The older and more stable an ecosystem is, the more perseverant the species living there and the more stable the species communities. An international team of researchers led by the Justus Liebig University of Giessen and the University of Cologne gained these new insights into evolution by means of deep drilling in Lake Ohrid. The study has been published in ‘Science Advances’. The 1.4-million-year-old lake on the border between Albania and Northern Macedonia is not only the oldest lake in Europe, but with more than 300 endemic species that are only found there, it is also the continent’s lake most rich in species.
In order to study the evolutionary events since the formation of the lake, the scientists combined the environmental and climate data of a 568-meter-long sediment core with the fossil records of over 150 endemic diatom species contained in it. This revealed that shortly after the formation of the lake, new species emerged within a few thousand years. However, many of them died out very quickly in the then relatively small and shallow lake. The research team explains this by the fact that young, small lakes offer many new ecological opportunities, but also react particularly sensitively to environmental influences such as fluctuations in temperature, water level, and nutrients.
After the lake became deeper and larger, the species formation and extinction processes slowed down dramatically. The research team attributes this to the fact that fewer new habitats were created, the species richness approached an ecological capacity limit, and the lake was able to better cushion the environmental influences. The finding that during the development of Lake Ohrid, a dynamic accumulation of short-lived species is transformed into a stable community of long-lived species provides a new understanding of the evolutionary dynamics in ecosystems.
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Publication:
https://advances.sciencemag.org/content/6/40/eabb2943