Human activities are unleashing a bigger threat on the environment than ever thought and a new study claims that marsh draining for agriculture and logging are increasingly destroying salt water and freshwater wetlands that cover just one per cent of the Earth’s surface.
They store more than 20 per cent of carbon dioxide absorbed by ecosystems worldwide. The study by a group of Dutch, American and German scientists published in Science says that it is high time to reverse the losses.
The scientists note that the key to success is using innovative restoration practices — identified in the new paper — that replicate natural landscape building processes and enhance the restored wet lands’ carbon-storing potential.
GOOD NEWS
Co author Brian R. Silliman, Rachel Carson, Professor of Marine Conservation Biology at Duke University pointed out that about one per cent of the world’s wetlands are being lost each year to pollution or marsh draining for agriculture, development and other human activities. The author mentioned that these wetlands once disturbed could release enormous amounts of Co, from their soils. It could release about five percent of global co, emissions annually.
“Hundreds, even thousands of years of stored carbon are exposed to air and start to rapidly decompose and release greenhouse gases. The result is an invisible reverse waterfall of Co, draining into the atmosphere. The wetlands switch from being carbon sinks to sources,” said Silliman.
However, he said that the good news is that the world now knows how to restore these wetlands at a scale that was never before possible and in a way that both stops this release of carbon and re-establishes the wetland’s carbon storing capacity.
LOCKING CO2
How does wetland become effective at carbon storage? The wetlands are formed and held together by plants that grow close to each other. Their dense above- and below ground mats of stems and roots trap nutrient-rich debris and defend the soil against erosion or drying out — all of which helps the plants to grow better and the soil layer to build up, locking in a lot more Co, in the process.
In the case of raised peat bogs, the process works a little differently, Silliman noted. Layers of living peat moss on the surface act as sponges, holding enormous amounts of rainwater that sustain its own growth and keeps a much thicker layer of dead peat moss below it permanently under water. This prevents the lower layer of peat, which can measure up to 10 meters thick, from drying out, decomposing, and releasing its stored carbon back into the atmosphere. As the living mosses gradually build up, the amount of carbon stored below ground continually grows.
Meanwhile, another author Jisse van der Heide of the Royal Institute for Sea Research and the University of Groningen in the Netherlands said that more than half of all wetland restorations fail because the landscape-forming properties of the plants are insufficiently taken into account. Planting seedlings and plugs in orderly rows equidistant from each other may seem logical, but it’s counter-productive, he added. “Restoration is much more successful when the plants are placed in large dense clumps, when their landscape-forming properties are mimicked, or simply when very large areas are restored in one go,” van der Heide said.
“Following this guidance will allow us to restore lost wetlands at a much larger scale and increase the odds that they will thrive and continue to store carbon and perform other vital ecosystem services for years to come,” Silliman said. “The plants win, the planet wins, we all win.”
Silliman and van der Heide conducted the new study with scientists from the Netherlands’ Royal Institute for Sea Research, Utrecht University, Radboud University, the University of Groningen, the University of Florida, Duke University, and Greifswald University. By synthesizing data on carbon capture from recent scientific studies, they found that oceans and forests hold the most co, globally, followed by wetlands. “But when we looked at the amount of co, stored per square meter, it turned out that wetlands store about five times more CO, than forests and as much as 500 times more than oceans,’ says Ralph Temmink, a researcher at Utrecht University, who was first author on the study.
