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

Today’s article about the global carbon sequestration potential of tidal marshes demonstrates how important these habitats are to us in a changing climate. The RSPB has been a strong proponent of the protection of existing intertidal habitat, and the creation of new saltmarsh by managed realignment, both for the conservation of wildlife and for the benefits that they provide for people.

We examined these benefits, known as ecosystem services, at a newly-realigned site at Hesketh Outmarsh on the Ribble Estuary, northwest England. Carbon sequestration was one of the key services that we estimated, using sediment accretion monitoring data collected by Alan Bedford of Edge Hill University, and our own measurements of the carbon content of those sediments. We found that the value of the carbon stored annually in those sediments far outweighed the income lost from farming the land. However, there were additional benefits to people, because the creation of a nature reserve provides the opportunity to visit and view nature, and because the saltmarsh provides extra protection against storm surges. There are many places within the UK where managed realignment could be used to provide a range of benefits, and we hope that this paper highlighting the role that intertidal habitats can play in mitigating the threat of climate change will encourage decision-makers.

Intertidal habitats are also important in the UK Overseas Territories. For example, the Central Mangrove Wetland, in the Cayman Islands, is the largest intact mangrove in the Caribbean. It plays an important role in carbon storage, as it sits on deep peat that continues to accumulate. This mangrove also provides crucial fish nursery habitat, influences the local climate on Grand Cayman, and helps to maintain an important freshwater lens. This wetland is a risk from sea level rise, and also from encroaching development, and once again we hope that this important paper will illuminate the value that it provides and support its protection.

Photo: Central Mangrove Wetland, in the Cayman Islands, is the largest intact mangrove in the Caribbean (Credit Olly Watts)