Department Fish Ecology and Evolution

Fish Ecology & Evolution (FishEc)

We study ecology, evolution and biodiversity of fishes and other aquatic organisms. We are interested in the mechanisms that drive the origins, the maintenance and the loss of species, genetic and functional diversity.


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Joana Meier, Laurent Excoffier, Ole Seehausen and colleagues published a paper in Nature Communications. They shed light on how 700 diverse cichlid species could evolve in only 150,000 years in the Lake Victoria Region. By combining extensive taxon sampling and genomic analyses, they demonstrate that the entire “superflock” evolved from a hybrid swarm of two divergent cichlid lineages. The hybridization event facilitated the adaptive radiations by providing genetic variation that subsequently became recombined and sorted into many new species.

Original publication

Eawag News

Tim Alexander, Pascal Vonlanthen und Ole Sehhausen reviewed research on eutrophication of lakes and its effects on biodiversity as well as added new data, coming from Projet Lac, to this discussion. Eutrophication of lakes commonly results in reduced ecological specialization as well as genetic and phenotypic homogenization among lakes and among niches within lakes. Tim et al. argue that the associated loss in functional diversity and niche differentiation may lead to decreased carrying capacity and lower resource-use efficiency by consumers. This is an example of how evolutionary dynamics driven by anthropogenic environmental change can have lasting effects on biodiversity and ecosystem functioning.

Alexander,T.J.; Vonlanthen,P.; Seehausen,O. (2016) Does eutrophication-driven evolution change aquatic ecosystems?, Philosophical Transactions of The Royal Society B, 10 pp., doi:10.1098/rstb.2016.0041, Institutional Repository

Miguel Leal, Ole Seehausen and Blake Matthews published an opinion paper in TREE about the ecology and evolution of stoichiometric phenotypes. The stoichiometric or elemental phenotype is defined by the elemental composition, assimilation, allocation, or excretion of an individual, measured as its elemental content or ratios between elements. Miguel et al discuss how variation in the elemental phenotype among individuals can affect individual fitness variation and how the evolution of elemental phenotype can influence ecosystem processes. They make suggestions for a research program to address these questions. This research might improve our ability to predict how organisms adapt to changing environmental conditions and may contribute to our understanding of eco-evolutionary feedbacks.

Leal,M.C.; Seehausen,O.; Matthews,B. (2017) The ecology and evolution of stoichiometric phenotypes, Trends in Ecology and Evolution, 10 pp., doi:10.1016/j.tree.2016.11.006, Institutional Repository

Research Projects

We investigate the mechanisms of speciation and adaptive radiation
Genome evolution and genomic divergence across the Swiss Alpine whitefish radiation
Investigating the interactions between migration ecology, local adaptation and diversification