A Historical Investigation of Solent Saltmarsh as Key Coastal Nursery Habitat Areas (NECR404)

Saltmarsh habitats provide a wide variety of social, economic and environmental benefits to coastal environments; such as coastal protection, carbon sequestration and nursery habitats for a plethora of marine species. However, saltmarshes across the United Kingdom have been eroding rapidly throughout the past 50 years, at a continuing rate of about 100 ha year−1, due to anthropogenic disturbances and global sea level rise. Understanding how much saltmarsh has been lost from within the Solent is crucial to understand the reduction in carbon sequestration and input of juvenile fish to the collapsing fishing industries. Here we present extent data for every site within the Solent containing saltmarsh from as far back as 1943 up to 2020, with the maximum loss of saltmarsh at a given site reaching 91.52 % and a combined total recorded loss of 1784.3 ha across the Solent. For most sites, saltmarsh loss has slowed since the 1980’s, leaving the recalcitrant saltmarsh to slowly erode. The species composition of each saltmarsh is also given, with sites showing gradual succession down estuaries, many sites showing the main species classes that have been lost and those species that still remain. This report highlights future work required to identify ground-based reasons for loss of saltmarsh and saltmarsh restoration possibilities. Overall, 90 % of Solent saltmarsh are in unfavourable conditions, 5 % are extinct and 0 % are in good condition.