The vital nature sanctuaries hidden in the heart of Dublin
Published 04/05/2015 | 02:30
A disused toilet block on Bull Island perhaps best tells the story of the ever-changing face of Dublin Bay.
Originally erected on the beach in 1971, it is now nestled deep in the sand dunes. The reason? Bull Island is expanding as tonnes of sand and sediment are deposited every year.
A conference organised to celebrate the 300th anniversary of Dublin Port, called 'Dublin Bay: History and Environment', paints a fascinating picture of the wide variety of wildlife on the doorstep of our capital city.
Uniquely in Europe, it is home to more than 40 species of birds; eight of the 24 species of whales, dolphins and porpoises are found in the bay and the creation of sea walls from the 18th Century means it continues to evolve.
Prior to the 1700s, access to the port was very difficult, but construction of the South Bull Wall from 1748 and the North Bull Wall from 1819 helped change this.
It also resulted in sand and sediment being pushed north, creating the nature sanctuary on Bull Island.
"If we look at an old toilet block built in the 1970s on Bull Island, it was built on the beach," Bord na Mona ecologist Mark McCorry said. "These dunes are still growing. We find on Bull Island there's nine different habitats. These are all rare and threatened in a European context, and this has only developed in the last 200 years."
This sanctuary in the heart of the city is just one of many. The sea cliffs at Howth, mudflats at Sandymount Strand, Rocky Shore at Seapoint and Booterstown Marsh are also home to a wide variety of wildlife.
Richard Nairn, from Natura Environmental Consultants, says that birds are attracted to Dublin because of a rich food source and copious number of nesting sites free from predators. Surprisingly, they include a relic from the port.
"The largest colony is on an old mooring structure on Poolbeg, which is used by 470 pairs, and is more than 100 years old," he said.
"There can be two or three nests per square metre. When the chicks hatch, they run around the top of this structure. The Port Company has funded a wooden barrier which prevents the chicks from falling into the sea.
"Only certain parts of the bay are suitable for nesting, and the terns are nesting on islands and on structures in the port. They seek a good flat area, with good visibility so they can see predators, such as Merrion Strand and on a sandspit developing near Booterstown DART station.
"Oystercatchers also move into grassland, like roadside areas and sports pitches. They also use structures in the port. Floating pontoons are also being trialled, with one in Clontarf."
It's not just birds which call Dublin home. Dr Simon Berrow from the Irish Whale and Dolphin Group says as many as 300 seals are present, continuing a long period of colonisation - records of grey seals from Dalkey Island are carbon-dated to 6,400 years ago.
Grey seals are more common than the common seal, and the latter have been tracked travelling as far north as Co Down and south to Co Wexford over a period of just 20 days.
Of the 24 species of whale, dolphin and porpoise in Ireland, eight have been sighted in Dublin. Harbour porpoises are small, elusive and avoid boats, with as many as 445 present.
Bottlenose dolphin are regularly seen.
"We can't catch and tag dolphins. We use markings and know they travel to Donegal and Connemara, using the whole coastline. For about two or three years there were three individuals in Killiney Bay, but one was seen in Mayo before arriving in Killiney, and two more were spotted in Kerry - one was hanging out with Fungi.
"How many capital cities can boast such a rich marine megafauna?" he added. "Dublin Bay is so important for marine mammals, it's an amazing spot."
Most of Dublin Bay is designated for nature conservation, and the council wants to designate the entire area north to Malahide and south to Killiney as a biosphere so it can be properly managed.
"We need to focus on what can be done, and what can be done differently," Maryann Harris from Dublin City Council said.
"The city is over 1,000 years old, and species do adapt to disturbance. We don't want to look at people as the negative factor, but do need to look at pressure like water pollution.
"It's a case of trying to see what we can do to enhance the environment."