Dr. Boone Kauffman, Oregon State University
In addition to their intrinsic values, mangroves provide a number of ecosystem services including habitats for many species of fish and shellfish, storm protection, influences on water quality, wood, aesthetics, and a source of nutrients and energy for adjacent marine ecosystems. Further, they are important in terms of global carbon dynamics; C stocks of mangroves are among the highest of any forest type on Earth. We have measured the ecosystem carbon stocks in mangroves across the world and found them to range from ≈109 to >2000 Mg C/ha. Because the numerous values associated with mangroves are well known, it is ironic that rates of deforestation largely relating to land use/land cover change are among the highest of any forest type on earth exceeding that of tropical rain forests. Dominant causes of deforestation include conversion to aquaculture (shrimp), agricultural conversion, and coastal development. The greenhouse gas emissions arising from conversion of mangroves to other uses is exceptionally high. This is because vulnerability of the soil carbon stocks to losses with conversion. Emissions from conversion of mangrove to shrimp ponds range from about 800 to over 3000 Mg CO2e/ha. This places the carbon footprint of shrimp arising from such ponds as among the highest of any food product available. Of great interest is the potential value of mangroves in carbon marketing strategies and other financial incentives that are derived from the conservation of standing forests. This is because of the combination of high carbon stocks in intact mangroves, the high greenhouse gas emissions arising from their conversion, and the conservation of other valuable ecosystem services provided by intact mangroves.