Effects of seascape connectivity on reserve performance along exposed coastlines

The spatial properties of landscapes influence numerous ecological attributes on land and in the sea, including the efficacy of conservation areas. In this context, seascape connectivity (landscape connectivity in the sea) has been shown to modify reserve performance in low‐energy marine ecosystems (e.g. coral reefs, mangroves, seagrass), but it is not clear whether similar spatial linkages also shape reserve effectiveness on high‐energy, exposed coastlines. We used the surf zones of ocean beaches in eastern Australia as a model system to test how seascape connectivity and reserve attributes combine to shape conservation outcomes. Spatial patterns in fish assemblages were measured in 12 marine reserves and 15 fished beaches, across two thousand kilometers of exposed coastline, using baited remote underwater video stations. Reserve performance was shaped by both the characteristics of reserves, and the spatial properties of the coastal seascapes in which reserves were embedded. More fish species and a greater abundance of harvested fishes were recorded in surf‐zone reserves that had three key attributes: i) they encompassed a sizeable area of surf‐zone habitat (>1.5 km of coastline); ii) were located close (<100 m) to rocky headlands; and iii) included pocket beaches in a heterogeneous seascape. Conservation outcomes for exposed coastlines might, therefore, be enhanced by prioritizing sufficiently large areas of seascapes, with strong linkages to abutting complementary habitats. Our findings have broader implications for coastal conservation planning, which is limited by the absence of empirical data to describe how the ecological features of high‐energy shorelines influence conservation outcomes, and we suggest that seascape connectivity might have similar ecological effects on reserve performance on both sheltered and exposed coastlines.