5.5.10 Parc Naturel Marin d'Iroise: Scenario description

• Firstly, the model is designed to test the efficiency of adaptive strategies (= scenarios) on the ecosystem services levels for the reference situation. Can a better trade-off be reached for the actual set of external conditions (same alginate demand, same winter storms frequency, same demand of MPA areas)? The reference year chosen is 2013, before the set-up of large closed areas by the 2014-9271 regulation.
• Secondly, the model predicts the effect of the adaptive strategies taken in response to the exogenous changes described in trending scenarios. These prospective scenarios consider evolution of one exogenous factor at a time or combine evolutions on different factors to test model responses to extreme perspectives. The modelling of extreme climatic changes could consist in increasing the frequency or cumulating the occurrences of winter storms, based on the magnitude of those observed in 2014.

Trending and adaptive scenarios which have been built with stakeholders were as realistic as possible in order to reflect the social demand and acceptability. In addition to these realistic or acceptable scenarios, some more contrasted perspectives, which could be seen as unrealistic for instance from the kelp sector point of view, were also investigated with the simulation model of the kelp socio-ecosystem as ”purely exploratory scenarios”.