Evidence review on the sensitivity of saltmarsh to nutrients

Descriptions

The aim of this evidence review is to collate the evidence on the response of saltmarsh to changing nutrient concentrations in estuarine ecosystems and further our understanding on how these relationships are affected by other environmental and ecological factors. There is evidence to suggest that saltmarsh habitats are sensitive to nutrient enrichment. These habitats provide many ecosystem services and are either designated feature, sub-feature or supporting habitat in most estuarine and coastal MPAs. One of the main pressures causing the decline of these key habitats is nutrient enrichment, usually though smothering by opportunistic macroalgae, or via changes in the root structure of the saltmarsh itself. Eutrophication has also been known to impact saltmarsh indirectly through increase in dominance/productivity of upper species such as Sea Couch, creating species-poor monocultures of grass species. In order to manage MPAs, and give appropriate advice, it is important for Natural England to understand the nutrient and water quality conditions that will lead to the favourable condition of saltmarsh habitats. This will enable conservation targets to be ecologically relevant and applied at the appropriate scale.