Greening of grey and murky harbours: enhancing biodiversity and ecosystem functioning on artificial shorelines

Abstract

<p>Shoreline armouring in coastal cities can cause habitat degradation and biodiversity loss, often exacerbated by common anthropogenic stressors. Boulders are used as riprap to create revetments walls; but the homogenous surface and absence of shelter reduces intertidal biodiversity and ecosystem functioning. Eco-engineering can mitigate habitat loss through the addition of water retention and other microhabitats. We deployed four eco-engineered designs in a degraded harbour riprap for 18 months. Two units with site-specific designs combined multiple microhabitat types, attracting the highest species diversity. All four designs generally increased within-site β diversity and fish diversity compared to nearby unmanipulated ripraps. Suspension-feeding species and more species within key functional groups colonised eco-engineered units at patch and site scale. Tailored, site-specific eco-engineering shows great potential to rehabilitate degraded ripraps into functional, novel ecosystems. Combining eco-engineering with anthropogenic stress reduction to enable recovery can enhance biodiversity and ecosystem functioning in coastal cities.<br></p>