POOLE Harbour is set to get additional protection as Natural England is designating four more areas of land as a Site of Special Scientific Interest (SSSI).

Parts of the harbour were first made a SSSI in 1990, but this could now be extended to include additional land which encompasses estuarial open water, saltmarsh, and wetland.

Poole Harbour, which is the largest microtidal estuary in Britain, is a nationally and internationally important site for its estuarine habitats. Large numbers of water birds and rare marine invertebrates call the area home, as well as the red squirrel which lives on Brownsea Island.

The previous seaward boundary of the SSSI was drawn to the Mean Low Watermark (MLW) and subtidal estuarial waters and lower shore intertidal mudflats were not included.

Natural England has identified four areas of additional land for protection – a total of 1,836ha (4,536 acres). The largest of these areas is the open water below the MLW, which extends to the harbour mouth in the east and westwards to where the estuary meets the Rivers Piddle and Frome.

The other three areas comprise saltmarsh, wetland and supporting habitats around the fringes of Lytchett Bay and Holes Bay.

The extended Poole Harbour SSSI would cover a total of 4,112ha (10,160 acres).

Members of the public are invited to have their say about the new designation by responding to Natural England’s consultation, which closes on September 24.

A spokesperson for Natural England said the additional land supports wintering water birds and breeding seabirds.

“In particular, intertidal mudflats below MLW are used by wintering water birds when foraging on mud exposed at low spring tides.

“Other water birds such as the common goldeneye and red-breasted merganser use subtidal areas for feeding and resting. Therefore the additional land contributes to supporting the important aggregations of wintering wildfowl and waders for which the site is of special interest.

“Subtidal areas are also used by foraging common terns and Sandwich terns and are therefore essential for supporting the breeding colonies of these two species for which the site is also of special interest.”

They added: “Amongst the estuarine habitats of importance in the additional land are benthic (seabed) habitats (such as peacock worm and eelgrass marina beds) which are predominantly found below MLW.”