Global implications of Welsh research

The Resilicoast cluster, featuring scientists from universities around Wales was instituted to forge the multidisciplinary aspects of ecosystem resilience and coastal planning as synergistic partners. Funded by the Low Carbon Energy and Environment Research Network Wales the partners set out to quantify natural flood protection and the value of wetland ecosystems. Hear how funding research in Wales led to global impact.

It seems that Wales’ coastal saltmarshes are an overlooked landscape feature by many, when in fact they are responsible for a great deal of climate change mitigation and flood prevention as well as a vital habitat for wildlife.

Research taking place here, on Welsh saltmarshes, is leading the way for flood and habitat resilience around the world. Photo © Tom Fairchild

Human development of the land and our coast affects saltmarshes in every way. Whether that be changed sediment from upstream dams and farming or man-made coastal flood defences which are designed to protect the urban communities that have built-up along our shorelines; each action alters the dynamic habitat with its natural ability to attenuate storm surges and hold carbon stores.

The Resilicoast team, from institutions around Wales and beyond, came together to establish the resilience and value of saltmarshes; from how they are perceived in society to the quantifiable affects they have on flood mitigation, how they are affected by human practices and to establish when they are best able to sequester the largest amount of carbon.

Dr John Griffin from Swansea University entered the team from an ecology perspective, concerned with how biodiversity and species interactions affect the functioning of coastal ecosystems.

“Salt marshes are over-looked and taken for granted. Historically they’ve been thought of as wastegrounds. In reality, they offer Wales protection from floods, mitigate the effects of floods and are important carbon stores”.

The initial funding from the research network allowed John’s side of the team to expand and seek further funding sources to explore the role of estuarine saltmarsh plants in holding back the tide. Multidisciplinary collaboration was a key aspect of this expansion, working with Professor Harshinie Karunarathna, an expert in numerical modelling of coastal environments, in Swansea University’s civil engineering department.

“Previously, we’d only looked at marshes on coastal edges. Now, we were able to examine how the plants along the estuary were able to reduce storm surges by causing drag along the full distance of the saltmarsh from the coastal river mouth back inland.” Photo © Tom Fairchild

“Using data on saltmarshes around Wales, we modelled different storm scenarios around our coast and looked at how the surges affected upriver flooding. Within each scenario we tested the model with and without saltmarshes. We saw that where estuarine salt marshes were present, the average flooding extent was reduced by 35%!”

There’s a financial benefit to flood protection from saltmarshes too. The direct annual cost saving of merely having saltmarshes present on an estuary is £8 million in terms of reduced mitigation activities and knock on costs of floods on people and their livelihoods.

“There was a snowball affect from the funding we received to set up the Resilicoast cluster of researchers. Firstly, we brought in people at the PhD and post-doc level, having an immediate impact on their careers personally as well as affording us the scope to expand our research. Secondly, we built up our expertise in the field which enabled us to draw in more money from larger funding sources. All of this meant we gained momentum and were able to branch out into new research strands.”

Today, the modelling methodology created by the cluster is being used by the Office for National Statistics who consulted with the Resilicoast team to apply the methods more broadly to estimate saltmarsh food attenuation values on a national scale.

“Following hurricane Irma in the United States, RESILICOAST gave use the momentum and expertise to apply for a NERC Urgency grant to investigate what factors support post-hurricane recovery of dunes”

The team’s work in the aftermath of the hurricane has shown that storm wrack, the biological debris left in the wake of a storm, actually supports recovery of the coastline. Their research showed that storm wrack enables the stabilising plant matter to grow better, resulting in dunes recovering to a higher level than where the wrack may have been ‘tidied’ away. A systematic review conducted by the team shows that wide plant diversity also supports post-storm recovery.

“If planners can take biological aspects like this into account, they can better prepare their people and lands from storm damage”.

Members of the cluster subsequently worked with Plymouth Marine Lab on a UKRI NERC funded project, Coastweb, looking further into coastal protection and wave attenuation as well as the benefits of saltmarsh environments to human health and wellbeing.

A related PhD research opportunity that sprung out of the cluster was investigating the impact of grazing on saltmarsh ecosystems around the world. Researcher Kate Davidson amalgamated saltmarsh information from previous studies on European sites and in the Americas to establish the effect of horse, cattle and sheep grazing on the species which could be found there. Whilst there were nuances to each site, she found that overall plant diversity was often increased by grazing activity. Conversely, grazing generally negatively affected the number of plant-eating insects found at each site.

“It’s possible that the reduced numbers of invertebrates on grazed salt marshes has a negative effect on the fish and crustaceans that feed in these marshy areas.”

Kate Davidson

Kate went on to further research in the same area, shifting her attention to the pollinators that rely on the saltmarsh communities across Wales.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                “Saltmarshes can support extensive flowering meadows, and during a time of global pollinator decline it’s incredibly important to identify which habitats are valuable to them”.

Kate’s research showed that where saltmarshes were grazed, the plants would often not reach flowering stage, rendering those particular plants of no value to pollinators. The consequent reduction in flowers was shown to reduce overall bee abundance and to reduce the number of different bee species that would use a site. Relative to an ungrazed site, bee numbers on grazed marshes were halved. When the site was intensively grazed that number was reduced in half again.

“To protect our native bees, we now recommend that ungrazed marshes remain ungrazed and that where saltmarsh grazing occurs it is maintained at a low-level”

Kate Davidson
Saltmarshes, like any other habitat are complex. We’re now starting to unpick their intricacies with innovative research around Wales leading the way for countries around the globe. Photo © Tom Fairchild

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