We study the ecological and genetic mechanisms by which life diversifies – diversification within a species, speciation, and large species radiations. We also study adaptive radiations in a community ecology context and we wish to understand how adaptation, speciation, and adaptive radiation affect species richness and ecosystem function. We also work on effects of environmental change on species assemblages built to variable extents through immigration and through speciation. Eventually, we would like to know why different evolutionary lineages vary so enormously in their diversity and in their responses to environmental change across scales of space and time.
Why are there tens or hundreds of species of cichlids in many large lakes in Africa, and more than 30 species of whitefish in subalpine lakes, when there is only one species of most other fish groups in these same lakes? How do these large radiations affect the large lake ecosystems and what are the causes and the consequences of mass extinctions? What are the roles of immigration and speciation in the assembly of fish communities, and how did recent climate history and even more recent anthropogenic perturbations affect these mechanisms?
Our approach to these questions is interdisciplinary. We use tools from experimental and field ecology, behavioral sciences, phenotype analysis, population genomics, phylogenomics, and bioinformatics. Our study systems are species radiations, such as the incredibly diverse cichlid fish in the great lakes of Africa, the whitefish, and char in archipelagos of deep subalpine and sub-polar lakes, the species, life history forms, and ecotypes of trout that used to dominate the alpine and subalpine river networks and the diversity of ecotypes and incipient species of stickleback.
Finally, we work towards providing scientific foundations for biodiversity conservation and habitat restoration, and scientifically sound methodology for mitigating biodiversity loss in rivers and lakes under climate change.