A fifth of Abu Dhabi's mangroves in moderate or poor health, study shows

A new assessment finds Abu Dhabi mangrove coverage has increased by 61 per cent since 2001

Abu Dhabi’s mangroves. Alex Atack for The National. 

An estimated 20 per cent of Abu Dhabi’s mangroves are in deteriorating or moderate health, a new assessment by the Environment Agency Abu Dhabi revealed.

More than 150 square kilometres of Abu Dhabi's coastline are covered in mangrove forests, whose dense thickets are a breeding ground for fish, birds, insects and marine invertebrates, and a carbon sink.

Satellite mapping found that 80 per cent of the emirate's mangroves are healthy, while 15 per cent are in moderate condition and 5 per cent are in deteriorating health.

“This gives a snapshot of the condition right now and can help identify areas under stress,” said Amna Al Mansoori, an assistant scientist in marine habitats at the agency’s terrestrial and marine biodiversity section. “This project can give us a bird’s-eye view.”

Mangrove health was determined by measuring the spectral reflectance of the forests. The greener the mangroves, the healthier the site. Patches of the Eastern Mangroves on Abu Dhabi island were found to be under stress.

Some areas will naturally be less dense. In other areas, this will be caused by man-made habitat degradation. The deteriorating health conditions may have been caused by recent developmental activities around Abu Dhabi island, said the agency.

Dredging has taken place in the past year and this could have put the mangroves under stress. “Dredging and landfill are the greatest anthropogenic threats to mangroves because they actually suffocate the roots,” Ms Al Mansoori said.

“This project could help us a lot in seeing annual trends because you don’t see the effect right away, it takes at least a few months.”

The assessment will provide a baseline for future analysis and be used to develop conservation targets, mitigation and compensation policies.

The EAD compared coastal changes in 1987, 2001 and 2017. More than a quarter of forests were lost in just 14 years, between 1987 and 2001.

After this, regeneration efforts between 2001 and last year led to an increase in coverage of 61 per cent.

The EAD led a Mangrove Rehabilitation Programme and planted 3.1 million saplings since 2009 on the coasts of Al Gharbia, Saadiyat, Jubail and Habitat islands.

This has helped coastal development but young mangroves are no substitute for older trees. For example, kalbaensis — a subspecies of the blue-and-white collared kingfisher that found only on the east coast of the UAE and Oman — builds nests in the gnarled cracks and holes of aged mangroves.

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Abu Dhabi’s mangroves store an estimated 41 million tonnes of carbon dioxide in the soil and biomass. These tidal forests filter the water by removing trace metals and pollutants and protect the coastline from erosion caused by storms, currents and waves.

"The results of the assessment add great value to our efforts in conserving the mangroves by providing information on the extent and health status in a rapid manner," said Dr Shaikha Al Dhaheri, the executive director of the agency's terrestrial and marine biodiversity section. "It also helps in identifying anthropogenic and natural impacts on this highly critical and sensitive habitat."

The study is part of an emirate-wide habit-mapping programme and ongoing monitoring of Abu Dhabi’s mangroves and wetlands.

A map covering 90,000 square kilometres of land and sea was created between 2011 and 2013.

Mangroves are protected by federal regulation but each emirate takes a different approach to conservation.

The UAE has seven sites designated as Wetlands of International Importance in Abu Dhabi, Dubai, Sharjah, Fujairah, and Ajman, but mangroves continue to be cut for coastal developments.

A national standard of mangrove and wetland conservation would be valuable, Ms Al Mansoori said.

“It would be really beneficially to see that level of protection consistent throughout all the emirates because we see habitat as habitat.”

The Ministry of Climate Change and Environment will host the 13th Meeting of the Conference of the Contracting Parties to the Ramsar Convention on Wetlands in Dubai next week, from October 21 to 29.