The Source, Annual Review 2020

A typical hectare of mangrove holds more than a thousand tonnes of carbon, up to five times more than the same area of rainforest

In Panama City, mangroves offer the cheapest and most effective system of defence against storms and flooding, which has devestated the city in previous years.

This is the latest phase in work by Wetlands International over many years highlighting the importance of mangroves and promoting their protection and restoration through interactions with governments and local communities, from Guinea-Bissau and the Rufiji delta in Tanzania to Java in Indonesia and the coastal defences of Panama City. These local networks help identify and root out mangrove plunderers, draw up local management plans with communities, and help with the nitty gritty of mangrove restoration, whether through planting or protecting habitat to allow natural reseeding and recovery. Guinea-Bissau has long been a focus. In total, it has some 250,000 hectares of mangroves. They protect more than 70% of its coastline. Unusually, it has seen a net gain in mangroves of 330 hectares since 1996. One reason has been our long-running work in the Cacheu River Mangroves National Park in northern Guinea Bissau. Covering almost 90,000 hectares, it has the largest dense assemblage of mangroves in West Africa. We have helped with restoration of mangroves on abandoned rice fields in many areas of the park.

The JAXA radar collects data from every mangrove region around once a week. The advantage of radar monitoring is that it can see through clouds that often persist in coastal regions, says de Boer. A specially devised model then compares the raw data with stored baseline information, and sends out an alert if there has been a change. In just one month, it issued more than a thousand mangrove disturbance alerts. The changes may be complete clear-cuts or something more subtle, such as defoliation or construction work amid the trees. The images from Guinea-Bissau showed a dirt road constructed across a creek near the site of mangrove disturbance – evidence of a new human invasion. As well as triggering rapid responses to illegal mangrove conversion, the GMW data will generate annual maps identifying areas under threat and forest loss trends. This will all support the work of the Global Mangrove Alliance, a coalition of NGOs set up by Wetlands International and others in 2017 with the ultimate aim of increasing mangrove cover by 20% from 2015 to 2030 – making good the losses suffered since 1980.

Not only do mangroves offer vital protection for coastal communities, their tangled roots are also vital nurseries for an estimated one-tenth of all marine life.


Wetlands International Annual Review 2020

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