Soil samples from mangroves in the Dominican Republic reveal these coastal ecosystems may have the richest carbon stores in the Western Hemisphere, according to new data collected by noted ecologist Dr. Boone Kauffman. His fieldwork, and recent success in standardizing the scientific methodologies behind quantifying this “blue carbon,” is blazing a trail toward incentivizing its conservation.
Kauffman presented his findings at an Oct. 12 symposium in Washington, D.C., sponsored by Counterpart International, which is working with communities and partners to develop sustainable resource management plans that benefit both coastal ecosystems and the people who depend on them.
As part of Counterpart’s larger coastal community project, Kauffman led staff from the nonprofit and its Dominican partner AgroFrontera, as well as local marine biology students, in sampling soil from Monte Cristi National Park, where Counterpart has a five year-old program to increase biodiversity conservation and create sustainable livelihoods for fishermen and farmers. Monte Cristi is home to up to 40 percent of the country’s mangroves.
The team tested the soil rooted by tall, medium and dwarf mangroves and, to evaluate the carbon lost in deforestation, from abandoned shrimp farms where mangroves had been cleared.
“This is a pretty simple approach, but it’s a very powerful data set that we create,” says Kauffman, who is a professor at Oregon State University.
The results from Monte Cristi showed deeper deposits of carbon-rich soil than scientists anticipated; Kauffman found several feet of organic matter under not just the tallest mangroves, as assumed, but even under dwarf varieties. With an extremely slow rate of decomposition, he saw bits of leaves in the soil that had fallen from their limbs as long as 7,000 years ago.
In stark contrast, preliminary lab results showed the soil where mangroves had been cleared for shrimp farms held ten times less carbon, and 90 percent less nitrogen.
In places where coastal ecosystems have been degraded, you also see poverty and hopelessness, says Kauffman. Since mangroves provide habitat for 75 percent of all commercial tropical fish, act as nature’s water filtration system, and protect against storms and floods, their loss quietly destroys the livelihoods of millions.
Kauffman’s results reveal that cutting down mangroves and other coastal ecosystems releases even more damaging carbon into the atmosphere than originally thought – more than razing other types of forest. They also underscore not just the value of conservation, but coastal deforestation’s incredibly high cost to people.
His findings are urgent: coastal ecosystems are being destroyed faster than any other landscape on the planet.
Land use choices threaten mangroves as they are converted to rice paddies, shrimp farms, roads, or even resorts. Climate change, the very phenomenon these ecosystems help protect against, appears to be harming them as well.
Between 50 percent and 60 percent of the world’s mangroves, which grow in 123 countries, have already been lost.
“The loss of coastal ecosystems is often driven by people excluded from the fruits of development,” says Joan Parker, President and CEO of Counterpart International. Many of those who cut down mangroves do so for firewood or to sell as timber, their current needs more tangible than carbon loss and climate change.
Protecting these ecosystems could really pay if they were accurately valued: Mangroves are worth up to $900,000 per hectare in coastal protection value, and $4,850 per hectare in fish value. The “social value” of the blue carbon stored in their soils has been estimated at $41 per ton.
By creating a system for blue carbon accounting that will accurately value these soils, communities can participate in conserving and restoring them.
“Sustainable communities have productive natural assets that create livelihood options near home,” says Parker. “By working with individual communities – one, by one, by one – we can help them manage these assets in a way that brings inclusive benefits.”
The end goal of such management goes well beyond individual communities: It is nothing short of mitigating global climate change and its symptomatic threats of sea level rise, species extinction, mass human displacement, severe weather, and other planet-altering effects.