This article originally appeared on the USDA Forest Service site, but is no longer accessible there. Wayback Machine link of the original link: https://research.fs.usda.gov/psw/news/featured/mighty-mangroves-forest-service-researchers-help-conserve-coastal-guardians
Mangroves help curb climate change, create wildlife habitat, and protect communities. And Pacific Southwest Research Station ecologist Rich MacKenzie’s mission is to promote their conservation.
MacKenzie’s research focuses on mangroves in Micronesia, which includes Palau, the Marshall Islands, Guam, the Northern Mariana Islands, and the Federated States of Micronesia. This region’s area of ocean is equivalent to the size of the continental U.S., and the land mass could fit within Rhode Island.
“Mangroves here colonize coastlines, and their optimal elevation level is just above mean or average tide. They thrive outside of water on the exposed forest floor,” MacKenzie stated.
Superstars of carbon absorption, mangroves fall under the umbrella of blue carbon, which includes wetlands, sea grass, and the ocean. These critical carbon sinks sustain a healthy planet.
“I’m particularly proud to work for the Forest Service, because it is leading the way in blue carbon research and mangroves are a big part of that. Forest Service funding and a grant from U.S. Geological Survey’s Pacific Island Climate Adaptation Science Center is helping make mangrove research possible,” MacKenzie stated.
Photo Credit USDA Forest Service photo
Rich MacKenzie climbs a tree to take measurements while performing research in a mangrove forest.
Concerned about these vulnerable species, the U.S. Forest Service and U.S. Geological Survey joined forces to form a mangrove research partnership in the 1990s. MacKenzie took over the group in 2005 and renamed it the Pacific Islands Mangrove Monitoring Network.
Installing forest monitoring plots that include rod surface elevation tables (r- SETS), researchers trudge through water and mud, lugging heavy equipment and maneuvering around aerial roots called pneumatophores, which tower up to three feet high and resemble spiky stalagmites.
Once they reach their location, they jackhammer steel rods into the entire depth of the mangrove forest and concrete them in place. They then attach a receiver to which they affix an r-SET arm. Through the r-SET arm, they place fiber glass pins which rest on the forest floor. Based on whether the pins rise or fall, researchers determine whether the surface of the forest floor is losing or gaining elevation.
Concerned about these vulnerable species, the U.S. Forest Service and U.S. Geological Survey joined forces to form a mangrove research partnership in the 1990s. MacKenzie took over the group in 2005 and renamed it the Pacific Islands Mangrove Monitoring Network.
Installing forest monitoring plots that include rod surface elevation tables (r- SETS), researchers trudge through water and mud, lugging heavy equipment and maneuvering around aerial roots called pneumatophores, which tower up to three feet high and resemble spiky stalagmites.
Once they reach their location, they jackhammer steel rods into the entire depth of the mangrove forest and concrete them in place. They then attach a receiver to which they affix an r-SET arm. Through the r-SET arm, they place fiber glass pins which rest on the forest floor. Based on whether the pins rise or fall, researchers determine whether the surface of the forest floor is losing or gaining elevation.
Photo Credit USDA Forest Service photo
A close-up view of mangrove roots.
Using a naturally occurring radioactive particle called Lead-210, researchers can also measure elevation changes in mangrove forests. Lead-210 travels from the atmosphere down to the Earth’s surface and breaks down in soil.
“Lead-210 allows us to analyze soil cores for the last 100 years and tells us a lot about mangrove forests. For instance, we know mangroves store 80 to 90 percent of carbon in their soil. Lead-210 has identified that this is due to high rates of carbon burial,” MacKenzie noted.
Unlike terrestrial forests, which have drier soil with air pockets, mangroves have water-logged soil with low oxygen levels. Fungi, bacteria, and other invertebrates can’t break down carbon in mangrove forests, because there’s not enough oxygen for them to breathe.
If left undisturbed, mangrove forests are bank accounts for carbon deposits, becoming increasingly rich over thousands of years. These storage vats of carbon mitigate climate change.
Along with powerhouses for carbon storage, mangroves are coastal guardians for communities. They serve as barriers during storm surges and tsunamis, safeguarding local communities and critical infrastructure. In Palau, mangrove roots create nurseries for young fish, which grow into larger species, and become a vital food source for Pacific Island communities. Along with fish, mangroves provide habitat for fruit bats and crocodiles. They also protect coral reefs from upland erosion and sediment build-up. Their contributions to the natural beauty of Palau draw tourists from around the world who contribute to the local economy.
“When you have healthy, resilient mangroves, you have healthy, resilient people. But when people deforest mangroves, they release tons of carbon back into the atmosphere. You lose all the other goods and services that benefit people. Conserving these trees is critical,” MacKenzie emphasized.
New technology offers hope to bolster mangrove conservation. MacKenzie and partners from the Rochester Institute of Technology and USGS are testing out LiDAR or 3D lasers from iPhones to gather key data about mangrove forests. Once tested and vetted, island foresters and conservation groups can use this technology to track the health of mangrove forests, locally and globally.
“I’m excited about this new technology and remain optimistic. I want to believe mangroves can sense sea level rise and kick underground productivity into high gear. They’ve withstood sea level rise for 65 million years. That gives me hope,” MacKenzie stated.