Journal of Applied Ecology are discussed. These papers suggest that saltmarsh erosion is linked to bioturbation, and concentrate on the role of the ragworm Nereis diversicolor. The authors also suggest that new saltmarsh will not develop in realignment sites because bioturbation will prevent the establishment of saltmarsh plants. We dispute their analysis and offer evidence that inferences derived from their experimental work are erroneous. 2. Experience from the current range of managed realignment sites in the UK shows that saltmarsh communities are developing, and include the lower marsh Salicornia communities that they suggest are vulnerable to the effects of bioturbation and grazing by N. diversicolor. 3. Further evidence of the benefits of managed realignment, even in situations where realignment sites lie below existing seaward mudflat levels, is provided by the saltmarshes that developed on sites that were not re-enclosed after the 1953 flood in eastern England. 4. We highlight the importance of maintaining positive sediment budgets in order that saltmarshes may continue to adjust to sea level rise and to ensure that sufficient sediment exists to allow realignment sites to warp up to levels at which pioneer saltmarsh may develop. 5. We also draw attention to a range of initiatives that seek to maintain sediment levels within estuaries in south-east England, and highlight the broader conceptual approach that looks upon dredged sediment as an important resource and not a waste material. None of these is designed to change permanently the estuarine tidal prism, as suggested by . 6. Synthesis and applications. We present evidence to show that coastal realignment is effective in managing and reversing saltmarsh erosion. We dispute the conclusions presented in the recent papers by and . We suggest that infauna play an essential role in saltmarsh ecology and that N. diversicolor does not play a destructive role in saltmarsh establishment. In the broader context of coastal management, the long-term benefits of managed realignment in sea defence and in delivering nature conservation benefit are quite clear. Sustainable sediment management will play a key role in sustaining saltmarsh habitats in the future.

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In the UK, Cumulative Impact Assessment (CIA) has become a staple component of the licensing and regulatory assessment process. CIA considers the prospective impacts originating from new developments alongside impacts arising from existing activities. This assessment provides a representation of the disturbance experienced within UK waters, yet international transboundary effects are often overlooked or data is not freely available. An assessment of Atlantic herring Clupea harengus spawning beds was conducted. Seabed sediment maps, fisheries information and larval survey data were used to identify likely spawning sites. Interactions with seabed user activities and cumulative effects were then assessed for UK waters only. This methodology and the subsequent assessment have informed revised ICES management advice on activities interacting with spawning beds. The benefit of assessing single species interactions with developments is recognised, and the need for expanding the assessment to transcend territorial boundaries accepted. To extend this assessment to cover the geographic range of a mobile species such as Atlantic herring requires more data than considered previously. A proposed wider mapping project seeks to include data from fisheries, renewable energy companies, dredging companies, and statistics and mapping experts. This co-ordination between sea users and policy makers will allow a more robust assessment of the interaction of Atlantic herring with marine activities. Extending beyond this initial single species assessment it is suggested that there is a requirement for the quantifiable assessment of other individual transboundary receptors such as habitats, and mobile species such as birds and mammals. This can only be achieved through effective co-operation and free data exchange between developers and policy makers. Without clear co-ordination and the inclusion of all parameters in a CIA the true extent of impacts on the receptor cannot be determined.

In the UK, Cumulative Impact Assessment (CIA) has become a staple component of the licensing and regulatory assessment process. CIA considers the prospective impacts originating from new developments alongside impacts arising from existing activities. This assessment provides a representation of the disturbance experienced within UK waters, yet international transboundary effects are often overlooked or data is not freely available.An assessment of Atlantic Herring Clupea harengus spawning beds was conducted. Seabed sediment maps, fisheries information and larval survey data were used to identify likely spawning sites. Interactions with seabed user activities and cumulative effects were then assessed for UK waters only. This methodology and the subsequent assessment have informed revised ICES management advice on activities interacting with spawning beds. The benefit of assessing single species interactions with developments is recognised, and the need for expanding the assessment to transcend territorial boundaries accepted. To extend this assessment to cover the geographic range of a mobile species such as Atlantic Herring requires more data than considered previously. A proposed wider mapping project seeks to include data from fisheries, renewable energy companies, dredging companies, and statistics and mapping experts. This co-ordination between sea users and policy makers will allow a more robust assessment of the interaction of Atlantic Herring with marine activities.Extending beyond this initial single species assessment it is suggested that there is a requirement for the quantifiable assessment of other individual transboundary receptors such as habitats, and mobile species such as birds and mammals. This can only be achieved through effective co-operation and free data exchange between developers and policy makers. Without clear co-ordination and the inclusion of all parameters in a CIA the true extent of impacts on the receptor cannot be determined.PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.1861v1 | CC-BY 4.0 Open Access |