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Jordi Pagès, del Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, oferirà el seminari titulat: «ANTHROPOGENIC AND BIOPHYSICAL FEEDBACKS OF SALTMARSH RESILIENCE». El seminari serà en català.
The damage and cost implications of coastal storms and floods illustrate how vulnerable society is to environmental change. Predictions are that such extreme events will become more frequent with the advance of climate change. On the coast, sea level rise and increasing storminess will put further pressure on infrastructure that seeks to limit shoreline erosion and flooding. Natural ecosystems provide us with an array of benefits, which underpin our livelihoods and buffer us against extreme events such as floods. Salt marshes are profoundly important regulators of the coastal environment and economy. They provide recreational habitat, food and habitat for protected species such as birds. Crucially, salt marshes protect our coastline against floods and erosion by buffering waves and locking the soils into plant root-nets. This ‘service’ delivered by salt marshes translates to a very substantial economic saving on constructing artificial coastal defences. Not surprisingly, considerable effort is made by UK and international governments to plan ahead for the future under climate change and to protect important ecosystems such as salt marshes. Shoreline management planning is central to this process; it decides which stretches of coast to protect with artificial structures, where the line might be advanced, where there will be no intervention, and where the natural migration of the shoreline is to be permitted (managed realignment). These decisions depend crucially on accurate predictions of the degree of protection offered by natural systems such as salt marshes. Unfortunately, current predictions greatly lack in evidence on how resilient marshes are to climate change. Some marshes undergo sudden ‘state shifts’ – they change into a mudflat, or they dramatically shift their distribution, for instance from one part of an estuary to another. The causes for such shifts are not known, although some are thought to be natural. State shifts are found in many ecosystems, but our capacity to forecast them or to understand what drives them is still very basic. State shifts in salt marshes presents a headache to shoreline management planning. Currently there are no predictions as to when or where state shifts will occur. The inability to account for such long-term ecosystem dynamics is the main knowledge gap that hampers the effective use of natural systems for flood defence, and the protection of other ecosystem services from marshes.