References of "Bourland, Nils"
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See detailLe mythe des forêts intactes - Etat des lieux
Bourland, Nils ULg; Federspiel, Michèle; Philippart, Julien ULg et al

Conference (2011, September)

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See detailA new methodological approach to try to link past disturbances and modern landscapes
Bourland, Nils ULg; Livingstone Smith, Alexandre; Doucet, Jean-Louis ULg

in Primate Tidings (2011, July), 24

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See detailDevelopment and characterization of microsatellite loci in Pericopsis elata (Fabaceae) using a cost-efficient approach
Micheneau, Claire; Dauby, Gilles; Bourland, Nils ULg et al

in American Journal of Botany (2011)

Premise of the study : Microsatellite loci were developed in the endangered Pericopsis elata using a combination of low-cost procedures. Methods and Results : Microsatellite isolation was performed ... [more ▼]

Premise of the study : Microsatellite loci were developed in the endangered Pericopsis elata using a combination of low-cost procedures. Methods and Results : Microsatellite isolation was performed simultaneously on three distinct species through a newly available procedure that associates multiplex microsatellite enrichment and next-generation sequencing, allowing the rapid and low-cost development of microsatellite-enriched libraries through the use of a 1/32nd GS-FLX plate. Genotyping using M13-like label- ing in multiplexed reactions allowed additional cost savings. From 72 primers selected for initial screening, 21 positively amplified P. elata , and 11 showed polymorphism with two to 11 alleles per locus and a mean value of 5.4 alleles per locus. Conclusions : These microsatellite loci will be useful to further investigate the level of genetic variation within and between natural populations of P. elata in Africa. [less ▲]

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See detailSpatial aggregation of tropical trees at multiple spatial scales
Réjou-Méchain, Maxime; Flores, Olivier; Bourland, Nils ULg et al

in Journal of Ecology (2011), 99

1. In tropical forests, species distribution patterns may be strongly context-dependent owing to local stochasticity of recruitment and⁄ or to the specific history and environment of each site. Recent ... [more ▼]

1. In tropical forests, species distribution patterns may be strongly context-dependent owing to local stochasticity of recruitment and⁄ or to the specific history and environment of each site. Recent studies have reported, however, that the degree of spatial aggregation of tropical tree species is partly determined by some species traits irrespectively of site conditions, at least at a very local scale (<200 m). 2. Here, we used standardized large-scale forest inventories of five Central African tropical forests (9670 0.5-ha plots spread over 5550 km2) to quantify the spatial aggregation of 106 tropical tree species at larger spatial scales. For this purpose, we developed a new statistic to quantify the respective contributions of different spatial scales to the aggregation patterns, and we tested whether patterns were consistent across sites. We finally asked whether species characteristics related to dispersal ability, to response to disturbances and to biogeographical range could significantly explain aggregation patterns. 3. Although aggregation patterns varied substantially among sites within each species, they displayed inter-site consistencies (21–24%of the total variance explained by species identity) at the local scale (0.2–1 km) and at the mesoscale (1–10 km) but not at the landscape scale (>10 km). At the two former scales, upper taxonomical levels (family and⁄or order) significantly explained variation in the degree of species aggregation, while at the landscape scale, aggregation was entirely contingent on the site considered. Few species characteristics, except dispersal syndromes and wood density, were able to significantly explain aggregation patterns. 4. Synthesis. One of our most striking results is the high context dependence of species aggregation patterns, whatever the spatial scale considered. However, we showed that species distribution patterns can be predicted, to an extent, at spatial scales much larger than previously investigated in this context. Such patterns may be explained by traits displaying phylogenetic conservatism [less ▲]

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See detailPericopsis elata (Harms) Meeuwen in southeastern Cameroon: ecological and pedological approaches to improve the management of an endangered commercial timber species
Bourland, Nils ULg; Kouadio, Yao Lambert; Colinet, Gilles ULg et al

in International Forestry Review (2010), 12(5), 111

Pericopsis elata (gregarious Fabaceae), a moist semi-deciduous hardwood logged in Central African forests, is on the IUCN Red List and in CITES Appendix II. Our study evaluated its main ecological and ... [more ▼]

Pericopsis elata (gregarious Fabaceae), a moist semi-deciduous hardwood logged in Central African forests, is on the IUCN Red List and in CITES Appendix II. Our study evaluated its main ecological and pedological parameters in Cameroon. We obtained a mean diameter increment of 0.32 ± 0.04 cm.year–1. Minimum fertile and effective fruiting diameters were 32 and 35 cm, respectively. Flowering started in March-April, and fruits ripened over 7 months. Seed rain was studied in 1 × 45 m cleared corridors in each cardinal direction around 4 isolated mother trees. Indehiscent pods (average weight: 131.6 ± 10.1 cg) were dispersed mainly to the west: 86% of the variation of the number of collected fruits could be explained by the distance to the mother tree and the direction (GLM analysis, p < 0.001). The proportion of seeds eaten by insect larvae depended on the mother tree (10–95% – χ2 test, p < 0.001). Soils were compared at a regional scale: soils with P. elata contain higher levels of C (2.2 ± 0.5 SD- g.100g–1), Fe (261 ± 83 mg.kg–1), and P (33 ± 10 mg.kg–1), and were more acidic (pH 4.0 ± 0.2). A planting method in logging gaps is currently being tested taking into account physicochemical soil parameters [less ▲]

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See detailCpDNA-based species identification and phylogeography: application to African tropical tree species
Duminil, Jérôme; Heuertz, Myriam; Doucet, Jean-Louis ULg et al

in Molecular Ecology (2010), 19(24), 5469-5483

Despite the importance of the African tropical rainforests as a hotspot of biodiversity, their history and the processes that have structured their biodiversity are understood poorly. With respect to past ... [more ▼]

Despite the importance of the African tropical rainforests as a hotspot of biodiversity, their history and the processes that have structured their biodiversity are understood poorly. With respect to past demographic processes, new insights can be gained through characterizing the distribution of genetic diversity. However, few studies of this type have been conducted in Central Africa, where the identification of species in the field can be difficult. We examine here the distribution of chloroplast DNA (cpDNA) diversity in Lower Guinea in two tree species that are difficult to distinguish, Erythrophleum ivorense and Erythrophleum suaveolens (Fabaceae). By using a blind-sampling approach and comparing molecular and morphological markers, we first identified retrospectively all sampled individuals and determined the limits of the distribution of each species. We then performed a phylogeographic study using the same genetic data set. The two species displayed essentially parapatric distributions that were correlated well with the rainfall gradient, which indicated different ecological requirements. In addition, a phylogeographic structure was found for E. suaveolens and, for both species, substantially higher levels of diversity and allelic endemism were observed in the south (Gabon) than in the north (Cameroon) of the Lower Guinea region. This finding indicated different histories of population demographics for the two species, which might reflect different responses to Quaternary climate changes. We suggest that a recent period of forest perturbation, which might have been caused by humans, favoured the spread of these two species and that their poor recruitment at present results from natural succession in their forest formations. [less ▲]

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See detailEtude de l'écologie de Pericopsis elata (afrormosia) au sud-est du Cameroun
Bourland, Nils ULg; Doucet, Jean-Louis ULg

Scientific conference (2009, June 03)

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See detailPeut-on expliquer les patrons d’agrégation spécifiques d’arbres tropicaux à partir de leurs traits ? Une analyse de l’échelle locale à l’échelle régionale.
Rejou-Mechain, Maxime; Bourland, Nils ULg; Flores, O. et al

in Laboratoire d'Ecologie de la FUSAGx (Ed.) ECOVEG 5 - Cinquième colloque d'écologie des communautés végétales (2009, April 08)

Les processus qui génèrent la répartition spatiale des arbres tropicaux ont fait l’objet de nombreuses études. Trois processus semblent déterminants pour la répartition des végétaux : la dispersion ... [more ▼]

Les processus qui génèrent la répartition spatiale des arbres tropicaux ont fait l’objet de nombreuses études. Trois processus semblent déterminants pour la répartition des végétaux : la dispersion limitée, l’histoire de la zone (perturbations anthropiques et histoire climatique) et la différenciation de niche. Leur importance relative est aujourd’hui largement débattue et dépend certainement de l’échelle spatiale considérée. Dans cette étude notre objectif général est de comprendre quels sont les principaux mécanismes qui génèrent les patrons spatiaux des espèces et à quelles échelles ils interviennent. Les données traitées proviennent d’inventaires botaniques réalisés à grande échelle (460000 ha) par des sociétés forestières, en Afrique Centrale (Cameroun et République Centrafricaine). Des mesures d’agrégation spatiale sont réalisées sur 121 espèces d’arbre (individus > à 30 cm de diamètre), dans 4 sites différents et à 3 échelles spatiales : l’échelle locale (0-1 km), l’échelle intermédiaire (1-10 km) et l’échelle du paysage (> à 10 km). Nous testons la relation entre l’agrégation spatiale spécifique et une série de caractéristiques propres aux espèces : le type de diaspore, la tolérance à l’ombre, le type biologique, le système de reproduction et le type phytogéographique. Nos résultats montrent que les patrons d’agrégation spécifiques sont cohérents à travers les sites, jusqu’à l’échelle intermédiaire, mais que les caractéristiques propres aux espèces permettent peu de les prédire. La variation de l’agrégation entre sites pour une même espèce est toutefois très importante et suggère que les patrons d’agrégation observés sont en grande partie dépendants des sites et de leur histoire. Nos résultats suggèrent que les patrons spatiaux spécifiques sont liés à une dispersion limitée à une échelle très locale alors que les patterns observés à des échelles supérieures sont principalement dus à l’histoire des sites et dans certains cas à une forte hétérogénéité environnementale. [less ▲]

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