Resilience of Marine Benthic Communities in an Area Highly Impacted by Human Activities: The Case of the English Channel
摘要
Multiple anthropogenic disturbances occur in the English Channel, an epicontinental and megatidal sea which is one of the most anthropized marine areas in the world: maritime traffic, civil engineering works, fisheries, sediment dredging and dumping, eutrophication, introduction of non-indigenous species, pollution and contamination of the biological components. An assessment of its ecological status is difficult due to permanent natural hydrodynamic disturbances which generate diverse benthic abiotic conditions ranging from muddy sand to pebble substrates, and extending from the coastal zone, where there is a concentration of anthropogenic activities, to the offshore zone with moderate disturbances. However, in spite of these cumulative pressures, the soft-bottom macrobenthic communities exhibit variable degrees of resistance to stressors, with high resilience defined here as the ability of a habitat to recuperate its initial structure after a certain time following a disturbance. Some examples are chosen here to illustrate the resistance and resilience responses of coastal marine ecosystems in the English Channel, as well the effects of anthropogenic disturbances on their structure and functioning: (1) hydrocarbon pollution of the benthic communities of the Bay of Morlaix; (2) estuarine isolation of the River Rance during the construction of the tidal power plant; (3) resilience and marinization of the Seine estuary; (4) dumping sediment in the eastern part of the Bay of Seine; and (5) aggregate extraction in the eastern part of the English Channel.