Chapter 1 Study site & sampling

1.1 Study site

The study was conducted in the Paracou field station, in the coastal forests of French Guiana, South America. The site is characterized by an average of 3,041 mm annual rainfall and a mean air temperature of 25.71 °C (Aguilos et al. 2018). Old tropical forest with an exceptional richness (i.e. over 750 woody species) grows across the succession of small hills of this area, which rise to 10–40 m a.s.l. (Gourlet-Fleury et al. 2004). The site comprises 16 permanent plots (fifteen 6.25 ha plus one 25 ha) which have been censused (DBH>10) every 1-2 years for more than 35 years. Nine of the plots were logged and subjected to human-induced disturbance in 1986 (details on the experiment in Hérault & Piponiot 2018).

1.2 Plant material

Four hundred and two individuals of Symphonia globulifera (Clusiaceae) were sampled in 2017 during the dry season (from September to December) in Paracou. Symphonia globulifera L.f (Clusiaceae) was previously recognized as composed of two morphotypes in French Guiana (Sabatier et al. 1997; Molino & Sabatier 2001; Baraloto et al. 2007). S. globulifera sensu stricto and Symphonia sp.1 occur in sympatry but in differentiated habitats, with S. globulifera preferentially growing in valley bottoms with an acquisitive functional strategy and S. sp1 preferentially exploiting a variety of drier habitats with a conservative functional strategy (Allié et al. 2015; Schmitt 2020, in prep; Schmitt et al. 2020). Symphonia have been highlighted as a species complex with low (phylo-)genetic species resolution and high levels of plastid DNA sharing among sister species (Baraloto et al. 2012; Gonzalez et al. 2009; Torroba-Balmori et al. 2017; Caron et al. 2019). In addition, outgroups for genetic analysis in Symphonia were comprised of 13 individuals of Symphonia globulifera from Africa (Sao Tome, Gabon, Cameroon, Congo, Benin, Liberia, Ivory Coast, and Ghana), seven Symphonia globulifera from South America (Brazil, Costa Rica and Panama), two Symphonia nectarifera Jum. & H. Perrier from Madagascar, two Symphonia urophylla (Decne. ex Planch. & Triana) Benth. & Hook.f. ex Vesque from Madagascar, five Pentadesma butyracea Sabine from Benin and Cameroon and one Pentadesma grandifolia Baker f. from Cameroon. Leaves were collected from the 432 individuals (402 + 30 outgroups) and dessicated using silica gel.

References

Aguilos, M., Stahl, C., Burban, B., Hérault, B., Courtois, E., Coste, S., Wagner, F., Ziegler, C., Takagi, K. & Bonal, D. (2018). Interannual and Seasonal Variations in Ecosystem Transpiration and Water Use Efficiency in a Tropical Rainforest. Forests, 10, 14. Retrieved from http://www.mdpi.com/1999-4907/10/1/14

Allié, E., Pélissier, R., Engel, J., Petronelli, P., Freycon, V., Deblauwe, V., Soucémarianadin, L., Weigel, J. & Baraloto, C. (2015). Pervasive local-scale tree-soil habitat association in a tropical forest community. PLoS ONE, 10, 1–16.

Baraloto, C., Hardy, O.J., Paine, C.E.T., Dexter, K.G., Cruaud, C., Dunning, L.T., Gonzalez, M.-A., Molino, J.-F., Sabatier, D., Savolainen, V. & Chave, J. (2012). Using functional traits and phylogenetic trees to examine the assembly of tropical tree communities. Journal of Ecology, 100, 690–701. Retrieved from http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2745.2012.01966.x/abstract

Baraloto, C., Morneau, F., Bonal, D., Blanc, L. & Ferry, B. (2007). Seasonal water stress tolerance and habitat associations within four Neotropical tree genera. Ecology, 88, 478–489.

Caron, H., Molino, J., Sabatier, D., Léger, P., Chaumeil, P., Scotti-Saintagne, C., Frigério, J., Scotti, I., Franc, A. & Petit, R.J. (2019). Chloroplast DNA variation in a hyperdiverse tropical tree community. Ecology and Evolution, 9, ece3.5096. Retrieved from https://onlinelibrary.wiley.com/doi/abs/10.1002/ece3.5096

Gonzalez, M.A., Baraloto, C., Engel, J., Mori, S.A., Pétronelli, P., Riéra, B., Roger, A., Thébaud, C. & Chave, J. (2009). Identification of amazonian trees with DNA barcodes. PLoS ONE, 4, e7483. Retrieved from http://dx.plos.org/10.1371/journal.pone.0007483

Gourlet-Fleury, S., Guehl, J.-M. & Laroussine, O. (2004). Ecology and management of a neotropical rainforest : lessons drawn from Paracou, a long-term experimental research site in French Guiana Ecology and management of a neotropical rainforest : lessons drawn from Paracou, a long-term experimental research sit. Paris: Elsevier. Retrieved from http://agritrop.cirad.fr/522004/

Hérault, B. & Piponiot, C. (2018). Key drivers of ecosystem recovery after disturbance in a neotropical forest. Forest Ecosystems, 5, 2. Retrieved from https://forestecosyst.springeropen.com/articles/10.1186/s40663-017-0126-7

Molino, J.-F. & Sabatier, D. (2001). Tree Diversity in Tropical Rain Forests: A Validation of the Intermediate Disturbance Hypothesis. Science, 294, 1702–1704. Retrieved from http://science.sciencemag.org/content/294/5547/1702 http://www.sciencemag.org/cgi/doi/10.1126/science.1060284

Sabatier, D., Grimaldi, M., Prévost, M.F., Guillaume, J., Godron, M., Dosso, M. & Curmi, P. (1997). The influence of soil cover organization on the floristic and structural heterogeneity of a Guianan rain forest. Plant Ecology, 131, 81–108.

Schmitt, S. (2020). Génomique écologique de l’exploitation de niche et de la performance individuelle chez les arbres forestiers tropicaux. PhD thesis, University of Bordeaux. Retrieved from https://phdthesissylvainschmitt.netlify.app/

Schmitt, S., Hérault, B., Ducouret, É., Baranger, A., Tysklind, N., Heuertz, M., Marcon, É., Cazal, S.O. & Derroire, G. (2020). Topography consistently drives intra- and inter-specific leaf trait variation within tree species complexes in a Neotropical forest. Oikos, 129, 1521–1530. Retrieved from https://onlinelibrary.wiley.com/doi/abs/10.1111/oik.07488 https://onlinelibrary.wiley.com/doi/10.1111/oik.07488

Torroba-Balmori, P., Budde, K.B., Heer, K., González-Martínez, S.C., Olsson, S., Scotti-Saintagne, C., Casalis, M., Sonké, B., Dick, C.W. & Heuertz, M. (2017). Altitudinal gradients, biogeographic history and microhabitat adaptation affect fine-scale spatial genetic structure in African and Neotropical populations of an ancient tropical tree species. PLOS ONE, 12, e0182515. Retrieved from http://dx.plos.org/10.1371/journal.pone.0182515