Corridors and barriers to marine connectivity around southern Africa

Abstract

Detailed knowledge on connectivity, i.e. the exchange of marine organisms among geographically separated populations, is essential for effective marine spatial planning strategies and the design of marine protected areas (MPAs) in coastal ecosystems. Coastal waters around southern Africa are characterized by complex oceanographic processes that strongly influence connectivity, challenging the design and management of marine ecosystems. Here we reviewed connectivity studies conducted across 25° of latitude on both the southeastern and southwestern sides of Africa based on biophysical modelling, ecological and molecular approaches, and identified 7 corridors and 8 barriers recognized to influence marine connectivity for a variety of vertebrate and invertebrate taxa of commercial and ecological interest. These corridors and barriers were generally consistent across studies, species and methodological approaches, and were reflected in marine bioregion breaks. Nevertheless, life history traits appear to be important to understanding why some corridors and barriers may be notable for some species and life stages and not for others. Our review underlines the value of including studies from different disciplines in order to have a broad view of marine connectivity, and, in particular, the complementarity of larval-dispersal biophysical models and seascape genetics is emphasized. The corridors and barriers to connectivity identified in this review represent baselines to critically assess existing MPAs and prioritize new spatial management efforts to mitigate human impacts on marine ecosystems.