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Daniel Pauly, biologist of fishings, were accomodated in residence by the IRD at the halieutic Research centre Mediterranean and Tropical of Sète during several months.
Many species manage to coexist in the same ecosystem. How do they do this and share the available resources? Since Darwin and his species theory 150 years ago, ecologists have been seeking to determine the factors favouring diversity in nature. In almost a century of research, the most strongly supported hypothesis has been the niche theory. This model postulates that a species occupies an ecological niche( 1)
of its own, to which it is well adapted. However, a second hypothesis, the neutral theory, with diametrically opposing principles, has come to the fore since the early 2000s. According to this the various species in the ecosystem have equivalent roles.
A population study on marine phytoplankton( 2), led IRD researchers and their partners( 3) to call this dichotomy into question. They put forward a new intermediary model, combining the two main theories, to explain biodiversity and, in the long term, help preserve it.
The cichlids are tropical freshwater fish well known to aquarists for their display of magnificent colours and the unparalleled diversity of species. Moreover, those of the East African Great Lakes (Malawi, Tanganyika and Victoria) are renowned among evolution researchers : they give an ...