Low-crested coastal defence structures as artificial habitats for marine life: Using ecological criteria in design

As part of the DELOS project, targeted studies were carried out throughout Europe to assess the ecological similarity of low-crested coastal defence structures (LCS) to natural rocky shores and to investigate the influence of LCS design features on the colonising marine epibiota. LCSs can be considered as a relatively poor surrogate of natural rocky shores. Epibiotic communities were qualitatively similar to those on natural rocky shores as both habitats are regulated by the same physical and biological factors. However, there were quantitative differences in the diversity and abundance of epibiota on artificial structures. Typically, epibiotic assemblages were less diverse than rocky shore communities. Also, LCSs offered less structurally complex habitats for colonisation and in some locations experienced higher disturbance than natural shores. We propose several criteria that can be integrated into the design and construction of LCSs to minimise ecological impacts and allow targeted management of diversity and natural living resources.