Genomic consequences of geographic range expansion
How do changes in selective pressures resulting from expansion into range margins affect genomic variation? One of my current projects focuses on identifying loci under selection in populations of the nine-banded armadillo and assessing associations with environmental variation along a latitudinal gradient. We're generating molecular markers using a hybrid capture-RADSeq approach to tackle these questions.
Convergent evolution of range-expanding mammals
Convergent evolution can arise when organisms face similar ecological challenges. I'm interested in investigating convergence at the genomic level among warm-adapted mammals that are experiencing geographic range expansions into colder climatic regimes. This work will build on the armadillo project and incorporate other range-expanding mammals worldwide.
Species-specific traits and speciation
A major topic of ongoing interest involves the investigation of factors that promote differences in diversity among clades. In particular, an important problem is the contribution of species-specific traits to disparities among clades in rates of speciation and extinction. By incorporating digestive physiology in a model of speciation rate, I found that in the terrestrial, herbivorous mammals rates of speciation are higher in niche generalists than niche specialists. You can find the paper here.
Climatic stability and the structure and function of mammal assemblages
A related question is, how does the history of changes in climate explain the differences in diversity among clades that we see across the tree of life? We expect biodiversity to be low in regions that experienced historically high levels of climatic instability but high in climatically stable regions. One of my current projects assesses the structure and function of assemblages of terrestrial, herbivorous mammals in regions of low and high climatic instability during the Pleistocene.
Ecological opportunity and diversification
At a lower hierarchical level, what factors generate differences in diversity within clades? Using morphological and phylogenetic data, I found that the availability of new environments promoted the diversification of colobine monkeys in Asia and led to greater diversity in Asia than Africa. You can find the paper here.
Anthropogenic disturbance and genomic diversity
I'm also interested in the effects of human activities on the genetics of natural populations. We're working on a RADSeq data set of southwestern Ugandan populations of the black-and-white colobus monkey to disentangle the effects of habitat size and connectivity from habitat quality on genomic diversity.