Ecological development (Benthos, saltmarsh and birds)
The ecological development of Managed Realignment (MR) and Regulated Tidal Exchange (RTE) schemes has been well studied and is now well understood, especially with respect to mudflat benthos, saltmarsh vegetation, overwintering birds and, to a lesser degree, fish and shellfish. It is clear that appropriately-designed realignments can deliver high ecological and biodiversity value in a short space of time.
Benthic invertebrates colonise accreting mudflat fairly rapidly (e.g. Tollesbury, Allfleet’s Marsh, Chowder Ness, Paull Holme Strays) and saltmarsh colonisation also occurs quickly if drainage and elevation conditions are right (e.g. Chowder Ness, Freiston and Allfleet’s Marsh). Managed realignment sites can also rapidly develop into important roosting and feeding sites for waterbirds. Some sites may initially mainly be utilised as roost sites but, as prey diversity and biomass increases, so should the proportion of feeding birds (e.g. Welwick, Tollesbury, Orplands, Allfleet’s Marsh). The process of achieving full equivalency with mature habitats may take much longer (esp. for saltmarsh) but the relevance of this needs to be better understood, agreed and communicated amongst coastal managers.
This paper reviews the findings from past monitoring to identify residual gaps in understanding and to inform one of the primary considerations for all interested parties and that is: how and when can we objectively say that ecological success is achieved especially when the newly restored habitats are functioning from the moment they are created and from then on are consistently evolving?