The damage and cost implications of the UK 2013–14 winter storms and floods illustrate how vulnerable society is to environmental change. Sea level rises and an increasing frequency of extreme events such as storms are predicted with climate change, placing further pressure on coastal infrastructure that protects against erosion and flooding. Natural ecosystems provide an array of benefits which underpin our livelihoods and buffer us against extreme events such as floods. Salt marshes, in particular, are important regulators of the coastal environment providing recreational space, food, and habitat for protected species such as birds. Crucially, salt marshes protect our coastline against floods and erosion by absorbing waves and locking the soils into plant root-nets. This ‘ecosystem service’represents a substantial economic saving on constructing coastal defences.
Considerable effort is made by government to protect salt marshes. In Europe, Shoreline Management Planning (SMP) is central to this process; it decides which stretches of coast to protect with artificial structures (the so-called ‘hold the line’ policy), where the line might be advanced, where there will be no intervention, and where the natural migration of the shoreline is to be permitted (managed realignment). SMP decisions rely on accurate predictions of the future distribution and extent of coastal salt marshes. Yet, some marshes undergo sudden ‘state shifts’ – they change position or transform into unvegetated mudflats. State shifts are found in many ecosystems, but our capacity to forecast them and to understand what drives them is limited. State shifts in salt marshes present a headache to Shoreline Management Planning. There are no predictions as to when or where state shifts will occur, which hampers the use of marshes for flood protection and the management of other ecosystem benefits.
RESILCOAST is a multi-disciplinary project with University, research and Government partners from Wales, England and the Netherlands. We will deliver fundamental biological and geo-morphological research to understand what governs marsh resilience to change, and to numerically model how state shifts will be affected by climate change and interactions from human exploitation, such as livestock grazing.
Our research uses state of the art hydrological flumes as well as extensive field experimentation to examine the resilience of marshes to environmental disturbance or change. Using historical fly-over photography of marshes, we will develop novel approaches to forecasting state shifts – something that is lacking for most global ecosystems. Biodiversity underpins many processes in nature, from production of food to regulation of climate. We examine, for the first time, the hypothesis that biodiversity of saltmarsh vegetation – the foundation of the saltmarsh environment – will enhance saltmarsh resilience against erosion and disturbance, thereby boosting shoreline stabilisation and ecosystem benefits. We couple this environmental research to research on shoreline management policy and planning, placing a particular emphasis on estuaries in Wales. We want to know: what benefits do we currently have from these salt marshes and how valuable are these? How capable is the current shoreline management policy of considering state shifts? How well does shoreline management planning accommodate natural resilience?