Scaled-up approaches to eco-engineering in marine habitats

Caoimhe Morris¹

¹University College Dublin, Ireland

Increased urbanisation along our coastlines has led to increased development of artificial structures that pose a significant threat to marine coastal ecosystems across the globe. Natural habitats are frequently replaced by infrastructure for shipment facilities or coastal defence structures. Artificial structures differ from natural rocky shorelines in both composition and configuration, and are typically vertical and featureless, lacking crevices and ridges formed organically on natural habitats. Such habitat characteristics are important in structuring marine assemblages, affecting key interactions and species distribution. Moreover, these structures can favour non-indigenous species and solutions to promote native over non-native species must be sought for.
Combining ecology and engineering, eco-engineering aims to fulfill the needs of both humans and marine organisms by incorporating features on artificial structures to support greater numbers of native biota. Surface complexity is the most evident difference between natural shores and artificial structures. The absence of these features are associated with lower species diversity on artificial substrates. As such, eco-engineering microhabitats during the construction of infrastructure or retrofitting them to existing structures can increase their value as habitats for marine biota.
Much of the eco-engineering research to date has been done at patch-scale while larger scale projects have involved designs of geometrically simplified microhabitats. Using approaches used in development of natural topography tiles we have designed large wall panels and habitat units that use natural topography to test if they can increase biodiversity in marine environments.
In particular, our research aims are to test the efficacy of scaled up eco-engineered structures to improve biodiversity on both intertidal seawalls and rock armour.
In order to address these aims, three replicate 180 x 150cm wall panels with incorporated natural topography were deployed on seawalls in Dublin Port, Kilmore Quay and Wexford Harbor. In addition, eight replicate habitat units (100x100x100cm) with integrated topography were deployed in two intertidal habitats in Dublin Port.
An overview of the approaches taken within this research will be presented along with preliminary findings on the efficacy of scaled up eco-engineered approaches to act as a solution for improving the diversity and abundance of species on artificial structures.
The predicted outcomes of this project will increase our understanding of eco-engineered habitats, building upon the evidence base for use in both future designs or for retrofitting existing artificial structures at larger scales to reduce the impact on biodiversity and ecosystem functioning.