Disturbances, biodiversity changes and ecosystem stability

Increased river outflow

Climate models predict increasing variance in rainfall, with increased frequency of droughts paralleled by unusual amounts of rainfall and floods. In anticipation of this, the Mediterranean region is now being subjected to extensive river damming, which can have far reaching impacts on coastal food webs. For instance, the diets of the five most abundant flat fish species of the Gulf of Lions and their prey depend on river inputs. The common sole largely profits from the contributions from terrestrial organic matter, via their main prey: deposit-feeding polychaete worms. Therefore inland climate changes may affect coastal marine food webs, through variation in river flow.

Combined impacts

Climate change scenarios predict an increase in physical stress (e.g. by storms) and organic matter. Local activities cause the loss of some of the key species in the ecosystems such as large seaweeds, seagrasses and burrowing worms. It is not yet known how these different impacts might combine to affect ecosystem processes.

This information is essential for the implementation of environmental legislation such as the new EU Marine Framework Strategy Directive. Such legislation also requires that specific management strategies are developed for different regions in Europe.