Institute Of Recherches Agronomiques Et Forestieres Iraf

Libreville, Gabon

Institute Of Recherches Agronomiques Et Forestieres Iraf

Libreville, Gabon
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Duminil J.,Bioversity International | Duminil J.,Roosevelt University | Duminil J.,CIRAD - Agricultural Research for Development | Mendene Abessolo D.T.,Bioversity International | And 5 more authors.
Forest Ecology and Management | Year: 2016

Mating system and gene flow are major influencing factors of species population dynamics and evolution. These factors are often not characterized in tropical tree species, yet they constitute basic information that must be considered to implement sustainable management practices. In particular, as logging implies a reduction of the density of congeneric mates, the connectivity through pollination between individuals has to be well characterized (selfing versus outcrossing rates, distances between mates). We conducted a genetic-based analysis (using 10 nuclear microsatellites) to determine the mating system and gene flow characteristics of an emblematic timber tree species from lowland rain forests of the Congo Basin, Baillonella toxisperma (Sapotaceae). The species, which is frequently exploited for its wood and for a number of non-timber forest products, naturally occurs at low densities (ca. 0.01–0.1 individuals/ha). It is supposedly an entomophilous species whose seeds are probably dispersed by mammals. We have shown that the species presents a mixed-mating system (about 20–40% of selfing depending on analysis method). However, the comparison of inbreeding parameters among cohorts suggests that inbred individuals die between seedling and mature tree stages. The mean pollen dispersal distance was relatively low for such a low-density population species (estimated to be 690 or 777 m depending on analysis method) and, together with a low mean number of pollen donors (NEP = 2.76), it suggests a pattern of nearest-neighbour mating where allo-pollen could be a limiting factor. However, B. toxisperma presents a relatively weak genetic structure (Sp statistic = 0.0095) indicative of long gene dispersal distance (σg = 3–5 km according to the assumed effective population density). Overall, this would indicate that gene flow occurs mainly by extensive seed dispersal in this species. These results suggest that mammals and local populations involved in the dispersal of the species play a key role by lowering biparental inbreeding effects. Sustainable population management might require assisted regeneration using unrelated planting material. © 2016 The Author(s)

Bartolozzi L.,University of Florence | Loudit S.M.B.,Institute Of Recherches Agronomiques Et Forestieres Iraf
Zootaxa | Year: 2011

The genus Myrmecobrenthus Kleine, 1920 is revised and a key for the species of this genus is provided. Myrmecobrenthus susinii sp. nov. is described from Gabon, and compared with the closely related M. ater Damoiseau, 1961 and M. wasmanni Kleine, 1920, from which it mainly differs in the shape of the male head and rostrum. Myrmecobrentus wasmanni is recorded for the first time from Gabon. Copyright © 2011 · Magnolia Press.

Ndiade-Bourobou D.,Institute Of Recherches Agronomiques Et Forestieres Iraf | Hardy O.J.,Roosevelt University | Favreau B.,CIRAD - Agricultural Research for Development | Moussavou H.,Institute Of Recherches Agronomiques Et Forestieres Iraf | And 3 more authors.
Molecular Ecology | Year: 2010

We analysed the spatial distribution of genetic diversity to infer gene flow for Baillonella toxisperma Pierre (Moabi), a threatened entomophilous pollinated and animal-dispersed Central African tree, with typically low density (5-7 adults trees/km2). Fifteen nuclear and three universal chloroplast microsatellites markers were used to type 247 individuals localized in three contiguous areas with differing past logging intensity. These three areas were within a natural forest block of approximately 2886km2 in Gabon. Expected heterozygosity and chloroplast diversity were He nuc=0.570 and Hcp=0.761, respectively. FIS was only significant in one area (FIS=0.076, P<0.01) and could be attributed to selfing. For nuclear loci, Bayesian clustering did not detect discrete gene pools within and between the three areas and global differentiation (FSTnuc=0.007, P>0.05) was not significant, suggesting that they are one population. At the level of the whole forest, both nuclear and chloroplast markers revealed a weak correlation between genetic relatedness and spatial distance between individuals: Spnuc=0.003 and Spcp=0.015, respectively. The extent of gene flow (σ) was partitioned into global gene flow (σg) from 6.6 to 9.9km, seed dispersal (σs) from 4.0 to 6.3km and pollen dispersal (σp) from 9.8 to 10.8km. These uncommonly high dispersal distances indicate that low-density canopy trees in African rainforests could be connected by extensive gene flow, although, given the current threats facing many seed disperser species in Central Africa, this may no longer be the case. © 2010 Blackwell Publishing Ltd.

Anguilet E.C.F.,University of Liège | Anguilet E.C.F.,Institute Of Recherches Agronomiques Et Forestieres Iraf | Nguyen B.K.,University of Liège | Ndong T.B.,Institute Of Recherches Agronomiques Et Forestieres Iraf | And 2 more authors.
Biotechnology, Agronomy and Society and Environment | Year: 2015

Introduction. Meliponini and Apini contribute to the pollination of flowering plants and to improving agricultural yields. These bees’ diversity, distribution and abundance depend on the ecosystem in which they evolve. The present work aims to summarize the diversity, distribution, abundance, potential threats, challenges and issues faced with respect to these social bees in Africa. Literature. In Africa, there were 21 species of Meliponini and 2 species of Apini (Apis). Aspects related to the species diversity, distribution, biology, ecology and abundance of nests are poorly documented, especially for Meliponini. This deficit could be related to a lack of interest of the authors or the various difficulties in performing these studies in Africa. With regard to the difficulties, there is a need to clarify the taxonomy of Meliponini, and the observation of nests in certain forest environments is difficult. Nest predation and habitat loss are the main threats that could cause the depopulation of certain social bee species in Africa. If there is currently new evidence that diseases and pests did not endanger these bees, then there is a need for further studies for better assessment of the risks that are associated with these potential threats. Conclusions. Work on the diversity, distribution and abundance of the social bees must be strengthened to address the challenges that are related to these insects in Africa. Indeed, this approach will contribute to answering the challenges of sustainable management of the biodiversity and economic and agricultural issues. © 2015, FAC UNIV SCIENCES AGRONOMIQUES GEMBLOUX .All Rights Reserved.

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