Reduced density due to logging and its consequences on mating system and pollen flow in the African mahogany Entandrophragma cylindricum

Lourmas Mathieu, Kjellberg Finn, Dessard Hélène, Joly Hélène, Chevallier Marie-Hélène. 2007. Reduced density due to logging and its consequences on mating system and pollen flow in the African mahogany Entandrophragma cylindricum. Heredity, 99 (2) : 151-160.

Résumé : In tropical forests, selective logging removes large trees that are often the main contributors to pollination. We studied pollination patterns of the African mahogany, Entandrophragma cylindricum (Sapelli). We investigated two plots in Cameroon corresponding to three tree densities: unlogged forest (Ndama 2002), a mildly logged forest 1 year after logging (Ndama 2003) and a severely logged forest 30 years after logging (Dimako). We used four microsatellite markers to perform paternity analysis. Selfing remained below 2% in all treatments. Pollen flow was mainly long distance but with some proximity effects. Average observed within-plot pollination distances were 338, 266 and 385 m, and pollination by trees outside the plots was 70% (Ndama 2002), 74% (Ndama 2003) and 66% (Dimako). Despite sampling a limited number of seeds from a limited number of mother trees, we obtained seeds sired by 35.6-38.3% of the potential within-plot pollen donors. While trees 20cm in diameter contributed to pollination, results in Dimako suggest that individual larger trees contribute more to pollination than small ones. This effect was not detected in the other treatments. The results suggest extensive pollen flow in Sapelli. Hence, in Sapelli, the main limiting factor for regeneration after logging may be a reduction in the number of trees capable of producing seeds rather genetic effects due to limits to pollen dispersal.

Mots-clés Agrovoc : Entandrophragma, forêt tropicale

Mots-clés géographiques Agrovoc : Cameroun

Mots-clés complémentaires : Entandrophragma cylindricum

Classification Agris : F63 - Physiologie végétale - Reproduction
F40 - Écologie végétale
K10 - Production forestière

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

• Lourmas Mathieu, CIRAD-FORET-UPR Dynamique forestière (FRA)
• Kjellberg Finn, CNRS (FRA)
• Dessard Hélène, CIRAD-FORET-UPR Dynamique forestière (FRA)
• Joly Hélène, CIRAD-FORET-UPR Ressources génétiques (FRA)
• Chevallier Marie-Hélène, CIRAD-FORET-UPR Dynamique forestière (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/542349/)

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