On the morning of September 10th, 2017, Hurricane Irma, one of the strongest hurricanes on record, made landfall in the Florida Keys and took aim west, sparing Floridians in the state’s densely populated eastern coast from the hurricane’s most destructive power. Irma’s path, however, had a direct impact on the western Florida Everglades, bringing along a 9-foot storm surge.
Hurricanes are a natural and common occurrence in the Everglades as they are part of the natural processes shaping the landscape by throwing mud onto the coast and helping to build up the land. During Hurricane Irma, the mangrove forest acted as a wave barrier against storm surge, protecting the rest of the system. At the same time, as it was the case with Irma, hurricanes can bring destruction to natural systems including visible damage to mangrove forests. Restoration of the Everglades ecosystem to build its resilience to changing conditions is critical to protect South Florida.
Dr. Stephen Davis from The Everglades Foundation had the opportunity to fly over the Everglades the day after the hurricane. The first after-storm images he captured showed defoliated trees throughout the coastal mangrove forests and dark, stained water draining from the wetlands into the Gulf of Mexico. Scientists from the Coastal Everglades Long Term Ecological Research program (FCE LTER) quickly mobilized teams to assess the effects of the storm and secured RAPID funding from NSF (Florida International University) and NASA (University of Maryland) to determine the damage and recovery on the ground and from the air.
Their collections show that about half of the coastal mangrove forest canopy was destroyed. A 3-10 cm storm surge precipitate – mud from the Gulf of Mexico – was deposited onto the forest floor, bringing high increases in salinity that triggered unfavorable conditions for mangrove survival. In terms of recovery, however, storm surges can represent good news. As Dr. Evelyn Gaiser, Principal Investigator of the FCE LTER, notes “the storm surge deposit contains phosphorus-rich mud and the availability of this nutrient helps the seedlings recover. Moreover, these seedlings are able to grow faster because the canopy above them has opened up and more light can get to them.”
Months after the initial observations, the team of scientists has detected signs of recovery in several trees, but mortality continues to occur in areas where storm surge salts are likely concentrating and causing tree death. Looking out to the future, they anticipate that if the region is hurricane-free for several years, the forest may continue to recover. Their hopes are that the 2019 hurricane season is calm, as the forest is still in a fragile state.
*The Florida Coastal Everglades Long Term Ecological Research (FCE LTER) Team that was part of this project is comprised of Dr. Evelyn Gaiser, Dr. Jennifer Rehage, Dr. John Kominoski, Dr. Tiffany Troxler, Dr. Michael Heithaus, Dr. Keqi Zhang, Dr. Edward Castaneda, Dr. David Lagomasino and Dr. Teminola Fatoyinbo.
This work is the result of a powerful partnership between FIU and the Everglades Foundation. We pride ourselves on pooling our expertise and reach to train undergraduate and graduate students, conduct leading science to inform policy and management decisions, and engage and inform the public to protect and restore America’s Everglades.
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