Le vendredi 20 novembre 2015 à 13h00, salle de conférences de l'OSUR, bât. 14b, Campus de Beaulieu, UR1

Interactions of food-web structure and ecosystem functions in freshwaters and their riparian zones


Abstract :
Alterations to food webs through disturbances can result in losses and gains of species, and result in changes to the rates of ecosystem functions. We have experimentally manipulated the structure of stream food webs to determine the effects of specific changes on rates of decomposition, primary production, secondary production and carbon dioxide emissions. We have demonstrated that the responses depend on particular features of the species, as well as trophic position. In general, loss of predators is not as easy to compensate for (not easily replaced) as is the case for lower trophic levels. We have also shown that trophic position and not body size is more important for impacts on ecosystem functions. Finally, cross-ecosystem resource subsidies are a major input to many ecosystems, and have large impacts on stream and riparian areas, depending on the trophic level at which they enter.

Contact : John RICHARDSON