After the rain subsides, Nigel George makes his way to the serene shores of Sandown Bay on the Isle of Wight. The tranquil ambiance is only interrupted by a few walkers exploring the shoreline. Nigel’s purpose today is to inspect a wooden groyne, an essential structure designed to prevent coastal erosion. Stretching out into the sea and towards France, this groyne has been equipped with small, rough concrete structures that Artecology, Nigel’s organization, calls “Vertipools” – vertical rockpools. These artificial environments provide safe havens for marine life in intertidal habitats, the dynamic zones between land and sea that experience periodic exposure and submersion by tides.

The Threat of Coastal Squeeze

Around the UK, developers and scientists have installed approximately 1,000 fake rockpools on hard coastal structures in a bid to combat a significant global threat known as “coastal squeeze.” This phenomenon occurs as rising sea levels, driven by global heating, push tidal low-water marks further inland. Concurrently, humans are erecting hard coastal structures, such as sea walls, to protect themselves from the encroaching waters and worsening storms. These human interventions impede the natural movement of the tide’s high-water mark, effectively squeezing and reducing the size of intertidal habitats.

Impacts on Coastal Wildlife

The impact of coastal squeeze on coastal wildlife has been severe. Species such as barnacles, limpets, crabs, starfish, and snails that rely on these habitats for survival have faced challenging conditions.

“Species that inhabit the intertidal zone have evolved to live in that environment,” said Pip Moore, a professor of marine science at Newcastle University. These animals find the world’s rising temperatures very stressful, she says. “Lots of organisms use the natural heterogeneity in the rocky shore to hide away from those stresses – [but] a seawall or even a “riprap” boulder don’t have that complexity of habitat.”

While the full extent of the damage remains unclear, scientists have found that structures like Artecology’s Vertipools exhibit significantly greater species richness compared to traditional seawalls after five years of implementation. Notably, one study conducted by Bournemouth University documented the presence of previously absent crab, fish, and periwinkle species living within these artificial habitats.

“If you deploy these objects in the intertidal zone they can support life that you would expect to find on a horizontal plane,” George says.

Innovations in Artificial Habitats

In response to coastal squeeze, organizations worldwide have explored diverse approaches to protect intertidal habitats and support marine life. One such approach is employed by Sydney-based company Living Seawalls, which uses 3D printers to create reinforced concrete interlocking panels mimicking rocky shorelines. These panels, some scored with deep crevices and others shaped like honeycombs, have been attached to hard coastal structures in Australia, Singapore, Gibraltar, and the UK. While some designs, such as the rockpool-like panels, proved highly successful in hosting over 100 different species, others, like the honeycomb structure, exhibited minimal improvement compared to flat panels.

Marineff, another project, introduced “eco-engineered” breakwater blocks with crevices and holes to enhance support for wildlife in Cherbourg harbor, France. These blocks, composed of concrete mixed with 20% oyster shell, offer a bio-mimetic surface for marine life to thrive. Moreover, the US government’s Rebuild by Design initiative undertook one of the most extensive intertidal interventions, investing $60 million in a six-kilometer “living breakwater” featuring 600 concrete rockpools. These rockpools, significantly larger than Artecology’s Vertipools, weigh about 1.4 tonnes each and are designed by the company ECOncrete.

According to ECOncrete, the incoming organisms that grow in these rockpools contribute to the breakwater’s protection. “They absorb wave and debris forces, so the actual concrete that’s contained within them is maintained for a much longer time,” says Andrew Rella, the project’s director at ECOncrete, which is based in Israel. “Really, we’re creating a barrier between the concrete element and the natural environment.” This approach has also been deployed in the Netherlands, Hong Kong, and the UAE.

Environmental Considerations

While these artificial habitats hold promise for conservation efforts, environmental concerns have been raised due to the vast amounts of concrete used in their construction. Cement production contributes significantly to global CO2 emissions, making it imperative to address sustainability concerns. Advocates of eco-engineered habitats argue that they offset emissions by hosting wildlife capable of carbon sequestration. Nevertheless, balancing the ecological benefits with environmental impacts remains a critical consideration in implementing such interventions.

The Role of Ecological Legislation

As awareness of the urgent need to protect coastal ecosystems grows, governments worldwide are enacting ecological legislation to promote biodiversity conservation. One such initiative is the UK’s upcoming “biodiversity net gain” requirement, set to become mandatory in late 2023. This requirement will oblige building developers to achieve a 10% overall biodiversity gain for new projects, encouraging the creation of structures that provide better habitats for intertidal wildlife or compensate for damage elsewhere.

“Exactly how this will play out for all coastal developments, and in the future for offshore areas, is still being worked out – it’s still fairly new,” said Dr Kevin Linnane, an associate director at development consulting group RPS. He said that most developers supported the net gain policy.

However, the successful enforcement and governance of such regulations pose challenges, as indicated in a paper published in the journal Conservation Letters. “Reconciling infrastructure expansion with biodiversity conservation is deeply challenging,” the authors wrote. “Even ambitious policies are subject to huge uncertainties that risk undermining their biodiversity benefits.”

The Necessity of Systemic Change

Nigel George firmly believes that addressing intertidal habitat loss requires a paradigm shift in how society perceives and values the natural world. To achieve this transformation, Artecology is actively engaging the local community on the Isle of Wight through educational initiatives. These include free daylong craft sessions at a local school for children with special needs and a free two-day arts and science festival for families in October. Nigel is now in the early stages of developing an educational Centre for Flexible Learning and Bio-Innovation at Artecology’s studio, aiming to create a lasting impact on how people interact with and protect the environment.

“They need to understand what’s going on and why,” he said. “We’re not going to get the take-up we need when we don’t have the support of our communities and people.

“It’s as much about human beings as it is wildlife.”