BIODIVERSITY BENEFITS OF SCALING UP MARINE ECO-ENGINEERING

Abstract

Marine construction is a growing source of biodiversity loss in our oceans. The ecological impacts of marine constructions arise both from their destruction and degradation of natural habitats, but also their flat and often featureless surfaces, which provide little protection to marine life from predation and environmental stressors (Bulleri, Chapman 2010; Airoldi et al. 2005). The net effect is loss of native biodiversity, and spread of pest species. Marine “eco-engineering” seeks to mitigate some of these impacts by co-designing marine constructions for humans and nature (Chapman et al. 2018). Small-scale experiments indicate benefits to biodiversity of adding complex surface geometries to marine built structures (Strain et al. 2018, 2020). However, there are few examples where habitat complexity has been added to marine constructions at scale. We assessed the biodiversity benefits of adding habitat complexity to seawalls at scales of tens of meters, We also compared the efficacy of different types of habitat complexity in benefiting biodiversity.