THE Poole Harbour Site of Special Scientific Interest (SSSI) has been extended by a further 1,800 hectares, an increase of 40 per cent.

It now becomes the first SSSI to specifically include sub-tidal areas, which will protect the feeding areas of internationally important tern populations.

Designated by Natural England, SSSIs are protected under law, with local planning authorities required to have specific policies that further safeguard the sites.

Birds of Poole Harbour charity co-founder Paul Morton explained: "The SSSI extension is in recognition of the importance the whole harbour has to waders and wildfowl.

"Natural England deserve a huge 'well done' for bringing this together, as do all the organisations that helped collate the relevant data."

Species in the harbour include foraging terns, spoonbills, avocets, black-tailed godwits, rare sponges and sub-tidal seagrass beds.

Dorset Wildlife Trust marine conservation officer Emma Rance said: "The channels beneath the busy waterways of Poole Harbour are home to a myriad of species.

"Supporting habitats such as seagrass beds provide refuge for juvenile fish and shellfish which become a rich food source for overwintering and roosting seabirds.

"We very much welcome the SSSI extension to further enhance the conservation value of our highly prized harbour."

This increased designation will complement the newly-extended Poole Harbour Special Protection Area, which was announced last year.

The Department for Environment Food & Rural Affairs (Defra) says the SSSI extension connects a wide network of habitats.

Defra says Dorset heathlands are among the best examples of lowland heath in the world and that Poole Harbour opens out onto outstanding marine habitat.

Environment Secretary Michael Gove said: "Part of Thomas Hardy’s Wessex landscape, this protection of a large part of Poole Harbour will continue to ensure that generations to come can enjoy the Dorset coast.

"Through this action, Natural England is making a vital contribution to our nation’s cultural and environmental heritage.

"Our 25 year environment plan includes a commitment to develop a nature recovery network to protect and restore wildlife.

"Improving our protected areas will play an important role as we develop this network and work to realise our ambition to become the first generation to leave the environment in a better state than we found it."

Meanwhile, Natural England interim chief executive Marian Spain added: "Natural England is here to make sure that people and nature can thrive, through sustainable stewardship of the land and sea.

"I am delighted therefore that we have been able to extend the protection for this internationally important site. Poole Harbour is one of the very few SSSIs to include important sub-tidal habitat, home to an abundance of species including dense forests of Peacock Worms.

"The support from our partners and stakeholders across the area has been vital to our work and we look forward to continuing to work with them so that Poole Harbour can continue be enjoyed and cared for by everyone long into the future."