Mangroves: no time to waste
According to a study carried out in 2006 by the Climate Change in Guinea project, rising sea levels linked to global warming should result in stronger coastal currents, higher tides and sea encroachment of land. Guinea’s coastal region, home to West Africa’s largest and richest mangroves, will therefore bear the brunt of global climate change. The region’s entire economy is now under threat. “The main victims of all these climate variations will be people living near the coast. As far as the economy is concerned, estimates are that more than 2 million people will suffer income losses”, says the study.

In an effort to limit the foreseeable damage, Guinea has launched a national plan of action for climate change adaptation (PANA-CC), adopted in April 2008, which sets out priorities, among them measures for protecting the coastal areas. It outlines vigorous action for saving the mangroves and reforesting the region, planting teak and cashew.
At the same time, there is an urgent need to encourage the production of biogas and the use of butane gas as substitutes for the fuel wood which is the main source of energy for almost all households in Guinea. “In my opinion the government is being rather slow to establish a national policy for gas production. If this is not done, we will continue to suffer the effects of desertification”, warns Ahmed Faya Traoré, who heads the Climate Change in Guinea project.
Faced with rising water levels, communities are being advised to build sea walls and plant trees along the coast in order to protect the rice fields that have taken the place of mangroves. Other recommendations include enforcing laws on coastal settlements and tackling pollution. For these adaptation measures to work, it is crucial that local people be provided with environmental education and prepared for possible catastrophes in the future.

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Transplanting coral in the Caribbean
For coral reefs in the Caribbean, 2005 was not a good year. Water surface temperatures of 30° C or more led to severe bleaching of 50-95% of coral colonies over a huge area, killing many of them. What if you could move the coral to more favourable places?
Various factors can put corals under stress, but elevated sea surface temperature appears to be one of the main threats. A study using data from 263 sites across the Caribbean found that hard coral now covers just 10% of reefs, down from 50% a few years ago. In 2005, the University of the West Indies and the Barbados Coastal Zone Management Unit collected data from 4,600 colonies of 29 species of hard corals. Bleaching ranged from 59% to 86% and affected 26 species. These observations support other reports from the region that a consistent water temperature of 30-31° C is the precipitating factor in bleaching.

 

Coral can be transplanted to prevent its bleaching and death.

But the ability of some species to resist bleaching in specific physical conditions may offer hope for conservation. The discovery of over 700 magnificent hard coral colonies led to a 3-week delay of an extension project at the Bridgetown port in Barbados, while the colonies were relocated.
Marine biologist Andre Miller was called in: “No one thought that there would have been so many large coral colonies, and since we were working against the clock we decided to initially focus on carefully severing and removing all viable hard corals.”
While awaiting transplantation, the corals were kept in barrels of fresh salt water. A marine park was chosen as the new site. The corals were reattached with a non-toxic mix perfected by Miller and fellow divers, based on ordinary cement and various additives. Prepared on board the dive boat and taken underwater in plastic bags, the mix had to be the right consistency to bond the base to the substrate but not immediately dissolve in the water. Once secured, the corals were marked with coloured plastic tags and monitored regularly. Within just a few months, it was difficult to differentiate between the original and transplanted colonies as natural calcification had started to fuse the base of each colony onto the substrate.
The technique, also used on Australia’s Great Barrier Reef, offers the possibility of re-populating damaged reefs. Since species have differing responses to bleaching at various depths, transplanting could also be used to redistribute colonies to more favourable locations.
Miller and his highly trained team have worked on several coral transplant projects in Barbados, the Grenadines, Jamaica and St Lucia, and in all cases the survival exceeded 90%. Corals left in their original areas would already have been smothered. The future for coral transplantation as a management tool seems bright.

Andy Taitt

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