Combining seascape connectivity with cumulative impact assessment in support of ecosystem-based marine spatial planning

1. Cumulative impact assessment (CIA) is a promising approach to guide marine spatial planning (MSP) and management. One limitation of CIA is the neglect of seascape connectivity, which may spread the impact of localised pressures to ambient areas, e.g. through lost dispersal and recruitment of organisms.

2. We here, for the first time, incorporate seascape connectivity into a traditional CIA model using a connectivity matrix, exemplified by dispersal of propagules estimated through biophysical modelling. Two connectivity impactsare identified: the source impact represents downstream areas losing recruits because of reduced larval dispersal from sites affected by the pressure, and the sink impact represents loss of recruits originating from upstream areas prevented from settlement in the site affected by the local pressure.

3. By including seascape connectivity into the Swedish MSP-guiding CIA tool Symphony we demonstrate how to practically account for remote effects of local envi...