Half a million mangroves planted on Saadiyat

Saplings planted along the water's edge to rehabilitate area after its rapid development.

Labourers plant saplings of the UAE's only mangrove species, Avicenia marina, on Jubail island.

In one corner of Saadiyat Island stands a prototype of the Louvre Abu Dhabi museum, a hint of what is to come when it opens in 2013. Saadiyat will soon be one of the capital's busiest building sites, with cultural institutions rising from the sand.

While the high-profile construction of the Cultural District will attract most of the headlines, in another corner of the island, another equally important development is under way. Along the island's eastern side, mangrove seeds are being coaxed to grow into saplings, with half a million to be planted until 2011. Many of these saplings have already been planted around the island to rehabilitate the area. Some mangroves had to be sacrificed to allow for the rapid expansion of Saadiyat.

"In some places we have to remove the mangroves if it is necessary," said Nasser al Shaiba, the director of environmental affairs at the Tourism Development & Investment Company (TDIC), the developers of Saadiyat. "If we take one, we plant two." Mr al Shaiba was standing in front of a two-hectare nursery, set up by TDIC with the help of scientists from UAE University. The nursery has already produced 750,000 saplings in two years, he said.

Once fully grown, the mangroves will provide a rich habitat for all manner of wildlife. Mangroves form the foundation of one of the most biologically productive ecosystems in the UAE, and provide breeding grounds for commercially valuable marine creatures such as shrimp, snapper, grunt and sea bream, and are also a habitat for turtles and many species of birds. The nursery is also contributing to a programme by the Environment Agency-Abu Dhabi (EAD), which is planting mangroves on neighbouring Jubail island.

It is not a straightforward task. In addition to mangroves, the area also features salt marshes and mudflats. These other ecosystems do not enjoy the high profile of the mangroves, but offer shelter and feeding grounds to many species of rare animals. If mangroves are planted indiscriminately, they can threaten the local environment. Back at the nursery, however, the priority is to ensure enough mangrove saplings are produced.

"There are now 200,000 trees here," said Najamuddin Vistro, the mangrove project manager at Barari Forest Management, a consultant for the EAD. The saplings, he said, were the offspring of trees growing nearby. The seeds were collected between August and October, and each seed was planted in its own pot. After a month, they are already between 10cm and 15cm tall. They need a full year before reaching 40-45cm, the size most suitable for planting. The saplings do not require fresh water; situated on the tip of the island, the plants are irrigated, or rather inundated, by the rising tides.

"Within two hours, the trees will be covered by a metre of water," said Mr Vistro. The process is similar to what happens in nature; mangroves grow in intertidal areas, in regular contact with seawater. Their ability to withstand high salinity makes them the perfect carbon sink in the UAE, where freshwater resources are fast depleting. The mangrove has sophisticated mechanisms to ensure its survival in harsh conditions. Because the mud where the trees grow contains very little oxygen, grey mangroves have developed above-ground roots, allowing them to breathe. As they live in salt water, they are able to secrete the salt through special glands on their leaves. But the full array of tricks that mangroves use to withstand harsh conditions is not fully understood.

The saplings in the Saadiyat nursery are of the same species, Avicennia marina. Known as the black or grey mangrove, it is among the most salt-tolerant of mangrove species a fact that explains its ability to survive in the UAE, where seawater is especially salty. It is the only mangrove species in the country and covers about 50 square kilometres, most of which - around 35 square kilometres - is in Abu Dhabi. Besides Saadiyat, Abu Al Abyadh, Al Aryam, Al Dhabeia, Al Feiyae, Al Bazm, Sir Bani Yas, Muhaimat, Qaffay and Marawah islands all have mangrove forests. Parts of Abu Dhabi's shoreline are also rich with mangroves - in Ras Ghanada, Khasifa, Grain Al Aish, and Themayriya.

Although black mangroves in most tropical areas can reach up to 14 metres, they do not grow as tall in the Arabian Gulf. In the Marawah Marine Biosphere Reserve, the average height is around five metres. The trees on the islands surrounding the capital are even smaller, reaching just three metres, said Himansu Das, an EAD scientist. "They are not as healthy as the mangroves in Marawah but they are important because of their proximity to Abu Dhabi," he said.

This is why, besides the TDIC replanting effort in Saadiyat, the EAD launched its own programme focusing on Jubail. "We started at the end of October; until now we have planted 75,000 trees," said Dr Thabit al Abdessalaam, the EAD's director of the marine biodiversity sector. The effort will pause next month and resume in mid-February, as winter temperatures reduce the saplings' chances of survival. By mid-April, 250,000 saplings will be planted, said Dr al Abdessalaam. A year later, the new trees will number half a million.

The areas where the trees will be planted were identified after surveying the terrain to ensure salt marshes and mudflats will not suffer. After an aerial survey, EAD employees examined the area on foot, recording the location of suitable sites using global positioning devices. "Our concern is to preserve the migratory bird habitat and the other species," said Dr al Abdessalaam. In effect, the EAD plan is to fill in the gaps between trees in some areas to make the mangroves look more dense.

"We do not want to create a new mangrove area, we just want to enhance the existing one," said Mr Das. He believes that in five years, the area where the new saplings have been planted will become richer in its biodiversity. However, it remains to be seen how a projected rise in boat traffic as well as the arrival of more people will affect the area. There is talk of further infrastructure development as well.

Dr al Abdessalaam said the agency was working with the Urban Planning Council to put together a detailed master plan for the area, following an earlier document. Meanwhile, said Mr Das, the EAD was also working to make up for the losses caused by current development. "You cannot stop development, it will be there and it will come," said Mr Das. "Then, when you cannot do this, it is better to have a compromise formula where you can save something. Even if we are losing somewhere, we win somewhere."

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