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Post-doctoral researcher

phone: +32 (0)2 650 45 14

e-mail: gdauby@ulb.ac.be










Post-doctoral project



My project aims at testing the relative importance of ecological gradients and historical contingency for explaining the actual distribution of species and of genetic lineages within species, using Central African forest trees as a study model. Integrating the intra-specific and inter-specific levels, it will be implemented through original data analyses and modeling works establishing the links between patterns and processes with the following specific objectives:


Goal 1. Test the spatial congruence between gene pools and areas of endemism of tree species in Central African forests using niche modelling tools.

Goal 2. Evaluate to what extent niche modelling methods based on environmental correlates can correctly infer environmental constraints in the distribution of species/lineages using coalescent-based simulations.

Goal 3. Characterize the phylogenetic structure within and among communities in Central African forests and evaluate the spatial congruence with the within-species level of organization and the environmental gradients.

Goal 4. Evaluate the ability of various metrics of phylogenetic structure for inferring processes from patterns using an individual-based spatially explicit community model.




Thesis



Structuration spatiale de la diversité intra- et interspecifique en Afrique centrale

Supervisors: O. Hardy and T. Stévart


The relative importance of historical, stochastic and deterministic factors on the spatial structure of species diversity (SSDS) in the central African forests has been highly debated. The SSDS is moreover still not well characterized, particularly the spatial variation of community composition (beta diversity).

One hypothesis often evoked regarding the origin of the centres of diversity and endemism is historical: these centres could have been forest refuges during dry climatic periods of the Quaternary. However, the high level of environmental heterogeneity in these regions could equally explain the SSDS.

The main goal of my thesis was to weight the relative importance of these factors. If historical factors are determinants, a spatial congruence between the SSDS and the spatial structure of within-species diversity (SSDG) should be observed. The variability of neutral genetic structure within species is indeed largely controlled by processes that affect equally the SSDS (genetic/ecological drift and gene flow/species dispersal). The approach used was therefore to compare and evaluate the spatial congruence between the SSDS and the SSDG.

The biological model and the geographical frame of this study were communities and populations of tree species within moist Atlantic Central African forests, with a special focus on Gabonese forests. The SSDS was studied on the basis of standardized inventories of tree communities (16.308 individuals) whereas the SSDG was characterized on the basis of chloroplastic DNA sequences of six tree species (Greenwayodendron suaveolens, Scorodophloeus zenkeri, Afrostyrax lepidophyllus, Afrostyrax kamerunensis, Santiria trimera and Erythrophleum suaveolens).

Four specific aims had been defined: (i) Develop a methodological framework allowing the estimation of the SSDS and evaluate its statistical performance when the diversity is estimated by community samples; (ii) Quantify the SSDS and evaluate the impact of environmental gradients; (iii) Test the spatial congruence of SSDG among the six tree species; and (iv) Evaluate the spatial concordance between SSDS and SSDG.




Publications



Dauby G, Hardy OJ (2012) Sampled-based estimation of diversity sensu stricto by transforming Hurlbert diversities into Effective Number of Species. Ecography 35, 661-672.

Piñeiro R, Micheneau C, Dauby G, Hardy OJ (2012) Isolation of nuclear microsatellite loci in the African tree Scorodophloeus zenkeri (Fabaceae). Conservation Genetics Resources, 5, 219-221.

Sosef M, Dauby G (2012) Contribution to the taxonomy of Garcinia (Clusiaceae) in Africa, including two new species from Gabon and a key to the Lower Guinean species. PhytoKeys 17, 41-62.

Sosef M, Dauby G (2012) Flore du Gabon (Clusiaceae).

Micheneau C, Dauby G, Bourland N, Doucet J-L, Hardy OJ (2011) Development and characterization of microsatellite loci in Pericopsis elata (Fabaceae) using a cost-efficient approach. American Journal of Botany 98, 268-270.

Parmentier I, Harrigan RJ, Buermann W, et al. (2011) Predicting alpha diversity of African rain forests: models based on climate and satellite-derived data do not perform better than a purely spatial model. Journal of Biogeography 38, 1164-1176.

Walters G, Dauby G, Stévart T, Dessein S, Niangadouma R, Lachenaud O (2011) Novitates gabonenses 80. Additions and corrections to the flore of Gabon. Edinburgh Journal of Botany, 68, 1-20.

Dauby G, Duminil J, Heuertz M, Hardy OJ (2010) Chloroplast DNA polymorphism and phylogeography of a Central African tree species widespread in mature rainforests: Greenwayodendron suaveolens (Annonaceae). Tropical Plant Biology 3, 4-13.

Dauby G, Leal M, Stevart T (2008) Vascular plant checklist of the coastal National Park of Pongara, Gabon. Systematics and Geography of Plants 78, 155-216.

Dauby G, Parmentier I, Stevart T (2007) Afrothismia gabonensis sp nov (Burmanniaceae) from Gabon. Nordic Journal of Botany 25, 268-271.









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  1. Gilles Dauby

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