Environmental damage caused by human activity can reduce the number of plant and animal species dramatically. At the same time, only very little is known about how biodiversity recovers after the ecosystem has stopped being polluted and has been cleaned up. As was common in the mid-1900s, Lake Constance, one of the largest freshwater lakes in Europe, suffered from eutrophication, or nutrient contamination caused by agricultural and waste water run-off. A study by the universities in Konstanz and Glasgow (Scotland, UK) has now revealed that one European whitefish species expanded its genetic variation through hybridization with other whitefish species during the period of eutrophication. The study, led by the Konstanz-based biologist Dr Jasminca Behrmann Godel along with her colleague Dr Kathryn R. Elmer from the University of Glasgow, was published in the journal Nature Ecology and Evolution. This genetic mixture contributed to an expansion in biodiversity once the ecosystem recovered.
The diminished water quality in Lake Constance due to elevated nutrient contamination (eutrophication) destroyed the natural habitats and led to the extinction of two of the five whitefish species that had only existed in this lake as well as to the hybridization of the three remaining species. This had an impact on commercial fisheries in the lake. In the 1980s, concerted efforts to reduce eutrophication quickly re-established Lake Constance’s original state.
Read more at University of Konstanz
Image: These are European whitefish from Lake Constance. (Credit: Reiner Eckmann)