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Ecosystem Services of Blue Forests

Amber Himes-Cornell, Université de Bretagne Occidentale

Story by Blue Forests Project April 6th, 2017

The GEF Blue Forests Project Helps Protect Coastal Blue Carbon Ecosystems that Provide Many Beneficial Services

The nine sites of the Global Environment Facility’s (GEF’s) Blue Forests Project focus on coastal ecosystems, including mangroves, seagrass beds and salt marshes. They provide a wide range of ecosystem services ranging from coastal protection and fish habitat to water filtration and recreation, among others.


Mangroves are coastal forests that have adapted to high salinity conditions and mostly occur in the tropics and subtropics. They provide benefits to both local communities and to those living far away. These benefits, known as ecosystem services, include timber and fisheries production, storm protection, erosion control, nutrient cycling, and tourism and recreation.

Mangrove forests are home to a wide variety of species and act as nursery grounds for juvenile fish, thus supporting the growth of local fish populations. Mangroves also store carbon with incredible efficiency in their roots and the sediment around them, which is an extreme benefit in the face of global climate change

Mangroves, however, are under threat. Estimates show that more than 25% of mangroves worldwide were lost between 1980 and 2000. The biggest threats include mangrove disturbance, degradation and conversion, coastline disturbance, pollution, overharvesting and upstream soil loss.

It is imperative that countries harboring precious mangrove habitats are better able to conserve them and manage the threats to them for the health of our planet.

Photo Credit: Wade Fairley/WorldFish CC 2.0 Flickr
Photo Credit: Peter Prokosch/GRID-Arendal CC 2.0 Flickr
Photo Credit: Peter Prokosch/GRID-Arendal CC 2.0 Flickr
Photo Credit: Lawrence Hislop/GRID-Arendal CC 2.0 Flickr


Seagrasses are flowering plants fully submerged in shallow marine waters. They provide significant benefits to local communities, supporting local fisheries, sequestering carbon into their biomass and sediments, cycling nutrients, reducing particles suspended in the water and protecting coastlines against waves and storms.

Similar to other coastal habitats, seagrass beds have decreased by almost 30% in recent decades. The most common reasons are eutrophication, overharvesting, coastal development, aquaculture, dredging, vegetation disturbance, climate change and sea level rise.

Photo Credit: Steven Lutz/GRID-Arendal
Photo Credit: Steven Lutz/GRID-Arendal
Photo Credit: Steven Lutz/GRID-Arendal
Photo Credit: Steven Lutz/GRID-Arendal


Salt marshes are intertidal grasslands that form along continental margins, bays, and estuaries. They work as shoreline protection by absorbing wave energy and accreting sediments, serve as nursery habitats for many marine species, provide feeding grounds for many bird species, and help to improve water quality by trapping sediments and filtering excess nutrients. An important quality of salt marshes is their ability to sequester carbon from the atmosphere into their biomass and sediments.

Almost half of the salt marshes worldwide had been lost or degraded in recent decades. The heaviest impacts come from marsh reclamation, vegetation disturbance, climate change, sea level rise, pollution, biological invasion and altered hydrological regimes.


Efforts to understand the socio-economic value of coastal blue carbon ecosystem services as a means to advocate for their conservation are still relatively new.

As part of the GEF Blue Forests project, economists and social scientists at the European Institute of Marine Studies and the University of West Brittany have embarked on a research project to understand how values have historically been calculated for ecosystem services associated with mangrove forests, salt marshes and seagrass beds.

The goal of the study is to provide a critical review of previously conducted valuation studies in order to help improve such valuations in the future, specifically in developing world case studies. The project focuses on summarizing the valuation methods commonly used for these habitats, the ecosystem services valued and the calculated values. The study will also provide a critique of the inconsistencies found between uses of various valuation methods and gaps in ecosystem service valuation studies for these habitats. Ultimately, the goal is to provide a set of lessons learned that can be applied to future ecosystem service valuation studies focused on these habitats.

Photo Credit: Steven Lutz/GRID-Arendal
Photo Credit: Steven Lutz/GRID-Arendal
Footnote: Photo Credit: Matthew D. Potenski/Marine Photobank