Benefits of coastal managed realignment for society

Blog by Dr Michael MacDonald, Senior Conservation Scientist, RSPB Centre for Conservation Science

Conservation actions, such as coastal managed realignment, have the potential to deliver both nature conservation and other benefits to people, but these benefits are rarely quantified. In a recent paper we highlight how taking into account ecosystem services, such as climate change mitigation and nature-based recreation, outweighs the loss of agricultural production.

TESSA: Toolkit for Ecosystem Service Site-based Assessment
We assessed the benefits of managed realignment for people at two sites in the UK: Hesketh Outmarsh West in northwest England, and the Inner Forth in Scotland. To do this we used a toolkit that the RSPB has helped to develop in partnership with colleagues in other organisations as part of the Cambridge Conservation Initiative. This toolkit is called TESSA (Toolkit for Ecosystem Service Site-based Assessment), and it guides the user through potential methods to collect relevant data to make comparisons between different states at a site of interest. We used the toolkit to collect our own data, or to use suitable published data, on climate change mitigation (sequestration/emission of greenhouse gases and accretion of carbon-rich sediments), flood protection, nature-based recreation, and agricultural production.

What we were comparing
In our case, we were comparing managed realignment with the continued provision of hard sea defences, allowing agricultural production on claimed land. At Hesketh Outmarsh West, the sea walls had been breached several years previously, and we now have a nature reserve managed by the RSPB. We compared the provision of ecosystem services at this reserve with those from adjacent land that was still being farmed. In the other site, at the Inner Forth, realignment is not in place yet but proposed at several sites, including Inch of Ferryton, so we compared the current situation with how we predict things would be if realignment took place.
We found that agricultural production is lost when realignment takes place and land is flooded, although at the Inner Forth some farmland would remain. However, there would be considerable benefits in terms of climate change mitigation, because carbon-rich sediments accrete on the intertidal habitats, removing that carbon from the cycle of emission to the atmosphere as carbon dioxide. The creation of new wetland habitat not only attracts great numbers of birds, such as wintering wigeon and teal, or breeding waders such as lapwings, but also allows people to enjoy the salt marshes, for bird watching and walking; because of this, these sites are especially important for local people.

Photo: Hesketh Outmarsh West following breaches of the sea wall, RSPB

Valuing ecosystem services
It is difficult to put monetary values on ecosystem services that are not part of a formal market, and there is uncertainty associated with this. However, it can also be a useful way to integrate the values of different services that are measured using different units. We estimated that the net annual value of services (i.e. the difference between the realigned and agricultural states) for Hesketh Outmarsh West was £262,935 for (£1460.75/ha), and for Inch of Ferryton (one of the Inner Forth sites) was £93,216 (£574.70/ha). The value for Hesketh Outmarsh West was higher because we included flood protection provided by an improved seawall that was constructed as part of the realignment process.

Future realignment plans
At Hesketh Outmarsh, further realignment has already taken place since we did our analysis, with adjacent sea walls being breached just last week. At the Inner Forth, it continues to be promoted by the RSPB as a response to coastal squeeze and the desire to create habitat for wildlife. The results of this study help to support the arguments for managed realignment elsewhere in the UK by demonstrating that people can also benefit from it!

MacDonald, M.A., de Ruyck, C., Field, R.H., Bedford, A. & Bradbury, R.B. (2017) Benefits of coastal managed realignment for society: Evidence from ecosystem service assessments in two UK regions. Estuarine, Coastal and Shelf Science. https://doi.org/10.1016/j.ecss.2017.09.007

Photo: Inch of Ferryton sea wall, by Chris de Ruyck