Building Mangrove Resilience

By Jonathan Cook, WWF-US

For the past six months, I have managed a WWF project, supported by the Global Environment Facility and United Nations Environment Program, that tries to address the significant adaptation challenges facing a fascinating but often neglected ecosystem: mangrove forests. Mangroves – the guardians of tropical coastlines – are among the many ecosystems that will be lost or negatively affected by climate change unless adaptive management strategies are developed for them. Many human livelihoods will be affected as well.

Mangroves occur most extensively on low-energy, sedimentary shorelines of the tropics, in intertidal areas such as deltas and estuaries. Their unusual aerial roots are an adaptation to their salty environment. These trees act as nurseries for fish and invertebrate species that later live on coral reefs and in the pelagic zone, and they control aspects of water chemistry in coastal zones.

They provide food, fuel, and other services to human communities. And they serve as a critical buffer against storms and other extreme events. During the 2004 Asian tsunami, areas with intact mangroves suffered significantly less damage than areas where they had been cleared.

Yet mangroves are among the most critically threatened ecosystems in the world – threatened by conversion for aquaculture, agriculture and tourism; by unsustainable fishing and harvesting of wood products; and by altered salinity and sediment levels due to upstream pollution and development. Less than 1 percent of the remaining mangrove forests are adequately protected. The impacts of climate change, particularly sea level rise, will make conditions even more precarious for mangroves and heighten the urgent need to improve their management and protection.

We are working to understand the threats of climate change to mangrove ecosystems and to protect mangrove areas of high biodiversity. The project seeks to build the capacity of natural resource managers to (1) assess the vulnerability of mangroves and associated coastal ecosystems to expected climate change impacts, and (2) develop and promote adaptation strategies that respond to these impacts. This effort will run through June 2010, with further activities now being planned beyond that date.

Our project focal areas are in Cameroon, Tanzania, and Fiji. More information about the threats that the mangroves in these areas face and what strategies we are employing to improve their situation is included at the end of the post.

Overall, in each project focal area we are conducting detailed vulnerability assessments which will help us understand what the greatest risks to the system are. Our assessments combine remote sensing, reconstruction of past sea-level trends, site-based monitoring, community-based approaches and other methods. This information is being used to formulate and test a range of adaptation strategies such as the designation and improved management of marine and coastal protected areas, reforestation with “climatesmart” mangrove species, coastal planning that takes many more factors into consideration, and collaboration with local communities to improve natural resource use efficiency.

Testing vulnerability assessments and adaptation methods in geographically diverse locations within a common habitat type aims to increase their potential to be applied to other conservation efforts around the globe. In 2010, the project will develop a generalizable methodology for assessing vulnerability and developing adaptation strategies in mangrove ecosystems. Produced in the form of a “toolkit”-style manual, this will be made available to practitioners around the world. We are already sharing lessons and testing approaches with other WWF offices working in mangrove areas from Belize to India to Madagascar.

Project Focal Areas:

  1. Cameroon: The Gulf of Guinea contains Africa’s most extensive mangroves, which help to stabilize a large part of the West African shoreline. The area is already under considerable stress from urbanization, industrialization, agriculture, and timber and petroleum exploitation. The project focuses on the Douala-Edea estuary, near Cameroon’s commercial capital, Douala; the Ntem estuary, near Campo Ma’an National Park; and the Rio del Rey estuary in the vicinity of the proposed Ndongore National Park., we are funding the construction of more efficient smokehouses, which are used by local communities for fish processing. Overharvesting of wood for this activity is a big threat to mangrove forests.
  2. Tanzania: East African mangroves are among the most threatened in the world. In Tanzania’s Rufiji Delta, the main threats are cutting for charcoal, poles and timber, and unplanned rice farming. These problems are potentially compounded by the impacts of climate change. Extensive coral reefs in the area present an opportunity to integrate marine and terrestrial assessments and resource management adaptation strategies. Project activities are concentrated on the mangroves of the Rufiji Delta and adjacent reef areas on the west side of Mafia Island and northern Kilwa. In Tanzania, we are working with the Forestry Division to replant and restore mangrove habitats degraded by illegal rice farming. This will enhance the resilience of these habitats to future climate impacts such as sea level rise.
  3. Fiji: Fiji has the third-largest mangrove area in the Pacific Island region. Climatic variation across the larger islands in Fiji influences mangrove distribution and ecology, and different locations are expected to experience distinct effects of climate change. Project activities are taking place in three areas: Verata; Tikina Wai, situated on Viti Levu; and Kubulau on Vanua Levu. The latter two are the largest islands of the Fiji group. In Fiji, we are working with national stakeholders to mainstream mangrove protection into national adaptation planning, and helping communities to monitor local impacts of climate change through a “Climate Witness” program.