Dr Veronica Farrugia Drakard1, Dr Ally Evans3, Prof. Tasman P. Crowe1, Prof. Pippa J. Moore2, Ms Jennifer Coughlan1, Dr Paul Brooks1
1UCD Earth Institute and School of Biology and Environmental Science, University College Dublin, Dublin, Ireland, 2School of Natural and Environmental Sciences, Newcastle University, Newcastle-Upon-Tyne, United Kingdom, 3Biosciences Department, Swansea University, Swansea, United Kingdom
Artificial structures are widespread features of coastal marine environments, but are poor surrogates of natural rocky shores as they generally support depauperate assemblages with reduced population sizes. This has generated significant interest in eco-engineering solutions, including retrofitting seawalls with artificial rockpools to increase water retention and provide microhabitats. Although these have proven effective at individual sites, widespread uptake is contingent on evidence of consistent benefits in a range of contexts. In this study, commercially-available artificial rockpools (Vertipools© by Artecology Ltd.) were deployed on concrete seawalls at 8 locations with differing environmental contexts. Locations were classified as ‘estuarine’ or ‘marine’ and as ‘urban’ or ‘rural’, with two locations selected for each combination of factors. Over a period of two years, regular samples were taken of cover and abundance of seaweeds, and measurements were made of productivity and respiration. Initial stages of colonisation were dominated by benthic diatoms, which varied in concentration between sites but not across environmental contexts. Later stages of seaweed colonisation were similar to patterns described for marine systems in general, consisting of early dominance by ephemeral species followed by the appearance and eventual establishment of perennial habitat-formers. Overall species richness differed between sites and on different features (bowls, rims, and outer surfaces) of the Vertipools, indicating that different surfaces present unique microhabitats for colonisation. By 24 months, all sites supported populations of large habitat-forming seaweeds. Productivity and community respiration differed between sites by up to 0.5 mg O2 L-1 min-1, but not across environmental contexts at any timepoint. This study demonstrates that Vertipools attract similar levels of colonisation by biota in a variety of environmental contexts, and should be considered for widespread implementation as an eco-engineering solution.
Biography:
Veronica Farrugia Drakard is a seaweed ecologist based in Juneau, Alaska, where she works on the impacts of local and global stressors on farmed kelp. Veronica holds a PhD from University College Dublin in marine ecology. Her thesis explored aspects of the ecology of seaweeds on artificial structures, as well as the effectiveness of eco-engineering solutions in facilitating natural seaweed assemblages on such structures.
