Velocity of climate change drives unexpected and resilient responses in species of the Western Mediterranean Sea

Marine species range shifts in response to climate change are generalized and accelerated, both at global and regional scale. However, the role of the complex underlaying mechanisms at play are still poorly understood. The Mediterranean Sea is a highly vulnerable and semi-enclosed system where the climatic risk exposure to multiple impacts is known to be very high and species are expected to display a variety of resilient responses. The reorganization and possible resilient and adaptive responses of species in Western Mediterranean are expected to follow a meridionalization pattern (i.e. northward displacement). However, this can be also related to the dynamic processes of seascape connectivity, in which the climatic connectivity has a strong impact. Velocity of climate change (VoCC), often used as analytical predictor for climate connectivity, is the speed and direction at which isolines of a specified climate travel across landscape and seascape due to climate change, being a function of spatial and temporal variation in climate conditions. The paths that point on an isoline of climate analogues are called climate trajectories. Here, VoCC has been calculated for the contemporary climate (1987 to 2019) at 0.16¿¿ grid cell for sea surface temperature and related to resilient and adaptive responses of observed in the main species of the continental shelf community. To do that, spatial indicators (i.e. the center of gravity, inertia, index of patchiness, index of dispersion and the index of aggregation) and their temporal rates of change have been calculated to quantify the space-time patterns of benthopelagic species using historical data of scientific bottom trawl surveys of the Western Mediterranean Sea from 1994 to 2019. Combining our results on VoCC and spatial indicators demonstrate unexpected significant southward patterns of Mediterranean marine species in response to climate change contrary to the meridionalization expectations of the Mediterranean communitie