Ecological Enhancement of Coastal Infrastructure

This study looks at the influence of fine scale surface texture, from the mm to 10s off mm scale, on the colonisation and biodiversity of rocky intertidal organisms on engineered structures. In the largest UK ecological enhancement trial to date, 184 concrete tiles (150x150mm) of nine experimental designs were deployed in 2016 at three sites across the UK. These designs varied in both their complexity and surface texture, which was manipulated to examine how different textures influence colonisation and diversity. Through design manipulation, this study aimed to replicate the topographic features of rocky shores that are of high ecological importance, such as cracks, crevices and texture, as this influences species recruitment and community composition on artificial structures. Concrete tiles were deployed on vertical concrete coastal structures to test the effectiveness of the designs and to recruit specifically for barnacles which can be used as bioprotection (Coombes et al., 2015). These tiles were developed with the aim of better informing the design of coastal marine infrastructure and providing prototypes for larger surfaces for walls, stepped revetments, textured rock armour and breakwaters.

Results at six months post-installation highlight the importance of topographic complexity, as mm-scale texture (intermediate roughness) shows the highest levels of barnacle abundance, compared to low levels on plain-cast control tiles that represent the typical texture of concrete coastal defences. Greater complexity at the 10s of mm scale was observed to have higher levels of species richness as several periwinkle species, crabs and topshells were frequently observed in monitoring. Designing for nature, by replicating natural rocky shore features and complexity, will aid in enhancing the ecological potential and habitat value of coastal defences.