Creating Novel Seashore Habitats
Celtest enhances biodiversity on man-made coastal structures in Wales
In response to increasingly destructive sea water floods, many coastal areas have created artificial defences such as granite breakwaters and sea walls. However, these structures do not generally support the biodiverse animal life found on natural rocky shores which provide moisture, shelter and food at low tide.
Scientists from Aberystwyth University wanted to trial the creation of new ‘homes’ for sea life on the rocky groynes along Prestatyn beach in North Wales.
The project involved drilling artificially created holes in the rocks which would fill with seawater at high tide, and the water would remain behind as the tide receded. In time, the holes would become rock pools, inhabited by various sea creatures such as crabs, anemones, small fish and seaweed.
Challenges included environmental issues of working on the beach area and the natural rocks, limited daylight hours to accommodate the tides, and health & safety.
The work entailed drilling holes of varying depth (5-12cm) that would become the artificial rock pools. Vehicles were not allowed on the beach as there was a risk of them becoming stuck as the tides came in, therefore the equipment had to be sufficiently light and modular so that it could be carried easily along the beach at the start and finish of each shift.
The tides meant the site could be accessed only at only low tide, so the team were restricted to a few hours of working time each day. This meant that the contract took a month to complete.
Health & Safety regulations also had to be followed, which included making sure there was no pollution of the beach through spilled diesel, petrol, or oil. Slips trips and falls were a potential hazard in the working area because of the wet rocks, seaweed, and natural rocky surface with cracks and holes. Public access to the beach meant working a safe distance from sunbathers and walkers.
The concept of the artificial rock pools was initially trialled at Towyn in mid-Wales.
However, as Dr Ally Evans (Postdoctoral Research Associate, Ecostructure Project Aberystwyth University) explains: “The aim at Prestatyn is to test the design more thoroughly – to find out how well the rock pools will work in different conditions and how many we would need to really make a difference to biodiversity. Prestatyn is the ideal place to run this experiment because there are many similar structures on the same beach. This provides a unique opportunity to scale up the experiment and generate strong scientific evidence of how well they work.”
After the rock pools were established, local community groups were encouraged to be involved and record what was living in the pools, submitting the results to the University project team.
Although the novel habitats did not support the same animal communities as natural rock pools, they provided important habitat for several species that were otherwise absent at mid-shore height on the breakwater.
These findings reveal the potential of drill-cored rock pools as an affordable and easily replicated means of enhancing biodiversity on a variety of coastal defence structures, both at the design stage and retrospectively.
The experiment is part of the EU-funded Ecostructure project, exploring ways of enhancing biodiversity on man-made structures around Irish Sea coastlines in Wales and Ireland.
Ecostructure is part-funded by the European Regional Development Fund (ERDF) through the Ireland Wales Cooperation Programme 2014-2020. The project will raise awareness of eco-engineering solutions to the challenges of coastal adaptation to climate change.