Kyle G. Dexter
Curriculum Vitae
Postdoctoral Fellow
Centre National de la Recherche Scientifique
Laboratoire Evolution et Diversité Biologique Université Paul Sabatier, Toulouse, France
Post-doc Mentor: Jérôme Chave
Contact information
kgdexter at gmail.com
Laboratoire Evolution et Diversité Biologique Université Paul Sabatier UMR 5174, Bâtiment 4R3 118 Route de Narbonne 31062, Toulouse, France
+33 (0) 5.61.55.64.33

Post-doctoral Research Projects

1) Geographic Variation in DNA Barcodes

DNA barcoding in plants is still in its infancy. As we aim to arrive at a consensus for DNA barcoding markers, it is imperative to evaluate the performance of proposed markers. We are examining the ability of proposed markers to successfully delimit and identify tropical tree species across multiple sites in French Guiana.

2) Comparative Ecology of Inga Species in French Guiana and Peru

As part of my dissertation research, I quantified the niche of Inga species in Peru with respect to soil preference, canopy level, and regeneration strategy. Many of these Inga species are also found in French Guiana, but there, they experience a vastly different abiotic and biotic environment. Do these species occupy the same niche in French Guiana? Are they successfully maintaining gene flow across such vast geographic distances? What are the implications of the results for speciation in this hyper-diverse genus?

3) Functional Variation in Tree Species along a Climatic Gradient in French Guiana

There is a strong climatic gradient along the coast of French Guiana from the border with Brazil (3500-4000 mm/year precip) to the border with Suriname (2500-3000mm/year precip). Do functional traits vary across this climatic gradient? Do species restricted to one end of the gradient differ functionally from species restricted to the other end of the gradient? Do species which occur across the entire gradient demonstrate more phenotypic plasticity than species restricted to either end of the gradient? Climate change is expected to alter precipitation patterns in the tropics, and this data will help us predict the consequences for Amazonian tree communities.

Ongoing Research Projects

1) The Role of Dispersal in Structuring Tropical Tree Communities

I have documented patterns in the distribution and abundance of Inga species across the southern Peruvian Amazon. The neutral theory of S.P. Hubbell predicts certain levels of dispersal given patterns in the distribution and abundance of species. I use population genetic estimates of dispersal across many Inga species to determine if the observed dispersal rates are commensurate with that expected given neutral dynamics.

2) Phylogenetic Structure of Inga Communities and Evolution of Species' Niches
Using a species-level phylogeny of the genus Inga in southern Peru (~55 species), I am examining the phylogenetic structure of surveyed Inga communities. I am also examining which aspects of species' niches are phylogenetically conserved versus labile.

3) Accuracy of Tropical Tree Species Identification and the Impact of Errors on Ecological Studies

I used DNA sequence data to assess the accuracy of species indentifications in a conventional ecological study of Inga species in southern Peru. I first quantified errors rates. I then corrected bad identifications and assessed how the original results may have been affected by the bad identifications.

4) Long-term vegetation monitoring in Great Smoky Mountains National Park
Collaborator: Erin Tripp (Rancho Santa Anna Botanic Garden)
Climate change and other anthropogenic impacts upon plant communities are inevitable in the future. One important issue is how these communities will respond to changing environments. Through annual surveys of a plot in Great Smoky Mountains National Park (North Carolina, USA), we are documenting how plant communities are changing through time. We survey several levels of plant diversity (trees, saplings, herbs, and lichens) to determine if trends are correlated across species and how different plant groups may be impacting each other through time (e.g. if trees are leafing out earlier, will herbs respond in their phenological timing?). Note: for the purposes of the discussion here, lichens are referred to as plants.