Toward a Benthic Functional Diversity Approach of the English Channel Coarse Sediments
Résumé
The English Channel is one of the most anthropized marine ecosystems in the world. It is
exposed to both multiple anthropogenic activities (development of renewable marine energies,
aggregate extraction, dredging and trawling) and natural disturbances (e.g. strong
hydrodynamics, extreme events). These pressures occur in a context of climate change and
modify the structure of benthic communities. One of the particularities of the English Channel
is that it is composed of more than 80% coarse sediments.
Traditionally, these habitats have been mainly described using semi-quantitative tools and,
more recently, studied from quantitative data to evaluate the functional response of these
ecosystems to natural and anthropogenic disturbances. These data coupled with the analysis of
biological traits of benthic macrofauna, will allow to better understand ecosystem functioning
by linking abiotic parameters, community structure and traits distribution.
The two main objectives of this PhD thesis are: (1) acquire a better knowledge of coarse
sediments of the Channel in a highly hydrodynamic environment; (2) couple traditional ecology
studies (species diversity, abundances and biomasses) with functional diversity calculated from
biological traits of species.
All the analyses will be based on the exploitation of different data sets describing the evolution
of the diversity of coarse benthic communities exposed to various pressures.
Thus, this PhD thesis will provide a better understanding of the spatio-temporal organization of
the functional diversity of the benthic macrofauna in the eastern English Channel. It will also
provide a better understanding of the response of coarse sediment ecosystems to natural and
anthropogenic disturbances.