Page 82 - FAO-IPCC Expert meeting on climate change

Appendix 01: Speakers’ summary notes
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Degradation of mangrove ecosystems and implications for greenhouse gas emissions, biodiversity and food security
DANIEL MURDIYARSO
PLENARY SESSION 4:
HUMAN-DIRECTED IMPACTS ON WATER SCARCITY, BIODIVERSITY AND IMPLICATIONS FOR FOOD SECURITY
Globally mangroves cover an area of around 14 million hectares, distributed in more than 30 countries, mainly in
the tropics. With more than 50 mangrove species and multitude of fish and shellfish species these tidally influenced vegetation are biologically diverse. Their enormous ecosystem services ranging from provisioning (fish habitat, wood, fuel, and food), supporting (nutrient cycling and land building) and regulating (pollution, salinity, carbon storage, wave, storm surges, and tsunami) services are well documented.
The capacity of mangroves and other blue carbon ecosystems in sequestering atmospheric carbon is due to their high carbon burial rates, which are around 20 times higher than any terrestrial ecosystems (McLeod et al. 2011). Therefore, the carbon stocks in mangrove ecosystem is high as four times (ca. 1000 Mg/ha) compared to other terrestrial ecosystem (Donato et al. 2011, Alongi et al. 2014, Murdiyarso et al. 2105).
Mangroves are often highly productive and harbor a unique assemblage of aquatic and terrestrial biodiversity. The net primary production of mangroves ecosystem is the highest compared with any terrestrial ecosystem.
Sustainable value change of fish product from the coastal landscape is associated with food security in aquaculture systems. The issue may range from the access to land, distribution and quality (nutrition) of fish products.
Mangroves and other coastal ecosystems are facing tremendous pressure due to land-use change for aquaculture, agriculture and infrastructure development. The world’s mangrove has lost more than 40% in the past 30 years. Mangrove deforeatation potentially costs up to US$ 40 billion per annum (Pendleton et al. 2012).
The implications of mangrove deforestation is multitude. The most immediate one is GHG emissions. The rate is staggering as it is estimated to range between 0.02 and 0.12 Pg annually (Donato et al. 2011). This amount is 10% of emissions from deforestation globally, despite accounting for just 0.7% of tropical forest area.
Although biodiversity as many facets, mangrove deforestation with regeneration has the potential of re-introducing mono-species. This will substantially affect species diversity in all coastal settings. Aquatic biota will be tremendously affected as the nutrient cycling is altered.
Food security in the context of coastal community is closely related to the sustainability of fish production. Unless
the ponds or farms receive high inputs, it is unlikely that the current supply can be maintained (Lebel et al. 2002). A new finding confirms that food production and security is associated with mangrove conversions for oil palm and rice production (Richards and Freiss 2015).
Managing mangrove and other coastal wetlands ecosystem through conservation and rehabilitation should consider human dimension vis-à-vis multi-stakeholder objectives and biodiversity. Working with local community, embracing their agenda and understanding of mangrove hydrology are key ingredients for the success of mangrove restoration.
References
Alongi D. 2014. Carbon Cycling and Storage in Mangrove Forests. Annu. Rev. Mar. Sci. 2014. 6:195–219
Donato, D.C., Kauffman, J. B., Murdiyarso, D., Kurnianto, S. & Stidham, M. 2011. Mangroves among the most carbon- rich forests in the tropics. doi:10.1038/NGEO1123.
Lebel L., Nguyen, H.T., Saengnoree A. et al. 2002. Industrial transformation and shrimp aquaculture in Thailand and Vietnam: pathways to ecological, social, and economic sustainability? Ambio 31, 311–23.
FAO-IPCC Expert meeting on climate change, land use and food security