Successful mangrove establishment along an artificially created tidal creek at Port Hedland, Western Australia

There is growing interest in innovative ways to minimise the environmental footprint of port developments. Herein we present results of a mangrove planting trial along an artificial tidal creek at Port Hedland, Western Australia. A 75 m-long tidal creek with exposed sloping and terraced banks was constructed, creating ∼1000m2 of intertidal area in which 800 nursery-raised seedlings of four mangrove species (Avicennia marina, Rhizophora stylosa, Ceriops australis and Aegiceras corniculatum) were transplanted. Planting followed a randomised block design to test seedling performance against tidal elevation, bank design and erosion protection. After 3 years, 142 seedlings (18%) had survived. Another 1171 mangrove seedlings, dominated by A. corniculatum (75%) and Aegitialis annulata (15%), had recruited naturally into the site. Performance and survival of planted and recruited seedlings was significantly affected by tidal elevation (P≤0.002), but not by bank design or erosion protection. A. marina showed highest survival (46%), followed by R. stylosa (18%). These results demonstrate that by creating appropriate environmental conditions conducive to mangrove growth, seedlings will recruit and establish naturally. Owing to the slow growth typical of semi-arid mangroves, it may take well over a decade before vegetation at this site is comparable to adjacent natural creeks.