title: Relationships between population density, fine-scale genetic structure, mating system and pollen dispersal in a timber tree from African rainforests.
abstract: Owing to the reduction of population density and/or the environmental changes it induces, selective logging could affect the demography, reproductive biology and evolutionary potential of forest trees. This is particularly relevant in tropical forests where natural population densities can be low and isolated trees may be subject to outcross pollen limitation and/or produce low-quality selfed seeds that exhibit inbreeding depression. Comparing reproductive biology processes and genetic diversity of populations at different densities can provide indirect evidence of the potential impacts of logging. Here, we analysed patterns of genetic diversity, mating system and gene flow in three Central African populations of the self-compatible legume timber species Erythrophleum suaveolens with contrasting densities (0.11, 0.68 and 1.72 adults per ha). The comparison of inbreeding levels among cohorts suggests that selfing is detrimental as inbred individuals are eliminated between seedling and adult stages. Levels of genetic diversity, selfing rates (∼16%) and patterns of spatial genetic structure (Sp ∼0.006) were similar in all three populations. However, the extent of gene dispersal differed markedly among populations: the average distance of pollen dispersal increased with decreasing density (from 200 m in the high-density population to 1000 m in the low-density one). Overall, our results suggest that the reproductive biology and genetic diversity of the species are not affected by current logging practices. However, further investigations need to be conducted in low-density populations to evaluate (1) whether pollen limitation may reduce seed production and (2) the regeneration potential of the species.
authors.affiliation: Bioversity International, Forest Genetic Resources Programme, Sub-Regional Office for Central Africa, Yaoundé, Cameroon.|Service Evolution Biologique et Ecologie, Faculté des Sciences, Université Libre de Bruxelles, Brussels, Belgium.|Département BIOSE, Gestion des Ressources forestières, Foresterie Tropicale, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Duminil
authors.affiliation: Service Evolution Biologique et Ecologie, Faculté des Sciences, Université Libre de Bruxelles, Brussels, Belgium.|Département BIOSE, Gestion des Ressources forestières, Foresterie Tropicale, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium.|Nature+ asbl, Wavre, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Daïnou
authors.affiliation: Bioversity International, Forest Genetic Resources Programme, Sub-Regional Office for Central Africa, Yaoundé, Cameroon.|Laboratoire de Génétique, Amélioration des Plantes et Biotechnologie, Faculté des Sciences, Université de Kisangani, Kisangani, Democratic Republic of Congo.
authors.forename: D K
authors.initials: DK
authors.lastname: Kaviriri
authors.affiliation: Service Evolution Biologique et Ecologie, Faculté des Sciences, Université Libre de Bruxelles, Brussels, Belgium.|Département BIOSE, Gestion des Ressources forestières, Foresterie Tropicale, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Gillet
authors.affiliation: Bioversity International, Headquarters, Via dei Tre Denari, Maccarese (Fiumicino), Rome, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Loo
authors.affiliation: Département BIOSE, Gestion des Ressources forestières, Foresterie Tropicale, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium.
authors.forename: J-L
authors.initials: JL
authors.lastname: Doucet
authors.affiliation: Service Evolution Biologique et Ecologie, Faculté des Sciences, Université Libre de Bruxelles, Brussels, Belgium.
authors.forename: O J
authors.initials: OJ
authors.lastname: Hardy
mesh_terms: D000349:Africa; D007887:Fabaceae / Q000235:genetics*; D016468:Forestry; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D007178:Inbreeding; D008957:Models, Genetic; D054817:Pollination; D011156:Population Density; D065947:Rainforest; D014197:Trees / Q000235:genetics*