Fishes are the most diverse group of vertebrates, are key players in aquatic ecosystems, provide a diverse set of ecosystem services, and are sensitive to environmental change. We study their ecology, evolution and conservation. We work with fish diversity from traits and genes in populations to the diversity of species assemblages, their change through time and the ecosystem consequences. We are particularly interested in understanding the evolution of endemic diversity within individual ecosystems, such as the radiations of cichlid fish in African lakes and the radiation of whitefish in the lakes around the European Alps. We are a single research group led by Ole Seehausen at the University of Bern but Ole also leads the Department Fish Ecology and Evolution at the Eawag Center for Ecology, Evolution and Biogeochemistry, Kastanienbaum, where we currently host four other research groups that are all associated with the IEE too. The work of the Eawag department is motivated by the aim to contribute to the emerging synthesis between evolutionary biology and ecosystems ecology. There we also host the Swiss Fisheries Advisory Service. Researchers in the department of vertebrates at the Natural History Museum Bern, NMBE, are also affiliated with our University division.
NatureComm - The coincidence of ecological opportunity with hybridization explains rapid adaptive radiation in Lake Mweru cichlid fishes
Joana, Ole and colleagues published a paper in Nature Communications in which they ask what is more conducive to adaptive radiation into new ecological niches: isolation from related lineages (reduced competition), or contact between related lineages with hybridization generating genetic variation? They did this by studying several cichlid species radiations that had hitherto remained unknown. The greater biotic isolation in Lake Bangweulu would predict fewer constraints by competition yet no lineage had radiated in that lake. In nearby Lake Mweru, where related lineages from different river systems met and hybridized, all hybridizing lineages radiated. The authors conclude that in this system, large amounts of genetic variation generated by hybridization, may have been more important for adaptive radiation than reduced competition.