Thesis defence by Adrien Latli

Many large European rivers have undergone multiple pressures that have strongly impaired ecosystem functioning at different spatial and temporal scales. Global warming and human activities have favored the invasion of exotic species, deeply modifying the structure of aquatic communities in large rivers. In many rivers, exogenous species alter trophic interactions within assemblages by increasing the predation risk for potential prey species and limiting the dynamics of others via the limitation of resource availabilities. Effects of these alterations according to the degree of river channelization have been poorly investigated so far. Rivers laid out for navigation could be more sensitive to trophic perturbations due to a lower diversity of available resources and a stronger trophic redundancy within communities.

The main objective of this thesis was to evaluate the influence of planktonic resource decrease on the functioning of macroinvertebrates and fish communities in relation to the degree of hydromorphological anthropization of the River Meuse. This research took place within a multi-stressor context where it is complex and difficult to statistically explain the variation of a single dependent metric by a specific independent variable because of potential confounding effects. Nevertheless, the study highlighted (i) the importance of trophic relationships in community dynamics, (ii) the potential role of new exotic taxa in the trophic functioning of rivers, and (iii) the potential influence of channelization that can unbalance the trophic functioning, reducing the fish community diversity and magnifying trophic disturbances.

Adrien will present the results of his PhD thesis he conducted in the Research Unit of Environmental and Evolutionary Biology (URBE) under the supervision of Patrick Kestemont. (The presentation will be in French)

Read the complete abstract in English.
More information in French.