Learning from successes AND failures is key to help improve mangrove rehabilitation practice, says Professor Karen Diele

Date posted

24 February 2020


An international team of researchers have found that there is now cause for conservation optimism, with the global loss rate of mangroves less alarming than previously suggested.

Mangrove forests occur along the shorelines of more than 100 countries. They deliver critical benefits to people, including protection from coastal erosion and storm damage, natural filters for pollution and sediment, and climate change mitigation.

General view of mangroves

They provide millions of people with fuelwood, construction materials and fisheries resources. Despite their many benefits, these ecosystems have long been in peril, mostly due to shrimp aquaculture, agriculture and urban development.

More than a decade ago, academics warned mangroves were being lost faster than almost any other ecosystem, including coral reefs and tropical rainforests.

Now the team of 22 researchers from 24 institutes – including Edinburgh Napier’s Professor Karen Diele - say the picture is improving.

Led by Associate Professor Daniel Friess and Dr Erik Yando from the National University of Singapore (NUS), they found that globally loss rates have reduced from what was previously estimated at one to three per cent per year to about 0.3 to 0.6 per cent per year. This was thanks in large part to successful mangrove conservation efforts.

Assoc Prof Friess said: “The team deduced that the reduction in mangrove global loss rates has resulted from improved monitoring and data access, changing industrial practices, expanded management and protection, increased focus on rehabilitation, and stronger recognition of the ecosystem services provided by mangroves.”

The team’s key points, crystallized during a workshop following the Fifth International Mangrove Macrobenthos and Management conference (MMM5), the world’s largest mangrove conference, held in Singapore last year, are summarised in the scientific journal Current Biology.

Assoc Prof Friess said: “There is strong evidence that positive conservation change is occurring. Mangrove conservation has gained substantial momentum, with greater public and government awareness leading to investment and on-the-ground action.

“However, despite recent mangrove conservation successes, tempered optimism is necessary, as conservation gains are not evenly spread, nor guaranteed into the future”, particularly in new deforestation frontiers that are emerging in parts of Southeast Asia and West Africa.

They also note that while mangrove rehabilitation is lauded as a method to offset losses and can yield long-term ecosystem service provision, successful rehabilitation is still a challenge to achieve at scale. 

Edinburgh Napier marine ecologist Professor Karen Diele said: “The challenge of mangrove rehabilitation is to ensure that the best practices are executed correctly, including monitoring of rehabilitation projects, both in terms of flora and fauna, to learn from failure and successes. This is what our current UK-Indonesian research project ‘As Good As (G)Old: Comparing Biodiversity and Ecosystem Services of Natural and Restored Mangroves’ is assessing in Indonesia.”

“Work is required to overcome key socio-political hurdles. These include lack of training, unclear land tenure, and national governments or NGO targets that incentivise rehabilitation efforts in unsuitable coastal locations. These are not insurmountable challenges and can be addressed through engagement with policy makers and stakeholders.”

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