the highest species-richness (27) in terms of logged trees species. Local populations perceived Isoberlinia doka, Isoberlinia tomentosa and Daniellia oliveri as most abundant woody species while Milicia excelsa, K. senegalensis and P. erinaceus as rare. The five priorities species for active conservation were K. senegalensis, Khaya grandifoliola, Afzelia africana, Milicia excelsa, and P. erinaceus. The highest germination for P. erinaceus seeds was recorded from the Sudanian zone, up to 45% on day 39 after sowing.

Structural parameters of P. erinaceus trees differed significantly (p < 0.05) across the three biogeographical zones. The scarcity of large individuals in all vegetation type comes from the overexploitation of the species. Moreover, many environmental variables could be used to predict dendrometric parameters of P. erinaceus. Sylvicultural management of native timber species is requiring for it long term productivity in plantations. Implications of the study for conservation and management were discussed and future research avenues were suggested.

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